Company: BLLN
Filing Date: 2025-06-20
Form Type: DRS
Source: 0000950123-25-006095
Chunk: 0

Company: BillionToOne, Inc.
Filing Date: 2025-06-20
Form: DRS
Chunk 0
---
As submitted confidentially to the Securities and Exchange Commission on June 20, 2025. This draft registration statement has not been filed publicly with the Securities and Exchange Commission and all information contained herein remains strictly confidential. Registration Statement No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 BILLIONTOONE, INC. (Exact name of Registrant as specified in its charter)

| Delaware                        |     |                         8071 |     | 81-1082020            |
| (State or other jurisdiction of 
 incorporation or organization)  |     | -Primary Standard Industrial 
   Classification Code Number |     | -I.R.S. Employer      
 Identification Number |

1035 O’Brien Drive Menlo Park, CA 94025 (650) 460-2551 (Address, including zip code, and telephone number, including area code, of Registrant’s principal executive offices) Oguzhan Atay Chief Executive Officer BillionToOne, Inc. 1035 O’Brien Drive Menlo Park, CA 94025 (650) 460-2552 (Name, address, including zip code, and telephone number, including area code, of agent for service)

|                                        |     | Copies to:           |     |                                        |
| Nicholas B. Harley                     
 Andrew D. Thorpe                       
 Alexa Belonick                         
 Elena M. Vespoli Gunderson Dettmer     
 Stough Villeneuve Franklin &           
 Hachigian, LLP 1 Bush Street #1200     
 San Francisco, CA 94104 (415) 978-9803 |     | Thomas Lynch         
 General Counsel      
 BillionToOne, Inc.   
 1035 O’Brien Drive   
 Menlo Park, CA 94025 
 (650) 460-2552       |     | Dave Peinsipp                          
 Kristin VanderPas                      
 Denny Won                              
 Mark Ballantyne Cooley LLP             
 3 Embarcadero Center, 20th Floor       
 San Francisco, CA 94111 (415) 693-2000 |

Approximate date of commencement of proposed sale to the public:As soon as practicable after this Registration Statement is declared effective. If any of the securities being registered on this form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box. ☐ If this form is filed to