{"transactions":[{"id":4636413,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10093,"kind":"person","name":"Schafer Douglas M. JR","position":1,"cik":"0002079445","reported_name":"Schafer Douglas M. JR","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP and CIO"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-10-06T21:28:46.000Z","date":"2026-10-02","kind":"exercise","planned":true,"acquired":false,"shares":40000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested."}],"balance_after":155334,"derivative":{"exercise_price":12,"expiration_date":"2029-07-31","underlying":"Common Stock","underlying_shares":40000},"source":{"system":"sec-edgar","filing":"0001628280-26-065268","document":"wk-form4_1791322124.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2079445/000162828026065268/wk-form4_1791322124.xml","form_type":"4"}},{"id":4636412,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10093,"kind":"person","name":"Schafer Douglas M. JR","position":1,"cik":"0002079445","reported_name":"Schafer Douglas M. JR","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP and CIO"}}],"security":"Common Stock","published_at":"2026-10-06T21:28:46.000Z","date":"2026-10-02","kind":"sale","planned":true,"acquired":false,"shares":40000,"price":33.34,"value":1333600.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 16, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $32.91 to $33.97. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."}],"balance_after":387414,"source":{"system":"sec-edgar","filing":"0001628280-26-065268","document":"wk-form4_1791322124.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2079445/000162828026065268/wk-form4_1791322124.xml","form_type":"4"}},{"id":4636411,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10093,"kind":"person","name":"Schafer Douglas M. JR","position":1,"cik":"0002079445","reported_name":"Schafer Douglas M. JR","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP and CIO"}}],"security":"Common Stock","published_at":"2026-10-06T21:28:46.000Z","date":"2026-10-02","kind":"exercise","planned":true,"acquired":true,"shares":40000,"price":12,"value":480000.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 16, 2025."}],"balance_after":427414,"source":{"system":"sec-edgar","filing":"0001628280-26-065268","document":"wk-form4_1791322124.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2079445/000162828026065268/wk-form4_1791322124.xml","form_type":"4"}},{"id":4628381,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":25944,"kind":"person","name":"Jayabalan Harish","position":1,"cik":"0002080538","reported_name":"Jayabalan Harish","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CISO and CRO"}}],"security":"Incentive Stock Option (Right to Buy)","published_at":"2026-09-29T20:46:16.000Z","date":"2026-09-25","kind":"exercise","planned":false,"acquired":false,"shares":8333,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F1","text":"The options are fully vested."}],"balance_after":8333,"derivative":{"exercise_price":12,"expiration_date":"2027-10-12","underlying":"Common Stock","underlying_shares":8333},"source":{"system":"sec-edgar","filing":"0001628280-26-063831","document":"wk-form4_1790714773.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2080538/000162828026063831/wk-form4_1790714773.xml","form_type":"4"}},{"id":4628380,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":25944,"kind":"person","name":"Jayabalan Harish","position":1,"cik":"0002080538","reported_name":"Jayabalan Harish","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CISO and CRO"}}],"security":"Common Stock","published_at":"2026-09-29T20:46:16.000Z","date":"2026-09-25","kind":"exercise","planned":false,"acquired":true,"shares":8333,"price":12,"value":99996.0,"ownership":{"direct":true},"balance_after":86398,"source":{"system":"sec-edgar","filing":"0001628280-26-063831","document":"wk-form4_1790714773.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080538/000162828026063831/wk-form4_1790714773.xml","form_type":"4"}},{"id":4621495,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":31771,"kind":"person","name":"Brown Shelly","position":1,"cik":"0002080506","reported_name":"Brown Shelly","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, Chief Strategy Officer"}}],"security":"Common Stock","published_at":"2026-09-17T20:43:30.000Z","date":"2026-09-16","kind":"sale","planned":true,"acquired":false,"shares":21217,"price":38.61,"value":819188.37,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 22, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $37.84 to $39.56. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."}],"balance_after":316490,"source":{"system":"sec-edgar","filing":"0002080506-26-000027","document":"wk-form4_1789677808.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080506/000208050626000027/wk-form4_1789677808.xml","form_type":"4"}},{"id":4615910,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":31771,"kind":"person","name":"Brown Shelly","position":1,"cik":"0002080506","reported_name":"Brown Shelly","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, Chief Strategy Officer"}}],"security":"Common Stock","published_at":"2026-09-11T20:23:21.000Z","date":"2026-09-11","kind":"tax_withholding","planned":false,"acquired":false,"shares":16283,"price":42.54,"value":692678.82,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"Represents shares that have been surrendered to the Company to satisfy tax withholding and remittance obligations in connection with the net settlement of restricted stock awards and does not represent a sale by the reporting person."}],"balance_after":337707,"source":{"system":"sec-edgar","filing":"0002080506-26-000025","document":"wk-form4_1789158198.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080506/000208050626000025/wk-form4_1789158198.xml","form_type":"4"}},{"id":4611,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Incentive Stock Option (Right to Buy)","published_at":"2026-09-04T20:35:00.000Z","date":"2026-09-03","kind":"exercise","planned":true,"acquired":false,"shares":4464,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F5","text":"4,464 of the shares subject to this incentive stock option are vested. 4,464 shares subject to this incentive stock option will vest on June 16, 2027 and the remaining 4,464 shares subject to this incentive stock option will vest on June 16, 2028, subject to the Reporting Person's continued service to the Issuer or its subsidiaries through the applicable vesting date."}],"balance_after":8928,"derivative":{"exercise_price":22.4,"expiration_date":"2035-06-15","underlying":"Common Stock","underlying_shares":4464},"source":{"system":"sec-edgar","filing":"0002080477-26-000018","document":"wk-form4_1788554097.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":11,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000208047726000018/wk-form4_1788554097.xml","form_type":"4"}},{"id":4610,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Incentive Stock Option (Right to Buy)","published_at":"2026-09-04T20:35:00.000Z","date":"2026-09-03","kind":"exercise","planned":true,"acquired":false,"shares":13140,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"The options are fully vested."}],"balance_after":0,"derivative":{"exercise_price":15.22,"expiration_date":"2031-01-27","underlying":"Common Stock","underlying_shares":13140},"source":{"system":"sec-edgar","filing":"0002080477-26-000018","document":"wk-form4_1788554097.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":10,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000208047726000018/wk-form4_1788554097.xml","form_type":"4"}},{"id":4609,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Incentive Stock Option (Right to Buy)","published_at":"2026-09-04T20:35:00.000Z","date":"2026-09-03","kind":"exercise","planned":true,"acquired":false,"shares":8333,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"The options are fully vested."}],"balance_after":0,"derivative":{"exercise_price":12,"expiration_date":"2029-07-30","underlying":"Common Stock","underlying_shares":8333},"source":{"system":"sec-edgar","filing":"0002080477-26-000018","document":"wk-form4_1788554097.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":9,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000208047726000018/wk-form4_1788554097.xml","form_type":"4"}},{"id":4608,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Incentive Stock Option (Right to Buy)","published_at":"2026-09-04T20:35:00.000Z","date":"2026-09-03","kind":"exercise","planned":true,"acquired":false,"shares":16666,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"The options are fully vested."}],"balance_after":0,"derivative":{"exercise_price":12,"expiration_date":"2028-05-28","underlying":"Common Stock","underlying_shares":16666},"source":{"system":"sec-edgar","filing":"0002080477-26-000018","document":"wk-form4_1788554097.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":8,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000208047726000018/wk-form4_1788554097.xml","form_type":"4"}},{"id":4607,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-09-04T20:35:00.000Z","date":"2026-09-03","kind":"exercise","planned":true,"acquired":false,"shares":47000,"price":0,"value":0.0,"ownership":{"direct":false,"nature":"By Gallagher Investments, LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 29, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"The options are fully vested."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC."}],"balance_after":188000,"derivative":{"exercise_price":12,"expiration_date":"2028-05-28","underlying":"Common Stock","underlying_shares":47000},"source":{"system":"sec-edgar","filing":"0002080477-26-000018","document":"wk-form4_1788554097.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":7,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000208047726000018/wk-form4_1788554097.xml","form_type":"4"}},{"id":4606,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Common Stock","published_at":"2026-09-04T20:35:00.000Z","date":"2026-09-03","kind":"exercise","planned":true,"acquired":true,"shares":4464,"price":22.4,"value":99993.6,"ownership":{"direct":true},"balance_after":786542,"source":{"system":"sec-edgar","filing":"0002080477-26-000018","document":"wk-form4_1788554097.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":6,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000208047726000018/wk-form4_1788554097.xml","form_type":"4"}},{"id":4605,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Common Stock","published_at":"2026-09-04T20:35:00.000Z","date":"2026-09-03","kind":"exercise","planned":true,"acquired":true,"shares":13140,"price":15.22,"value":199990.8,"ownership":{"direct":true},"balance_after":782078,"source":{"system":"sec-edgar","filing":"0002080477-26-000018","document":"wk-form4_1788554097.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000208047726000018/wk-form4_1788554097.xml","form_type":"4"}},{"id":4604,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Common Stock","published_at":"2026-09-04T20:35:00.000Z","date":"2026-09-03","kind":"exercise","planned":true,"acquired":true,"shares":8333,"price":12,"value":99996.0,"ownership":{"direct":true},"balance_after":768938,"source":{"system":"sec-edgar","filing":"0002080477-26-000018","document":"wk-form4_1788554097.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000208047726000018/wk-form4_1788554097.xml","form_type":"4"}},{"id":4603,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Common Stock","published_at":"2026-09-04T20:35:00.000Z","date":"2026-09-03","kind":"exercise","planned":true,"acquired":true,"shares":16666,"price":12,"value":199992.0,"ownership":{"direct":true},"balance_after":760605,"source":{"system":"sec-edgar","filing":"0002080477-26-000018","document":"wk-form4_1788554097.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000208047726000018/wk-form4_1788554097.xml","form_type":"4"}},{"id":4602,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Common Stock","published_at":"2026-09-04T20:35:00.000Z","date":"2026-09-03","kind":"sale","planned":true,"acquired":false,"shares":47000,"price":42.43,"value":1994210.0,"ownership":{"direct":false,"nature":"By Gallagher Investments, LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 29, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $42.00 to $42.68. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC."}],"balance_after":1423275,"source":{"system":"sec-edgar","filing":"0002080477-26-000018","document":"wk-form4_1788554097.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000208047726000018/wk-form4_1788554097.xml","form_type":"4"}},{"id":4601,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Common Stock","published_at":"2026-09-04T20:35:00.000Z","date":"2026-09-03","kind":"exercise","planned":true,"acquired":true,"shares":47000,"price":12,"value":564000.0,"ownership":{"direct":false,"nature":"By Gallagher Investments, LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 29, 2025."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC."}],"balance_after":1470275,"source":{"system":"sec-edgar","filing":"0002080477-26-000018","document":"wk-form4_1788554097.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000208047726000018/wk-form4_1788554097.xml","form_type":"4"}},{"id":4576,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10124,"kind":"person","name":"Comly Barbara J.","position":1,"cik":"0002080878","reported_name":"Comly Barbara J.","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, GC & Corporate Secretary"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-09-04T20:31:13.000Z","date":"2026-09-02","kind":"exercise","planned":true,"acquired":false,"shares":44445,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 18, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested."}],"balance_after":44444,"derivative":{"exercise_price":12,"expiration_date":"2028-05-28","underlying":"Common Stock","underlying_shares":44445},"source":{"system":"sec-edgar","filing":"0002080878-26-000016","document":"wk-form4_1788553869.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2080878/000208087826000016/wk-form4_1788553869.xml","form_type":"4"}},{"id":4575,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10124,"kind":"person","name":"Comly Barbara J.","position":1,"cik":"0002080878","reported_name":"Comly Barbara J.","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, GC & Corporate Secretary"}}],"security":"Common Stock","published_at":"2026-09-04T20:31:13.000Z","date":"2026-09-02","kind":"sale","planned":true,"acquired":false,"shares":44445,"price":40.49,"value":1799578.05,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 18, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $39.66 to $41.80. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."}],"balance_after":839564,"source":{"system":"sec-edgar","filing":"0002080878-26-000016","document":"wk-form4_1788553869.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2080878/000208087826000016/wk-form4_1788553869.xml","form_type":"4"}},{"id":4574,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10124,"kind":"person","name":"Comly Barbara J.","position":1,"cik":"0002080878","reported_name":"Comly Barbara J.","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, GC & Corporate Secretary"}}],"security":"Common Stock","published_at":"2026-09-04T20:31:13.000Z","date":"2026-09-02","kind":"exercise","planned":true,"acquired":true,"shares":44445,"price":12,"value":533340.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 18, 2025."}],"balance_after":884009,"source":{"system":"sec-edgar","filing":"0002080878-26-000016","document":"wk-form4_1788553869.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080878/000208087826000016/wk-form4_1788553869.xml","form_type":"4"}},{"id":4546,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10102,"kind":"person","name":"Deitzel Edward","position":1,"cik":"0002080671","reported_name":"Deitzel Edward","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CRO, CCO MIAX Exchanges"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-09-04T20:28:01.000Z","date":"2026-09-03","kind":"exercise","planned":true,"acquired":false,"shares":11000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 30, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested."}],"balance_after":66000,"derivative":{"exercise_price":12,"expiration_date":"2029-07-31","underlying":"Common Stock","underlying_shares":11000},"source":{"system":"sec-edgar","filing":"0002080671-26-000016","document":"wk-form4_1788553678.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2080671/000208067126000016/wk-form4_1788553678.xml","form_type":"4"}},{"id":4545,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10102,"kind":"person","name":"Deitzel Edward","position":1,"cik":"0002080671","reported_name":"Deitzel Edward","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CRO, CCO MIAX Exchanges"}}],"security":"Common Stock","published_at":"2026-09-04T20:28:01.000Z","date":"2026-09-03","kind":"sale","planned":true,"acquired":false,"shares":11000,"price":42.21,"value":464310.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 30, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $42.00 to $42.32. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."}],"balance_after":119601,"source":{"system":"sec-edgar","filing":"0002080671-26-000016","document":"wk-form4_1788553678.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2080671/000208067126000016/wk-form4_1788553678.xml","form_type":"4"}},{"id":4544,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10102,"kind":"person","name":"Deitzel Edward","position":1,"cik":"0002080671","reported_name":"Deitzel Edward","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CRO, CCO MIAX Exchanges"}}],"security":"Common Stock","published_at":"2026-09-04T20:28:01.000Z","date":"2026-09-03","kind":"exercise","planned":true,"acquired":true,"shares":11000,"price":12,"value":132000.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 30, 2025."}],"balance_after":130601,"source":{"system":"sec-edgar","filing":"0002080671-26-000016","document":"wk-form4_1788553678.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080671/000208067126000016/wk-form4_1788553678.xml","form_type":"4"}},{"id":4513,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10093,"kind":"person","name":"Schafer Douglas M. JR","position":1,"cik":"0002079445","reported_name":"Schafer Douglas M. JR","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP and CIO"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-09-04T20:25:10.000Z","date":"2026-09-02","kind":"exercise","planned":true,"acquired":false,"shares":4666,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 16, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested."}],"balance_after":195334,"derivative":{"exercise_price":12,"expiration_date":"2029-07-31","underlying":"Common Stock","underlying_shares":4666},"source":{"system":"sec-edgar","filing":"0002079445-26-000017","document":"wk-form4_1788553507.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/2079445/000207944526000017/wk-form4_1788553507.xml","form_type":"4"}},{"id":4512,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10093,"kind":"person","name":"Schafer Douglas M. JR","position":1,"cik":"0002079445","reported_name":"Schafer Douglas M. JR","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP and CIO"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-09-04T20:25:10.000Z","date":"2026-09-02","kind":"exercise","planned":true,"acquired":false,"shares":43334,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 16, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested."}],"balance_after":0,"derivative":{"exercise_price":12,"expiration_date":"2028-05-17","underlying":"Common Stock","underlying_shares":43334},"source":{"system":"sec-edgar","filing":"0002079445-26-000017","document":"wk-form4_1788553507.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/2079445/000207944526000017/wk-form4_1788553507.xml","form_type":"4"}},{"id":4511,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10093,"kind":"person","name":"Schafer Douglas M. JR","position":1,"cik":"0002079445","reported_name":"Schafer Douglas M. JR","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP and CIO"}}],"security":"Common Stock","published_at":"2026-09-04T20:25:10.000Z","date":"2026-09-02","kind":"sale","planned":true,"acquired":false,"shares":48000,"price":40.48,"value":1943040.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 16, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $39.69 to $41.80. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."}],"balance_after":387414,"source":{"system":"sec-edgar","filing":"0002079445-26-000017","document":"wk-form4_1788553507.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2079445/000207944526000017/wk-form4_1788553507.xml","form_type":"4"}},{"id":4510,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10093,"kind":"person","name":"Schafer Douglas M. JR","position":1,"cik":"0002079445","reported_name":"Schafer Douglas M. JR","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP and CIO"}}],"security":"Common Stock","published_at":"2026-09-04T20:25:10.000Z","date":"2026-09-02","kind":"exercise","planned":true,"acquired":true,"shares":4666,"price":12,"value":55992.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 16, 2025."}],"balance_after":435414,"source":{"system":"sec-edgar","filing":"0002079445-26-000017","document":"wk-form4_1788553507.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2079445/000207944526000017/wk-form4_1788553507.xml","form_type":"4"}},{"id":4509,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10093,"kind":"person","name":"Schafer Douglas M. JR","position":1,"cik":"0002079445","reported_name":"Schafer Douglas M. JR","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP and CIO"}}],"security":"Common Stock","published_at":"2026-09-04T20:25:10.000Z","date":"2026-09-02","kind":"exercise","planned":true,"acquired":true,"shares":43334,"price":12,"value":520008.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 16, 2025."}],"balance_after":430748,"source":{"system":"sec-edgar","filing":"0002079445-26-000017","document":"wk-form4_1788553507.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2079445/000207944526000017/wk-form4_1788553507.xml","form_type":"4"}},{"id":4492,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10086,"kind":"person","name":"Teekell Judson Gray","position":1,"cik":"0001959770","reported_name":"Teekell Judson Gray","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-09-04T20:21:38.000Z","date":"2026-09-02","kind":"sale","planned":true,"acquired":false,"shares":3000,"price":40.89,"value":122670.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F3","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 17, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $40.31 to $41.53. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."}],"balance_after":69251,"source":{"system":"sec-edgar","filing":"0001959770-26-000012","document":"wk-form4_1788553296.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1959770/000195977026000012/wk-form4_1788553296.xml","form_type":"4"}},{"id":4491,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10086,"kind":"person","name":"Teekell Judson Gray","position":1,"cik":"0001959770","reported_name":"Teekell Judson Gray","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-09-04T20:21:38.000Z","date":"2026-09-02","kind":"sale","planned":true,"acquired":false,"shares":5545,"price":41.58,"value":230561.1,"ownership":{"direct":false,"nature":"By estate of Byrum W. Teekell"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction involved a sale by the Reporting Person in connection with his duties as Executor of the Estate of Byrum W. Teekell."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $41.02 to $41.80. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."}],"balance_after":81000,"source":{"system":"sec-edgar","filing":"0001959770-26-000012","document":"wk-form4_1788553296.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1959770/000195977026000012/wk-form4_1788553296.xml","form_type":"4"}},{"id":680315,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Common Stock","published_at":"2026-08-20T20:12:06.000Z","date":"2026-08-19","kind":"sale","planned":true,"acquired":false,"shares":149700,"price":41.13,"value":6157161.0,"ownership":{"direct":false,"nature":"By Gallagher Investments, LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F3","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 29, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $38.85 to $42.56. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC."}],"balance_after":1423275,"source":{"system":"sec-edgar","filing":"0002080477-26-000016","document":"wk-form4_1787256723.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000208047726000016/wk-form4_1787256723.xml","form_type":"4"}},{"id":680314,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Common Stock","published_at":"2026-08-20T20:12:06.000Z","date":"2026-08-18","kind":"tax_withholding","planned":true,"acquired":false,"shares":150300,"price":42.41,"value":6374223.0,"ownership":{"direct":false,"nature":"By Gallagher Investments, LLC"},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"Represents shares that have been surrendered to the Company to satisfy tax withholding and remittance obligations in connection with the net settlement of restricted stock awards and does not represent a sale by the reporting person."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC."}],"balance_after":1572975,"source":{"system":"sec-edgar","filing":"0002080477-26-000016","document":"wk-form4_1787256723.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000208047726000016/wk-form4_1787256723.xml","form_type":"4"}},{"id":680317,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10124,"kind":"person","name":"Comly Barbara J.","position":1,"cik":"0002080878","reported_name":"Comly Barbara J.","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, GC & Corporate Secretary"}}],"security":"Common Stock","published_at":"2026-08-20T20:11:31.000Z","date":"2026-08-18","kind":"tax_withholding","planned":false,"acquired":false,"shares":43420,"price":42.41,"value":1841442.2,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"Represents shares that have been surrendered to the Company to satisfy tax withholding and remittance obligations in connection with the net settlement of restricted stock awards and does not represent a sale by the reporting person."}],"balance_after":839564,"source":{"system":"sec-edgar","filing":"0002080878-26-000014","document":"wk-form4_1787256687.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080878/000208087826000014/wk-form4_1787256687.xml","form_type":"4"}},{"id":681794,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":21756,"kind":"person","name":"Schwarzkopf Cynthia","position":1,"cik":"0002080596","reported_name":"Schwarzkopf Cynthia","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Stock Option (Right to Buy)","published_at":"2026-08-19T20:12:08.000Z","date":"2026-08-17","kind":"exercise","planned":true,"acquired":false,"shares":5000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on March 12, 2026."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested."}],"balance_after":11916,"derivative":{"exercise_price":12,"expiration_date":"2027-05-31","underlying":"Common Stock","underlying_shares":5000},"source":{"system":"sec-edgar","filing":"0001628280-26-057950","document":"wk-form4_1787170325.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2080596/000162828026057950/wk-form4_1787170325.xml","form_type":"4"}},{"id":681793,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":21756,"kind":"person","name":"Schwarzkopf Cynthia","position":1,"cik":"0002080596","reported_name":"Schwarzkopf Cynthia","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-08-19T20:12:08.000Z","date":"2026-08-17","kind":"sale","planned":true,"acquired":false,"shares":5000,"price":42.85,"value":214250.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on March 12, 2026."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $42.54 to $43.33. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."}],"balance_after":88545,"source":{"system":"sec-edgar","filing":"0001628280-26-057950","document":"wk-form4_1787170325.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2080596/000162828026057950/wk-form4_1787170325.xml","form_type":"4"}},{"id":681792,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":21756,"kind":"person","name":"Schwarzkopf Cynthia","position":1,"cik":"0002080596","reported_name":"Schwarzkopf Cynthia","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-08-19T20:12:08.000Z","date":"2026-08-17","kind":"exercise","planned":true,"acquired":true,"shares":5000,"price":12,"value":60000.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on March 12, 2026."}],"balance_after":93545,"source":{"system":"sec-edgar","filing":"0001628280-26-057950","document":"wk-form4_1787170325.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080596/000162828026057950/wk-form4_1787170325.xml","form_type":"4"}},{"id":681796,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":21758,"kind":"person","name":"Emmons Lance","position":1,"cik":"0002080679","reported_name":"Emmons Lance","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP and CFO"}}],"security":"Common Stock","published_at":"2026-08-19T20:10:19.000Z","date":"2026-08-17","kind":"sale","planned":true,"acquired":false,"shares":35000,"price":42.83,"value":1499050.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 17, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $42.23 to $43.54. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."}],"balance_after":86538,"source":{"system":"sec-edgar","filing":"0001628280-26-057946","document":"wk-form4_1787170215.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080679/000162828026057946/wk-form4_1787170215.xml","form_type":"4"}},{"id":694430,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":25945,"kind":"person","name":"Eckert Kurt M.","position":1,"cik":"0002080678","reported_name":"Eckert Kurt M.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Stock Option (Right to Buy)","published_at":"2026-08-06T20:11:57.000Z","date":"2026-08-04","kind":"exercise","planned":true,"acquired":false,"shares":1063,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 18, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested"}],"balance_after":0,"derivative":{"exercise_price":12,"expiration_date":"2027-05-31","underlying":"Common Stock","underlying_shares":1063},"source":{"system":"sec-edgar","filing":"0002080678-26-000008","document":"wk-form4_1786047114.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2080678/000208067826000008/wk-form4_1786047114.xml","form_type":"4"}},{"id":694429,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":25945,"kind":"person","name":"Eckert Kurt M.","position":1,"cik":"0002080678","reported_name":"Eckert Kurt M.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-08-06T20:11:57.000Z","date":"2026-08-04","kind":"sale","planned":true,"acquired":false,"shares":1063,"price":45.8,"value":48685.4,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 18, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $45.14 to $46.57. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."}],"balance_after":149612,"source":{"system":"sec-edgar","filing":"0002080678-26-000008","document":"wk-form4_1786047114.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2080678/000208067826000008/wk-form4_1786047114.xml","form_type":"4"}},{"id":694428,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":25945,"kind":"person","name":"Eckert Kurt M.","position":1,"cik":"0002080678","reported_name":"Eckert Kurt M.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-08-06T20:11:57.000Z","date":"2026-08-04","kind":"exercise","planned":true,"acquired":true,"shares":1063,"price":12,"value":12756.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 18, 2025."}],"balance_after":150675,"source":{"system":"sec-edgar","filing":"0002080678-26-000008","document":"wk-form4_1786047114.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080678/000208067826000008/wk-form4_1786047114.xml","form_type":"4"}},{"id":694418,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10086,"kind":"person","name":"Teekell Judson Gray","position":1,"cik":"0001959770","reported_name":"Teekell Judson Gray","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-08-06T20:10:57.000Z","date":"2026-08-04","kind":"sale","planned":true,"acquired":false,"shares":3000,"price":45.79,"value":137370.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 17, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $45.13 to $46.56. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."}],"balance_after":72251,"source":{"system":"sec-edgar","filing":"0001959770-26-000010","document":"wk-form4_1786047054.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1959770/000195977026000010/wk-form4_1786047054.xml","form_type":"4"}},{"id":694414,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":25944,"kind":"person","name":"Jayabalan Harish","position":1,"cik":"0002080538","reported_name":"Jayabalan Harish","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CISO and CRO"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-08-06T20:10:12.000Z","date":"2026-08-04","kind":"exercise","planned":true,"acquired":false,"shares":5832,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on March 9, 2026."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested."}],"balance_after":17598,"derivative":{"exercise_price":15.22,"expiration_date":"2030-11-30","underlying":"Common Stock","underlying_shares":5832},"source":{"system":"sec-edgar","filing":"0002080538-26-000006","document":"wk-form4_1786047009.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/2080538/000208053826000006/wk-form4_1786047009.xml","form_type":"4"}},{"id":694413,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":25944,"kind":"person","name":"Jayabalan Harish","position":1,"cik":"0002080538","reported_name":"Jayabalan Harish","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CISO and CRO"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-08-06T20:10:12.000Z","date":"2026-08-04","kind":"exercise","planned":true,"acquired":false,"shares":14168,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on March 9, 2026."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested."}],"balance_after":0,"derivative":{"exercise_price":12,"expiration_date":"2029-07-31","underlying":"Common Stock","underlying_shares":14168},"source":{"system":"sec-edgar","filing":"0002080538-26-000006","document":"wk-form4_1786047009.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/2080538/000208053826000006/wk-form4_1786047009.xml","form_type":"4"}},{"id":694412,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":25944,"kind":"person","name":"Jayabalan Harish","position":1,"cik":"0002080538","reported_name":"Jayabalan Harish","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CISO and CRO"}}],"security":"Common Stock","published_at":"2026-08-06T20:10:12.000Z","date":"2026-08-04","kind":"sale","planned":true,"acquired":false,"shares":20000,"price":45.9,"value":918000.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on March 9, 2026."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $45.04 to $46.78. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."}],"balance_after":78065,"source":{"system":"sec-edgar","filing":"0002080538-26-000006","document":"wk-form4_1786047009.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2080538/000208053826000006/wk-form4_1786047009.xml","form_type":"4"}},{"id":694411,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":25944,"kind":"person","name":"Jayabalan Harish","position":1,"cik":"0002080538","reported_name":"Jayabalan Harish","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CISO and CRO"}}],"security":"Common Stock","published_at":"2026-08-06T20:10:12.000Z","date":"2026-08-04","kind":"exercise","planned":true,"acquired":true,"shares":5832,"price":15.22,"value":88763.04,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on March 9, 2026."}],"balance_after":98065,"source":{"system":"sec-edgar","filing":"0002080538-26-000006","document":"wk-form4_1786047009.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2080538/000208053826000006/wk-form4_1786047009.xml","form_type":"4"}},{"id":694410,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":25944,"kind":"person","name":"Jayabalan Harish","position":1,"cik":"0002080538","reported_name":"Jayabalan Harish","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CISO and CRO"}}],"security":"Common Stock","published_at":"2026-08-06T20:10:12.000Z","date":"2026-08-04","kind":"exercise","planned":true,"acquired":true,"shares":14168,"price":12,"value":170016.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on March 9, 2026."}],"balance_after":92233,"source":{"system":"sec-edgar","filing":"0002080538-26-000006","document":"wk-form4_1786047009.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080538/000208053826000006/wk-form4_1786047009.xml","form_type":"4"}},{"id":694427,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10124,"kind":"person","name":"Comly Barbara J.","position":1,"cik":"0002080878","reported_name":"Comly Barbara J.","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, GC & Corporate Secretary"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-08-06T20:09:36.000Z","date":"2026-08-04","kind":"exercise","planned":true,"acquired":false,"shares":44445,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"date","element":"transactionDate","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 18, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested."}],"balance_after":88889,"derivative":{"exercise_price":12,"expiration_date":"2028-05-28","underlying":"Common Stock","underlying_shares":44445},"source":{"system":"sec-edgar","filing":"0002080878-26-000012","document":"wk-form4_1786046972.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2080878/000208087826000012/wk-form4_1786046972.xml","form_type":"4"}},{"id":694426,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10124,"kind":"person","name":"Comly Barbara J.","position":1,"cik":"0002080878","reported_name":"Comly Barbara J.","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, GC & Corporate Secretary"}}],"security":"Common Stock","published_at":"2026-08-06T20:09:36.000Z","date":"2026-08-04","kind":"sale","planned":true,"acquired":false,"shares":44445,"price":45.69,"value":2030692.05,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 18, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $45.09 to $46.78. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."}],"balance_after":882984,"source":{"system":"sec-edgar","filing":"0002080878-26-000012","document":"wk-form4_1786046972.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2080878/000208087826000012/wk-form4_1786046972.xml","form_type":"4"}},{"id":694425,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10124,"kind":"person","name":"Comly Barbara J.","position":1,"cik":"0002080878","reported_name":"Comly Barbara J.","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, GC & Corporate Secretary"}}],"security":"Common Stock","published_at":"2026-08-06T20:09:36.000Z","date":"2026-08-04","kind":"exercise","planned":true,"acquired":true,"shares":44445,"price":12,"value":533340.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 18, 2025."}],"balance_after":927429,"source":{"system":"sec-edgar","filing":"0002080878-26-000012","document":"wk-form4_1786046972.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080878/000208087826000012/wk-form4_1786046972.xml","form_type":"4"}},{"id":694421,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10102,"kind":"person","name":"Deitzel Edward","position":1,"cik":"0002080671","reported_name":"Deitzel Edward","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CRO, CCO MIAX Exchanges"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-08-06T20:08:39.000Z","date":"2026-08-04","kind":"exercise","planned":true,"acquired":false,"shares":11000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 30, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested."}],"balance_after":77000,"derivative":{"exercise_price":12,"expiration_date":"2029-07-31","underlying":"Common Stock","underlying_shares":11000},"source":{"system":"sec-edgar","filing":"0002080671-26-000014","document":"wk-form4_1786046917.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2080671/000208067126000014/wk-form4_1786046917.xml","form_type":"4"}},{"id":694420,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10102,"kind":"person","name":"Deitzel Edward","position":1,"cik":"0002080671","reported_name":"Deitzel Edward","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CRO, CCO MIAX Exchanges"}}],"security":"Common Stock","published_at":"2026-08-06T20:08:39.000Z","date":"2026-08-04","kind":"sale","planned":true,"acquired":false,"shares":11000,"price":45.78,"value":503580.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 30, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $45.11 to $46.57. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."}],"balance_after":119601,"source":{"system":"sec-edgar","filing":"0002080671-26-000014","document":"wk-form4_1786046917.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2080671/000208067126000014/wk-form4_1786046917.xml","form_type":"4"}},{"id":694419,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10102,"kind":"person","name":"Deitzel Edward","position":1,"cik":"0002080671","reported_name":"Deitzel Edward","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CRO, CCO MIAX Exchanges"}}],"security":"Common Stock","published_at":"2026-08-06T20:08:39.000Z","date":"2026-08-04","kind":"exercise","planned":true,"acquired":true,"shares":11000,"price":12,"value":132000.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 30, 2025."}],"balance_after":130601,"source":{"system":"sec-edgar","filing":"0002080671-26-000014","document":"wk-form4_1786046917.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080671/000208067126000014/wk-form4_1786046917.xml","form_type":"4"}},{"id":694417,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10093,"kind":"person","name":"Schafer Douglas M. JR","position":1,"cik":"0002079445","reported_name":"Schafer Douglas M. JR","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP and CIO"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-08-06T20:06:34.000Z","date":"2026-08-04","kind":"exercise","planned":true,"acquired":false,"shares":48000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 16, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested."}],"balance_after":43334,"derivative":{"exercise_price":12,"expiration_date":"2028-05-17","underlying":"Common Stock","underlying_shares":48000},"source":{"system":"sec-edgar","filing":"0002079445-26-000015","document":"wk-form4_1786046792.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2079445/000207944526000015/wk-form4_1786046792.xml","form_type":"4"}},{"id":694416,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10093,"kind":"person","name":"Schafer Douglas M. JR","position":1,"cik":"0002079445","reported_name":"Schafer Douglas M. JR","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP and CIO"}}],"security":"Common Stock","published_at":"2026-08-06T20:06:34.000Z","date":"2026-08-04","kind":"sale","planned":true,"acquired":false,"shares":48000,"price":45.71,"value":2194080.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 16, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $45.09 to $46.78. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."}],"balance_after":387414,"source":{"system":"sec-edgar","filing":"0002079445-26-000015","document":"wk-form4_1786046792.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2079445/000207944526000015/wk-form4_1786046792.xml","form_type":"4"}},{"id":694415,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10093,"kind":"person","name":"Schafer Douglas M. JR","position":1,"cik":"0002079445","reported_name":"Schafer Douglas M. JR","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP and CIO"}}],"security":"Common Stock","published_at":"2026-08-06T20:06:34.000Z","date":"2026-08-04","kind":"exercise","planned":true,"acquired":true,"shares":48000,"price":12,"value":576000.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 16, 2025."}],"balance_after":435414,"source":{"system":"sec-edgar","filing":"0002079445-26-000015","document":"wk-form4_1786046792.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2079445/000207944526000015/wk-form4_1786046792.xml","form_type":"4"}},{"id":694424,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-08-06T20:05:47.000Z","date":"2026-08-04","kind":"exercise","planned":true,"acquired":false,"shares":48334,"price":0,"value":0.0,"ownership":{"direct":false,"nature":"By Gallagher Investments, LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 29, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"The options are fully vested."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC."}],"balance_after":235000,"derivative":{"exercise_price":12,"expiration_date":"2028-05-28","underlying":"Common Stock","underlying_shares":48334},"source":{"system":"sec-edgar","filing":"0002080477-26-000014","document":"wk-form4_1786046744.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000208047726000014/wk-form4_1786046744.xml","form_type":"4"}},{"id":694423,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Common Stock","published_at":"2026-08-06T20:05:47.000Z","date":"2026-08-04","kind":"sale","planned":true,"acquired":false,"shares":48334,"price":45.69,"value":2208380.46,"ownership":{"direct":false,"nature":"By Gallagher Investments, LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 29, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $45.09 to $46.78. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC."}],"balance_after":1723275,"source":{"system":"sec-edgar","filing":"0002080477-26-000014","document":"wk-form4_1786046744.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000208047726000014/wk-form4_1786046744.xml","form_type":"4"}},{"id":694422,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Common Stock","published_at":"2026-08-06T20:05:47.000Z","date":"2026-08-04","kind":"exercise","planned":true,"acquired":true,"shares":48334,"price":12,"value":580008.0,"ownership":{"direct":false,"nature":"By Gallagher Investments, LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 29, 2025."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC."}],"balance_after":1771609,"source":{"system":"sec-edgar","filing":"0002080477-26-000014","document":"wk-form4_1786046744.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000208047726000014/wk-form4_1786046744.xml","form_type":"4"}},{"id":708273,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":21756,"kind":"person","name":"Schwarzkopf Cynthia","position":1,"cik":"0002080596","reported_name":"Schwarzkopf Cynthia","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Stock Option (Right to Buy)","published_at":"2026-07-16T20:15:10.000Z","date":"2026-07-15","kind":"exercise","planned":true,"acquired":false,"shares":5000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on March 12, 2026."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"The options are fully vested."}],"balance_after":16916,"derivative":{"exercise_price":12,"expiration_date":"2027-05-31","underlying":"Common Stock","underlying_shares":5000},"source":{"system":"sec-edgar","filing":"0002080596-26-000006","document":"wk-form4_1784232907.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2080596/000208059626000006/wk-form4_1784232907.xml","form_type":"4"}},{"id":708272,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":21756,"kind":"person","name":"Schwarzkopf Cynthia","position":1,"cik":"0002080596","reported_name":"Schwarzkopf Cynthia","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-07-16T20:15:10.000Z","date":"2026-07-15","kind":"sale","planned":true,"acquired":false,"shares":5000,"price":42,"value":210000.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on March 12, 2026."}],"balance_after":88545,"source":{"system":"sec-edgar","filing":"0002080596-26-000006","document":"wk-form4_1784232907.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2080596/000208059626000006/wk-form4_1784232907.xml","form_type":"4"}},{"id":708271,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":21756,"kind":"person","name":"Schwarzkopf Cynthia","position":1,"cik":"0002080596","reported_name":"Schwarzkopf Cynthia","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-07-16T20:15:10.000Z","date":"2026-07-15","kind":"exercise","planned":true,"acquired":true,"shares":5000,"price":12,"value":60000.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on March 12, 2026."}],"balance_after":93545,"source":{"system":"sec-edgar","filing":"0002080596-26-000006","document":"wk-form4_1784232907.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080596/000208059626000006/wk-form4_1784232907.xml","form_type":"4"}},{"id":709953,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10124,"kind":"person","name":"Comly Barbara J.","position":1,"cik":"0002080878","reported_name":"Comly Barbara J.","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, GC & Corporate Secretary"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-07-14T20:07:17.000Z","date":"2026-07-13","kind":"exercise","planned":true,"acquired":false,"shares":28000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 18, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested."}],"balance_after":0,"derivative":{"exercise_price":12,"expiration_date":"2026-08-02","underlying":"Common Stock","underlying_shares":28000},"source":{"system":"sec-edgar","filing":"0001628280-26-048154","document":"wk-form4_1784059634.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2080878/000162828026048154/wk-form4_1784059634.xml","form_type":"4"}},{"id":709952,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10124,"kind":"person","name":"Comly Barbara J.","position":1,"cik":"0002080878","reported_name":"Comly Barbara J.","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, GC & Corporate Secretary"}}],"security":"Common Stock","published_at":"2026-07-14T20:07:17.000Z","date":"2026-07-13","kind":"sale","planned":true,"acquired":false,"shares":28000,"price":41.98,"value":1175440.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 18, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $41.40 to $43.52. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."}],"balance_after":882984,"source":{"system":"sec-edgar","filing":"0001628280-26-048154","document":"wk-form4_1784059634.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2080878/000162828026048154/wk-form4_1784059634.xml","form_type":"4"}},{"id":709951,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10124,"kind":"person","name":"Comly Barbara J.","position":1,"cik":"0002080878","reported_name":"Comly Barbara J.","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, GC & Corporate Secretary"}}],"security":"Common Stock","published_at":"2026-07-14T20:07:17.000Z","date":"2026-07-13","kind":"exercise","planned":true,"acquired":true,"shares":28000,"price":12,"value":336000.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 18, 2025."}],"balance_after":910984,"source":{"system":"sec-edgar","filing":"0001628280-26-048154","document":"wk-form4_1784059634.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080878/000162828026048154/wk-form4_1784059634.xml","form_type":"4"}},{"id":709950,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-07-14T20:04:36.000Z","date":"2026-07-13","kind":"exercise","planned":true,"acquired":false,"shares":70000,"price":0,"value":0.0,"ownership":{"direct":false,"nature":"By Gallagher Investments, LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 29, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"The options are fully vested."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC."}],"balance_after":0,"derivative":{"exercise_price":12,"expiration_date":"2026-08-02","underlying":"Common Stock","underlying_shares":70000},"source":{"system":"sec-edgar","filing":"0001628280-26-048149","document":"wk-form4_1784059473.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000162828026048149/wk-form4_1784059473.xml","form_type":"4"}},{"id":709949,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Common Stock","published_at":"2026-07-14T20:04:36.000Z","date":"2026-07-13","kind":"sale","planned":true,"acquired":false,"shares":70000,"price":42.52,"value":2976400.0,"ownership":{"direct":false,"nature":"By Gallagher Investments, LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 29, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $42.00 to $43.49. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC."}],"balance_after":1723275,"source":{"system":"sec-edgar","filing":"0001628280-26-048149","document":"wk-form4_1784059473.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000162828026048149/wk-form4_1784059473.xml","form_type":"4"}},{"id":709948,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Common Stock","published_at":"2026-07-14T20:04:36.000Z","date":"2026-07-13","kind":"exercise","planned":true,"acquired":true,"shares":70000,"price":12,"value":840000.0,"ownership":{"direct":false,"nature":"By Gallagher Investments, LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 29, 2025."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC."}],"balance_after":1793275,"source":{"system":"sec-edgar","filing":"0001628280-26-048149","document":"wk-form4_1784059473.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000162828026048149/wk-form4_1784059473.xml","form_type":"4"}},{"id":711782,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":31201,"kind":"person","name":"BROWN DAVID A","position":1,"cik":"0001394399","reported_name":"BROWN DAVID A","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-07-09T20:04:37.000Z","date":"2026-07-08","kind":"tax_withholding","planned":false,"acquired":false,"shares":171,"price":43.72,"value":7476.12,"ownership":{"direct":true},"footnotes":[{"field":"shares","element":"transactionShares","label":"F1","text":"Represents shares that have been surrendered to the Company to satisfy tax withholding and remittance obligations in connection with the net settlement of restricted stock units and does not represent a sale by the Reporting Person."}],"balance_after":7066,"source":{"system":"sec-edgar","filing":"0001628280-26-047778","document":"wk-form4_1783627475.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1438472/000162828026047778/wk-form4_1783627475.xml","form_type":"4"}},{"id":713871,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-07-07T21:03:20.000Z","date":"2026-07-07","kind":"exercise","planned":true,"acquired":false,"shares":28228,"price":0,"value":0.0,"ownership":{"direct":false,"nature":"By Gallagher Investments, LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 29, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F5","text":"The options are fully vested."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC."}],"balance_after":70000,"derivative":{"exercise_price":12,"expiration_date":"2026-08-02","underlying":"Common Stock","underlying_shares":28228},"source":{"system":"sec-edgar","filing":"0001628280-26-047530","document":"wk-form4_1783458198.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":6,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000162828026047530/wk-form4_1783458198.xml","form_type":"4"}},{"id":713870,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-07-07T21:03:20.000Z","date":"2026-07-06","kind":"exercise","planned":true,"acquired":false,"shares":41772,"price":0,"value":0.0,"ownership":{"direct":false,"nature":"By Gallagher Investments, LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 29, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F5","text":"The options are fully vested."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC."}],"balance_after":98228,"derivative":{"exercise_price":12,"expiration_date":"2026-08-02","underlying":"Common Stock","underlying_shares":41772},"source":{"system":"sec-edgar","filing":"0001628280-26-047530","document":"wk-form4_1783458198.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000162828026047530/wk-form4_1783458198.xml","form_type":"4"}},{"id":713869,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Common Stock","published_at":"2026-07-07T21:03:20.000Z","date":"2026-07-07","kind":"sale","planned":true,"acquired":false,"shares":28228,"price":42.27,"value":1193197.56,"ownership":{"direct":false,"nature":"By Gallagher Investments, LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 29, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $42.00 to $42.50. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC."}],"balance_after":1723275,"source":{"system":"sec-edgar","filing":"0001628280-26-047530","document":"wk-form4_1783458198.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000162828026047530/wk-form4_1783458198.xml","form_type":"4"}},{"id":713868,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Common Stock","published_at":"2026-07-07T21:03:20.000Z","date":"2026-07-07","kind":"exercise","planned":true,"acquired":true,"shares":28228,"price":12,"value":338736.0,"ownership":{"direct":false,"nature":"By Gallagher Investments, LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 29, 2025."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC."}],"balance_after":1751503,"source":{"system":"sec-edgar","filing":"0001628280-26-047530","document":"wk-form4_1783458198.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000162828026047530/wk-form4_1783458198.xml","form_type":"4"}},{"id":713867,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Common Stock","published_at":"2026-07-07T21:03:20.000Z","date":"2026-07-06","kind":"sale","planned":true,"acquired":false,"shares":41772,"price":42.09,"value":1758183.48,"ownership":{"direct":false,"nature":"By Gallagher Investments, LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 29, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F3","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $42.00 to $42.32. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC."}],"balance_after":1723275,"source":{"system":"sec-edgar","filing":"0001628280-26-047530","document":"wk-form4_1783458198.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000162828026047530/wk-form4_1783458198.xml","form_type":"4"}},{"id":713866,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10131,"kind":"person","name":"Gallagher Thomas P.","position":1,"cik":"0002080477","reported_name":"Gallagher Thomas P.","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chairman & CEO"}}],"security":"Common Stock","published_at":"2026-07-07T21:03:20.000Z","date":"2026-07-06","kind":"exercise","planned":true,"acquired":true,"shares":41772,"price":12,"value":501264.0,"ownership":{"direct":false,"nature":"By Gallagher Investments, LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 29, 2025."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F2","text":"Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC."}],"balance_after":1765047,"source":{"system":"sec-edgar","filing":"0001628280-26-047530","document":"wk-form4_1783458198.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080477/000162828026047530/wk-form4_1783458198.xml","form_type":"4"}},{"id":713854,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":25944,"kind":"person","name":"Jayabalan Harish","position":1,"cik":"0002080538","reported_name":"Jayabalan Harish","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CISO and CRO"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-07-07T20:14:52.000Z","date":"2026-07-06","kind":"exercise","planned":true,"acquired":false,"shares":2499,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on March 9, 2026."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested."}],"balance_after":14168,"derivative":{"exercise_price":12,"expiration_date":"2029-07-31","underlying":"Common Stock","underlying_shares":2499},"source":{"system":"sec-edgar","filing":"0001628280-26-047497","document":"wk-form4_1783455290.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":7,"url":"https://www.sec.gov/Archives/edgar/data/2080538/000162828026047497/wk-form4_1783455290.xml","form_type":"4"}},{"id":713853,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":25944,"kind":"person","name":"Jayabalan Harish","position":1,"cik":"0002080538","reported_name":"Jayabalan Harish","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CISO and CRO"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-07-07T20:14:52.000Z","date":"2026-07-06","kind":"exercise","planned":true,"acquired":false,"shares":16667,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on March 9, 2026."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested."}],"balance_after":0,"derivative":{"exercise_price":12,"expiration_date":"2028-05-17","underlying":"Common Stock","underlying_shares":16667},"source":{"system":"sec-edgar","filing":"0001628280-26-047497","document":"wk-form4_1783455290.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":6,"url":"https://www.sec.gov/Archives/edgar/data/2080538/000162828026047497/wk-form4_1783455290.xml","form_type":"4"}},{"id":713852,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":25944,"kind":"person","name":"Jayabalan Harish","position":1,"cik":"0002080538","reported_name":"Jayabalan Harish","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CISO and CRO"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-07-07T20:14:52.000Z","date":"2026-07-06","kind":"exercise","planned":true,"acquired":false,"shares":834,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on March 9, 2026."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested."}],"balance_after":0,"derivative":{"exercise_price":12,"expiration_date":"2027-10-12","underlying":"Common Stock","underlying_shares":834},"source":{"system":"sec-edgar","filing":"0001628280-26-047497","document":"wk-form4_1783455290.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/2080538/000162828026047497/wk-form4_1783455290.xml","form_type":"4"}},{"id":713851,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":25944,"kind":"person","name":"Jayabalan Harish","position":1,"cik":"0002080538","reported_name":"Jayabalan Harish","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CISO and CRO"}}],"security":"Common Stock","published_at":"2026-07-07T20:14:52.000Z","date":"2026-07-06","kind":"sale","planned":true,"acquired":false,"shares":20000,"price":42.12,"value":842400.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on March 9, 2026."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $42.00 to $42.32. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."}],"balance_after":78065,"source":{"system":"sec-edgar","filing":"0001628280-26-047497","document":"wk-form4_1783455290.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/2080538/000162828026047497/wk-form4_1783455290.xml","form_type":"4"}},{"id":713850,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":25944,"kind":"person","name":"Jayabalan Harish","position":1,"cik":"0002080538","reported_name":"Jayabalan Harish","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CISO and CRO"}}],"security":"Common Stock","published_at":"2026-07-07T20:14:52.000Z","date":"2026-07-06","kind":"exercise","planned":true,"acquired":true,"shares":2499,"price":12,"value":29988.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on March 9, 2026."}],"balance_after":98065,"source":{"system":"sec-edgar","filing":"0001628280-26-047497","document":"wk-form4_1783455290.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2080538/000162828026047497/wk-form4_1783455290.xml","form_type":"4"}},{"id":713849,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":25944,"kind":"person","name":"Jayabalan Harish","position":1,"cik":"0002080538","reported_name":"Jayabalan Harish","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CISO and CRO"}}],"security":"Common Stock","published_at":"2026-07-07T20:14:52.000Z","date":"2026-07-06","kind":"exercise","planned":true,"acquired":true,"shares":16667,"price":12,"value":200004.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on March 9, 2026."}],"balance_after":95566,"source":{"system":"sec-edgar","filing":"0001628280-26-047497","document":"wk-form4_1783455290.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2080538/000162828026047497/wk-form4_1783455290.xml","form_type":"4"}},{"id":713848,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":25944,"kind":"person","name":"Jayabalan Harish","position":1,"cik":"0002080538","reported_name":"Jayabalan Harish","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CISO and CRO"}}],"security":"Common Stock","published_at":"2026-07-07T20:14:52.000Z","date":"2026-07-06","kind":"exercise","planned":true,"acquired":true,"shares":834,"price":12,"value":10008.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on March 9, 2026."}],"balance_after":78899,"source":{"system":"sec-edgar","filing":"0001628280-26-047497","document":"wk-form4_1783455290.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080538/000162828026047497/wk-form4_1783455290.xml","form_type":"4"}},{"id":713865,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10102,"kind":"person","name":"Deitzel Edward","position":1,"cik":"0002080671","reported_name":"Deitzel Edward","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CRO, CCO MIAX Exchanges"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-07-07T20:13:59.000Z","date":"2026-07-06","kind":"exercise","planned":true,"acquired":false,"shares":3667,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 30, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested."}],"balance_after":88000,"derivative":{"exercise_price":12,"expiration_date":"2029-07-31","underlying":"Common Stock","underlying_shares":3667},"source":{"system":"sec-edgar","filing":"0001628280-26-047496","document":"wk-form4_1783455236.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/2080671/000162828026047496/wk-form4_1783455236.xml","form_type":"4"}},{"id":713864,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10102,"kind":"person","name":"Deitzel Edward","position":1,"cik":"0002080671","reported_name":"Deitzel Edward","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CRO, CCO MIAX Exchanges"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-07-07T20:13:59.000Z","date":"2026-07-06","kind":"exercise","planned":true,"acquired":false,"shares":7333,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 30, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested."}],"balance_after":0,"derivative":{"exercise_price":12,"expiration_date":"2028-05-17","underlying":"Common Stock","underlying_shares":7333},"source":{"system":"sec-edgar","filing":"0001628280-26-047496","document":"wk-form4_1783455236.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/2080671/000162828026047496/wk-form4_1783455236.xml","form_type":"4"}},{"id":713863,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10102,"kind":"person","name":"Deitzel Edward","position":1,"cik":"0002080671","reported_name":"Deitzel Edward","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CRO, CCO MIAX Exchanges"}}],"security":"Common Stock","published_at":"2026-07-07T20:13:59.000Z","date":"2026-07-06","kind":"sale","planned":true,"acquired":false,"shares":11000,"price":42.04,"value":462440.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 30, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $42.00 to $42.17. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."}],"balance_after":119601,"source":{"system":"sec-edgar","filing":"0001628280-26-047496","document":"wk-form4_1783455236.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2080671/000162828026047496/wk-form4_1783455236.xml","form_type":"4"}},{"id":713862,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10102,"kind":"person","name":"Deitzel Edward","position":1,"cik":"0002080671","reported_name":"Deitzel Edward","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CRO, CCO MIAX Exchanges"}}],"security":"Common Stock","published_at":"2026-07-07T20:13:59.000Z","date":"2026-07-06","kind":"exercise","planned":true,"acquired":true,"shares":3667,"price":12,"value":44004.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 30, 2025."}],"balance_after":130601,"source":{"system":"sec-edgar","filing":"0001628280-26-047496","document":"wk-form4_1783455236.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2080671/000162828026047496/wk-form4_1783455236.xml","form_type":"4"}},{"id":713861,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10102,"kind":"person","name":"Deitzel Edward","position":1,"cik":"0002080671","reported_name":"Deitzel Edward","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, CRO, CCO MIAX Exchanges"}}],"security":"Common Stock","published_at":"2026-07-07T20:13:59.000Z","date":"2026-07-06","kind":"exercise","planned":true,"acquired":true,"shares":7333,"price":12,"value":87996.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 30, 2025."}],"balance_after":126934,"source":{"system":"sec-edgar","filing":"0001628280-26-047496","document":"wk-form4_1783455236.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080671/000162828026047496/wk-form4_1783455236.xml","form_type":"4"}},{"id":713874,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":31771,"kind":"person","name":"Brown Shelly","position":1,"cik":"0002080506","reported_name":"Brown Shelly","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, Chief Strategy Officer"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-07-07T20:10:47.000Z","date":"2026-07-06","kind":"exercise","planned":true,"acquired":false,"shares":16000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 22, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested."}],"balance_after":0,"derivative":{"exercise_price":12,"expiration_date":"2026-08-02","underlying":"Common Stock","underlying_shares":16000},"source":{"system":"sec-edgar","filing":"0001628280-26-047491","document":"wk-form4_1783455045.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2080506/000162828026047491/wk-form4_1783455045.xml","form_type":"4"}},{"id":713873,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":31771,"kind":"person","name":"Brown Shelly","position":1,"cik":"0002080506","reported_name":"Brown Shelly","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, Chief Strategy Officer"}}],"security":"Common Stock","published_at":"2026-07-07T20:10:47.000Z","date":"2026-07-06","kind":"sale","planned":true,"acquired":false,"shares":16000,"price":42.13,"value":674080.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 22, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $42.00 to $42.32. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."}],"balance_after":353990,"source":{"system":"sec-edgar","filing":"0001628280-26-047491","document":"wk-form4_1783455045.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2080506/000162828026047491/wk-form4_1783455045.xml","form_type":"4"}},{"id":713872,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":31771,"kind":"person","name":"Brown Shelly","position":1,"cik":"0002080506","reported_name":"Brown Shelly","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, Chief Strategy Officer"}}],"security":"Common Stock","published_at":"2026-07-07T20:10:47.000Z","date":"2026-07-06","kind":"exercise","planned":true,"acquired":true,"shares":16000,"price":12,"value":192000.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 22, 2025."}],"balance_after":369990,"source":{"system":"sec-edgar","filing":"0001628280-26-047491","document":"wk-form4_1783455045.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080506/000162828026047491/wk-form4_1783455045.xml","form_type":"4"}},{"id":713860,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10086,"kind":"person","name":"Teekell Judson Gray","position":1,"cik":"0001959770","reported_name":"Teekell Judson Gray","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-07-07T20:09:38.000Z","date":"2026-07-02","kind":"sale","planned":true,"acquired":false,"shares":3000,"price":40,"value":120000.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 17, 2025."}],"balance_after":75251,"source":{"system":"sec-edgar","filing":"0001628280-26-047489","document":"wk-form4_1783454974.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1959770/000162828026047489/wk-form4_1783454974.xml","form_type":"4"}},{"id":713880,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":25945,"kind":"person","name":"Eckert Kurt M.","position":1,"cik":"0002080678","reported_name":"Eckert Kurt M.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Stock Option (Right to Buy)","published_at":"2026-07-07T20:08:48.000Z","date":"2026-07-02","kind":"exercise","planned":true,"acquired":false,"shares":5250,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 18, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"The options are fully vested"}],"balance_after":1063,"derivative":{"exercise_price":12,"expiration_date":"2027-05-31","underlying":"Common Stock","underlying_shares":5250},"source":{"system":"sec-edgar","filing":"0001628280-26-047488","document":"wk-form4_1783454926.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2080678/000162828026047488/wk-form4_1783454926.xml","form_type":"4"}},{"id":713879,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":25945,"kind":"person","name":"Eckert Kurt M.","position":1,"cik":"0002080678","reported_name":"Eckert Kurt M.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-07-07T20:08:48.000Z","date":"2026-07-02","kind":"sale","planned":true,"acquired":false,"shares":5250,"price":39.35,"value":206587.5,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 18, 2025."}],"balance_after":149612,"source":{"system":"sec-edgar","filing":"0001628280-26-047488","document":"wk-form4_1783454926.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2080678/000162828026047488/wk-form4_1783454926.xml","form_type":"4"}},{"id":713878,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":25945,"kind":"person","name":"Eckert Kurt M.","position":1,"cik":"0002080678","reported_name":"Eckert Kurt M.","relationship":{"director":true,"officer":false,"ten_percent_owner":false,"other":false}}],"security":"Common Stock","published_at":"2026-07-07T20:08:48.000Z","date":"2026-07-02","kind":"exercise","planned":true,"acquired":true,"shares":5250,"price":12,"value":63000.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 18, 2025."}],"balance_after":154862,"source":{"system":"sec-edgar","filing":"0001628280-26-047488","document":"wk-form4_1783454926.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080678/000162828026047488/wk-form4_1783454926.xml","form_type":"4"}},{"id":713877,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10124,"kind":"person","name":"Comly Barbara J.","position":1,"cik":"0002080878","reported_name":"Comly Barbara J.","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, GC & Corporate Secretary"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-07-07T20:06:57.000Z","date":"2026-07-02","kind":"exercise","planned":true,"acquired":false,"shares":28000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 18, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested."}],"balance_after":28000,"derivative":{"exercise_price":12,"expiration_date":"2026-08-02","underlying":"Common Stock","underlying_shares":28000},"source":{"system":"sec-edgar","filing":"0001628280-26-047486","document":"wk-form4_1783454814.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2080878/000162828026047486/wk-form4_1783454814.xml","form_type":"4"}},{"id":713876,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10124,"kind":"person","name":"Comly Barbara J.","position":1,"cik":"0002080878","reported_name":"Comly Barbara J.","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, GC & Corporate Secretary"}}],"security":"Common Stock","published_at":"2026-07-07T20:06:57.000Z","date":"2026-07-02","kind":"sale","planned":true,"acquired":false,"shares":28000,"price":41.22,"value":1154160.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 18, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $39.79 to $41.79. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."}],"balance_after":882984,"source":{"system":"sec-edgar","filing":"0001628280-26-047486","document":"wk-form4_1783454814.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2080878/000162828026047486/wk-form4_1783454814.xml","form_type":"4"}},{"id":713875,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10124,"kind":"person","name":"Comly Barbara J.","position":1,"cik":"0002080878","reported_name":"Comly Barbara J.","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP, GC & Corporate Secretary"}}],"security":"Common Stock","published_at":"2026-07-07T20:06:57.000Z","date":"2026-07-02","kind":"exercise","planned":true,"acquired":true,"shares":28000,"price":12,"value":336000.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 18, 2025."}],"balance_after":910984,"source":{"system":"sec-edgar","filing":"0001628280-26-047486","document":"wk-form4_1783454814.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2080878/000162828026047486/wk-form4_1783454814.xml","form_type":"4"}},{"id":713859,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10093,"kind":"person","name":"Schafer Douglas M. JR","position":1,"cik":"0002079445","reported_name":"Schafer Douglas M. JR","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP and CIO"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-07-07T20:06:06.000Z","date":"2026-07-02","kind":"exercise","planned":true,"acquired":false,"shares":42000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 16, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested."}],"balance_after":91334,"derivative":{"exercise_price":12,"expiration_date":"2028-05-17","underlying":"Common Stock","underlying_shares":42000},"source":{"system":"sec-edgar","filing":"0001628280-26-047484","document":"wk-form4_1783454763.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/2079445/000162828026047484/wk-form4_1783454763.xml","form_type":"4"}},{"id":713858,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10093,"kind":"person","name":"Schafer Douglas M. JR","position":1,"cik":"0002079445","reported_name":"Schafer Douglas M. JR","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP and CIO"}}],"security":"Nonqualified Stock Option (Right to Buy)","published_at":"2026-07-07T20:06:06.000Z","date":"2026-07-02","kind":"exercise","planned":true,"acquired":false,"shares":6000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 16, 2025."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are fully vested."}],"balance_after":0,"derivative":{"exercise_price":12,"expiration_date":"2026-08-02","underlying":"Common Stock","underlying_shares":6000},"source":{"system":"sec-edgar","filing":"0001628280-26-047484","document":"wk-form4_1783454763.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/2079445/000162828026047484/wk-form4_1783454763.xml","form_type":"4"}},{"id":713857,"issuer":{"id":4026,"kind":"organization","name":"MIAMI INTERNATIONAL HOLDINGS, INC.","symbol":"MIAX"},"owners":[{"id":10093,"kind":"person","name":"Schafer Douglas M. JR","position":1,"cik":"0002079445","reported_name":"Schafer Douglas M. JR","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"EVP and CIO"}}],"security":"Common Stock","published_at":"2026-07-07T20:06:06.000Z","date":"2026-07-02","kind":"sale","planned":true,"acquired":false,"shares":48000,"price":41.22,"value":1978560.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 16, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"This transaction was executed in multiple trades throughout the day at prices ranging from $39.79 to $41.79. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected."}],"balance_after":387414,"source":{"system":"sec-edgar","filing":"0001628280-26-047484","document":"wk-form4_1783454763.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2079445/000162828026047484/wk-form4_1783454763.xml","form_type":"4"}}],"next_cursor":"2026-07-07T20:06:06.000000Z,713857"}