Company: BLLN
Filing Date: 2025-10-17
Form Type: S-1/A
Source: 0001193125-25-242632
Chunk: 288

Company: BillionToOne, Inc.
Filing Date: 2025-10-17
Form: S-1/A
Chunk 288
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issory note agreements whereby we sold and issued convertible promissory notes in an aggregate principal amount of $30.0 million (the 2022 Note Financing). Each convertible promissory note had an interest rate of 8% per annum. The aggregate principal and accrued interest converted into 1,726,823 shares of our Series C-1redeemable convertible preferred stock at a conversion price of $19.6143 per share upon the closing of our Series D financing in May 2024, and the rights and obligations under the convertible promissory note agreements were terminated and canceled. Each share of Series C-1redeemable convertible preferred stock will convert automatically into a share of our Class A common stock, on a one-for-one basis, immediately prior to the completion of this offering. 214

The following table summarizes purchases of our convertible promissory notes in the 2022 Note Financing by entities affiliated with certain of our directors and holders of more than 5% of our capital stock.

| Purchaser                                    |     | Aggregate principal amount of convertible 
 promissory notes                          |            |
|:---------------------------------------------|:----|:------------------------------------------|-----------:|
| Entities affiliated with Adams Street        
 Partners(1)                                  |     | $                                         |  3,000,000 |
| Entities affiliated with Libertus Capital(2) |     | $                                         | 15,000,000 |

| (1) |     | Entities affiliated with Adams Street Partners that purchased convertible promissory notes in our 2022 Note Financing 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 Private Equity Navigator Fund LLC (f/k/a 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) |     | Libertus Capital holds greater than 5% of our capital stock. Entities affiliated with Libertus Capital that purchased convertible promissory notes in our 2022 Note Financing include: (i) Libertus Capital I and 
 (ii) Libertus Capital II.