Firat Ileri - 05 Nov 2025 Form 3 Insider Report for BillionToOne, Inc.

Role
Director, 10%+ Owner
Signature
/s/ Thomas P. Lynch, Attorney-in-Fact
Issuer symbol
BLLN on Nasdaq
Transactions as of
05 Nov 2025
Net transactions value
$0
Form type
3
Filing time
05 Nov 2025, 21:32:07 UTC
Next filing
10 Nov 2025
SEC
View on sec.gov

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 05 Nov 2025 0002087908

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
holding BLLN Common Stock 179,999 05 Nov 2025 See footnotes F1, F2, F8

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
holding BLLN Series A-6 Convertible Preferred Stock 05 Nov 2025 Common Stock 28,981 Direct F1, F3
holding BLLN Series B-2 Convertible Preferred Stock 05 Nov 2025 Common Stock 640,727 See footnotes F1, F3, F4, F8
holding BLLN Series B-1 Convertible Preferred Stock 05 Nov 2025 Common Stock 18,845 See footnotes F1, F3, F5, F8
holding BLLN Series C Convertible Preferred Stock 05 Nov 2025 Common Stock 1,569,015 See footnotes F1, F3, F6, F8
holding BLLN Series D Convertible Preferred Stock 05 Nov 2025 Common Stock 446,103 See footnotes F1, F3, F6, F8
holding BLLN Series A-1 Convertible Preferred Stock 05 Nov 2025 Common Stock 20,000 See footnotes F1, F2, F3, F8
holding BLLN Series A-2 Convertible Preferred Stock 05 Nov 2025 Common Stock 33,000 See footnotes F1, F2, F3, F8
holding BLLN Series B-1 Convertible Preferred Stock 05 Nov 2025 Common Stock 2,261,377 See footnotes F1, F2, F3, F8
holding BLLN Series C Convertible Preferred Stock 05 Nov 2025 Common Stock 137,288 See footnotes F1, F2, F3, F8
holding BLLN Series A-6 Convertible Preferred Stock 05 Nov 2025 Common Stock 2,260,520 See footnotes F1, F3, F7, F8
holding BLLN Series B-2 Convertible Preferred Stock 05 Nov 2025 Common Stock 320,363 See footnotes F1, F3, F7, F8
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 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.
F2 The reported security is directly held by Hummingbird Opportunity Fund II CommV.
F3 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.
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 Ventures III CommV.
F8 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. Firat 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.

Remarks:

Exhibit 24 - Power of Attorney