SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person* Mastrangelo Joe (Last) (First) (Middle) C/O EOS ENERGY ENTERPRISES, INC. 3920 PARK AVENUE (Street) EDISON NJ 08820 (City) (State) (Zip)	2. Date of Event Requiring Statement (Month/Day/Year) 11/16/2020	3. Issuer Name and Ticker or Trading Symbol Eos Energy Enterprises, Inc. [ EOSE ]
		4. 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	5. If Amendment, Date of Original Filed (Month/Day/Year)
			6. Individual or Joint/Group Filing (Check Applicable Line) X Form filed by One Reporting Person Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Restricted Stock Units	(1)	(2)	Common Stock	74,531	0	D
Options	(3)	10/23/2030	Common Stock	1,037,484	8.67	D

Explanation of Responses:

1. The reporting person received restricted stock units which vest in full when the per share price of the Company's common stock quals or exceeds $12.00 at any time.

2. Not applicable

3. Beginning on 10/23/2020, so long as the reporting person remains in service, 691,691 of the shares of common stock subject to this option will vest as to 33.33% on each of the first three anniversaries of June 22, 2020; provided, that such shares shall vest in full upon the consummation of a change in control of the Company. The remaining number of shares subject to this option will vest, provided that the reporting person remains in service, on the day the Board determines that the Company has successfully closed an equity financing transaction prior to June 22, 2023. If no such transaction is consummated by June 22, 2023, any unvested portion of the option shall imeediately terminate.

	/s/ Joe Mastrangelo	11/23/2020
	** 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 5 (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).
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