BillionToOne (NASDAQ: BLLN) CFO discloses 250K stock options and IPO reclassification

Rhea-AI Filing Summary

BillionToOne, Inc. (BLLN) filed a Form 4 reporting equity award activity for its Chief Financial Officer. The filing shows stock options with exercise prices of $11.55 and $30.78 covering 175,000 and 75,000 shares, respectively. These options are listed both before and after a reclassification in connection with the company’s initial public offering of Class A common stock.

The filing explains that, under a reclassification exempt under Rule 16b-7, each share of Common Stock was automatically converted into one share of Class A common stock immediately prior to completion of the IPO. The $11.55 options vest over four years, with 25% vested on January 8, 2025 and the rest in monthly installments over three years. The $30.78 options vest in equal monthly installments over four years starting September 15, 2025, contingent on continued service.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Taylor Ross

(Last) (First) (Middle)

C/O BILLIONTOONE, INC.

1035 O'BRIEN DRIVE

(Street)

MENLO PARK CA 94025

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
BillionToOne, Inc. [ BLLN ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Financial Officer

3. Date of Earliest Transaction (Month/Day/Year)
11/07/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (right to buy)	$11.55	11/07/2025		J(1)			175,000	(2)	01/13/2034	Common Stock	175,000	(1)	0	D
Stock Option (right to buy)	$11.55	11/07/2025		J(1)		175,000		(2)	01/13/2034	Class A Common Stock	175,000	(1)	175,000	D
Stock Option (right to buy)	$30.78	11/07/2025		J(1)			75,000	(3)	09/30/2035	Common Stock	75,000	(1)	0	D
Stock Option (right to buy)	$30.78	11/07/2025		J(1)		75,000		(3)	09/30/2035	Class A Common Stock	75,000	(1)	75,000	D

Explanation of Responses:

1. 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.

2. The options are subject to a service-based vesting requirement, which shall be satisfied over a four-year period. Twenty-five percent of the options vested on January 8, 2025. The remaining 75% vest and become exercisable in equal monthly installments over the following three years, subject to the Reporting Person's continuous service with the Issuer through each such vesting date.

3. 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.

	/s/ Thomas P. Lynch, Attorney-in-Fact	11/12/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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FAQ

What does the BillionToOne (BLLN) Form 4 report for the CFO?

The Form 4 reports stock option activity for BillionToOne’s Chief Financial Officer, including options over 175,000 shares at $11.55 and 75,000 shares at $30.78, and their treatment in a reclassification tied to the company’s IPO.

How many BillionToOne (BLLN) shares are covered by the reported options?

The reported options cover 175,000 shares at an exercise price of $11.55 and 75,000 shares at an exercise price of $30.78, each linked to Class A common stock after reclassification.

What is the reclassification mentioned in the BillionToOne (BLLN) Form 4?

The Form 4 states that, under 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 completion of BillionToOne’s initial public offering of Class A common stock.

How do the $11.55 options for BillionToOne’s CFO vest?

The $11.55 options are subject to a four-year service-based vesting schedule, with 25% vested on January 8, 2025 and the remaining 75% vesting in equal monthly installments over the following three years, conditioned on continuous service.

What is the vesting schedule for the $30.78 options reported by BillionToOne (BLLN)?

The $30.78 options vest and become exercisable in equal monthly installments over four years, commencing on September 15, 2025, as long as the CFO continues service with BillionToOne through each vesting date.

Does the BillionToOne (BLLN) Form 4 indicate direct or indirect ownership of the options?

The Form 4 shows the reported derivative securities as held with direct ownership, as indicated by the ownership code "D" in the derivative securities table.