Company: INKT
Filing Date: 2025-11-07
Form Type: S-3
Source: 0001193125-25-272532
Chunk: 1

Company: MiNK Therapeutics, Inc.
Filing Date: 2025-11-07
Form: S-3
Chunk 1
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 Securities Act, check the following box. ☐ If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box. ☐ Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-acceleratedfiler, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2of the Exchange Act.

| Large accelerated filer |     | ☐ |     | Accelerated filer         |     | ☐ |
| Non-accelerated filer   |     | ☒ |     | Smaller reporting company |     | ☒ |
|                         |     |   |     | Emerging growth company   |     | ☒ |

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐ The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended, or until this registration statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

EXPLANATORY NOTE This registration statement contains:

| • |     | a base prospectus, which covers the offering, issuance and sale by us of up to $150,000,000 in the aggregate of                        
 the registrant’s common stock, preferred stock, warrants, debt securities and/or units from time to time in one or more offerings; and |

| • |     | a prospectus supplement, which covers the offering, issuance and sale by us of up to $50,000,000 in the aggregate                    
 of shares of our common stock that may be issued and sold under an At Market Issuance Sales Agreement with B. Riley Securities, Inc. |

The base prospectus immediately follows this explanatory note. The specific terms of any securities to be offered pursuant to