{"transactions":[{"id":4618869,"issuer":{"id":5127,"kind":"organization","name":"Horizon Quantum Holdings Ltd.","symbol":"HQ"},"owners":[{"id":55959,"kind":"person","name":"Tan Si-Hui","position":1,"cik":"0002120880","reported_name":"Tan Si-Hui","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Science Officer"}}],"security":"Restricted Stock Unit","published_at":"2026-09-16T01:31:13.000Z","date":"2026-09-12","kind":"exercise","planned":false,"acquired":true,"shares":5728,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each restricted stock unit (\"RSU\") represents a contingent right to receive one Class A ordinary share, with no par value (\"Class A Ordinary Share\"), of Horizon Quantum Holdings Ltd. (the \"Company\") upon vesting, for no consideration."},{"field":"shares","element":"transactionShares","label":"F3","text":"On September 12, 2026, 5,728 of Dr. Tan's RSU's vested."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"On September 12, 2026, 5,728 of Dr. Tan's RSU's vested."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"On June 12, 2026 (the \"June Grant Date\"), Dr. Tan was granted a total of 91,659 unvested RSUs. The RSUs granted to Dr. Tan vest in sixteen approximately equal installments on successive quarterly anniversaries of the June Grant Date and are subject to Dr. Tan's continued employment with the Company through each applicable vesting date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"On June 12, 2026 (the \"June Grant Date\"), Dr. Tan was granted a total of 91,659 unvested RSUs. The RSUs granted to Dr. Tan vest in sixteen approximately equal installments on successive quarterly anniversaries of the June Grant Date and are subject to Dr. Tan's continued employment with the Company through each applicable vesting date."}],"balance_after":85931,"derivative":{"exercise_price":0,"underlying":"Class A Ordinary Shares","underlying_shares":5728},"source":{"system":"sec-edgar","filing":"0001213900-26-100280","document":"ownership.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":6,"url":"https://www.sec.gov/Archives/edgar/data/2120880/000121390026100280/ownership.xml","form_type":"4"}},{"id":4618868,"issuer":{"id":5127,"kind":"organization","name":"Horizon Quantum Holdings Ltd.","symbol":"HQ"},"owners":[{"id":55959,"kind":"person","name":"Tan Si-Hui","position":1,"cik":"0002120880","reported_name":"Tan Si-Hui","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Science Officer"}}],"security":"Restricted Stock Unit","published_at":"2026-09-16T01:31:13.000Z","date":"2026-06-12","kind":"grant","planned":false,"acquired":true,"shares":91659,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F2","text":"Each restricted stock unit (\"RSU\") represents a contingent right to receive one Class A ordinary share, with no par value (\"Class A Ordinary Share\"), of Horizon Quantum Holdings Ltd. (the \"Company\") upon vesting, for no consideration."},{"field":"shares","element":"transactionShares","label":"F4","text":"On June 12, 2026 (the \"June Grant Date\"), Dr. Tan was granted a total of 91,659 unvested RSUs. The RSUs granted to Dr. Tan vest in sixteen approximately equal installments on successive quarterly anniversaries of the June Grant Date and are subject to Dr. Tan's continued employment with the Company through each applicable vesting date."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"On June 12, 2026 (the \"June Grant Date\"), Dr. Tan was granted a total of 91,659 unvested RSUs. The RSUs granted to Dr. Tan vest in sixteen approximately equal installments on successive quarterly anniversaries of the June Grant Date and are subject to Dr. Tan's continued employment with the Company through each applicable vesting date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F4","text":"On June 12, 2026 (the \"June Grant Date\"), Dr. Tan was granted a total of 91,659 unvested RSUs. The RSUs granted to Dr. Tan vest in sixteen approximately equal installments on successive quarterly anniversaries of the June Grant Date and are subject to Dr. Tan's continued employment with the Company through each applicable vesting date."},{"field":"derivative.underlying_shares","element":"underlyingSecurityShares","label":"F4","text":"On June 12, 2026 (the \"June Grant Date\"), Dr. Tan was granted a total of 91,659 unvested RSUs. The RSUs granted to Dr. Tan vest in sixteen approximately equal installments on successive quarterly anniversaries of the June Grant Date and are subject to Dr. Tan's continued employment with the Company through each applicable vesting date."}],"balance_after":91659,"derivative":{"exercise_price":0,"underlying":"Class A Ordinary Shares","underlying_shares":91659},"source":{"system":"sec-edgar","filing":"0001213900-26-100280","document":"ownership.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/2120880/000121390026100280/ownership.xml","form_type":"4"}},{"id":4618867,"issuer":{"id":5127,"kind":"organization","name":"Horizon Quantum Holdings Ltd.","symbol":"HQ"},"owners":[{"id":55959,"kind":"person","name":"Tan Si-Hui","position":1,"cik":"0002120880","reported_name":"Tan Si-Hui","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Science Officer"}}],"security":"Stock Option (Right to Buy)","published_at":"2026-09-16T01:31:13.000Z","date":"2026-03-19","kind":"grant","planned":false,"acquired":true,"shares":55000,"ownership":{"direct":false,"nature":"By Spouse"},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F6","text":"Each stock option has an exercise price of $2.88 and is exercisable for approximately 2.43499 Class A Ordinary Shares of the Company. In aggregate, Dr. Tan's spouse's stock options, once fully vested, are exercisable for 133,924 Class A Ordinary Shares of the Company."},{"field":"date","element":"transactionDate","label":"F7","text":"Of the 55,000 stock options, 37,811 stock options are currently fully vested and exercisable. The remaining stock options vest in five approximately equal quarterly installments beginning on November 20, 2026, subject to Dr. Tan's spouse's continued employment with the Company."},{"field":"shares","element":"transactionShares","label":"F7","text":"Of the 55,000 stock options, 37,811 stock options are currently fully vested and exercisable. The remaining stock options vest in five approximately equal quarterly installments beginning on November 20, 2026, subject to Dr. Tan's spouse's continued employment with the Company."},{"field":"price","element":"transactionPricePerShare","label":"F8","text":"As a result of the closing of the Company's business combination on March 19, 2026, Dr. Tan's spouse's 55,000 Legacy Horizon stock options were exchanged for 55,000 stock options of the Company of an equivalent economic value, with an exercise price per Class A Ordinary Share of $2.88."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F7","text":"Of the 55,000 stock options, 37,811 stock options are currently fully vested and exercisable. The remaining stock options vest in five approximately equal quarterly installments beginning on November 20, 2026, subject to Dr. Tan's spouse's continued employment with the Company."},{"field":"derivative.underlying_shares","element":"underlyingSecurityShares","label":"F6","text":"Each stock option has an exercise price of $2.88 and is exercisable for approximately 2.43499 Class A Ordinary Shares of the Company. In aggregate, Dr. Tan's spouse's stock options, once fully vested, are exercisable for 133,924 Class A Ordinary Shares of the Company."}],"balance_after":55000,"derivative":{"exercise_price":2.88,"expiration_date":"2035-02-01","underlying":"Class A Ordinary Shares","underlying_shares":133924},"source":{"system":"sec-edgar","filing":"0001213900-26-100280","document":"ownership.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/2120880/000121390026100280/ownership.xml","form_type":"4"}},{"id":4618866,"issuer":{"id":5127,"kind":"organization","name":"Horizon Quantum Holdings Ltd.","symbol":"HQ"},"owners":[{"id":55959,"kind":"person","name":"Tan Si-Hui","position":1,"cik":"0002120880","reported_name":"Tan Si-Hui","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Science Officer"}}],"security":"Class A Ordinary Shares","published_at":"2026-09-16T01:31:13.000Z","date":"2026-09-12","kind":"disposition_to_issuer","planned":false,"acquired":false,"shares":2991,"price":15.22,"value":45523.02,"ownership":{"direct":true},"footnotes":[{"field":"date","element":"transactionDate","label":"F5","text":"The reported disposition to the Company reflects the settlement in cash of a portion of the RSUs which vested on September 12, 2026, at a price per ordinary share of $15.22, the last reported sales price of the Company's Class A Ordinary Shares on September 11, 2026."},{"field":"shares","element":"transactionShares","label":"F5","text":"The reported disposition to the Company reflects the settlement in cash of a portion of the RSUs which vested on September 12, 2026, at a price per ordinary share of $15.22, the last reported sales price of the Company's Class A Ordinary Shares on September 11, 2026."},{"field":"price","element":"transactionPricePerShare","label":"F5","text":"The reported disposition to the Company reflects the settlement in cash of a portion of the RSUs which vested on September 12, 2026, at a price per ordinary share of $15.22, the last reported sales price of the Company's Class A Ordinary Shares on September 11, 2026."}],"balance_after":2737,"source":{"system":"sec-edgar","filing":"0001213900-26-100280","document":"ownership.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2120880/000121390026100280/ownership.xml","form_type":"4"}},{"id":4618865,"issuer":{"id":5127,"kind":"organization","name":"Horizon Quantum Holdings Ltd.","symbol":"HQ"},"owners":[{"id":55959,"kind":"person","name":"Tan Si-Hui","position":1,"cik":"0002120880","reported_name":"Tan Si-Hui","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Science Officer"}}],"security":"Class A Ordinary Shares","published_at":"2026-09-16T01:31:13.000Z","date":"2026-09-12","kind":"exercise","planned":false,"acquired":true,"shares":5728,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"date","element":"transactionDate","label":"F3","text":"On September 12, 2026, 5,728 of Dr. Tan's RSU's vested."},{"field":"shares","element":"transactionShares","label":"F4","text":"On June 12, 2026 (the \"June Grant Date\"), Dr. Tan was granted a total of 91,659 unvested RSUs. The RSUs granted to Dr. Tan vest in sixteen approximately equal installments on successive quarterly anniversaries of the June Grant Date and are subject to Dr. Tan's continued employment with the Company through each applicable vesting date."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"On June 12, 2026 (the \"June Grant Date\"), Dr. Tan was granted a total of 91,659 unvested RSUs. The RSUs granted to Dr. Tan vest in sixteen approximately equal installments on successive quarterly anniversaries of the June Grant Date and are subject to Dr. Tan's continued employment with the Company through each applicable vesting date."}],"balance_after":5728,"source":{"system":"sec-edgar","filing":"0001213900-26-100280","document":"ownership.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2120880/000121390026100280/ownership.xml","form_type":"4"}},{"id":4618864,"issuer":{"id":5127,"kind":"organization","name":"Horizon Quantum Holdings Ltd.","symbol":"HQ"},"owners":[{"id":55959,"kind":"person","name":"Tan Si-Hui","position":1,"cik":"0002120880","reported_name":"Tan Si-Hui","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Science Officer"}}],"security":"Class A Ordinary Shares","published_at":"2026-09-16T01:31:13.000Z","date":"2026-08-20","kind":"grant","planned":false,"acquired":true,"shares":3600,"price":0,"value":0.0,"ownership":{"direct":false,"nature":"By Spouse"},"footnotes":[{"field":"date","element":"transactionDate","label":"F1","text":"On August 20, 2026 (the \"August Grant Date\"), Dr. Tan's spouse was granted a total of unvested 3,600 RSUs. The RSUs granted to Dr. Tan's spouse are subject to his continued employment with the Company and vest in accordance with the following schedule: One quarter (1/4) of the total number of RSUs vest on the first anniversary of the August Grant Date with the remaining three quarters (3/4) vesting in twelve approximately equal quarterly installments on 20th day of each fiscal quarter."},{"field":"shares","element":"transactionShares","label":"F1","text":"On August 20, 2026 (the \"August Grant Date\"), Dr. Tan's spouse was granted a total of unvested 3,600 RSUs. The RSUs granted to Dr. Tan's spouse are subject to his continued employment with the Company and vest in accordance with the following schedule: One quarter (1/4) of the total number of RSUs vest on the first anniversary of the August Grant Date with the remaining three quarters (3/4) vesting in twelve approximately equal quarterly installments on 20th day of each fiscal quarter."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"Each restricted stock unit (\"RSU\") represents a contingent right to receive one Class A ordinary share, with no par value (\"Class A Ordinary Share\"), of Horizon Quantum Holdings Ltd. (the \"Company\") upon vesting, for no consideration."}],"balance_after":3600,"source":{"system":"sec-edgar","filing":"0001213900-26-100280","document":"ownership.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2120880/000121390026100280/ownership.xml","form_type":"4"}},{"id":827920,"issuer":{"id":5127,"kind":"organization","name":"Horizon Quantum Holdings Ltd.","symbol":"HQ"},"owners":[{"id":55959,"kind":"person","name":"Tan Si-Hui","position":1,"cik":"0002120880","reported_name":"Tan Si-Hui","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Science Officer"}}],"security":"Stock Option (Right to Buy)","published_at":"2026-03-25T20:21:12.000Z","date":"2026-03-19","kind":"grant","planned":false,"acquired":true,"shares":500000,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F1","text":"Each stock option is exercisable for 2.43499 Class A Ordinary Shares of Horizon Quantum Holdings Ltd. (the \"Company\") at a price per share of $0.15."},{"field":"date","element":"transactionDate","label":"F2","text":"Stock options received as part of the business combination (the \"Business Combination\") contemplated by the Business Combination Agreement, dated as of September 9, 2025 (the \"BCA\"), by and among Horizon Quantum Computing Pte. Ltd. (\"Legacy Horizon\"), dMY Squared Technology Group, Inc., the Company and certain other parties, as described in the Registration Statement on Form F-4, as amended and supplemented (File No. 333-292737), initially filed with the U.S. Securities and Exchange Commission on January 14, 2026, and declared effective on February 17, 2026. Upon the closing of the Business Combination on March 19, 2026, Dr. Tan's stock options exercisable for Legacy Horizon ordinary shares awarded by Legacy Horizon were exchanged for substitute stock option awards of the Company of an equivalent economic value."},{"field":"shares","element":"transactionShares","label":"F1","text":"Each stock option is exercisable for 2.43499 Class A Ordinary Shares of Horizon Quantum Holdings Ltd. (the \"Company\") at a price per share of $0.15."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"Pursuant to the BCA and as a result of the closing of the Business Combination, Dr. Tan's 500,000 Legacy Horizon stock options were exchanged for 500,000 stock options of the Company of an equivalent economic value, with an exercise price per Class A Ordinary Share of $0.15."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The stock options held by Dr. Tan are fully vested and exercisable."},{"field":"derivative.underlying_shares","element":"underlyingSecurityShares","label":"F1","text":"Each stock option is exercisable for 2.43499 Class A Ordinary Shares of Horizon Quantum Holdings Ltd. (the \"Company\") at a price per share of $0.15."}],"balance_after":500000,"derivative":{"exercise_price":0.15,"expiration_date":"2032-03-01","underlying":"Class A Ordinary Shares","underlying_shares":1217494},"source":{"system":"sec-edgar","filing":"0001213900-26-034087","document":"ownership.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2088256/000121390026034087/ownership.xml","form_type":"4"}}]}