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

Rhea-AI Filing Summary

Energy Recovery (ERII) disclosed insider transactions by its Chief Legal Officer. On 10/23/2025, the officer exercised 3,530 options at $7.5 and sold 3,530 shares at $17.5 under a Rule 10b5-1 trading plan.

On 10/24/2025, the officer exercised 5,638 options at $10.19 and 3,530 options at $7.5, then sold 5,638 and 3,530 shares at $18. Following these transactions, directly held common stock was 97,369 shares, with 5,568 shares held indirectly via spouse.

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)
10/23/2025

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	10/23/2025		M		3,530	A	$7.5	100,899	D
Common Stock	10/23/2025		S		3,530(1)	D	$17.5	97,369	D
Common Stock	10/24/2025		M		5,638	A	$10.19	103,007	D
Common Stock	10/24/2025		S		5,638(1)	D	$18	97,369	D
Common Stock	10/24/2025		M		3,530	A	$7.5	100,899	D
Common Stock	10/24/2025		S		3,530(1)	D	$18	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	10/23/2025		M			3,530	(2)	02/01/2028	Common Stock	3,530	$7.5	17,650	D
Employee Stock Option (Right to Buy)	$10.19	10/24/2025		M			5,638	(3)	02/02/2027	Common Stock	5,638	$10.19	16,229	D
Employee Stock Option (Right to Buy)	$7.5	10/24/2025		M			3,530	(2)	02/01/2028	Common Stock	3,530	$7.5	14,120	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.

3. 25% of these options fully vest on the 1st anniversary of the vesting start date of 02/02/2017; thereafter, the remaining 75% vest 1/36th per month.

Remarks:

	/s/ William Yeung	10/27/2025
	** 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?

Exercises of employee stock options and corresponding open-market sales executed under a Rule 10b5-1 trading plan.

What transactions occurred on 10/23/2025 for ERII?

Exercised 3,530 options at $7.5 and sold 3,530 shares at $17.5.

What transactions occurred on 10/24/2025 for ERII?

Exercised 5,638 options at $10.19 and 3,530 options at $7.5, then sold 5,638 and 3,530 shares at $18.

How many ERII shares were directly owned after the reported trades?

Direct beneficial ownership was 97,369 common shares after the reported transactions.

Is there any indirect ownership reported for ERII?

Yes. Indirect beneficial ownership via spouse was reported as 5,568 shares.

Were the ERII trades made under a 10b5-1 plan?

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