Costs Associated with Exit or Disposal Activities. On November 4, 2026, the board of directors of Eos Energy Enterprises, Inc.(“we”, “the Company” or “Eos”) adopted a plan that is intended to better align cost structure and support gross margin improvement to the Company’s target financial model, while also aligning manufacturing capabilities with current and anticipated business needs and the Company's strategic priorities. As part of this plan, the Company is consolidating the manufacturing…

and in the accompanying Exhibit 99.1 shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act regardless of any general incorporation language in such filing, unless expressly incorporated by specific reference in such filing.

and in the accompanying Exhibit 99.1 shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act regardless of any general incorporation language in such filing, unless expressly incorporated by specific reference in such filing.

Director — Mr. Kroeker: The filing discloses a negotiated separation agreement for Mr. Kroeker, indicating a departure from his role (likely Director or Officer) with standard severance benefits, which is a genuine loss of a senior individual but not necessarily a shock event like a CEO resignation.

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. As previously disclosed, on November 26, 2024, (i) Eos Energy Enterprises, Inc. (the “Company”), the U.S. Department of Energy (the “DOE”) and the Federal Financing Bank (the “FFB”) entered into a Note Purchase Agreement (the “FFB Note Purchase Agreement”) pursuant to which, among other things, the DOE provided a guarantee (the “DOE Guarantee”) of the Company’s (x) obligations to…

of this Report, including Exhibit 99.1, shall not be deemed to be incorporated by reference into the filings of the Company under the Securities Act of 1933, as amended (the “Securities Act”) or the Exchange Act, whether made before or after the date hereof and regardless of any general incorporation language in such filing. Forward-Looking Statements Except for the historical information contained herein, the matters set forth in this Report are forward-looking statements within the meaning…

Chief Commercial Officer — Nathan Kroeker: The Chief Commercial Officer is departing following a planned transition period with a named internal successor, indicating an orderly succession rather than a sudden loss of leadership.

Unregistered Sales of Equity Securities. The information set forth in

Entry Into A Material Definitive Agreement. Amended and Restated Limited Liability Company Agreement for Frontier On August 4, 2026, Eos Energy Enterprises, Inc. (the “ Company ”), CCM Frontier JV Holdco, LLC, an affiliate of Cerberus Capital Management, L.P. (“ CCM Frontier ”) and HBC MSF Capital Solutions Blocker II LLC, an affiliate of Hudson Bay Capital Management LP (“ HBC ”) entered into an Amended and Restated Limited Liability Company Agreement (the “ A&R LLCA ”) for Frontier Power US…

and in the accompanying Exhibit 99.1 shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act regardless of any general incorporation language in such filing, unless expressly incorporated by specific reference in such filing.

and in the accompanying Exhibit 99.1 shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act regardless of any general incorporation language in such filing, unless expressly incorporated by specific reference in such filing.

preferred stock director and Class III director — Greg Nixon and Nathaniel Fick: Greg Nixon resigned to devote more time to other business ventures, and Nathaniel Fick was appointed as a preferred stock director with Haiyan Song succeeding him as Class III director.

Other Events. Rights Offering On July 2, 2026, Eos Energy Enterprises, Inc. (the “Company”) issued a press release announcing the commencement of its previously-announced rights offering pursuant to a shelf registration statement filed on Form S-3 (File No. 333-295819) (the “Registration Statement”) with the Securities and Exchange Commission (“SEC”) on May 13, 2026, and the prospectus supplement relating to the rights offering filed with the SEC on July 2, 2026 (the prospectus supplement tog…

Other Events. Securities Purchase Agreement On July 1, 2026, the Company issued 13,683,634 shares (the “Shares”) of the Company’s common stock, par value $0.0001 per share (“Common Stock”), and 6,004,378 warrants (the “Warrants” and, together with the Shares, the “Securities”), each warrant to purchase one share of common stock at an exercise price of $5.481 per share, in its previously announced registered direct offering (the “Offering”) pursuant to that certain securities purchase agreemen…

Entry Into or Amendment of a Material Definitive Agreement. On June 30, 2026, Eos Energy Enterprises Inc. (the “ Company ”) entered into a binding amended and restated term sheet (the “ A&R Term Sheet ”) with CCM Frontier JV Holdco, LLC, an affiliate of Cerberus Capital Management, L.P. (“ CCM Frontier ”), and HBC MSF Capital Solutions Blocker II LLC, an affiliate of Hudson Bay Capital Management LP (“ HBC ”), which provides for upon the closing of the transactions contemplated by the A&R Ter…

Other Events. Second Limited Consent to DOE Loan Agreement On June 26, 2026, the Company entered into a limited consent (the “ Second DOE Limited Consent ”) to its Loan Guarantee Agreement, dated November 26, 2024, as amended by that certain Amendment to Loan Guarantee Agreement, dated as of March 25, 2025, and as further amended by that certain Second Amendment to Loan Guarantee Agreement, dated as of February 13, 2026, by and between the Company and the United States Department of Energy, a…

Entry into a Material Definitive Agreement. On May 12, 2026, Eos Energy Enterprises Inc. (the “ Company ”) entered into a binding term sheet (the “ Term Sheet ”) with CCM Frontier JV Holdco, LLC, an affiliate of Cerberus Capital Management, L.P. (“ CCM Frontier ”), which provides for, upon the closing of the transactions contemplated by the Term Sheet, the formation of a joint venture between the Company and CCM Frontier through Frontier Power USA Parent, LLC, a Delaware limited liability com…

and in the accompanying Exhibit 99.2 shall not be deemed “filed” for purposes of Section 18 of the Exchange Act, or incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act regardless of any general incorporation language in such filing, unless expressly incorporated by specific reference in such filing. Forward-Looking Statements and Important Information Except for the historical information contained herein, the matters set forth herein are…

and in the accompanying Exhibit 99.1 shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act regardless of any general incorporation language in such filing, unless expressly incorporated by specific reference in such filing.

Unregistered Sales of Equity Securities. The information set forth in

Chief Financial Officer — Alessandro Lagi: Eos Energy Enterprises appointed Alessandro Lagi as the new Chief Financial Officer.

and in the accompanying Exhibit 99.1 shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act regardless of any general incorporation language in such filing, unless expressly incorporated by specific reference in such filing.

Chief Administration Officer — Michelle Buczkowski: An employment agreement was signed with the Chief Administration Officer, Michelle Buczkowski.

Director — Nathaniel Fick: Appointment of Nathaniel Fick as a Class III director.

and in the accompanying Exhibit 99.1 shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act regardless of any general incorporation language in such filing, unless expressly incorporated by specific reference in such filing.