Company: BLLN
Filing Date: 2025-08-11
Form Type: DRS/A
Source: 0000950123-25-007483
Chunk: 347

Company: BillionToOne, Inc.
Filing Date: 2025-08-11
Form: DRS/A
Chunk 347
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 of U.S. Treasury zero-coupon issues with terms consistent with the expected term of the awards for its risk-free interest rate. |

| • |     | Expected dividends. The Company historically has not paid dividends on common stock and has no plans to 
 issue dividends in the foreseeable future.                                                              |

F-31

B ILLIONT OO NE, INC. Notes to Financial Statements The weighted average assumptions used to calculate the fair value of option grants issued under the 2018 Plan during the years ended December 31, 2023 and 2024 were as follows:

|                            |     |   |  2023 |   |     |   |  2024 |   |
|:---------------------------|:----|:--|------:|:--|:----|:--|------:|:--|
| Fair value of common stock |     | $ | 11.07 |   |     | $ | 16.47 |   |
| Dividend yield             |     |   |     - | % |     |   |     - | % |
| Risk-free interest rate    |     |   |   4.0 | % |     |   |   4.1 | % |
| Expected volatility        |     |   |    74 | % |     |   |    68 | % |
| Expected term (in years)   |     |   |  5.99 |   |     |   |  6.01 |   |

A summary of the Company’s stock option activity and related information is as follows:

|                                                     |     | Number of   
 Options     
 Outstanding |           |   |     | Weighted       
 Average        
 Exercise Price 
 Per Share      |       |     | Weighted-   
 Average     
 Remaining   
 Contractual 
 Life        
 (in years)  |     |     | Aggregate       
 Intrinsic Value 
 (in thousands)  |        |
|:----------------------------------------------------|:----|:------------|----------:|:--|:----|:---------------|------:|:----|:------------|----:|:----|:----------------|-------:|
| Outstanding as of January 1, 2023                   |     |             | 4,633,430 |   |     | $              |  3.33 |     |             | 8.4 |     | $               | 25,974 |
| Granted                                             |     |             | 2,096