BillionToOne CPO gifts 3,500 shares of stock

BillionToOne’s Chief Product Officer reported a bona fide gift of 3,500 BLLN shares, leaving 196,500 shares held directly afterward.

Rhea-AI Filing Summary

BillionToOne, Inc. (BLLN) reported that Chief Product Officer Shan Riku Sakakibara made a bona fide gift transfer of 3,500 shares of Class A Common Stock on September 10, 2026. No price was paid for the gift, and Sakakibara now holds 196,500 shares directly. No Rule 10b5-1 trading plan is reported.

Insider Trade Summary

3,500 shares gifted

Gift 1 txn

Insider Sakakibara Shan Riku

Role Chief Product Officer

Type	Security	Shares	Price	Value
Gift	Class A Common Stock	3,500	$0.00	$0.00

Holdings After Transaction: Class A Common Stock — 196,500 shares (Direct)

Key Figures

Shares gifted: 3,500 shares Price per share for gift: $0.00 per share Shares held after transaction: 196,500 shares

3 metrics

Shares gifted 3,500 shares Bona fide gift of Class A Common Stock on September 10, 2026

Price per share for gift $0.00 per share Reported consideration for the bona fide gift transfer

Shares held after transaction 196,500 shares Direct holdings of Class A Common Stock after the gift

Key Terms

bona fide gift, Class A Common Stock, Rule 10b5-1

3 terms

bona fide gift financial

"The transaction code is described as a bona fide gift transfer"

A bona fide gift is a genuine, voluntary transfer of money, property, or benefits from one party to another made without expectation of repayment, services, or hidden conditions. Investors care because such gifts can affect company disclosures, related‑party transaction rules, tax treatment, and perceived conflicts of interest; think of it like someone giving you a present with no strings attached — but on a corporate scale, auditors and regulators need to verify it really is unconditional.

Class A Common Stock financial

"The security involved is Class A Common Stock of BillionToOne, Inc."

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.

Rule 10b5-1 regulatory

"No Rule 10b5-1 trading plan is reported for this transaction"

Rule 10b5-1 is a regulation that allows company insiders to buy or sell their shares at predetermined times, even if they have access to non-public information. It acts like setting a schedule in advance for transactions, helping prevent accusations of unfair trading. This rule provides a way for insiders to plan trades transparently, giving investors confidence that these transactions are not based on hidden information.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction did BLLN report for Shan Riku Sakakibara?

The filing reports a bona fide gift transfer of 3,500 shares of BillionToOne, Inc. Class A Common Stock by Chief Product Officer Shan Riku Sakakibara on September 10, 2026, with no price paid per share for the gift.

How many BLLN shares were gifted in this Form 4?

Chief Product Officer Shan Riku Sakakibara gifted 3,500 shares of BillionToOne, Inc. Class A Common Stock. The transaction code is reported as a bona fide gift, and the per-share price is listed as $0.00, consistent with a non-cash transfer.

How many BLLN shares does the insider hold after the reported gift?

After the bona fide gift of 3,500 shares, Shan Riku Sakakibara is reported to hold 196,500 shares of BillionToOne, Inc. Class A Common Stock. These holdings are described as direct ownership in the Form 4 data.

Was the BLLN insider gift made under a Rule 10b5-1 trading plan?

No. The filing’s Rule 10b5-1 checkbox is not marked as an affirmative plan, and no footnote indicates a plan. The gift of 3,500 shares is therefore reported as not made under a Rule 10b5-1 trading plan.

What is the role of the insider involved in this BLLN Form 4?

The reporting person, Shan Riku Sakakibara, is identified as Chief Product Officer of BillionToOne, Inc. in the Form 4. The reported transaction is a bona fide gift of Class A Common Stock held in direct ownership.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/14/2026 - 06:47 PM Accepted by SEC EDGAR 09/14/2026 - 06:47 PM Learn about SEC filing dates

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^*

Sakakibara Shan Riku

(Last) (First) (Middle)

C/O BILLIONTOONE, INC.

1035 O'BRIEN DRIVE

(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)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/10/2026

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	09/10/2026		G		3,500	D	$0	196,500	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:

Remarks:

	/s/ Thomas P. Lynch, Attorney-in-Fact	09/14/2026
	** 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)