ERII insider reports 97,369 shares held after 10b5-1 trades

Rhea-AI Filing Summary

Energy Recovery (ERII): Chief Legal Officer reports Form 4 activity. On 10/20/2025, the officer exercised 3,530 employee stock options at $7.50 per share (code M) and sold 3,530 common shares at $17.00 (code S) pursuant to a Rule 10b5-1 trading plan.

Following these transactions, directly held common shares were 97,369. Indirect holdings include 5,568 shares held by spouse. Derivative holdings show 21,180 employee stock options remaining, with the exercised grant originally issued on February 1, 2018 and expiring on 02/01/2028 under a standard vesting schedule.

Insider Trade Summary

Net Seller: 3,530 shares ($60,010)

Net Sell 4 txns

Insider Yeung William

Role Chief Legal Officer

Sold 3,530 shs ($60K)

Type	Security	Shares	Price	Value
Exercise	Employee Stock Option (Right to Buy)	3,530	$7.50	$26K
Exercise	Common Stock	3,530	$7.50	$26K
Sale	Common Stock	3,530	$17.00	$60K
holding	Common Stock	--	--	--

Holdings After Transaction: Employee Stock Option (Right to Buy) — 21,180 shares (Direct); Common Stock — 100,899 shares (Direct); Common Stock — 5,568 shares (Indirect, Spouse)

Footnotes (1)

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

Form 4 Insider Transactions: What Each Field Means →

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)
10/20/2025

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	10/20/2025		M		3,530	A	$7.5	100,899	D
Common Stock	10/20/2025		S		3,530(1)	D	$17	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	10/20/2025		M			3,530	(2)	02/01/2028	Common Stock	3,530	$7.5	21,180	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	10/22/2025
	** 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 exercise of 3,530 employee stock options at $7.50 and a same‑day sale of 3,530 common shares at $17.00 under a Rule 10b5-1 plan.

How many ERII shares does the officer hold after the transactions?

Directly held common shares were 97,369 after the reported sale.

Are there any indirect holdings reported for ERII?

Yes. Indirect holdings include 5,568 common shares held by the spouse.

What derivative securities remain after the ERII transactions?

21,180 employee stock options remain outstanding.

When were the exercised options granted and when do they expire?

Granted on February 1, 2018, with an expiration date of 02/01/2028.

Were the ERII trades made under a prearranged plan?

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