{"transactions":[{"id":4638707,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2026-10-09T20:30:19.000Z","date":"2026-10-08","kind":"gift","planned":true,"acquired":false,"shares":17885,"price":0,"value":0.0,"ownership":{"direct":false,"nature":"By Hodgkins LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F6","text":"Represents a bona fide gift of 17,885 shares of stock from Hodgkins LLC, of which Reporting Person serves as manager, to a donor-advised fund pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 1, 2026."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F5","text":"Shares held by Hodgkins LLC, of which the Reporting Person serves as manager. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":370246,"source":{"system":"sec-edgar","filing":"0001470831-26-000934","document":"wk-form4_1791577816.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1991125/000147083126000934/wk-form4_1791577816.xml","form_type":"4"}},{"id":4638706,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2026-10-09T20:30:19.000Z","date":"2026-10-07","kind":"sale","planned":true,"acquired":false,"shares":58815,"price":17.4,"value":1023381.0,"ownership":{"direct":false,"nature":"By Hodgkins LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 1, 2026."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $17.00 to $17.63 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F5","text":"Shares held by Hodgkins LLC, of which the Reporting Person serves as manager. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":388131,"source":{"system":"sec-edgar","filing":"0001470831-26-000934","document":"wk-form4_1791577816.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1991125/000147083126000934/wk-form4_1791577816.xml","form_type":"4"}},{"id":4638705,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2026-10-09T20:30:19.000Z","date":"2026-10-07","kind":"sale","planned":true,"acquired":false,"shares":38667,"price":17.4,"value":672805.8,"ownership":{"direct":false,"nature":"By Hodgkins Trust"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 1, 2026."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $17.03 to $17.63 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F3","text":"Shares are owned directly by Hodgkins Trust for the benefit of the Reporting Person and the Reporting Person's family, and of which the trustee is an independent institution. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":55290,"source":{"system":"sec-edgar","filing":"0001470831-26-000934","document":"wk-form4_1791577816.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1991125/000147083126000934/wk-form4_1791577816.xml","form_type":"4"}},{"id":4627177,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2026-09-25T21:50:51.000Z","date":"2026-09-24","kind":"sale","planned":true,"acquired":false,"shares":800,"price":17.02,"value":13616.0,"ownership":{"direct":false,"nature":"By Hodgkins LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 1, 2026."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $17.00 to $17.03 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F4","text":"Shares held by Hodgkins LLC, of which the Reporting Person serves as manager. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":446946,"source":{"system":"sec-edgar","filing":"0001470831-26-000904","document":"wk-form4_1790373048.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1991125/000147083126000904/wk-form4_1790373048.xml","form_type":"4"}},{"id":4627176,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2026-09-25T21:50:51.000Z","date":"2026-09-24","kind":"sale","planned":true,"acquired":false,"shares":500,"price":17.02,"value":8510.0,"ownership":{"direct":false,"nature":"By Hodgkins Trust"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 1, 2026."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $17.00 to $17.03 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F3","text":"Shares are owned directly by Hodgkins Trust for the benefit of the Reporting Person and the Reporting Person's family, and of which the trustee is an independent institution. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":93957,"source":{"system":"sec-edgar","filing":"0001470831-26-000904","document":"wk-form4_1790373048.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1991125/000147083126000904/wk-form4_1790373048.xml","form_type":"4"}},{"id":670764,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2026-09-02T00:18:54.000Z","date":"2026-08-31","kind":"gift","planned":true,"acquired":false,"shares":17885,"price":0,"value":0.0,"ownership":{"direct":false,"nature":"By Hodgkins LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F6","text":"Represents a bona fide gift of 17,885 shares of stock from Hodgkins LLC, of which Reporting Person serves as manager, to a donor-advised fund pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 1, 2026."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F5","text":"Shares held by Hodgkins LLC, of which the Reporting Person serves as manager. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":447746,"source":{"system":"sec-edgar","filing":"0001470831-26-000870","document":"wk-form4_1788308332.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000870/wk-form4_1788308332.xml","form_type":"4"}},{"id":670763,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2026-09-02T00:18:54.000Z","date":"2026-08-31","kind":"sale","planned":true,"acquired":false,"shares":59615,"price":20.49,"value":1221511.35,"ownership":{"direct":false,"nature":"By Hodgkins LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 1, 2026."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $20.30 to $20.78 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F5","text":"Shares held by Hodgkins LLC, of which the Reporting Person serves as manager. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":465631,"source":{"system":"sec-edgar","filing":"0001470831-26-000870","document":"wk-form4_1788308332.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000870/wk-form4_1788308332.xml","form_type":"4"}},{"id":670762,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2026-09-02T00:18:54.000Z","date":"2026-08-31","kind":"sale","planned":true,"acquired":false,"shares":39167,"price":20.47,"value":801748.49,"ownership":{"direct":false,"nature":"By Hodgkins Trust"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 1, 2026."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $20.30 to $20.77 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F3","text":"Shares are owned directly by Hodgkins Trust for the benefit of the Reporting Person and the Reporting Person's family, and of which the trustee is an independent institution. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":94457,"source":{"system":"sec-edgar","filing":"0001470831-26-000870","document":"wk-form4_1788308332.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083126000870/wk-form4_1788308332.xml","form_type":"4"}},{"id":961707,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2025-12-19T21:04:22.000Z","date":"2025-12-17","kind":"sale","planned":true,"acquired":false,"shares":82672,"price":30.37,"value":2510748.64,"ownership":{"direct":false,"nature":"By Hodgkins LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 12, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $30.00 to $30.695 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F5","text":"Shares held by Hodgkins LLC, of which the Reporting Person serves as manager. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":525246,"source":{"system":"sec-edgar","filing":"0001470831-25-000442","document":"wk-form4_1766178258.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000442/wk-form4_1766178258.xml","form_type":"4"}},{"id":961706,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2025-12-19T21:04:22.000Z","date":"2025-12-17","kind":"sale","planned":true,"acquired":false,"shares":34878,"price":30.35,"value":1058547.3,"ownership":{"direct":false,"nature":"By Hodgkins Trust"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 12, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $30.00 to $30.71 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F3","text":"Shares are owned directly by Hodgkins Trust for the benefit of the Reporting Person and the Reporting Person's family, and of which the trustee is an independent institution. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":133624,"source":{"system":"sec-edgar","filing":"0001470831-25-000442","document":"wk-form4_1766178258.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000442/wk-form4_1766178258.xml","form_type":"4"}},{"id":964067,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2025-12-17T22:19:37.000Z","date":"2025-12-15","kind":"sale","planned":true,"acquired":false,"shares":600,"price":30.15,"value":18090.0,"ownership":{"direct":false,"nature":"By Hodgkins LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 12, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $30.15 to $30.155 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F5","text":"Shares held by Hodgkins LLC, of which the Reporting Person serves as manager. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":607918,"source":{"system":"sec-edgar","filing":"0001470831-25-000425","document":"wk-form4_1766009974.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000425/wk-form4_1766009974.xml","form_type":"4"}},{"id":964066,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2025-12-17T22:19:37.000Z","date":"2025-12-15","kind":"sale","planned":true,"acquired":false,"shares":157,"price":30.13,"value":4730.41,"ownership":{"direct":false,"nature":"By Hodgkins Trust"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 12, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $30.024 to $30.155 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F3","text":"Shares are owned directly by Hodgkins Trust for the benefit of the Reporting Person and the Reporting Person's family, and of which the trustee is an independent institution. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":168502,"source":{"system":"sec-edgar","filing":"0001470831-25-000425","document":"wk-form4_1766009974.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000425/wk-form4_1766009974.xml","form_type":"4"}},{"id":1001288,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2025-11-13T00:51:42.000Z","date":"2025-11-11","kind":"sale","planned":true,"acquired":false,"shares":2266,"price":30,"value":67980.0,"ownership":{"direct":false,"nature":"By Hodgkins LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 12, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F8","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $30.00 to $30.01 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F5","text":"Shares held by Hodgkins LLC, of which the Reporting Person serves as manager. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":608518,"source":{"system":"sec-edgar","filing":"0001470831-25-000310","document":"wk-form4_1762995098.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000310/wk-form4_1762995098.xml","form_type":"4"}},{"id":1001287,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2025-11-13T00:51:42.000Z","date":"2025-11-11","kind":"sale","planned":true,"acquired":false,"shares":545,"price":30,"value":16350.0,"ownership":{"direct":false,"nature":"By Hodgkins Trust"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 12, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F7","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $30.00 to $30.02 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F3","text":"Shares are owned directly by Hodgkins Trust for the benefit of the Reporting Person and the Reporting Person's family, and of which the trustee is an independent institution. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":168659,"source":{"system":"sec-edgar","filing":"0001470831-25-000310","document":"wk-form4_1762995098.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000310/wk-form4_1762995098.xml","form_type":"4"}},{"id":1001286,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2025-11-13T00:51:42.000Z","date":"2025-11-10","kind":"gift","planned":true,"acquired":false,"shares":40512,"price":0,"value":0.0,"ownership":{"direct":false,"nature":"By Hodgkins LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F6","text":"Represents a bona fide gift of 40,512 shares of stock from the Reporting Person to a donor-advised fund pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 12, 2025."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F5","text":"Shares held by Hodgkins LLC, of which the Reporting Person serves as manager. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":610784,"source":{"system":"sec-edgar","filing":"0001470831-25-000310","document":"wk-form4_1762995098.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000310/wk-form4_1762995098.xml","form_type":"4"}},{"id":1001285,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2025-11-13T00:51:42.000Z","date":"2025-11-10","kind":"sale","planned":true,"acquired":false,"shares":50920,"price":30.04,"value":1529636.8,"ownership":{"direct":false,"nature":"By Hodgkins LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 12, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $30.00 to $30.575 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F5","text":"Shares held by Hodgkins LLC, of which the Reporting Person serves as manager. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":651296,"source":{"system":"sec-edgar","filing":"0001470831-25-000310","document":"wk-form4_1762995098.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000310/wk-form4_1762995098.xml","form_type":"4"}},{"id":1001284,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2025-11-13T00:51:42.000Z","date":"2025-11-10","kind":"sale","planned":true,"acquired":false,"shares":8572,"price":30.05,"value":257588.6,"ownership":{"direct":false,"nature":"By Hodgkins Trust"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 12, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $30.00 to $30.56 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F3","text":"Shares are owned directly by Hodgkins Trust for the benefit of the Reporting Person and the Reporting Person's family, and of which the trustee is an independent institution. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":169204,"source":{"system":"sec-edgar","filing":"0001470831-25-000310","document":"wk-form4_1762995098.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000310/wk-form4_1762995098.xml","form_type":"4"}},{"id":1036910,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2025-09-17T20:40:28.000Z","date":"2025-09-15","kind":"gift","planned":true,"acquired":false,"shares":20260,"price":0,"value":0.0,"ownership":{"direct":false,"nature":"By Hodgkins LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F6","text":"Represents a bona fide gift of 20,260 shares of stock from the Reporting Person to a donor-advised fund pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 12, 2025."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F5","text":"Shares held by Hodgkins LLC, of which the Reporting Person serves as manager. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":702216,"source":{"system":"sec-edgar","filing":"0001470831-25-000217","document":"wk-form4_1758141626.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000217/wk-form4_1758141626.xml","form_type":"4"}},{"id":1036909,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2025-09-17T20:40:28.000Z","date":"2025-09-15","kind":"sale","planned":true,"acquired":false,"shares":67524,"price":31.73,"value":2142536.52,"ownership":{"direct":false,"nature":"By Hodgkins LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 12, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F4","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $31.15 to $31.98 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F5","text":"Shares held by Hodgkins LLC, of which the Reporting Person serves as manager. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":722476,"source":{"system":"sec-edgar","filing":"0001470831-25-000217","document":"wk-form4_1758141626.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000217/wk-form4_1758141626.xml","form_type":"4"}},{"id":1036908,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2025-09-17T20:40:28.000Z","date":"2025-09-15","kind":"sale","planned":true,"acquired":false,"shares":22224,"price":31.65,"value":703389.6,"ownership":{"direct":false,"nature":"By Hodgkins Trust"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 12, 2025."},{"field":"price","element":"transactionPricePerShare","label":"F2","text":"The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $31.07 to $31.965 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F3","text":"Shares are owned directly by Hodgkins Trust for the benefit of the Reporting Person and the Reporting Person's family, and of which the trustee is an independent institution. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":177776,"source":{"system":"sec-edgar","filing":"0001470831-25-000217","document":"wk-form4_1758141626.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000217/wk-form4_1758141626.xml","form_type":"4"}},{"id":1041154,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series B Common Stock","published_at":"2025-09-12T22:08:57.000Z","date":"2025-09-11","kind":"exercise","planned":false,"acquired":false,"shares":990000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_price","element":"conversionOrExercisePrice","label":"F1","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of  the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F1","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of  the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."},{"field":"derivative.expiration_date","element":"expirationDate","label":"F1","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of  the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":31999106,"derivative":{"underlying":"Series A Common Stock","underlying_shares":990000},"source":{"system":"sec-edgar","filing":"0001470831-25-000196","document":"wk-form4_1757714934.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000196/wk-form4_1757714934.xml","form_type":"4"}},{"id":1041153,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2025-09-12T22:08:57.000Z","date":"2025-09-11","kind":"gift","planned":false,"acquired":true,"shares":790000,"price":0,"value":0.0,"ownership":{"direct":false,"nature":"By Hodgkins LLC"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F2","text":"On September 11, 2025, the Reporting Person transferred 200,000 shares of Series A Common Stock to Hodgkins Trust and 790,000 shares of Series A Common Stock to Hodgkins LLC for estate planning purposes, in each case for no consideration."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F4","text":"Shares held by Hodgkins LLC, of which the Reporting Person serves as manager. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":790000,"source":{"system":"sec-edgar","filing":"0001470831-25-000196","document":"wk-form4_1757714934.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000196/wk-form4_1757714934.xml","form_type":"4"}},{"id":1041152,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2025-09-12T22:08:57.000Z","date":"2025-09-11","kind":"gift","planned":false,"acquired":true,"shares":200000,"price":0,"value":0.0,"ownership":{"direct":false,"nature":"By Hodgkins Trust"},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F2","text":"On September 11, 2025, the Reporting Person transferred 200,000 shares of Series A Common Stock to Hodgkins Trust and 790,000 shares of Series A Common Stock to Hodgkins LLC for estate planning purposes, in each case for no consideration."},{"field":"ownership.nature","element":"natureOfOwnership","label":"F3","text":"Shares are owned directly by Hodgkins Trust for the benefit of the Reporting Person and the Reporting Person's family, and of which the trustee is an independent institution. The Reporting Person disclaims Section 16 beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed to be an admission that he has beneficial ownership of such shares for Section 16 or any other purpose."}],"balance_after":200000,"source":{"system":"sec-edgar","filing":"0001470831-25-000196","document":"wk-form4_1757714934.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000196/wk-form4_1757714934.xml","form_type":"4"}},{"id":1041151,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2025-09-12T22:08:57.000Z","date":"2025-09-11","kind":"gift","planned":false,"acquired":false,"shares":990000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F2","text":"On September 11, 2025, the Reporting Person transferred 200,000 shares of Series A Common Stock to Hodgkins Trust and 790,000 shares of Series A Common Stock to Hodgkins LLC for estate planning purposes, in each case for no consideration."}],"balance_after":0,"source":{"system":"sec-edgar","filing":"0001470831-25-000196","document":"wk-form4_1757714934.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000196/wk-form4_1757714934.xml","form_type":"4"}},{"id":1041150,"issuer":{"id":3775,"kind":"organization","name":"Klaviyo, Inc.","symbol":"KVYO"},"owners":[{"id":17821,"kind":"person","name":"Hallen Ed","position":1,"cik":"0001991125","reported_name":"Hallen Ed","relationship":{"director":true,"officer":false,"ten_percent_owner":true,"other":false}}],"security":"Series A Common Stock","published_at":"2025-09-12T22:08:57.000Z","date":"2025-09-11","kind":"exercise","planned":false,"acquired":true,"shares":990000,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Each share of the Issuer's Series B Common Stock, par value $0.001 per share (\"Series B Common Stock\"), is convertible at any time at the option of the holder into one share of  the Issuer's Series A Common Stock, par value $0.001 per share (\"Series A Common Stock\"), and will automatically convert into one share of Series A Common Stock upon the occurrence of certain events as set forth in the Issuer's certificate of incorporation. The Series B Common Stock has no expiration date."}],"balance_after":990000,"source":{"system":"sec-edgar","filing":"0001470831-25-000196","document":"wk-form4_1757714934.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/1835830/000147083125000196/wk-form4_1757714934.xml","form_type":"4"}}]}