0001664710 2026-09-09 2026-09-09 0001664710 1 2026-09-09 2026-09-09 0001664710 2 2026-09-09 2026-09-09 0001664710 3 2026-09-09 2026-09-09 0001664710 4 2026-09-09 2026-09-09 0001664710 5 2026-09-09 2026-09-09 0001664710 6 2026-09-09 2026-09-09 iso4217:USD pure S-3 S-3 EX-FILING FEES 0001664710 Keros Therapeutics, Inc. N/A N/A 0.0001381 0.0001381 0.0001381 0.0001381 S-3 Keros Therapeutics, Inc. Equity Common Stock, $0.0001 par value per share true Equity Preferred stock, $0.0001 par value per share true Debt Debt Securities true Other Warrants true false Unallocated (Universal) Shelf true 232276802.04 0.0001381 32077.43 Equity Common Stock, $0.0001 par value per share true 117723197.96 S-3 333-279094 2024-05-03 17375.94 350000000.00 32077.43 0.00 0.00 32077.43 An unspecified number of securities or aggregate principal amount, as applicable, is being registered as may from time to time be offered at unspecified prices, and, in addition, an unspecified number of additional shares of common stock is being registered as may be issued from time to time upon conversion of any debt securities that are convertible into common stock or pursuant to any anti-dilution adjustments with respect to any such convertible debt securities. The maximum aggregate offering price is estimated solely for the purpose of calculating the registration fee. No separate consideration will be received for shares of common stock that are issued upon conversion of debt securities or preferred stock or upon exercise of common stock warrants registered hereunder. The aggregate maximum offering price of all securities issued pursuant to this registration statement will not exceed $350,000,000. The Registrant previously paid registration fees in the aggregate of $41,107.02 with respect to the prospectus supplement, filed on June 17, 2024, to the Registrant's registration statement on Form S-3ASR (File No. 333-279094) (the "Prior Registration Statement"). Pursuant to Rule 415(a)(6) ("Rule 415(a)(6)") promulgated under the Securities Act of 1933, as amended (the "Securities Act"), the securities registered pursuant to this Registration Statement on Form S-3 (this "Registration Statement") include $117,723,197.96 of securities previously registered on the Prior Registration Statement which remain unsold (the "Unsold Securities"). Pursuant to Rule 415(a)(6), the registration fee of $17,375.94 associated with the offering of the Unsold Securities (based on the filing fee rate in effect at the time of the filing of the Prior Registration Statement) is hereby carried forward to be applied to the Unsold Securities registered hereunder, and no additional filing fee is due with respect to the Unsold Securities in connection with the filing of this Registration Statement. The registrant is also registering new securities on this Registration Statement with an aggregate maximum offering price of $232,276,802.04 (the "New Securities"), which aggregate offering price is not specified as to each class of securities in reliance upon Rule 457(o) promulgated under the Securities Act. A filing fee of $32,077.43 with respect to the New Securities is being paid in connection with the filing of this Registration Statement. To the extent that, after the filing date hereof and prior to the effectiveness of this Registration Statement, the Registrant sells any Unsold Securities pursuant to the Prior Registration Statement, the Registrant will identify in a pre-effective amendment to this Registration Statement the updated number of Unsold Securities from the Prior Registration Statement to be included in this Registration Statement pursuant to Rule 415(a)(6) and the updated amount of additional new securities to be registered on this Registration Statement. Pursuant to Rule 415(a)(6), the offering of the Unsold Securities under the Prior Registration Statement will be deemed terminated as of the date of effectiveness of this Registration Statement. See footnote 1.