0001805077 1 2026-06-30 2026-06-30 0001805077 2 2026-06-30 2026-06-30 0001805077 2026-06-30 2026-06-30 iso4217:USD pure shares 424B5 EX-FILING FEES 0001805077 333-295819 N/A N/A S-3 Eos Energy Enterprises, Inc. false Equity Common Stock, par value true 19688012 5.4810 107909993.77 0.0001381 14902.37 false Equity Warrants to purchase Common Stock, par value true 6004378 0.00 0.00 0.0001381 0.00 107909993.77 14902.37 0.00 0.00 14902.37 Calculated in accordance with Rule 457(r) under the Securities Act of 1933, as amended (the “Securities Act”). The fee payable in connection with the offering pursuant to this prospectus supplement has been paid in accordance with Rule 456(b) under the Securities Act, and represents deferred payment of the registration fees in connection with the registrant’s Registration Statement on Form S-3 (File No. 333-295819). Subject to Rule 462(b) under the Securities Act, the aggregate maximum offering price of all securities issued by the Registrant pursuant to this registration statement from (a) the sale of 13,683,634 shares of common stock and the accompanying 6,004,378 warrants for an aggregate price of $74,999,997.95 and (b) the assumed exercise in full of all of the warrants, which would yield gross proceeds to the Company equal to a maximum of $32,909,995.82. No separate registration fee is payable with respect to the warrants offered hereby since the warrants offered hereby are being registered in the same registration statement as the shares of common stock underlying the warrants. In accordance with Rule 416 under the Securities Act of 1933, as amended, this registration statement shall be deemed to cover an indeterminate number of additional shares to be offered or issued from stock splits, stock dividends or similar transactions with respect to the securities being registered.