Firat Ileri - 06 Nov 2025 Form 4 Insider Report for BillionToOne, Inc.

Signature
/s/ Thomas P. Lynch, Attorney-in-Fact
Issuer symbol
BLLN on Nasdaq
Transactions as of
06 Nov 2025
Net transactions value
$0
Form type
4
Filing time
10 Nov 2025, 21:38:58 UTC
Previous filing
05 Nov 2025

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Ileri Firat Director, 10%+ Owner SQUARE VICTORIA REGAIN 1, SINT-JOOST-TEN-NODE, BELGIUM /s/ Thomas P. Lynch, Attorney-in-Fact 10 Nov 2025 0002087908

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction BLLN Common Stock Award $0 +8,333 $0.000000 8,333 06 Nov 2025 Direct F1
transaction BLLN Common Stock Conversion of derivative security +28,981 +348% 37,314 07 Nov 2025 Direct F2, F3
transaction BLLN Common Stock Conversion of derivative security +640,727 640,727 07 Nov 2025 See Footnotes F2, F3, F4, F9
transaction BLLN Common Stock Conversion of derivative security +18,845 18,845 07 Nov 2025 See Footnotes F2, F3, F5, F9
transaction BLLN Common Stock Conversion of derivative security +2,015,118 2,015,118 07 Nov 2025 See Footnotes F2, F3, F6, F9
transaction BLLN Common Stock Conversion of derivative security +2,451,665 +1362% 2,631,664 07 Nov 2025 See Footnotes F2, F3, F7, F9
transaction BLLN Common Stock Conversion of derivative security +2,580,833 2,580,833 07 Nov 2025 See Footnotes F2, F3, F8, F9
transaction BLLN Common Stock Other -37,314 -100% 0 07 Nov 2025 Direct F10
transaction BLLN Common Stock Other -640,727 -100% 0 07 Nov 2025 See Footnotes F4, F9, F10
transaction BLLN Common Stock Other -18,845 -100% 0 07 Nov 2025 See Footnotes F5, F9, F10
transaction BLLN Common Stock Other -2,015,118 -100% 0 07 Nov 2025 See Footnotes F6, F9, F10
transaction BLLN Common Stock Other -2,631,664 -100% 0 07 Nov 2025 See Footnotes F7, F9, F10
transaction BLLN Common Stock Other -2,580,833 -100% 0 07 Nov 2025 See Footnotes F8, F9, F10
transaction BLLN Class A Common Stock Other +37,314 37,314 07 Nov 2025 Direct F10
transaction BLLN Class A Common Stock Other +640,727 640,727 07 Nov 2025 See Footnotes F4, F9, F10
transaction BLLN Class A Common Stock Other +18,845 18,845 07 Nov 2025 See Footnotes F5, F9, F10
transaction BLLN Class A Common Stock Other +2,015,118 2,015,118 07 Nov 2025 See Footnotes F6, F9, F10
transaction BLLN Class A Common Stock Other +2,631,664 2,631,664 07 Nov 2025 See Footnotes F7, F9, F10
transaction BLLN Class A Common Stock Other +2,580,833 2,580,833 07 Nov 2025 See Footnotes F8, F9, F10

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction BLLN Series A-6 Convertible Preferred Stock Conversion of derivative security -28,981 -100% 0 07 Nov 2025 Common Stock 28,981 Direct F3
transaction BLLN Series B-2 Convertible Preferred Stock Conversion of derivative security -640,727 -100% 0 07 Nov 2025 Common Stock 640,727 See Footnotes F3, F4, F9
transaction BLLN Series B-1 Convertible Preferred Stock Conversion of derivative security -18,845 -100% 0 07 Nov 2025 Common Stock 18,845 See Footnotes F3, F5, F9
transaction BLLN Series C Convertible Preferred Stock Conversion of derivative security -1,569,015 -100% 0 07 Nov 2025 Common Stock 1,569,015 See Footnotes F3, F6, F9
transaction BLLN Series D Convertible Preferred Stock Conversion of derivative security -446,103 -100% 0 07 Nov 2025 Common Stock 446,103 See Footnotes F3, F6, F9
transaction BLLN Series A-1 Convertible Preferred Stock Conversion of derivative security -20,000 -100% 0 07 Nov 2025 Common Stock 20,000 See Footnotes F3, F7, F9
transaction BLLN Series A-2 Convertible Preferred Stock Conversion of derivative security -33,000 -100% 0 07 Nov 2025 Common Stock 33,000 See Footnotes F3, F7, F9
transaction BLLN Series B-1 Convertible Preferred Stock Conversion of derivative security -2,261,377 -100% 0 07 Nov 2025 Common Stock 2,261,377 See Footnotes F3, F7, F9
transaction BLLN Series C Convertible Preferred Stock Conversion of derivative security -137,288 -100% 0 07 Nov 2025 Common Stock 137,288 See Footnotes F3, F7, F9
transaction BLLN Series A-6 Convertible Preferred Stock Conversion of derivative security -2,260,520 -100% 0 07 Nov 2025 Common Stock 2,260,520 See Footnotes F3, F8, F9
transaction BLLN Series B-2 Convertible Preferred Stock Conversion of derivative security -320,363 -100% 0 07 Nov 2025 Common Stock 320,363 See Footnotes F3, F8, F9
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 Each restricted stock unit ("RSU") represents a contingent right to receive one share of the Issuer's Common Stock. The RSUs shall vest over three years in equal annual installments on the anniversary of November 6, 2025, subject to the Reporting Person's continuous service to the Issuer through each such vesting date.
F2 The total represents shares received upon conversion of shares of Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock, Series A-6 Convertible Preferred Stock, Series B-1 Convertible Preferred Stock, Series B-2 Convertible Preferred Stock, Series C Convertible Preferred Stock and/or Series D Convertible Preferred Stock.
F3 The reported security converted into the Issuer's Common Stock on a one-for-one basis automatically immediately prior to the closing of the Issuer's initial public offering of Class A common stock (the "Offering") without payment of further consideration. The shares have no expiration date.
F4 The reported security is directly held by HB&Q NV (HB&Q COMPARTMENT III).
F5 The reported security is directly held by Hummingbird Collective CommV.
F6 The reported security is directly held by Hummingbird Dragons CommV.
F7 The reported security is directly held by Hummingbird Opportunity Fund II CommV.
F8 The reported security is directly held by Hummingbird Ventures III CommV.
F9 Humming Bird Ventures Management NV is the managing member of Hummingbird Opportunity Fund II CommV, Hummingbird Ventures III CommV, Hummingbird Dragons CommV, Hummingbird Collective CommV, and HB&Q NV (HB&Q COMPARTMENT III) (the Hummingbird Funds) and, as a result, may be deemed to beneficially own shares held by the Hummingbird Funds. Mr. Ileri, Barend Van den Brande, and Lukas Decoster are partners of Hummingbird Ventures Management NV and may be deemed to have shared voting and investment power over the shares held by the Hummingbird Funds. The Reporting Person disclaims beneficial ownership of these shares except to the extent of his pecuniary interest therein.
F10 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 Offering.