Eos Energy (EOSE) CEO exercises 254,304 RSUs, 121,245 shares withheld

Rhea-AI Filing Summary

Eos Energy Enterprises Chief Executive Officer Joe Mastrangelo reported routine equity compensation activity. On 2026-07-05, he exercised derivative awards for 254,304 shares of common stock at a stated price of $0.0000 per share, converting restricted stock units into stock under the company’s 2020 Incentive Plan.

On 2026-07-06, 121,245 shares of common stock were withheld to satisfy tax obligations related to the vested RSU award. This tax-withholding disposition is not an open‑market sale. After these transactions, Mastrangelo directly owned 1,773,406 shares of Eos Energy common stock.

Insider Trade Summary

254,304 shares exercised/converted

Mixed 3 txns

Insider Mastrangelo Joe

Role Chief Executive Officer

Type	Security	Shares	Price	Value
Tax Withholding	Common Stock	121,245	$5.06	$613K
Exercise	Restricted Stock Units	254,304	$0.00	--
Exercise	Common Stock	254,304	$0.00	--

Holdings After Transaction: Common Stock — 1,773,406 shares (Direct, null); Restricted Stock Units — 0 shares (Direct, null)

Footnotes (1)

1. Each restricted stock unit ("RSU") represents a contingent right to receive one share of common stock. Represents shares withheld from vested restricted stock unit ("RSU") award to satisfy tax obligations, as permitted by the Company's Amended and Restated 2020 Incentive Plan. The reporting person received a grant of RSUs under the Issuer's 2020 Incentive Plan, which will vest in three equal installments on each of the first three anniversaries of the grant date, subject to continued service through each vesting date. Not applicable.

Key Figures

RSUs exercised: 254,304 shares Shares withheld for taxes: 121,245 shares Post-transaction holdings: 1,773,406 shares +2 more

5 metrics

RSUs exercised 254,304 shares Restricted Stock Units converted to common stock on 2026-07-05

Shares withheld for taxes 121,245 shares Tax-withholding disposition on 2026-07-06

Post-transaction holdings 1,773,406 shares Common stock directly owned after transactions

Stated exercise price $0.0000 per share RSU conversion price for common stock

Tax-withholding reference price $5.06 per share Price used for tax-withholding disposition of 121,245 shares

Key Terms

Restricted Stock Units, 2020 Incentive Plan, tax obligations, derivative security

4 terms

Restricted Stock Units financial

"Each restricted stock unit ("RSU") represents a contingent right to receive one share of common stock."

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

2020 Incentive Plan financial

"as permitted by the Company's Amended and Restated 2020 Incentive Plan."

tax obligations financial

"Represents shares withheld from vested restricted stock unit ("RSU") award to satisfy tax obligations"

derivative security financial

"transaction_code_description": "Exercise or conversion of derivative security""

A derivative security is a financial contract whose value comes from the price or performance of something else, such as a stock, bond, commodity, or market index. For investors it acts like an insurance policy or a wager: it can be used to protect against losses, lock in prices, or amplify gains and losses, so it can change a portfolio’s risk and potential return without owning the underlying asset directly.

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 07/07/2026 - 05:18 PM Accepted by SEC EDGAR 07/07/2026 - 05:18 PM Learn about SEC filing dates

FAQ

What did Eos Energy (EOSE) CEO Joe Mastrangelo report in this Form 4?

Joe Mastrangelo reported exercising restricted stock units into common shares and a related tax-withholding share disposition. The activity reflects routine equity compensation under Eos Energy’s 2020 Incentive Plan, rather than open-market buying or selling of EOSE stock.

How many Eos Energy (EOSE) shares did the CEO acquire through RSU exercise?

Joe Mastrangelo acquired 254,304 shares of Eos Energy common stock through the exercise of restricted stock units. Each RSU converted into one share, consistent with the company’s 2020 Incentive Plan terms governing equity-based compensation awards for executives.

How many Eos Energy (EOSE) shares were withheld for the CEO’s tax obligations?

A total of 121,245 Eos Energy common shares were withheld to cover Joe Mastrangelo’s tax obligations from the vested RSU award. This tax-withholding mechanism delivers shares to the tax authorities instead of an open-market sale by the executive.

How many Eos Energy (EOSE) shares does the CEO hold after these transactions?

Following the RSU exercise and related tax withholding, Joe Mastrangelo directly holds 1,773,406 shares of Eos Energy common stock. This post-transaction balance reflects his remaining direct equity stake as disclosed in the Form 4 filing.

Does this Eos Energy (EOSE) Form 4 show an open-market sale by the CEO?

No, the Form 4 does not show an open-market sale. It reports a derivative exercise of restricted stock units and a tax-withholding disposition, where shares were withheld to satisfy taxes rather than being sold on the open market.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Mastrangelo Joe

(Last) (First) (Middle)

C/O EOS ENERGY ENTERPRISES, INC.

3920 PARK AVENUE

(Street)

EDISON NEW JERSEY 08820

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Eos Energy Enterprises, Inc. [ EOSE ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Executive Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
07/05/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	07/05/2026		M		254,304	A	$0(1)	1,894,651	D
Common Stock	07/06/2026		F		121,245(2)	D	$5.06	1,773,406	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Restricted Stock Units(3)	(1)	07/05/2026		M			254,304	(4)	(4)	Common Stock	254,304	$0	0	D

Explanation of Responses:

1. Each restricted stock unit ("RSU") represents a contingent right to receive one share of common stock.

2. Represents shares withheld from vested restricted stock unit ("RSU") award to satisfy tax obligations, as permitted by the Company's Amended and Restated 2020 Incentive Plan.

3. The reporting person received a grant of RSUs under the Issuer's 2020 Incentive Plan, which will vest in three equal installments on each of the first three anniversaries of the grant date, subject to continued service through each vesting date.

4. Not applicable.

Remarks:

	/s/ Michael Silberman as attorney-in-fact for Joe Mastrangelo	07/07/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)