Makowski receives stock award at Advanced Drainage

ADVANCED DRAINAGE SYSTEMS, INC. officer Tim A. Makowski reported receiving 3,729 shares of common stock as a grant tied to performance-based units earned under the company’s 2017 Omnibus Incentive Plan, including 53 shares from dividend equivalents.

Rhea-AI Filing Summary

ADVANCED DRAINAGE SYSTEMS, INC. officer Tim A. Makowski reported receiving 3,729 shares of common stock as a grant tied to performance-based units earned under the company’s 2017 Omnibus Incentive Plan, including 53 shares from dividend equivalents. The filing also shows 192 shares of common stock withheld at prices of $131.59 and $136.83 to satisfy tax obligations related to vesting of restricted common stock. In addition to his direct holdings, Makowski has 17,556.8712 shares of common stock indirectly held through a KSOP as of May 19, 2026.

Insider Trade Summary

4 transactions reported

Mixed 4 txns

Insider MAKOWSKI TIM A

Role See Remarks

Type	Security	Shares	Price	Value
Exercise Price or Tax Liability	Common Stock	88	$136.83	$12K
Grant/Award	Common Stock	3,729	$0.00	$0.00
Exercise Price or Tax Liability	Common Stock	104	$131.59	$14K
holding	Common Stock	--	--	--

Holdings After Transaction: Common Stock — 6,004 shares (Direct); Common Stock — 17,556.8712 shares (Indirect, By KSOP)

Footnotes (3)

1. F1. Represents shares withheld to satisfy Reporting Person's tax obligations in connection with the vesting of shares of restricted common stock of the Issuer.
2. F2. Reflects grant of performance-based units, originally granted pursuant to the Issuer's 2017 Omnibus Incentive Plan, earned after the Issuer determined that certain performance goals for the performance period ended March 31, 2026 had been met. Total includes dividend equivalents in the amount of 53 shares, which dividend equivalents are settled in common stock.
3. F3. Represents current allocation under KSOP.

Key Figures

Stock grant: 3,729 shares Dividend equivalents: 53 shares Tax withholding at $131.59: 104 shares +3 more

6 metrics

Stock grant 3,729 shares Common stock from earned performance-based units

Dividend equivalents 53 shares Dividend equivalents settled in common stock within grant

Tax withholding at $131.59 104 shares Shares withheld to satisfy tax obligations

Tax withholding at $136.83 88 shares Shares withheld to satisfy tax obligations

Total tax-withheld shares 192 shares Total F-code tax-withholding dispositions

KSOP indirect holding 17,556.8712 shares Indirect ownership by KSOP as of May 19, 2026

Key Terms

restricted common stock, performance-based units, 2017 Omnibus Incentive Plan, dividend equivalents, +1 more

5 terms

restricted common stock financial

"vesting of shares of restricted common stock of the Issuer"

Restricted common stock is company shares that carry limits on selling or transferring for a set period or until certain conditions are met, like time-based vesting or regulatory clearance. Think of them as shares in a locked box that gradually open; they can become freely tradable later but initially reduce the number of shares available on the market. Investors watch restricted stock because its eventual release can change a company’s share supply, affect stock price, and influence control and dilution.

performance-based units financial

"Reflects grant of performance-based units, originally granted pursuant"

2017 Omnibus Incentive Plan financial

"originally granted pursuant to the Issuer's 2017 Omnibus Incentive Plan"

dividend equivalents financial

"Total includes dividend equivalents in the amount of 53 shares"

Payments tied to employee or contractor equity awards that mirror the cash dividends paid on the company’s stock; they give the holder the same economic benefit as owning the shares without transferring actual shares—often paid in cash or additional award units when the award becomes payable. Investors care because these payments affect a company’s compensation costs, cash flow and potential share dilution, and they signal how management is being rewarded and aligned with shareholders.

KSOP financial

"Represents current allocation under KSOP."

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did Tim A. Makowski report in this Form 4 for WMS?

Tim A. Makowski reported a grant of 3,729 shares of Advanced Drainage Systems common stock from earned performance-based units, with additional disclosure of share withholding for taxes and indirect holdings through a KSOP.

How many Advanced Drainage Systems (WMS) shares did Makowski receive?

Makowski received 3,729 shares of Advanced Drainage Systems common stock. These shares reflect performance-based units earned for a performance period ending March 31, 2026, and include 53 shares issued as dividend equivalents paid in common stock.

Why were some WMS shares withheld in Makowski’s Form 4 filing?

A total of 192 shares of WMS common stock were withheld to satisfy Makowski’s tax obligations arising from the vesting of restricted common stock. These tax-withholding dispositions occurred at prices of $131.59 and $136.83 per share.

What are the performance-based units mentioned in the WMS Form 4?

The performance-based units were originally granted under Advanced Drainage Systems’ 2017 Omnibus Incentive Plan and became earned after the company determined certain performance goals for the period ending March 31, 2026 were met. They were settled in common stock.

What does the KSOP holding mean in Makowski’s WMS filing?

The Form 4 notes an indirect holding of 17,556.8712 shares of WMS common stock "By KSOP." A footnote explains this represents Makowski’s current allocation under the KSOP, showing additional indirect ownership beyond his directly held shares.

How were dividend equivalents treated in Makowski’s WMS stock award?

Makowski’s performance-based award includes 53 shares described as dividend equivalents. According to the filing, these dividend equivalents are settled in Advanced Drainage Systems common stock, increasing the total number of shares received in the grant.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 05/21/2026 - 06:35 PM EDT Learn about SEC filing dates

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).

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^*

MAKOWSKI TIM A

(Last) (First) (Middle)

C/O ADVANCED DRAINAGE SYSTEMS, INC.

4024 GREEN STRIPE LANE

(Street)

HILLIARD OHIO 43026

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
ADVANCED DRAINAGE SYSTEMS, INC. [ WMS ]

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

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	See Remarks

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/19/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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	05/19/2026		F		104(1)	D	$131.59	2,363	D
Common Stock	05/20/2026		F		88(1)	D	$136.83	2,275	D
Common Stock	05/20/2026		A		3,729(2)	A	$0	6,004	D
Common Stock								17,556.8712	I	By KSOP(3)

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

Explanation of Responses:

1. Represents shares withheld to satisfy Reporting Person's tax obligations in connection with the vesting of shares of restricted common stock of the Issuer.

2. Reflects grant of performance-based units, originally granted pursuant to the Issuer's 2017 Omnibus Incentive Plan, earned after the Issuer determined that certain performance goals for the performance period ended March 31, 2026 had been met. Total includes dividend equivalents in the amount of 53 shares, which dividend equivalents are settled in common stock.

3. Represents current allocation under KSOP.

Remarks:

Vice President, Controller and Chief Accounting Officer

	/s/ Tim A. Makowski, by Scott A. Cottrill as attorney-in-fact	05/21/2026
	** 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.
* Form 4: SEC 1474 (03-26)