Company: BLLN
Filing Date: 2025-08-11
Form Type: DRS/A
Source: 0000950123-25-007483
Chunk: 263

Company: BillionToOne, Inc.
Filing Date: 2025-08-11
Form: DRS/A
Chunk 263
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| (1) |     | Entities affiliated with Adams Street Partners that purchased shares of our Series C redeemable convertible preferred stock include: (i) Adams Street 2019 Direct Growth Equity Fund LP, (ii) Adams Street 2020                    
 Direct Growth Equity Fund LP, (iii) Adams Street 2021 Direct Growth Equity Fund LP, (iv) Adams Street 2022 Direct Growth Equity Fund LP, (v) Adams Street Global Private Markets Fund LP, (vi) Adams Street Growth Equity Fund VII 
 LP, and (vii) FCPR GF—Lumyna Private Equity World Fund. Thomas Bremner, a member of our Board of Directors, is a partner at Adams Street Partners.                                                                                 |

| (2) |     | Entities affiliated with Hummingbird Ventures that purchased shares of Series C redeemable convertible preferred stock include: (i) Hummingbird Dragons CommV, and (ii) Hummingbird Opportunity Fund II CommV. 
 Firat Ileri, a member of our Board of Directors, is the managing partner of Hummingbird Ventures.                                                                                                              |

| (3) |     | Entities affiliated with Libertus Capital that purchase shares of Series C redeemable convertible preferred stock include: (i) Libertus Capital I and (ii) Libertus Capital II. Libertus Capital holds greater 
 than 5% of our capital stock.                                                                                                                                                                                  |

| (4) |     | Entities affiliated with Neotribe Ventures that purchased shares of our Series C redeemable convertible preferred stock include Neotribe SPV I BTO, LLC. Krishna Swaroop Kolluri, a member of our Board of Directors, is a 
 managing director at Neotribe Ventures.                                                                                                                                                                                    |

Secondary sales Pursuant to our 2018 Plan and the ROFR (as defined below), which is described below, certain holders of our capital stock and we or our assignees have a right of first refusal to purchase shares of our capital stock proposed to be sold by certain of our stockholders to other parties. These rights will terminate upon completion 204

of this offering. We waived or allowed to expire our right of first refusal in connection with the following transactions involving directors, officers and holders of more than 5% of our capital
stock:

In April 2022, Dr. Tsao entered into stock purchase agreements with us and certain affiliates of Libertus Capital, which holds more than 5% of our
capital stock. Pursuant to these agreements, Dr