Eos Energy Enterprises announces restructuring plan

Item 2.02 Results of Operations and Financial Condition.

On November 5, 2026, the Company issued a press release announcing its financial results for the quarter ended September 30, 2026.¹ A copy of the press release is furnished herewith as Exhibit 99.1.

The information furnished under this Item 2.02 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.

Item 2.05. 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.² As part of this plan, the Company is consolidating the manufacturing facilities located in Turtle Creek, Pennsylvania and Thorn Hill, Pennsylvania. We expect the actions defined under this plan will be largely completed by the end of June 2027 with the production line anticipated to be operational within the first quarter 2027.

The plan is expected to result in the Company recording cash restructuring charges in the aggregate amount of approximately $16 to $18 million on a GAAP basis, estimated to be comprised primarily of costs relating to moving and clean up.³

This Current Report on Form 8-K contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These statements are based on the Company's current expectations and are subject to significant risks and uncertainties. The estimates of the charges and future cash expenditures associated with the plan, as well as the estimated time for completion, are subject to a number of assumptions, and actual results may differ materially from these estimates. The Company may be required to revise these estimates in future periods, and such revisions could be material. The Company undertakes no obligation to update these forward-looking statements, except as required by law.

Item 9.01 Financial Statement and Exhibits.

(d) Exhibits

Exhibit

Number

Description of Document

99.1

Press release announcing financial results, dated November 5, 2026

104

Cover page of this Current Report on Form 8-K formatted in Inline XBRL

2

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.⁴

EOS ENERGY ENTERPRISES, INC.

Dated: November 5, 2026

By:

/s/ Alessandro Lagi

Name:

Alessandro Lagi

Title:

Chief Financial Officer

3

Eos Energy Enterprises Reports Third Quarter 2026 Revenue of $82.7 Million, Up 171% Year Over Year, with Gross Margin Improving 58 Percentage Points • Delivered record revenue of $82.7 million through deliveries to 10 projects • Gross margin improved 58 percentage points and adjusted EBITDA margin improved 96 percentage points year over year, the eighth consecutive quarter both metrics improved • Received $87 million first advance under the second tranche of the U.S. Department of Energy loan • Announced a project with MN8 Energy to deliver 10 MW/100 MWh of Z3™ zinc-based LDES in West Virginia, serving Google's data centers • Discharged 6.9 GWh of cumulative energy from Eos technology, up nearly 400 MWh sequentially • Line 2's performance reached first-pass yield parity with Line 1 within three months of operation, and Thorn Hill moved to 24-hour operations in October • Reaffirms full-year revenue outlook in the lower half of its $300 million - $350 million range Pittsburgh, PA – November 5, 2026 – Eos Energy Enterprises, Inc. (NASDAQ: EOSE) ("Eos" or the "Company"), America's leading innovator in designing, manufacturing, and providing zinc-based long- duration energy storage (LDES) systems sourced and manufactured in the United States, today announced its financial results for the third quarter ended September 30, 2026. Third Quarter Highlights • Revenue totaled $82.7 million, up 171% year over year and 20% sequentially, driven by a 216% increase in cube shipments year over year and 23% growth sequentially. • Gross margin of negative 53%, improving 58 percentage points year over year and 18 percentage points sequentially, driven by lower material costs, increased production volumes, and lower conversion costs.⁵ Gross loss was $44.2 million, compared to $33.9 million in the prior year period. • Adjusted gross margin improved to negative 44%, with adjusted gross loss improving $6.1 million sequentially to $36.8 million, excluding stock-based compensation and depreciation. • Net income attributable to shareholders totaled $125.0 million, primarily reflecting non-cash mark- to-market gains on warrants and debt resulting from changes in the Company's stock price. • Adjusted EBITDA margin was negative 77%, improving 96 percentage points year over year and 27 percentage points sequentially. Adjusted EBITDA loss improved to $63.8 million from $71.4 million in the prior quarter, reflecting improved operating leverage on 20% sequential revenue growth. • Total cash, including restricted cash, was $344.1 million as of September 30, 2026. • Backlog totaled $765 million, representing 3.2 GWh, up 19% year over year and down 5% from prior quarter, reflecting backlog conversion into record quarterly revenue of $82.7 million, partially offset by new bookings during the quarter, as of September 30, 2026.⁶ "Our third quarter shows operating model improvement. We delivered our highest quarterly revenue, improved gross margin by 18 points sequentially, and brought Line 2 first-pass yield equal to Line 1 four times faster," said Joe Mastrangelo, Chief Executive Officer of Eos. "While the transition to Thorn Hill lowers fourth-quarter capacity, it positions us to reduce cost per cube and improve manufacturing efficiency in future quarters. We remain on track to achieve the lower half of our full-year revenue outlook." 2026 Revenue Outlook The Company expects full-year 2026 revenue in the lower half of its $300 million to $350 million range.⁷ The Company accelerated the consolidation of manufacturing into Thorn Hill, beginning in late October, including the relocation and upgrade of Line 1 with capabilities incorporated into Line 2. This strategic move is expected to temporarily impact production capacity and the timing of certain shipments while accelerating the realization of a lower-cost, single-site manufacturing footprint and associated operating efficiencies in 2027.

Recent Business Highlights Commercial Momentum Eos ended the third quarter with a backlog of $765 million and a commercial opportunity pipeline of $24.9 billion. During the quarter, the Company booked six orders from four new customers and two existing customers. This included a previously announced $100 million purchase order that converted under an existing capacity reservation agreement and, as a result, did not contribute to quarter-over-quarter backlog growth. Demand continued across the commercial and industrial (C&I) and data center markets. Eos announced an agreement with MN8 Energy and Google to deliver 10 MW/100 MWh of Z3™ zinc-based LDES in West Virginia, serving Google's data centers in the region. Thorn Hill Production Ramp Eos continued to scale production at its Thorn Hill facility during the third quarter, its first full quarter with both battery lines in commercial production. Shipments increased 23% sequentially, driven by higher utilization at Thorn Hill and continued productivity gains at Turtle Creek. Line 2 contributed 17% of total battery output, up from approximately 1% in the second quarter, while operating on a partial shift schedule, and delivered approximately 20% higher battery output per shift than Line 1. Line 2 also reached first-pass yield parity with Line 1 within three months, demonstrating the design enhancements and manufacturing learnings built into the second line. Consolidation of Manufacturing Ope