Eos Energy Enterprises, Inc.

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers. Chief Commercial Officer Transition On August 24, 2026, Eos Energy Enterprises, Inc. (the "Company") implemented a leadership transition designed to align its commercial operations by bringing sales, business development, government affairs, marketing and communications under a unified commercial organization. In connection with this organizational change, effective August 24, 2026, Michelle Buczkowski, the Company's Chief Administration Officer, was appointed Chief Commercial Officer. The appointment also reflects the Company's succession planning efforts and continued focus on commercial execution. Nathan Kroeker, the Company's Chief Commercial Officer, will remain with the Company through October 20, 2026 to support an orderly transition and will depart the Company following such transition period. It is currently anticipated that Mr. Kroeker will enter into a separation agreement in connection with his departure, the terms of which have not been finalized as of the date of this filing. If the Company enters into a separation agreement with Mr. Kroeker, the material terms of such separation agreement will be disclosed in an amendment to this report. In connection with Ms. Buczkowski's appointment as Chief Commercial Officer, the Compensation Committee of the Board of Directors approved modifications to her compensation arrangements, effective August 24, 2026. Ms. Buczkowski's annual base salary was increased from $385,000 to $440,000. In addition, Ms. Buczkowski's target annual short-term incentive opportunity was increased to 100% of her annual base salary. Other than the foregoing changes, her compensation arrangements remain substantially unchanged.

Item 7.01 Regulation FD Disclosure On August 25, 2026, the Company issued a press release announcing the appointment of Michelle Buczkowski as Chief Commercial Officer and the planned departure of Nathan Kroeker following a transition period. A copy of the press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K. The information furnished under this Item 7.01 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 in such filing, unless expressly incorporated by specific reference in such filing.