[Form 4] Energy Recovery, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Energy Recovery (ERII) insider activity: the Chief Legal Officer exercised an employee stock option for 3,530 shares at $7.5 and, on the same day (10/16/2025), sold 3,530 shares at $16.5. The filing notes these trades were effected under a Rule 10b5-1 trading plan. Following the transactions, the reporting person held 97,369 shares directly and 5,568 shares indirectly through a spouse. Remaining derivative holdings included 24,710 employee stock options at a $7.5 exercise price expiring 02/01/2028.

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).

X

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^*

Yeung William

(Last) (First) (Middle)

C/O ENERGY RECOVERY, INC.

1717 DOOLITTLE DRIVE

(Street)

SAN LEANDRO CA 94577

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Energy Recovery, Inc. [ ERII ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
10/16/2025

4. 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 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	10/16/2025		M		3,530	A	$7.5	100,899	D
Common Stock	10/16/2025		S		3,530(1)	D	$16.5	97,369	D
Common Stock								5,568	I	Spouse

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
Employee Stock Option (Right to Buy)	$7.5	10/16/2025		M			3,530	(2)	02/01/2028	Common Stock	3,530	$7.5	24,710	D

Explanation of Responses:

1. These transactions reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.

2. This employee stock option was granted on February 1, 2018. 25% of the shares fully vest on the 1st anniversary of the vesting start date; thereafter, the remaining 75%, vest 1/36th per month.

Remarks:

	/s/ William Yeung	10/17/2025
	** 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.

FAQ

What did ERII's Chief Legal Officer report on Form 4?

An option exercise for 3,530 shares at $7.5 and a same‑day sale of 3,530 shares at $16.5 on 10/16/2025.

Was the ERII insider trade under a Rule 10b5-1 plan?

Yes. The filing states the transactions were effected under a Rule 10b5-1 trading plan.

How many ERII shares does the insider own after the trade?

Direct holdings are 97,369 shares; indirect holdings via spouse are 5,568 shares.

What options remain after the ERII transaction?

The reporting person holds 24,710 employee stock options with a $7.5 exercise price, expiring 02/01/2028.

What was the transaction date on the ERII Form 4?

The earliest transaction date reported is 10/16/2025.

What is the insider’s role at Energy Recovery (ERII)?

The reporting person is the company’s Chief Legal Officer.