Company: KROS
Filing Date: 2025-02-26
Form Type: S-8
Source: 0001664710-25-000020
Chunk: 1

Company: Keros Therapeutics, Inc.
Filing Date: 2025-02-26
Form: S-8
Chunk 1
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| Non-accelerated filer   |     | o  |     | Smaller reporting company |     | o |
|                         |     |    |     | Emerging growth company   |     | o |

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. ¨

### REGISTRATION OF ADDITIONAL SHARES PURSUANT TO GENERAL INSTRUCTION E
Keros Therapeutics, Inc. (the “Registran”) is filing this Registration Statement on Form S-8 for the purpose of registering (a) 1,622,188 shares of the Registrant’s common stock, par value $0.0001 (the “

#### Common Stock
”), issuable to eligible persons under the Registrant’s 2020 Equity Incentive Plan (the “

#### 2020 Plan
”), which Common Stock is in addition to the shares of Common Stock registered on (i) the Registrant’s Form S-8 filed with the Commission on April 17, 2020 (File No. 333-237732), (ii) the Registrant’s Form S-8 filed with the Commission on January 15, 2021 (File No. 333-252151), (iii) the Registrant’s Form S-8 filed with the Commission on March 9, 2022 (File No. 333-263394), (iv) the Registrant’s Form S-8 filed with the Commission on March 3, 2023 (File No. 333-270268) and (v) the Registrant’s Form S-8 filed with the Commission on February 29, 2024 (File No. 333-277483) (collectively, the “

#### Prior Registration Statements
”) and (b) 405,547 shares of Common Stock issuable to eligible persons under the Registrant’s 2020 Employee Stock Purchase Plan (the “

#### 2020 ESPP
”), which Common Stock is in addition to the shares of Common Stock registered on the Prior Registration Statements.

This Registration Statement relates to securities of the same class as that to which the Prior Registration Statements relate, and is submitted in accordance with General Instruction E to Form S-8 regarding Registration of Additional Securities. Pursuant to General Instruction E of Form S-8,