BLLN: Lynch Thomas P. discloses securities transactions

By AlphaYouPublished Sep 21, 2026Form 4

Stocks in this disclosure

Reported activity

Lynch Thomas P.

Reporting filer

Lynch Thomas P. reported Exercise or conversion in BillionToOne, Inc.: 19384 units of Class A Common Stock, dated 2026-09-17. The full Form 4 contains 12 transaction entries.

Disclosed: Sep 21, 2026

Reported details

12 entries

All validated entries in this disclosure
Security	Owner	Date	Code	Action	Quantity	Price	Following holdings	Reporting delay	Filed terms and references
Class A Common Stock	Lynch Thomas P.	2026-09-17	M	Exercise or conversion	19384	8.65	20,084	4 days	Filed terms security Title: Class A Common Stock transaction Date: 2026-09-17 transaction Form Type: 4 transaction Code: M equity Swap Involved: 0 id: F1 transaction Shares: 19384 transaction Price Per Share: 8.65 transaction Acquired Disposed Code: A shares Owned Following Transaction: 20084 direct Or Indirect Ownership: D
Class A Common Stock	Lynch Thomas P.	2026-09-17	M	Exercise or conversion	6968	11.55	27,052	4 days	Filed terms security Title: Class A Common Stock transaction Date: 2026-09-17 transaction Form Type: 4 transaction Code: M equity Swap Involved: 0 id: F1 transaction Shares: 6968 transaction Price Per Share: 11.55 transaction Acquired Disposed Code: A shares Owned Following Transaction: 27052 direct Or Indirect Ownership: D
Class A Common Stock	Lynch Thomas P.	2026-09-17	M	Exercise or conversion	2920	17.12	29,972	4 days	Filed terms security Title: Class A Common Stock transaction Date: 2026-09-17 transaction Form Type: 4 transaction Code: M equity Swap Involved: 0 id: F1 transaction Shares: 2920 transaction Price Per Share: 17.12 transaction Acquired Disposed Code: A shares Owned Following Transaction: 29972 direct Or Indirect Ownership: D
Class A Common Stock	Lynch Thomas P.	2026-09-17	M	Exercise or conversion	5840	30.78	35,812	4 days	Filed terms security Title: Class A Common Stock transaction Date: 2026-09-17 transaction Form Type: 4 transaction Code: M equity Swap Involved: 0 id: F1 transaction Shares: 5840 transaction Price Per Share: 30.78 transaction Acquired Disposed Code: A shares Owned Following Transaction: 35812 direct Or Indirect Ownership: D
Class A Common Stock	Lynch Thomas P.	2026-09-17	S	Sale	19384	110.3587	16,428	4 days	Filed terms security Title: Class A Common Stock transaction Date: 2026-09-17 transaction Form Type: 4 transaction Code: S equity Swap Involved: 0 id: F1 transaction Shares: 19384 transaction Price Per Share: 110.3587 id: F2 transaction Acquired Disposed Code: D shares Owned Following Transaction: 16428 direct Or Indirect Ownership: D
Class A Common Stock	Lynch Thomas P.	2026-09-17	S	Sale	6968	110.2986	9,460	4 days	Filed terms security Title: Class A Common Stock transaction Date: 2026-09-17 transaction Form Type: 4 transaction Code: S equity Swap Involved: 0 id: F1 transaction Shares: 6968 transaction Price Per Share: 110.2986 id: F3 transaction Acquired Disposed Code: D shares Owned Following Transaction: 9460 direct Or Indirect Ownership: D
Class A Common Stock	Lynch Thomas P.	2026-09-17	S	Sale	2920	110.3083	6,540	4 days	Filed terms security Title: Class A Common Stock transaction Date: 2026-09-17 transaction Form Type: 4 transaction Code: S equity Swap Involved: 0 id: F1 transaction Shares: 2920 transaction Price Per Share: 110.3083 id: F3 transaction Acquired Disposed Code: D shares Owned Following Transaction: 6540 direct Or Indirect Ownership: D
Class A Common Stock	Lynch Thomas P.	2026-09-17	S	Sale	5840	110.2931	700	4 days	Filed terms security Title: Class A Common Stock transaction Date: 2026-09-17 transaction Form Type: 4 transaction Code: S equity Swap Involved: 0 id: F1 transaction Shares: 5840 transaction Price Per Share: 110.2931 id: F2 transaction Acquired Disposed Code: D shares Owned Following Transaction: 700 direct Or Indirect Ownership: D
Stock Option (right to buy) (derivative)	Lynch Thomas P.	2026-09-17	M	Exercise or conversion	19384	8.65	48,974	4 days	Filed terms security Title: Stock Option (right to buy) conversion Or Exercise Price: 8.65 transaction Date: 2026-09-17 transaction Form Type: 4 transaction Code: M equity Swap Involved: 0 transaction Shares: 19384 transaction Price Per Share: 8.65 transaction Acquired Disposed Code: D id: F4 expiration Date: 2033-01-18 underlying Security Title: Class A Common Stock underlying Security Shares: 19384 shares Owned Following Transaction: 48974 direct Or Indirect Ownership: D
Stock Option (right to buy) (derivative)	Lynch Thomas P.	2026-09-17	M	Exercise or conversion	6968	11.55	4,063	4 days	Filed terms security Title: Stock Option (right to buy) conversion Or Exercise Price: 11.55 transaction Date: 2026-09-17 transaction Form Type: 4 transaction Code: M equity Swap Involved: 0 transaction Shares: 6968 transaction Price Per Share: 11.55 transaction Acquired Disposed Code: D id: F4 expiration Date: 2033-10-17 underlying Security Title: Class A Common Stock underlying Security Shares: 6968 shares Owned Following Transaction: 4063 direct Or Indirect Ownership: D
Stock Option (right to buy) (derivative)	Lynch Thomas P.	2026-09-17	M	Exercise or conversion	2920	17.12	5,417	4 days	Filed terms security Title: Stock Option (right to buy) conversion Or Exercise Price: 17.12 transaction Date: 2026-09-17 transaction Form Type: 4 transaction Code: M equity Swap Involved: 0 transaction Shares: 2920 transaction Price Per Share: 17.12 transaction Acquired Disposed Code: D id: F4 expiration Date: 2034-10-16 underlying Security Title: Class A Common Stock underlying Security Shares: 2920 shares Owned Following Transaction: 5417 direct Or Indirect Ownership: D
Stock Option (right to buy) (derivative)	Lynch Thomas P.	2026-09-17	M	Exercise or conversion	5840	30.78	30,834	4 days	Filed terms security Title: Stock Option (right to buy) conversion Or Exercise Price: 30.78 transaction Date: 2026-09-17 transaction Form Type: 4 transaction Code: M equity Swap Involved: 0 transaction Shares: 5840 transaction Price Per Share: 30.78 transaction Acquired Disposed Code: D id: F4 expiration Date: 2035-09-30 underlying Security Title: Class A Common Stock underlying Security Shares: 5840 shares Owned Following Transaction: 30834 direct Or Indirect Ownership: D

Class A Common Stock

Owner: Lynch Thomas P.
Date: 2026-09-17
Code: M
Action: Exercise or conversion
Quantity: 19384
Price: 8.65
Following holdings: 20,084
Reporting delay: 4 days
Filed terms and references: Filed terms
security Title: Class A Common Stock
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: M
equity Swap Involved: 0
id: F1
transaction Shares: 19384
transaction Price Per Share: 8.65
transaction Acquired Disposed Code: A
shares Owned Following Transaction: 20084
direct Or Indirect Ownership: D

Class A Common Stock

Owner: Lynch Thomas P.
Date: 2026-09-17
Code: M
Action: Exercise or conversion
Quantity: 6968
Price: 11.55
Following holdings: 27,052
Reporting delay: 4 days
Filed terms and references: Filed terms
security Title: Class A Common Stock
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: M
equity Swap Involved: 0
id: F1
transaction Shares: 6968
transaction Price Per Share: 11.55
transaction Acquired Disposed Code: A
shares Owned Following Transaction: 27052
direct Or Indirect Ownership: D

Class A Common Stock

Owner: Lynch Thomas P.
Date: 2026-09-17
Code: M
Action: Exercise or conversion
Quantity: 2920
Price: 17.12
Following holdings: 29,972
Reporting delay: 4 days
Filed terms and references: Filed terms
security Title: Class A Common Stock
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: M
equity Swap Involved: 0
id: F1
transaction Shares: 2920
transaction Price Per Share: 17.12
transaction Acquired Disposed Code: A
shares Owned Following Transaction: 29972
direct Or Indirect Ownership: D

Class A Common Stock

Owner: Lynch Thomas P.
Date: 2026-09-17
Code: M
Action: Exercise or conversion
Quantity: 5840
Price: 30.78
Following holdings: 35,812
Reporting delay: 4 days
Filed terms and references: Filed terms
security Title: Class A Common Stock
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: M
equity Swap Involved: 0
id: F1
transaction Shares: 5840
transaction Price Per Share: 30.78
transaction Acquired Disposed Code: A
shares Owned Following Transaction: 35812
direct Or Indirect Ownership: D

Class A Common Stock

Owner: Lynch Thomas P.
Date: 2026-09-17
Code: S
Action: Sale
Quantity: 19384
Price: 110.3587
Following holdings: 16,428
Reporting delay: 4 days
Filed terms and references: Filed terms
security Title: Class A Common Stock
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: S
equity Swap Involved: 0
id: F1
transaction Shares: 19384
transaction Price Per Share: 110.3587
id: F2
transaction Acquired Disposed Code: D
shares Owned Following Transaction: 16428
direct Or Indirect Ownership: D

Class A Common Stock

Owner: Lynch Thomas P.
Date: 2026-09-17
Code: S
Action: Sale
Quantity: 6968
Price: 110.2986
Following holdings: 9,460
Reporting delay: 4 days
Filed terms and references: Filed terms
security Title: Class A Common Stock
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: S
equity Swap Involved: 0
id: F1
transaction Shares: 6968
transaction Price Per Share: 110.2986
id: F3
transaction Acquired Disposed Code: D
shares Owned Following Transaction: 9460
direct Or Indirect Ownership: D

Class A Common Stock

Owner: Lynch Thomas P.
Date: 2026-09-17
Code: S
Action: Sale
Quantity: 2920
Price: 110.3083
Following holdings: 6,540
Reporting delay: 4 days
Filed terms and references: Filed terms
security Title: Class A Common Stock
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: S
equity Swap Involved: 0
id: F1
transaction Shares: 2920
transaction Price Per Share: 110.3083
id: F3
transaction Acquired Disposed Code: D
shares Owned Following Transaction: 6540
direct Or Indirect Ownership: D

Class A Common Stock

Owner: Lynch Thomas P.
Date: 2026-09-17
Code: S
Action: Sale
Quantity: 5840
Price: 110.2931
Following holdings: 700
Reporting delay: 4 days
Filed terms and references: Filed terms
security Title: Class A Common Stock
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: S
equity Swap Involved: 0
id: F1
transaction Shares: 5840
transaction Price Per Share: 110.2931
id: F2
transaction Acquired Disposed Code: D
shares Owned Following Transaction: 700
direct Or Indirect Ownership: D

Stock Option (right to buy) (derivative)

Owner: Lynch Thomas P.
Date: 2026-09-17
Code: M
Action: Exercise or conversion
Quantity: 19384
Price: 8.65
Following holdings: 48,974
Reporting delay: 4 days
Filed terms and references: Filed terms
security Title: Stock Option (right to buy)
conversion Or Exercise Price: 8.65
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: M
equity Swap Involved: 0
transaction Shares: 19384
transaction Price Per Share: 8.65
transaction Acquired Disposed Code: D
id: F4
expiration Date: 2033-01-18
underlying Security Title: Class A Common Stock
underlying Security Shares: 19384
shares Owned Following Transaction: 48974
direct Or Indirect Ownership: D

Stock Option (right to buy) (derivative)

Owner: Lynch Thomas P.
Date: 2026-09-17
Code: M
Action: Exercise or conversion
Quantity: 6968
Price: 11.55
Following holdings: 4,063
Reporting delay: 4 days
Filed terms and references: Filed terms
security Title: Stock Option (right to buy)
conversion Or Exercise Price: 11.55
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: M
equity Swap Involved: 0
transaction Shares: 6968
transaction Price Per Share: 11.55
transaction Acquired Disposed Code: D
id: F4
expiration Date: 2033-10-17
underlying Security Title: Class A Common Stock
underlying Security Shares: 6968
shares Owned Following Transaction: 4063
direct Or Indirect Ownership: D

Stock Option (right to buy) (derivative)

Owner: Lynch Thomas P.
Date: 2026-09-17
Code: M
Action: Exercise or conversion
Quantity: 2920
Price: 17.12
Following holdings: 5,417
Reporting delay: 4 days
Filed terms and references: Filed terms
security Title: Stock Option (right to buy)
conversion Or Exercise Price: 17.12
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: M
equity Swap Involved: 0
transaction Shares: 2920
transaction Price Per Share: 17.12
transaction Acquired Disposed Code: D
id: F4
expiration Date: 2034-10-16
underlying Security Title: Class A Common Stock
underlying Security Shares: 2920
shares Owned Following Transaction: 5417
direct Or Indirect Ownership: D

Stock Option (right to buy) (derivative)

Owner: Lynch Thomas P.
Date: 2026-09-17
Code: M
Action: Exercise or conversion
Quantity: 5840
Price: 30.78
Following holdings: 30,834
Reporting delay: 4 days
Filed terms and references: Filed terms
security Title: Stock Option (right to buy)
conversion Or Exercise Price: 30.78
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: M
equity Swap Involved: 0
transaction Shares: 5840
transaction Price Per Share: 30.78
transaction Acquired Disposed Code: D
id: F4
expiration Date: 2035-09-30
underlying Security Title: Class A Common Stock
underlying Security Shares: 5840
shares Owned Following Transaction: 30834
direct Or Indirect Ownership: D

Purchases, sales, grants and option exercises are different transactions. The reported code identifies the action; it does not establish a motive.

Filing context

Quantities and prices are shown in the units filed. No trade value is inferred from their product.
Lynch Thomas P.: See Remarks.
The filing reports a Rule 10b5-1 trading plan.
F1: The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on June 8, 2026.
F2: The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $110.000 to $110.970 per share, inclusive. The holder undertakes to provide, upon written request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.
F3: The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $110.000 to $110.890 per share, inclusive. The holder undertakes to provide, upon written request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.
F4: 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.

Original sources

SEC ownership filing

Prepared automatically from public filing data. Report a correction.

Security

Owner

Date

Code

Action

Quantity

Price

Following holdings

Reporting delay

Filed terms and references

Class A Common Stock

Lynch Thomas P.

2026-09-17

Exercise or conversion

19384

8.65

20,084

4 days

Filed terms

security Title: Class A Common Stock
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: M
equity Swap Involved: 0
id: F1
transaction Shares: 19384
transaction Price Per Share: 8.65
transaction Acquired Disposed Code: A
shares Owned Following Transaction: 20084
direct Or Indirect Ownership: D

Class A Common Stock

Lynch Thomas P.

2026-09-17

Exercise or conversion

6968

11.55

27,052

4 days

Filed terms

security Title: Class A Common Stock
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: M
equity Swap Involved: 0
id: F1
transaction Shares: 6968
transaction Price Per Share: 11.55
transaction Acquired Disposed Code: A
shares Owned Following Transaction: 27052
direct Or Indirect Ownership: D

Class A Common Stock

Lynch Thomas P.

2026-09-17

Exercise or conversion

2920

17.12

29,972

4 days

Filed terms

security Title: Class A Common Stock
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: M
equity Swap Involved: 0
id: F1
transaction Shares: 2920
transaction Price Per Share: 17.12
transaction Acquired Disposed Code: A
shares Owned Following Transaction: 29972
direct Or Indirect Ownership: D

Class A Common Stock

Lynch Thomas P.

2026-09-17

Exercise or conversion

5840

30.78

35,812

4 days

Filed terms

security Title: Class A Common Stock
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: M
equity Swap Involved: 0
id: F1
transaction Shares: 5840
transaction Price Per Share: 30.78
transaction Acquired Disposed Code: A
shares Owned Following Transaction: 35812
direct Or Indirect Ownership: D

Class A Common Stock

Lynch Thomas P.

2026-09-17

Sale

19384

110.3587

16,428

4 days

Filed terms

security Title: Class A Common Stock
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: S
equity Swap Involved: 0
id: F1
transaction Shares: 19384
transaction Price Per Share: 110.3587
id: F2
transaction Acquired Disposed Code: D
shares Owned Following Transaction: 16428
direct Or Indirect Ownership: D

Class A Common Stock

Lynch Thomas P.

2026-09-17

Sale

6968

110.2986

9,460

4 days

Filed terms

security Title: Class A Common Stock
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: S
equity Swap Involved: 0
id: F1
transaction Shares: 6968
transaction Price Per Share: 110.2986
id: F3
transaction Acquired Disposed Code: D
shares Owned Following Transaction: 9460
direct Or Indirect Ownership: D

Class A Common Stock

Lynch Thomas P.

2026-09-17

Sale

2920

110.3083

6,540

4 days

Filed terms

security Title: Class A Common Stock
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: S
equity Swap Involved: 0
id: F1
transaction Shares: 2920
transaction Price Per Share: 110.3083
id: F3
transaction Acquired Disposed Code: D
shares Owned Following Transaction: 6540
direct Or Indirect Ownership: D

Class A Common Stock

Lynch Thomas P.

2026-09-17

Sale

5840

110.2931

700

4 days

Filed terms

security Title: Class A Common Stock
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: S
equity Swap Involved: 0
id: F1
transaction Shares: 5840
transaction Price Per Share: 110.2931
id: F2
transaction Acquired Disposed Code: D
shares Owned Following Transaction: 700
direct Or Indirect Ownership: D

Stock Option (right to buy) (derivative)

Lynch Thomas P.

2026-09-17

Exercise or conversion

19384

8.65

48,974

4 days

Filed terms

security Title: Stock Option (right to buy)
conversion Or Exercise Price: 8.65
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: M
equity Swap Involved: 0
transaction Shares: 19384
transaction Price Per Share: 8.65
transaction Acquired Disposed Code: D
id: F4
expiration Date: 2033-01-18
underlying Security Title: Class A Common Stock
underlying Security Shares: 19384
shares Owned Following Transaction: 48974
direct Or Indirect Ownership: D

Stock Option (right to buy) (derivative)

Lynch Thomas P.

2026-09-17

Exercise or conversion

6968

11.55

4,063

4 days

Filed terms

security Title: Stock Option (right to buy)
conversion Or Exercise Price: 11.55
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: M
equity Swap Involved: 0
transaction Shares: 6968
transaction Price Per Share: 11.55
transaction Acquired Disposed Code: D
id: F4
expiration Date: 2033-10-17
underlying Security Title: Class A Common Stock
underlying Security Shares: 6968
shares Owned Following Transaction: 4063
direct Or Indirect Ownership: D

Stock Option (right to buy) (derivative)

Lynch Thomas P.

2026-09-17

Exercise or conversion

2920

17.12

5,417

4 days

Filed terms

security Title: Stock Option (right to buy)
conversion Or Exercise Price: 17.12
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: M
equity Swap Involved: 0
transaction Shares: 2920
transaction Price Per Share: 17.12
transaction Acquired Disposed Code: D
id: F4
expiration Date: 2034-10-16
underlying Security Title: Class A Common Stock
underlying Security Shares: 2920
shares Owned Following Transaction: 5417
direct Or Indirect Ownership: D

Stock Option (right to buy) (derivative)

Lynch Thomas P.

2026-09-17

Exercise or conversion

5840

30.78

30,834

4 days

Filed terms

security Title: Stock Option (right to buy)
conversion Or Exercise Price: 30.78
transaction Date: 2026-09-17
transaction Form Type: 4
transaction Code: M
equity Swap Involved: 0
transaction Shares: 5840
transaction Price Per Share: 30.78
transaction Acquired Disposed Code: D
id: F4
expiration Date: 2035-09-30
underlying Security Title: Class A Common Stock
underlying Security Shares: 5840
shares Owned Following Transaction: 30834
direct Or Indirect Ownership: D

Filing context

Quantities and prices are shown in the units filed. No trade value is inferred from their product.

Lynch Thomas P.: See Remarks.

The filing reports a Rule 10b5-1 trading plan.

F1: The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on June 8, 2026.

F2: The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $110.000 to $110.970 per share, inclusive. The holder undertakes to provide, upon written request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

F3: The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $110.000 to $110.890 per share, inclusive. The holder undertakes to provide, upon written request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

F4: 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.