{"transactions":[{"id":4617469,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Class A Common Stock","published_at":"2026-09-14T22:47:01.000Z","date":"2026-09-10","kind":"gift","planned":false,"acquired":false,"shares":3500,"price":0,"value":0.0,"ownership":{"direct":true},"balance_after":196500,"source":{"system":"sec-edgar","filing":"0002088547-26-000010","document":"wk-form4_1789426019.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000208854726000010/wk-form4_1789426019.xml","form_type":"4"}},{"id":697616,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Class A Common Stock","published_at":"2026-08-04T20:32:43.000Z","date":"2026-07-31","kind":"sale","planned":true,"acquired":false,"shares":4000,"price":140.21,"value":560840.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 6, 2026."}],"balance_after":200000,"source":{"system":"sec-edgar","filing":"0002088547-26-000008","document":"wk-form4_1785875561.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000208854726000008/wk-form4_1785875561.xml","form_type":"4"}},{"id":710771,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Stock Option (right to buy)","published_at":"2026-07-13T20:39:18.000Z","date":"2026-07-09","kind":"exercise","planned":true,"acquired":false,"shares":1354,"price":30.78,"value":41676.12,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"The options are fully vested and exercisable. The terms of the underlying option grant are as previously reported on the Reporting Person's Form 3 filed on November 5, 2025."}],"balance_after":61174,"derivative":{"exercise_price":30.78,"expiration_date":"2035-09-30","underlying":"Class A Common Stock","underlying_shares":1354},"source":{"system":"sec-edgar","filing":"0002088547-26-000006","document":"wk-form4_1783975155.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":13,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000208854726000006/wk-form4_1783975155.xml","form_type":"4"}},{"id":710770,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Stock Option (right to buy)","published_at":"2026-07-13T20:39:18.000Z","date":"2026-07-09","kind":"exercise","planned":true,"acquired":false,"shares":1355,"price":30.78,"value":41706.9,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"The options are fully vested and exercisable. The terms of the underlying option grant are as previously reported on the Reporting Person's Form 3 filed on November 5, 2025."}],"balance_after":62528,"derivative":{"exercise_price":30.78,"expiration_date":"2035-09-30","underlying":"Class A Common Stock","underlying_shares":1355},"source":{"system":"sec-edgar","filing":"0002088547-26-000006","document":"wk-form4_1783975155.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":12,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000208854726000006/wk-form4_1783975155.xml","form_type":"4"}},{"id":710769,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Stock Option (right to buy)","published_at":"2026-07-13T20:39:18.000Z","date":"2026-07-09","kind":"exercise","planned":true,"acquired":false,"shares":1117,"price":30.78,"value":34381.26,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"The options are fully vested and exercisable. The terms of the underlying option grant are as previously reported on the Reporting Person's Form 3 filed on November 5, 2025."}],"balance_after":63883,"derivative":{"exercise_price":30.78,"expiration_date":"2035-09-30","underlying":"Class A Common Stock","underlying_shares":1117},"source":{"system":"sec-edgar","filing":"0002088547-26-000006","document":"wk-form4_1783975155.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":11,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000208854726000006/wk-form4_1783975155.xml","form_type":"4"}},{"id":710768,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Stock Option (right to buy)","published_at":"2026-07-13T20:39:18.000Z","date":"2026-07-09","kind":"exercise","planned":true,"acquired":false,"shares":174,"price":8.65,"value":1505.1,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"The options are fully vested and exercisable. The terms of the underlying option grant are as previously reported on the Reporting Person's Form 3 filed on November 5, 2025."}],"balance_after":35826,"derivative":{"exercise_price":8.65,"expiration_date":"2033-01-18","underlying":"Class A Common Stock","underlying_shares":174},"source":{"system":"sec-edgar","filing":"0002088547-26-000006","document":"wk-form4_1783975155.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":10,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000208854726000006/wk-form4_1783975155.xml","form_type":"4"}},{"id":710767,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Class A Common Stock","published_at":"2026-07-13T20:39:18.000Z","date":"2026-07-09","kind":"sale","planned":true,"acquired":false,"shares":1354,"price":125,"value":169250.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 6, 2026."}],"balance_after":204000,"source":{"system":"sec-edgar","filing":"0002088547-26-000006","document":"wk-form4_1783975155.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":9,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000208854726000006/wk-form4_1783975155.xml","form_type":"4"}},{"id":710766,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Class A Common Stock","published_at":"2026-07-13T20:39:18.000Z","date":"2026-07-09","kind":"sale","planned":true,"acquired":false,"shares":1355,"price":125,"value":169375.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 6, 2026."}],"balance_after":205354,"source":{"system":"sec-edgar","filing":"0002088547-26-000006","document":"wk-form4_1783975155.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":8,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000208854726000006/wk-form4_1783975155.xml","form_type":"4"}},{"id":710765,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Class A Common Stock","published_at":"2026-07-13T20:39:18.000Z","date":"2026-07-09","kind":"sale","planned":true,"acquired":false,"shares":1117,"price":125,"value":139625.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 6, 2026."}],"balance_after":206709,"source":{"system":"sec-edgar","filing":"0002088547-26-000006","document":"wk-form4_1783975155.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":7,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000208854726000006/wk-form4_1783975155.xml","form_type":"4"}},{"id":710764,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Class A Common Stock","published_at":"2026-07-13T20:39:18.000Z","date":"2026-07-09","kind":"sale","planned":true,"acquired":false,"shares":174,"price":125,"value":21750.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 6, 2026."}],"balance_after":207826,"source":{"system":"sec-edgar","filing":"0002088547-26-000006","document":"wk-form4_1783975155.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":6,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000208854726000006/wk-form4_1783975155.xml","form_type":"4"}},{"id":710763,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Class A Common Stock","published_at":"2026-07-13T20:39:18.000Z","date":"2026-07-09","kind":"sale","planned":true,"acquired":false,"shares":4000,"price":125,"value":500000.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 6, 2026."}],"balance_after":208000,"source":{"system":"sec-edgar","filing":"0002088547-26-000006","document":"wk-form4_1783975155.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000208854726000006/wk-form4_1783975155.xml","form_type":"4"}},{"id":710762,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Class A Common Stock","published_at":"2026-07-13T20:39:18.000Z","date":"2026-07-09","kind":"exercise","planned":true,"acquired":true,"shares":1354,"price":30.78,"value":41676.12,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 6, 2026."}],"balance_after":212000,"source":{"system":"sec-edgar","filing":"0002088547-26-000006","document":"wk-form4_1783975155.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000208854726000006/wk-form4_1783975155.xml","form_type":"4"}},{"id":710761,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Class A Common Stock","published_at":"2026-07-13T20:39:18.000Z","date":"2026-07-09","kind":"exercise","planned":true,"acquired":true,"shares":1355,"price":30.78,"value":41706.9,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 6, 2026."}],"balance_after":210646,"source":{"system":"sec-edgar","filing":"0002088547-26-000006","document":"wk-form4_1783975155.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000208854726000006/wk-form4_1783975155.xml","form_type":"4"}},{"id":710760,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Class A Common Stock","published_at":"2026-07-13T20:39:18.000Z","date":"2026-07-09","kind":"exercise","planned":true,"acquired":true,"shares":1117,"price":30.78,"value":34381.26,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 6, 2026."}],"balance_after":209291,"source":{"system":"sec-edgar","filing":"0002088547-26-000006","document":"wk-form4_1783975155.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000208854726000006/wk-form4_1783975155.xml","form_type":"4"}},{"id":710759,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Class A Common Stock","published_at":"2026-07-13T20:39:18.000Z","date":"2026-07-09","kind":"exercise","planned":true,"acquired":true,"shares":174,"price":8.65,"value":1505.1,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 6, 2026."}],"balance_after":208174,"source":{"system":"sec-edgar","filing":"0002088547-26-000006","document":"wk-form4_1783975155.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000208854726000006/wk-form4_1783975155.xml","form_type":"4"}},{"id":725735,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Stock Option (right to buy)","published_at":"2026-06-26T21:20:13.000Z","date":"2026-06-24","kind":"exercise","planned":true,"acquired":false,"shares":4000,"price":8.65,"value":34600.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"The options are fully vested and exercisable. The terms of the underlying option grant are as previously reported on the Reporting Person's Form 3 filed on November 5, 2025."}],"balance_after":36000,"derivative":{"exercise_price":8.65,"expiration_date":"2033-01-18","underlying":"Class A Common Stock","underlying_shares":4000},"source":{"system":"sec-edgar","filing":"0002088547-26-000004","document":"wk-form4_1782508810.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000208854726000004/wk-form4_1782508810.xml","form_type":"4"}},{"id":725734,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Class A Common Stock","published_at":"2026-06-26T21:20:13.000Z","date":"2026-06-24","kind":"sale","planned":true,"acquired":false,"shares":4000,"price":110,"value":440000.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 6, 2026."}],"balance_after":208000,"source":{"system":"sec-edgar","filing":"0002088547-26-000004","document":"wk-form4_1782508810.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000208854726000004/wk-form4_1782508810.xml","form_type":"4"}},{"id":725733,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Class A Common Stock","published_at":"2026-06-26T21:20:13.000Z","date":"2026-06-24","kind":"sale","planned":true,"acquired":false,"shares":4000,"price":110,"value":440000.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 6, 2026."}],"balance_after":212000,"source":{"system":"sec-edgar","filing":"0002088547-26-000004","document":"wk-form4_1782508810.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000208854726000004/wk-form4_1782508810.xml","form_type":"4"}},{"id":725732,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Class A Common Stock","published_at":"2026-06-26T21:20:13.000Z","date":"2026-06-24","kind":"exercise","planned":true,"acquired":true,"shares":4000,"price":8.65,"value":34600.0,"ownership":{"direct":true},"balance_after":216000,"source":{"system":"sec-edgar","filing":"0002088547-26-000004","document":"wk-form4_1782508810.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000208854726000004/wk-form4_1782508810.xml","form_type":"4"}},{"id":743478,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Class A Common Stock","published_at":"2026-06-11T00:36:45.000Z","date":"2026-06-08","kind":"sale","planned":true,"acquired":false,"shares":4000,"price":100,"value":400000.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 6, 2026."}],"balance_after":212000,"source":{"system":"sec-edgar","filing":"0002088547-26-000002","document":"wk-form4_1781138203.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000208854726000002/wk-form4_1781138203.xml","form_type":"4"}},{"id":743477,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Class A Common Stock","published_at":"2026-06-11T00:36:45.000Z","date":"2026-06-08","kind":"sale","planned":true,"acquired":false,"shares":4000,"price":96.45,"value":385800.0,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 6, 2026."}],"balance_after":216000,"source":{"system":"sec-edgar","filing":"0002088547-26-000002","document":"wk-form4_1781138203.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000208854726000002/wk-form4_1781138203.xml","form_type":"4"}},{"id":1002433,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Stock Option (right to buy)","published_at":"2025-11-12T23:12:27.000Z","date":"2025-11-07","kind":"other","planned":false,"acquired":true,"shares":65000,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"Pursuant to a reclassification exempt under Rule 16b-7, each share of Common Stock was automatically reclassified into one share of Class A common stock immediately prior to the completion of the Issuer's initial public offering of Class A common stock."},{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Pursuant to a reclassification exempt under Rule 16b-7, each share of Common Stock was automatically reclassified into one share of Class A common stock immediately prior to the completion of the Issuer's initial public offering of Class A common stock."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"The options are subject to a service-based vesting requirement, which shall be satisfied over a four-year period. The options vest and become exercisable in equal monthly installments commencing on September 15, 2025, subject to the Reporting Person's continuous service with the Issuer through each such vesting date."}],"balance_after":65000,"derivative":{"exercise_price":30.78,"expiration_date":"2035-09-30","underlying":"Class A Common Stock","underlying_shares":65000},"source":{"system":"sec-edgar","filing":"0001193125-25-278137","document":"ownership.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":8,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000119312525278137/ownership.xml","form_type":"4"}},{"id":1002432,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Stock Option (right to buy)","published_at":"2025-11-12T23:12:27.000Z","date":"2025-11-07","kind":"other","planned":false,"acquired":false,"shares":65000,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"Pursuant to a reclassification exempt under Rule 16b-7, each share of Common Stock was automatically reclassified into one share of Class A common stock immediately prior to the completion of the Issuer's initial public offering of Class A common stock."},{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Pursuant to a reclassification exempt under Rule 16b-7, each share of Common Stock was automatically reclassified into one share of Class A common stock immediately prior to the completion of the Issuer's initial public offering of Class A common stock."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F4","text":"The options are subject to a service-based vesting requirement, which shall be satisfied over a four-year period. The options vest and become exercisable in equal monthly installments commencing on September 15, 2025, subject to the Reporting Person's continuous service with the Issuer through each such vesting date."}],"balance_after":0,"derivative":{"exercise_price":30.78,"expiration_date":"2035-09-30","underlying":"Common Stock","underlying_shares":65000},"source":{"system":"sec-edgar","filing":"0001193125-25-278137","document":"ownership.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":7,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000119312525278137/ownership.xml","form_type":"4"}},{"id":1002431,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Stock Option (right to buy)","published_at":"2025-11-12T23:12:27.000Z","date":"2025-11-07","kind":"other","planned":false,"acquired":true,"shares":40000,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"Pursuant to a reclassification exempt under Rule 16b-7, each share of Common Stock was automatically reclassified into one share of Class A common stock immediately prior to the completion of the Issuer's initial public offering of Class A common stock."},{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Pursuant to a reclassification exempt under Rule 16b-7, each share of Common Stock was automatically reclassified into one share of Class A common stock immediately prior to the completion of the Issuer's initial public offering of Class A common stock."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are subject to a service-based vesting requirement, which shall be satisfied over a four-year period. The options vest and become exercisable in equal monthly installments commencing on January 1, 2023, subject to the Reporting Person's continuous service with the Issuer through each such vesting date."}],"balance_after":40000,"derivative":{"exercise_price":8.65,"expiration_date":"2033-01-18","underlying":"Class A Common Stock","underlying_shares":40000},"source":{"system":"sec-edgar","filing":"0001193125-25-278137","document":"ownership.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":6,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000119312525278137/ownership.xml","form_type":"4"}},{"id":1002430,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Stock Option (right to buy)","published_at":"2025-11-12T23:12:27.000Z","date":"2025-11-07","kind":"other","planned":false,"acquired":false,"shares":40000,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"Pursuant to a reclassification exempt under Rule 16b-7, each share of Common Stock was automatically reclassified into one share of Class A common stock immediately prior to the completion of the Issuer's initial public offering of Class A common stock."},{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Pursuant to a reclassification exempt under Rule 16b-7, each share of Common Stock was automatically reclassified into one share of Class A common stock immediately prior to the completion of the Issuer's initial public offering of Class A common stock."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F3","text":"The options are subject to a service-based vesting requirement, which shall be satisfied over a four-year period. The options vest and become exercisable in equal monthly installments commencing on January 1, 2023, subject to the Reporting Person's continuous service with the Issuer through each such vesting date."}],"balance_after":0,"derivative":{"exercise_price":8.65,"expiration_date":"2033-01-18","underlying":"Common Stock","underlying_shares":40000},"source":{"system":"sec-edgar","filing":"0001193125-25-278137","document":"ownership.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":5,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000119312525278137/ownership.xml","form_type":"4"}},{"id":1002429,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Stock Option (right to buy)","published_at":"2025-11-12T23:12:27.000Z","date":"2025-11-07","kind":"other","planned":false,"acquired":true,"shares":50000,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"Pursuant to a reclassification exempt under Rule 16b-7, each share of Common Stock was automatically reclassified into one share of Class A common stock immediately prior to the completion of the Issuer's initial public offering of Class A common stock."},{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Pursuant to a reclassification exempt under Rule 16b-7, each share of Common Stock was automatically reclassified into one share of Class A common stock immediately prior to the completion of the Issuer's initial public offering of Class A common stock."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"The options are fully vested and exercisable."}],"balance_after":50000,"derivative":{"exercise_price":2.8,"expiration_date":"2031-06-07","underlying":"Class A Common Stock","underlying_shares":50000},"source":{"system":"sec-edgar","filing":"0001193125-25-278137","document":"ownership.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":4,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000119312525278137/ownership.xml","form_type":"4"}},{"id":1002428,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Stock Option (right to buy)","published_at":"2025-11-12T23:12:27.000Z","date":"2025-11-07","kind":"other","planned":false,"acquired":false,"shares":50000,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"Pursuant to a reclassification exempt under Rule 16b-7, each share of Common Stock was automatically reclassified into one share of Class A common stock immediately prior to the completion of the Issuer's initial public offering of Class A common stock."},{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Pursuant to a reclassification exempt under Rule 16b-7, each share of Common Stock was automatically reclassified into one share of Class A common stock immediately prior to the completion of the Issuer's initial public offering of Class A common stock."},{"field":"derivative.exercise_date","element":"exerciseDate","label":"F2","text":"The options are fully vested and exercisable."}],"balance_after":0,"derivative":{"exercise_price":2.8,"expiration_date":"2031-06-07","underlying":"Common Stock","underlying_shares":50000},"source":{"system":"sec-edgar","filing":"0001193125-25-278137","document":"ownership.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":3,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000119312525278137/ownership.xml","form_type":"4"}},{"id":1002427,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Class A Common Stock","published_at":"2025-11-12T23:12:27.000Z","date":"2025-11-07","kind":"other","planned":false,"acquired":true,"shares":220000,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"Pursuant to a reclassification exempt under Rule 16b-7, each share of Common Stock was automatically reclassified into one share of Class A common stock immediately prior to the completion of the Issuer's initial public offering of Class A common stock."},{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Pursuant to a reclassification exempt under Rule 16b-7, each share of Common Stock was automatically reclassified into one share of Class A common stock immediately prior to the completion of the Issuer's initial public offering of Class A common stock."}],"balance_after":220000,"source":{"system":"sec-edgar","filing":"0001193125-25-278137","document":"ownership.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":2,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000119312525278137/ownership.xml","form_type":"4"}},{"id":1002426,"issuer":{"id":3992,"kind":"organization","name":"BillionToOne, Inc.","symbol":"BLLN"},"owners":[{"id":26761,"kind":"person","name":"Sakakibara Shan Riku","position":1,"cik":"0002088547","reported_name":"Sakakibara Shan Riku","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Product Officer"}}],"security":"Common Stock","published_at":"2025-11-12T23:12:27.000Z","date":"2025-11-07","kind":"other","planned":false,"acquired":false,"shares":220000,"ownership":{"direct":true},"footnotes":[{"field":"kind","element":"transactionCoding","label":"F1","text":"Pursuant to a reclassification exempt under Rule 16b-7, each share of Common Stock was automatically reclassified into one share of Class A common stock immediately prior to the completion of the Issuer's initial public offering of Class A common stock."},{"field":"price","element":"transactionPricePerShare","label":"F1","text":"Pursuant to a reclassification exempt under Rule 16b-7, each share of Common Stock was automatically reclassified into one share of Class A common stock immediately prior to the completion of the Issuer's initial public offering of Class A common stock."}],"balance_after":0,"source":{"system":"sec-edgar","filing":"0001193125-25-278137","document":"ownership.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2088547/000119312525278137/ownership.xml","form_type":"4"}}]}