BillionToOne, Inc. (BLLN) CEO reports 45,000-share sale, option exercise

Q: How many BillionToOne (BLLN) options did Atay Oguzhan exercise and at what price?

Atay Oguzhan exercised stock options covering 32,500 shares of BillionToOne (BLLN) Class A Common Stock at an exercise price of $2.80 per share . The underlying options were fully vested, exercisable, and carried an expiration date of 2031-06-07 at the time of exercise.

Filing Impact

(Very High)

Filing Sentiment

(Very Negative)

Form Type

Rhea-AI Filing Summary

BillionToOne, Inc. Chairman and CEO Atay Oguzhan reported multiple equity transactions in Class A Common Stock. On August 3, 2026 he exercised stock options to acquire 32,500 shares at $2.80 per share from fully vested awards expiring 2031-06-07, and reported sales totaling 45,000 shares in numerous trades at weighted average prices between $132.500 and $139.500 per share, including shares held by his spouse. All transactions were effected under a Rule 10b5-1 trading plan adopted March 6, 2026.

Insights

Analyzing...

Insider Trade Summary 10b5-1

Exercise and sale activity reported; no spread calculated

Exercise and Sale 29 txns

Insider Atay Oguzhan

Role Chairman and CEO

Sold 45,000 shs ($6.17M)

Approx. gross sale proceeds $6.17M

Approx. exercise cost $91K

Type	Security	Shares	Price	Value
Exercise	Stock Option (right to buy) ^F10	20,000	$2.80	$56K
Exercise	Stock Option (right to buy) ^F10	6,250	$2.80	$18K
Exercise	Stock Option (right to buy) ^F10	6,250	$2.80	$18K
Exercise	Class A Common Stock ^F1	20,000	$2.80	$56K
Exercise	Class A Common Stock ^F1	6,250	$2.80	$18K
Exercise	Class A Common Stock ^F1	6,250	$2.80	$18K
Sale	Class A Common Stock ^{F1, F2}	269	$133.0074	$36K
Sale	Class A Common Stock ^{F1, F3}	555	$133.8083	$74K
Sale	Class A Common Stock ^{F1, F4}	135	$135.4241	$18K
Sale	Class A Common Stock ^{F1, F5}	6,354	$136.4246	$867K
Sale	Class A Common Stock ^{F1, F6}	9,989	$137.2456	$1.37M
Sale	Class A Common Stock ^{F1, F7}	2,431	$138.0892	$336K
Sale	Class A Common Stock ^{F1, F8}	267	$139.2052	$37K
Sale	Class A Common Stock ^{F1, F2}	84	$133.0045	$11K
Sale	Class A Common Stock ^{F1, F3}	173	$133.8076	$23K
Sale	Class A Common Stock ^{F1, F4}	44	$135.4122	$6K
Sale	Class A Common Stock ^{F1, F5}	1,981	$136.4246	$270K
Sale	Class A Common Stock ^{F1, F6}	3,124	$137.2453	$429K
Sale	Class A Common Stock ^{F1, F7}	762	$138.0897	$105K
Sale	Class A Common Stock ^{F1, F8}	82	$139.209	$11K
Sale	Class A Common Stock ^{F1, F2}	84	$133.0096	$11K
Sale	Class A Common Stock ^{F1, F3}	173	$133.8076	$23K
Sale	Class A Common Stock ^{F1, F4}	43	$135.4088	$6K
Sale	Class A Common Stock ^{F1, F5}	1,983	$136.424	$271K
Sale	Class A Common Stock ^{F1, F6}	3,125	$137.2457	$429K
Sale	Class A Common Stock ^{F1, F7}	760	$138.0901	$105K
Sale	Class A Common Stock ^{F1, F8}	82	$139.2042	$11K
Sale	Class A Common Stock ^{F1, F9}	6,250	$137.37	$859K
Sale	Class A Common Stock ^{F1, F9}	6,250	$137.37	$859K

Holdings After Transaction: Stock Option (right to buy) — 542,500 shares (Direct); Class A Common Stock — 0 shares (Direct); Class A Common Stock — 162,500 shares (Indirect, By spouse)

Footnotes (10)

F1. The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 6, 2026.
F2. The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $132.500 to $133.470 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 $133.510 to $133.9525 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 reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $134.6675 to $135.650 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.
F5. The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $135.745 to $136.740 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.
F6. The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $136.750 to $137.740 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.
F7. The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $137.750 to $138.740 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.
F8. The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $138.890 to $139.500 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.
F9. Represents shares held by the Reporting Person's spouse.
F10. The options are fully vested and exercisable.

Key Figures

Shares sold: 45,000 shares Shares acquired via option exercise: 32,500 shares Option exercise price: $2.80 per share +3 more

6 metrics

Shares sold 45,000 shares Total Class A Common Stock sales reported on 2026-08-03

Shares acquired via option exercise 32,500 shares Class A Common Stock from stock option exercises on 2026-08-03

Option exercise price $2.80 per share Exercise price for stock options converting into Class A Common Stock

Sale price range $132.500–$139.500 per share Weighted average sale price ranges across multiple transactions

Rule 10b5-1 plan adoption date March 6, 2026 Date the CEO adopted the trading plan governing these trades

Option expiration date 2031-06-07 Expiration date for the exercised stock options

Key Terms

Rule 10b5-1 trading plan, weighted average price, Stock Option (right to buy), Class A Common Stock

4 terms

Rule 10b5-1 trading plan regulatory

"The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

weighted average price financial

"The reported price in Column 4 is a weighted average price."

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

Stock Option (right to buy) financial

"security_title: Stock Option (right to buy)"

Class A Common Stock financial

"underlying_security_title: Class A Common Stock"

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.

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

See more from StockTitan in Google Search and AI answers. Adds StockTitan as a preferred source · opens Google

Add on Google

Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 08/05/2026 - 08:53 PM Accepted by SEC EDGAR 08/05/2026 - 08:52 PM

FAQ

What insider transactions did BillionToOne (BLLN) report on August 3, 2026?

BillionToOne (BLLN) reported that CEO Atay Oguzhan exercised stock options for 32,500 shares at $2.80 and reported sales totaling 45,000 Class A shares. The sales occurred in multiple trades at weighted average prices between $132.500 and $139.500 per share.

How many BillionToOne (BLLN) options did Atay Oguzhan exercise and at what price?

Atay Oguzhan exercised stock options covering 32,500 shares of BillionToOne (BLLN) Class A Common Stock at an exercise price of $2.80 per share. The underlying options were fully vested, exercisable, and carried an expiration date of 2031-06-07 at the time of exercise.

At what prices were BillionToOne (BLLN) shares sold in the CEO’s August 2026 trades?

Reported BillionToOne (BLLN) share sales used weighted average prices ranging from $132.500 to $139.500 per share. Individual trades occurred within narrower bands disclosed in footnotes, each covering specific price intervals inside that overall range across several transaction groups.

Were the BillionToOne (BLLN) insider trades executed under a Rule 10b5-1 plan?

Yes. All reported BillionToOne (BLLN) transactions were effected under a Rule 10b5-1 trading plan adopted by Atay Oguzhan on March 6, 2026. The filing also checks the Rule 10b5-1 box, confirming the use of a pre-arranged trading plan for these trades.

Did any BillionToOne (BLLN) insider transactions involve shares held by the CEO’s spouse?

Yes. Certain BillionToOne (BLLN) sales involved shares held by the reporting person’s spouse. Two transactions each covered 6,250 shares of Class A Common Stock at a reported weighted average price of $137.370 per share, classified as indirect ownership by spouse.

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^*

Atay Oguzhan

(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)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
08/03/2026

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Class A Common Stock	08/03/2026		M⁽¹⁾		20,000	A	$2.8	20,000	D
Class A Common Stock	08/03/2026		M⁽¹⁾		6,250	A	$2.8	26,250	D
Class A Common Stock	08/03/2026		M⁽¹⁾		6,250	A	$2.8	32,500	D
Class A Common Stock	08/03/2026		S⁽¹⁾		269	D	$133.0074⁽²⁾	32,231	D
Class A Common Stock	08/03/2026		S⁽¹⁾		555	D	$133.8083⁽³⁾	31,676	D
Class A Common Stock	08/03/2026		S⁽¹⁾		135	D	$135.4241⁽⁴⁾	31,541	D
Class A Common Stock	08/03/2026		S⁽¹⁾		6,354	D	$136.4246⁽⁵⁾	25,187	D
Class A Common Stock	08/03/2026		S⁽¹⁾		9,989	D	$137.2456⁽⁶⁾	15,198	D
Class A Common Stock	08/03/2026		S⁽¹⁾		2,431	D	$138.0892⁽⁷⁾	12,767	D
Class A Common Stock	08/03/2026		S⁽¹⁾		267	D	$139.2052⁽⁸⁾	12,500	D
Class A Common Stock	08/03/2026		S⁽¹⁾		84	D	$133.0045⁽²⁾	12,416	D
Class A Common Stock	08/03/2026		S⁽¹⁾		173	D	$133.8076⁽³⁾	12,243	D
Class A Common Stock	08/03/2026		S⁽¹⁾		44	D	$135.4122⁽⁴⁾	12,199	D
Class A Common Stock	08/03/2026		S⁽¹⁾		1,981	D	$136.4246⁽⁵⁾	10,218	D
Class A Common Stock	08/03/2026		S⁽¹⁾		3,124	D	$137.2453⁽⁶⁾	7,094	D
Class A Common Stock	08/03/2026		S⁽¹⁾		762	D	$138.0897⁽⁷⁾	6,332	D
Class A Common Stock	08/03/2026		S⁽¹⁾		82	D	$139.209⁽⁸⁾	6,250	D
Class A Common Stock	08/03/2026		S⁽¹⁾		84	D	$133.0096⁽²⁾	6,166	D
Class A Common Stock	08/03/2026		S⁽¹⁾		173	D	$133.8076⁽³⁾	5,993	D
Class A Common Stock	08/03/2026		S⁽¹⁾		43	D	$135.4088⁽⁴⁾	5,950	D
Class A Common Stock	08/03/2026		S⁽¹⁾		1,983	D	$136.424⁽⁵⁾	3,967	D
Class A Common Stock	08/03/2026		S⁽¹⁾		3,125	D	$137.2457⁽⁶⁾	842	D
Class A Common Stock	08/03/2026		S⁽¹⁾		760	D	$138.0901⁽⁷⁾	82	D
Class A Common Stock	08/03/2026		S⁽¹⁾		82	D	$139.2042⁽⁸⁾	0	D
Class A Common Stock	08/03/2026		S⁽¹⁾		6,250	D	$137.37	168,750	I	By spouse⁽⁹⁾
Class A Common Stock	08/03/2026		S⁽¹⁾		6,250	D	$137.37	162,500	I	By spouse⁽⁹⁾

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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Stock Option (right to buy)	$2.8	08/03/2026		M			20,000	⁽¹⁰⁾	06/07/2031	Class A Common Stock	20,000	$2.8	555,000	D
Stock Option (right to buy)	$2.8	08/03/2026		M			6,250	⁽¹⁰⁾	06/07/2031	Class A Common Stock	6,250	$2.8	548,750	D
Stock Option (right to buy)	$2.8	08/03/2026		M			6,250	⁽¹⁰⁾	06/07/2031	Class A Common Stock	6,250	$2.8	542,500	D

Explanation of Responses:

1. The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 6, 2026.

2. The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $132.500 to $133.470 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.

3. The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $133.510 to $133.9525 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.

4. The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $134.6675 to $135.650 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.

5. The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $135.745 to $136.740 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.

6. The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $136.750 to $137.740 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.

7. The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $137.750 to $138.740 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.

8. The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $138.890 to $139.500 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.

9. Represents shares held by the Reporting Person's spouse.

10. The options are fully vested and exercisable.

Remarks:

	/s/ Thomas P. Lynch, Attorney-in-Fact	08/05/2026
	** 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)

Source: View Original Filing on SEC EDGAR