Eos Energy CEO reports RSU conversion, tax share withholding

Eos Energy Enterprises, Inc. director and Chief Executive Officer Joe Mastrangelo reported equity transactions involving restricted stock units (RSUs) and common stock.

Rhea-AI Filing Summary

Eos Energy Enterprises, Inc. director and Chief Executive Officer Joe Mastrangelo reported equity transactions involving restricted stock units (RSUs) and common stock. On July 25, 2026, 333,334 RSUs, each representing a contingent right to one share of common stock, were converted into 333,334 shares of common stock at $0.00 per share, leaving 333,333 RSUs outstanding. On July 27, 2026, 159,154 shares of common stock at $3.61 per share were withheld to satisfy tax obligations arising from a vested RSU award under the company’s Amended and Restated 2020 Incentive Plan.

Insider Trade Summary

Exercise and sale activity reported; no spread calculated

Exercise and Sale 3 txns

Insider Mastrangelo Joe

Role Chief Executive Officer

Sold 159,154 shs ($575K)

Approx. gross sale proceeds $575K

Type	Security	Shares	Price	Value
Sale	Common Stock F2	159,154	$3.61	$575K
Exercise	Restricted Stock Units F1, F3	333,334	$0.00	$0.00
Exercise	Common Stock F1	333,334	$0.00	$0.00

Holdings After Transaction: Restricted Stock Units — 333,333 contracts (Direct); Common Stock — 1,947,586 shares (Direct)

Footnotes (3)

1. F1. Each restricted stock unit ("RSU") represents a contingent right to receive one share of common stock.
2. F2. 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. F3. Not applicable.

Key Figures

RSUs Converted: 333,334 units Common Shares Acquired from RSUs: 333,334 shares RSUs Remaining: 333,333 units +2 more

5 metrics

RSUs Converted 333,334 units Restricted stock units converted into common stock on July 25, 2026

Common Shares Acquired from RSUs 333,334 shares Common stock received upon RSU conversion at $0.00 per share

RSUs Remaining 333,333 units Restricted stock units held after the RSU conversion transaction

Shares Withheld for Taxes 159,154 shares Common shares withheld from vested RSU award to satisfy tax obligations

Withholding Share Price $3.61 per share Reported price for common stock withheld on July 27, 2026

Key Terms

Restricted Stock Units, contingent right, withheld, Amended and Restated 2020 Incentive Plan

4 terms

Restricted Stock Units financial

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

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.

contingent right financial

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

withheld financial

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

Amended and Restated 2020 Incentive Plan financial

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

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What stock transactions did EOSE CEO Joe Mastrangelo report on this Form 4?

Joe Mastrangelo reported the conversion of 333,334 RSUs into common stock and the withholding of 159,154 shares to cover tax obligations related to a vested RSU award.

How many EOSE restricted stock units did Joe Mastrangelo convert, and at what price?

Joe Mastrangelo converted 333,334 restricted stock units into the same number of common shares at a price of $0.00 per share, consistent with RSUs representing a contingent right to receive one share of common stock.

How many EOSE shares were withheld for Joe Mastrangelo’s tax obligations?

159,154 shares of Eos Energy Enterprises common stock were withheld to satisfy Joe Mastrangelo’s tax obligations from a vested RSU award under the Amended and Restated 2020 Incentive Plan.

What was the reported share price for the EOSE shares withheld for taxes?

The shares withheld for taxes were reported at $3.61 per share. These 159,154 shares were withheld from a vested RSU award to satisfy tax obligations under the company’s equity incentive plan.

How many EOSE restricted stock units does Joe Mastrangelo hold after these transactions?

After the reported RSU conversion, Joe Mastrangelo holds 333,333 restricted stock units, as indicated by the post-transaction derivative holdings in the Form 4 data for Eos Energy Enterprises.

Were Joe Mastrangelo’s EOSE transactions made under a Rule 10b5-1 trading plan?

The filing’s Rule 10b5-1 checkbox is not marked as affirming plan use, and the footnotes describe RSU mechanics and tax withholding only, without referencing any pre-arranged Rule 10b5-1 trading plan.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 07/28/2026 - 05:02 PM Accepted by SEC EDGAR 07/28/2026 - 05:02 PM Learn about SEC filing dates

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.

TWO ALLEGHENY CENTER, NOVA TOWER 2

(Street)

PITTSBURGH PENNSYLVANIA 15212

(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)
07/25/2026

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	07/25/2026		M		333,334	A	$0(1)	2,106,740	D
Common Stock	07/27/2026		S		159,154(2)	D	$3.61	1,947,586	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	(1)	07/25/2026		M			333,334	(3)	(3)	Common Stock	333,334	$0	333,333	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. Not applicable.

Remarks:

	/s/ Sumeet Puri as attorney-in-fact for Joe Mastrangelo	07/28/2026
	** 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)