Initial Statement of Beneficial Ownership (Form 3)

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES 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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(Print or Type Responses)

1. Name and Address of Reporting Person * NeoTribe Ventures I, L.P. 2. Date of Event Requiring Statement (Month/Day/Year) 11/05/2025 3. Issuer Name and Ticker or Trading Symbol BillionToOne, Inc. [BLLN] (Last) (First) (Middle) 1300 EL CAMINO REAL, SUITE 100 4. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) 5. If Amendment, Date Original Filed (Month/Day/Year) (Street) MENLO PARK, CA 94025 6. Individual or Joint/Group Filing (Check Applicable Line) ___ Form filed by One Reporting Person _X_ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Beneficially Owned

1.Title of Security (Instr. 4) 2. Amount of Securities Beneficially Owned (Instr. 4) 3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5) 4. Nature of Indirect Beneficial Ownership (Instr. 5) Common Stock(1) 119,999 I See footnote(2)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.			SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Series B-1 Convertible Preferred Stock	(3)	(3)	Common Stock(1)	1,177,800	(3)	I	See footnote(2)
Series C Convertible Preferred Stock	(3)	(3)	Common Stock(1)	242,216	(3)	I	See footnote(4)
Series A-1 Convertible Preferred Stock	(3)	(3)	Common Stock(1)	16,746(5)	(3)	D(6)
Series A-3 Convertible Preferred Stock	(3)	(3)	Common Stock(1)	19,985(7)	(3)	D(6)
Series A-6 Convertible Preferred Stock	(3)	(3)	Common Stock(1)	2,318,482(8)	(3)	D(6)
Series B-2 Convertible Preferred Stock	(3)	(3)	Common Stock(1)	320,363(9)	(3)	D(6)
Series C-1 Convertible Preferred Stock	(3)	(3)	Common Stock(1)	143,914(10)	(3)	D(6)

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
NeoTribe Ventures I, L.P. 1300 EL CAMINO REAL, SUITE 100 MENLO PARK, CA 94025		X
Neotribe Ignite Fund I, L.P. 1300 EL CAMINO REAL, SUITE 100 MENLO PARK, CA 94025		X
Neotribe SPV I BTO, LLC 1300 EL CAMINO REAL, SUITE 100 MENLO PARK, CA 94025		X
NeoTribe Associates I, L.P. 1300 EL CAMINO REAL, SUITE 100 MENLO PARK, CA 94025		X
Neotribe Ignite Partners I, LLC 1300 EL CAMINO REAL, SUITE 100 MENLO PARK, CA 94025		X
Neotribe Partners SPV I BTO, LLC 1300 EL CAMINO REAL, SUITE 100 MENLO PARK, CA 94025		X
NeoTribe Partners I, LLC 1300 EL CAMINO REAL, SUITE 100 MENLO PARK, CA 94025		X

Signatures

NeoTribe Ventures I, L.P., by: NeoTribe Partners I, LLC, its general partner, by: /s/ Krishna Kolluri, Managing Member		11/05/2025
**Signature of Reporting Person		Date
NeoTribe Associates I, L.P., by: NeoTribe Partners I, LLC, its general partner, by: /s/ Krishna Kolluri, Managing Member		11/05/2025
**Signature of Reporting Person		Date
Neotribe Ignite Fund I, L.P., by: Neotribe Ignite Partners I, LLC, its general partner, by: /s/ Krishna Kolluri, Managing Member		11/05/2025
**Signature of Reporting Person		Date
Neotribe SPV I BTO, LLC, by: Neotribe Partners SPV I BTO, LLC, its managing member, by: /s/ Krishna Kolluri, Managing Member		11/05/2025
**Signature of Reporting Person		Date
NeoTribe Partners I, LLC, by: /s/ Krishna Kolluri, Managing Member		11/05/2025
**Signature of Reporting Person		Date
Neotribe Ignite Partners I, LLC, by: /s/ Krishna Kolluri, Managing Member		11/05/2025
**Signature of Reporting Person		Date
Neotribe Partners SPV I BTO, LLC, by: /s/ Krishna Kolluri, Managing Member		11/05/2025
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 5(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).
(1)	Immediately prior to the completion of the Issuer's initial public offering of Class A common stock (the "Offering"), each share of Common Stock shall be reclassified into one share of Class A common stock.
(2)	The reported security is directly held by Neotribe Ignite Fund I, L.P. ("NTIF I"). Neotribe Ignite Partners I, LLC ("NTIP I") is the general partner of NTIF I. Krishna Kittu Kolluri ("Kolluri") is the managing member of NTIP I and therefore may be deemed to have voting and dispositive power over the shares held by NTIF I. Kolluri disclaims beneficial ownership of the shares held by NTIF I except to the extent of his pecuniary interest therein.
(3)	The reported security is convertible into the Issuer's Common Stock on a one-for-one basis at any time at the holder's election and shall automatically convert into Class A common stock immediately prior to the closing of the Offering without payment of further consideration. The shares have no expiration date.
(4)	The reported security is directly held by Neotribe SPV I BTO, LLC ("NT SPV I"). Neotribe Partners SPV I BTO, LLC ("NTP SPV I") is the managing member of NT SPV I. Kolluri is the managing member of NTP SPV I and therefore may be deemed to have voting and dispositive power over the shares held by NT SPV I. Kolluri disclaims beneficial ownership of the shares held by NT SPV I except to the extent of his pecuniary interest therein.
(5)	Consists of 16,098 shares held of record by NTV I for itself and 648 shares held of record by NTV I as nominee for NTA I.
(6)	The reported security is directly held by NeoTribe Ventures I, L.P. ("NTV I"), for itself and as nominee for NeoTribe Associates I, L.P. ("NTA I"). NeoTribe Partners I, LLC ("NTP I") is the general partner of NTV I and NTA I. Kolluri is the managing member of NTP I and therefore may be deemed to hold voting and dispositive power over the shares held by NTV I and NTA I. Kolluri disclaims beneficial ownership of the shares held by NTV I and NTA I except to the extent of his pecuniary interest therein
(7)	Consists of 19,211 shares held of record by NTV I for itself and 774 shares held of record by NTV I as nominee for NTA I.
(8)	Consists of 2,228,682 shares held of record by NTV I for itself and 89,800 shares held of record by NTV I as nominee for NTA I.
(9)	Consists of 307,955 shares held of record by NTV I for itself and 12,408 shares held of record by NTV I as nominee for NTA I.
(10)	Consists of 138,340 shares held of record by NTV I for itself and 5,574 shares held of record by NTV I as nominee for NTA I.
Remarks: This Form 3 is one of two Form 3s filed on the date hereof in respect of these shares. The Reporting Person for the other Form 3 is Krishna Kittu Kolluri.

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