BillionToOne (BLLN) director granted 3,017 RSUs with service-based vesting

Rhea-AI Filing Summary

Rai Akshay reported acquisition or exercise transactions in this Form 4 filing.

BillionToOne, Inc. director Akshay Rai received a grant of 3,017 restricted stock units (RSUs) linked to Class A Common Stock. Each RSU represents a right to receive one share for no cash payment. The RSUs vest when a service-based condition is met, on the earlier of the next annual stockholder meeting or the one-year anniversary of June 10, 2026. Following this equity award, Rai directly holds 14,026 shares of Class A Common Stock.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider Rai Akshay

Role null

Type	Security	Shares	Price	Value
Grant/Award	Class A Common Stock	3,017	$0.00	--

Holdings After Transaction: Class A Common Stock — 14,026 shares (Direct, null)

Footnotes (1)

1. [object Object]

Key Figures

RSUs granted: 3,017 RSUs Grant price per share: $0.00 per share Shares held after grant: 14,026 shares

3 metrics

RSUs granted 3,017 RSUs Equity award to director Akshay Rai in Class A Common Stock

Grant price per share $0.00 per share Stated price for each RSU linked to Class A Common Stock

Shares held after grant 14,026 shares Akshay Rai’s direct Class A Common Stock holdings following the RSU award

Key Terms

restricted stock units (RSUs), service-based vesting requirement, Class A Common Stock

3 terms

restricted stock units (RSUs) financial

"The Reporting Person was granted restricted stock units (RSUs), which represent a contingent right to receive one share"

Restricted stock units (RSUs) are a type of company promise to give employees shares of stock in the future, usually after certain conditions like working for a set time. They are like a gift promised today that you receive later, which can become valuable if the company's stock price goes up. RSUs matter because they are a way companies reward employees and can be a significant part of compensation.

service-based vesting requirement financial

"The RSUs are subject to a service-based vesting requirement, which shall be satisfied on the earlier"

Class A Common Stock financial

"one share of Class A common stock for each RSU"

Class A common stock is a category of a company’s shares that carries a specific set of ownership rights—most commonly defined voting power and claims on dividends—set out in the company’s charter. For investors it matters because the class determines how much influence you have over corporate decisions, the share’s likely dividend and trading behavior, and how it compares in value to other share classes, like choosing a particular seat with different privileges at the company’s decision-making table.

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Form 4 Insider Transactions: What Each Field Means →

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

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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^*

Rai Akshay

(Last) (First) (Middle)

2180 SAND HILL ROAD, STE. 100

(Street)

MENLO PARK CALIFORNIA 94025

(City) (State) (Zip)

UNITED STATES

(Country)

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

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/10/2026

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

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

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

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
Class A Common Stock	06/10/2026		A		3,017(1)	A	$0	14,026	D

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

Explanation of Responses:

1. The Reporting Person was granted restricted stock units (RSUs), which represent a contingent right to receive one share of Class A common stock for each RSU. The RSUs are subject to a service-based vesting requirement, which shall be satisfied on the earlier of (A) the date of the next annual meeting of stockholders, or (B) the one-year anniversary of June 10, 2026.

Remarks:

	/s/ Thomas P. Lynch, Attorney-in-Fact	06/11/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What insider transaction did BillionToOne (BLLN) disclose for Akshay Rai?

BillionToOne reported that director Akshay Rai received 3,017 restricted stock units (RSUs) tied to Class A Common Stock. These RSUs were granted at no cash cost and increase his direct ownership to 14,026 Class A shares after the award.

How many BillionToOne (BLLN) shares does Akshay Rai hold after this grant?

After the RSU grant, Akshay Rai directly holds 14,026 shares of BillionToOne Class A Common Stock. This figure reflects his updated position, including the 3,017 RSUs, which each entitle him to receive one share when they vest under the service condition.

What are the vesting terms of Akshay Rai’s BillionToOne (BLLN) RSU grant?

The RSUs vest upon satisfying a service-based requirement that is met on the earlier of the company’s next annual stockholder meeting or the one-year anniversary of June 10, 2026. Vesting determines when each RSU converts into one Class A Common share.

Is Akshay Rai’s BillionToOne (BLLN) RSU grant an open-market purchase?

No, the 3,017 RSUs granted to Akshay Rai are a compensation-related equity award, not an open-market stock purchase. The units were granted at a stated price of $0.00 per share and vest over time based on continued service conditions.

What type of security did Akshay Rai receive from BillionToOne (BLLN)?

Akshay Rai received restricted stock units (RSUs) that correspond to Class A Common Stock of BillionToOne. Each RSU represents a contingent right to one Class A share, subject to a service-based vesting requirement tied to future dates and stockholder meeting timing.