LYNCH THOMAS P. (See Remarks) sold 98.0% of their position (35.11K shares) of BILLIONTOONE, INC. on the open market

Open‑market sale worth $3.87M — a major position exit. Review remaining holdings and any 10b5‑1 plan disclosures.

S · 4 sales

LYNCH THOMAS P.

Filed: 9/21/2026ACC: 0002070849-26-000069

InsiderLYNCH THOMAS P.CIK 1659824

→

IssuerBILLIONTOONE, INC.CIK 2070849

Officer· See Remarks

Since Nov 2025

-35.11K

Net shares

Net seller

$3.87M

Total sold

Open market trades

0B · 4S

Total transactions

35.11K acquired · 70.22K disposed

Non-Derivative Transactions8

Class A Common Stock

Direct

M · Option Exercise

+19.38K

Price / share

$8.65

Trade value

$167.67K

% of position

2769.1%

9/17/2026

700.00→20.08K

Class A Common Stock

Direct

M · Option Exercise

+6.97K

Price / share

$11.55

Trade value

$80.48K

% of position

34.7%

9/17/2026

20.08K→27.05K

Class A Common Stock

Direct

M · Option Exercise

+2.92K

Price / share

$17.12

Trade value

$49.99K

% of position

10.8%

9/17/2026

27.05K→29.97K

Class A Common Stock

Direct

M · Option Exercise

+5.84K

Price / share

$30.78

Trade value

$179.76K

% of position

19.5%

9/17/2026

29.97K→35.81K

Class A Common Stock

Direct

S · Sale

−19.38K

Price / share

$110.36

Trade value

$2.14M

% of position

54.1%

9/17/2026

35.81K→16.43K

Class A Common Stock

Direct

S · Sale

−6.97K

Price / share

$110.30

Trade value

$768.56K

% of position

42.4%

9/17/2026

16.43K→9.46K

Class A Common Stock

Direct

S · Sale

−2.92K

Price / share

$110.31

Trade value

$322.10K

% of position

30.9%

9/17/2026

9.46K→6.54K

Class A Common Stock

Direct

S · Sale

−5.84K

Price / share

$110.29

Trade value

$644.11K

% of position

89.3%

9/17/2026

6.54K→700.00

Total

Net shares

+0.00

Net value

-$3.40M

Security	Date	Type	Shares	Price / Share	Trade Value	% of Position	Held Before	Held After
Class A Common Stock Direct	9/17/2026	M · Option Exercise	+19.38K	$8.65	$167.67K	2769.1%	700.00	20.08K
Class A Common Stock Direct	9/17/2026	M · Option Exercise	+6.97K	$11.55	$80.48K	34.7%	20.08K	27.05K
Class A Common Stock Direct	9/17/2026	M · Option Exercise	+2.92K	$17.12	$49.99K	10.8%	27.05K	29.97K
Class A Common Stock Direct	9/17/2026	M · Option Exercise	+5.84K	$30.78	$179.76K	19.5%	29.97K	35.81K
Class A Common Stock Direct	9/17/2026	S · Sale	−19.38K	$110.36	$2.14M	54.1%	35.81K	16.43K
Class A Common Stock Direct	9/17/2026	S · Sale	−6.97K	$110.30	$768.56K	42.4%	16.43K	9.46K
Class A Common Stock Direct	9/17/2026	S · Sale	−2.92K	$110.31	$322.10K	30.9%	9.46K	6.54K
Class A Common Stock Direct	9/17/2026	S · Sale	−5.84K	$110.29	$644.11K	89.3%	6.54K	700.00
Total			+0.00		-$3.40M

Derivative Transactions4

Stock Option (right to buy)

Direct

M · Option Exercise

Converts to

Class A Common Stock

19.38K shares

−19.38K

Strike price

8.65

Held after

48.97K

Exercisable

—

9/17/2026

Stock Option (right to buy)

Direct

M · Option Exercise

Converts to

Class A Common Stock

6.97K shares

−6.97K

Strike price

11.55

Held after

4.06K

Exercisable

—

9/17/2026

Stock Option (right to buy)

Direct

M · Option Exercise

Converts to

Class A Common Stock

2.92K shares

−2.92K

Strike price

17.12

Held after

5.42K

Exercisable

—

9/17/2026

Stock Option (right to buy)

Direct

M · Option Exercise

Converts to

Class A Common Stock

5.84K shares

−5.84K

Strike price

30.78

Held after

30.83K

Exercisable

—

9/17/2026

Security	Converts To	Date	Type	Shares	Strike Price	Exercisable	Held After
Stock Option (right to buy) Direct	Class A Common Stock19.38K shares	9/17/2026	M · Option Exercise	−19.38K	8.65	—	48.97K
Stock Option (right to buy) Direct	Class A Common Stock6.97K shares	9/17/2026	M · Option Exercise	−6.97K	11.55	—	4.06K
Stock Option (right to buy) Direct	Class A Common Stock2.92K shares	9/17/2026	M · Option Exercise	−2.92K	17.12	—	5.42K
Stock Option (right to buy) Direct	Class A Common Stock5.84K shares	9/17/2026	M · Option Exercise	−5.84K	30.78	—	30.83K