SEC Form 4 · accession 0001628280-26-062270
Eos Energy Enterprises, Inc. · EOSE
Statement of changes in beneficial ownership, as filed. Original on EDGAR ↗
Reporting owner
Joe Mastrangelo
Officer — Chief Executive Officer · Director
Period of report
Sep 14, 2026
Accepted (ET)
Sep 16, 2026 · 4:27 pm EDT
Rule 10b5-1 plan
yes — trade under a plan
Issuer CIK
0001805077
Table I — non-derivative securities
| Security | Date | Code | Shares | Price | A/D | Owned after | D/I | Nature of ownership |
|---|---|---|---|---|---|---|---|---|
| Common StockF1 | Sep 14, 2026 | A | 500,000 | $0.00 | A | 2,558,704 | D | |
| Common StockF3 | Sep 16, 2026 | S | 250,000 | $3.92 | D | 2,308,704 | D |
Table II — derivative securities
| Security | Conv. / exercise price | Date | Code | Shares | A/D | Exercisable | Expires | Underlying | Underlying shares | Owned after | D/I |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Performance-Based Restricted Stock UnitsF1,F4,F5 | — | Sep 14, 2026 | M | 500,000 | D | — | — | Common Stock | 500,000 | 0 | D |
Explanation of responses
- F1On July 5, 2024, the Reporting Person was granted performance-based restricted stock units ("2024 PRSU Awards"). The 2024 PRSU Awards are eligible to vest in up to two installments based on the total shareholder return of the Issuer over two- and three-year performance periods, each commencing on July 5, 2024. On September 14, 2026, the Compensation Committee of the Issuer's Board of Directors certified the achievement of the first performance period, resulting in the vesting of these shares.
- F2The sales reported in this Form 4 were effected automatically pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on September 15, 2025 to cover estimated tax withholding obligations in connection with the vesting of performance-based restricted stock units.
- F3The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $3.84 to $4.16, inclusive. The reporting person undertakes to provide the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth above.
- F4Represents the outstanding awarded and vested units pursuant to the 2024 PRSU Awards dated July 25, 2024 related to the achievement of certain total shareholder return objectives.
- F5Not applicable.