ERII Chief Legal Officer executes option exercises and sales on 10/03/2025

Rhea-AI Filing Summary

Insider transactions by William Yeung, Chief Legal Officer of Energy Recovery, Inc. (ERII) show option exercises and offsetting open-market sales on 10/03/2025. The reporting person exercised two employee stock options—$7.5 exercise price options for 1,038 and 2,529 shares—resulting in acquisitions of the underlying common stock. The Form 4 also shows contemporaneous dispositions reported at a $16 sale price for the same share blocks. Following the transactions the reporting person directly owned 97,369 shares and indirectly (spouse) held 5,568 shares. The filing notes the transactions were effected under a Rule 10b5-1 trading plan and that the options were originally granted on 02/01/2018 with standard vesting.

Positive

• Transactions executed under a Rule 10b5-1 trading plan, providing an affirmative defense for scheduled trades
• Exercise of long-dated options granted on 02/01/2018, reflecting use of existing compensation rather than new grants

Negative

• Reported open-market sales at $16 offsetting the exercised shares, reducing net insider stock ownership on the transaction date
• Direct beneficial ownership decreased to 97,369 shares after the reported dispositions

Insights

Corporate Insider Trading Analyst

TL;DR: Exercises funded share acquisition while matching sales were made under a 10b5-1 plan on 10/03/2025.

The reporting person exercised employee stock options with an $7.5 strike to acquire 3,567 underlying shares and reported contemporaneous open-market sales of those share blocks at $16. The filing explicitly states the trades were effected pursuant to a Rule 10b5-1 trading plan, which provides an affirmative defense under SEC rules when properly adopted.

Dependencies and near-term items to watch include any further Form 4 filings that update post-plan trades and the vesting schedule implications tied to the original 02/01/2018 grant. Monitor aggregate insider holdings for changes that could affect perceived alignment with shareholders within the next reporting cycle.

Compensation & Equity Plan Specialist

TL;DR: Option grant from 02/01/2018 shows customary multi-year vesting; some shares remain vested schedule-dependent.

The employee stock options granted on 02/01/2018 vest 25% after one year with the remainder vesting monthly over 36 months, a common structure for long-term retention. The exercised options match the grant’s strike price of $7.5 and show standard exercise behavior when options are in-the-money relative to recent sale price information in the filing.

Watch for additional exercises or sales as remaining vested tranches become exercisable; subsequent filings will clarify how much intrinsic value was realized and any continued reliance on the 10b5-1 plan during future sale windows.

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)
10/03/2025

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	10/03/2025		M		1,038	A	$7.5	98,407	D
Common Stock	10/03/2025		S		1,038(1)	D	$16	97,369	D
Common Stock	10/03/2025		M		2,529	A	$7.5	99,898	D
Common Stock	10/03/2025		S		2,529(1)	D	$16	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	10/03/2025		M			1,038	(2)	02/01/2028	Common Stock	1,038	$7.5	30,769	D
Employee Stock Option (Right to Buy)	$7.5	10/03/2025		M			2,529	(2)	02/01/2028	Common Stock	2,529	$7.5	28,240	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	10/07/2025
	** 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 William Yeung (ERII) report on the Form 4 filed for 10/03/2025?

The Form 4 reports the exercise of employee stock options for 1,038 and 2,529 shares at a $7.5 strike and contemporaneous sales of those share blocks at $16, executed under a Rule 10b5-1 plan.

How many shares does William Yeung beneficially own after the transactions?

Following the reported transactions the reporting person directly beneficially owned 97,369 shares and indirectly (spouse) beneficially owned 5,568 shares.

When were the exercised options originally granted and what is the vesting?

The options were granted on 02/01/2018. Vesting is 25% after the first anniversary of the vesting start date with the remaining 75% vesting monthly over 36 months.

Were these trades part of a pre-established trading plan?

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

What prices are reported for the exercises and sales?

The employee stock options had an exercise price of $7.5; the reported open-market sales price for the disposed shares is $16.