WMS officer reports 129-share tax withholding

ADVANCED DRAINAGE SYSTEMS, INC. officer Tim A. Makowski reported a routine tax-withholding transaction related to equity compensation.

Rhea-AI Filing Summary

ADVANCED DRAINAGE SYSTEMS, INC. officer Tim A. Makowski reported a routine tax-withholding transaction related to equity compensation. On May 22, 2026, 129 shares of common stock were disposed of at $133.00 per share to cover tax obligations from vesting restricted stock. After this, he directly holds 5,875 shares of common stock and indirectly holds 17,556.8712 shares through a KSOP allocation.

Insider Trade Summary

Exercise Price or Tax Liability: 129 shares

Exercise Price or Tax Liability 2 txns

Insider MAKOWSKI TIM A

Role See Remarks

Type	Security	Shares	Price	Value
Exercise Price or Tax Liability	Common Stock	129	$133.00	$17K
holding	Common Stock	--	--	--

Holdings After Transaction: Common Stock — 5,875 shares (Direct); Common Stock — 17,556.8712 shares (Indirect, By KSOP)

Footnotes (2)

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. Represents current allocation under KSOP.

Key Figures

Tax-withholding shares: 129 shares Tax-withholding price: $133.00 per share Direct holdings after transaction: 5,875 shares +2 more

5 metrics

Tax-withholding shares 129 shares Withheld to satisfy tax obligations on restricted stock vesting

Tax-withholding price $133.00 per share Value used for 129 shares withheld

Direct holdings after transaction 5,875 shares Common stock held directly after May 22, 2026

Indirect KSOP holdings 17,556.8712 shares Current allocation under KSOP after May 22, 2026

Tax-withholding transactions 1 transaction, 129 shares Form 4 transaction summary for code F

Key Terms

restricted common stock, KSOP, tax-withholding disposition, indirect ownership

4 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.

KSOP financial

"Represents current allocation under KSOP."

tax-withholding disposition financial

"transaction_action": "tax-withholding disposition""

A tax-withholding disposition is an event or transaction—such as selling or transferring securities, exercising options, or receiving compensation—that triggers a requirement to hold back part of the payment and remit it to tax authorities. It matters to investors because it reduces the cash they receive immediately and can change the timing and amount of taxable income, like a cashier taking a portion of your sale proceeds to pay taxes before you get the rest.

indirect ownership financial

"ownership_type": "indirect""

FAQ

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

What insider transaction did WMS officer Tim A. Makowski report?

Tim A. Makowski reported a tax-withholding disposition of 129 shares of ADVANCED DRAINAGE SYSTEMS common stock. The shares were withheld to satisfy tax obligations triggered by vesting restricted stock, rather than sold in an open-market transaction.

How many WMS shares were used for tax withholding in this Form 4?

A total of 129 shares of ADVANCED DRAINAGE SYSTEMS common stock were withheld for tax obligations. The shares were valued at $133.00 per share and relate to the vesting of restricted stock awards granted to the reporting person.

At what price were the WMS shares valued for the tax-withholding transaction?

The 129 ADVANCED DRAINAGE SYSTEMS shares used for tax withholding were valued at $133.00 per share. This price is used to calculate the value of shares withheld to cover the reporting person’s tax obligations from restricted stock vesting.

How many WMS shares does Tim A. Makowski hold after the reported transaction?

After the reported tax-withholding transaction, Tim A. Makowski holds 5,875 shares of ADVANCED DRAINAGE SYSTEMS common stock directly. He also has an indirect interest in 17,556.8712 shares through a KSOP allocation, reflecting retirement or savings plan holdings.

What does ‘shares withheld to satisfy tax obligations’ mean in the WMS Form 4?

It means the company retained 129 ADVANCED DRAINAGE SYSTEMS shares instead of delivering them fully in cash or stock. This withholding covers the reporting person’s tax liabilities triggered by restricted stock vesting, and is not an open-market sale decision.

What is the KSOP mentioned in Tim A. Makowski’s WMS holdings?

The KSOP reference indicates a current allocation of ADVANCED DRAINAGE SYSTEMS shares under a company-sponsored plan. Makowski indirectly holds 17,556.8712 shares through this KSOP, which typically combines retirement and stock ownership features in one plan structure.

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

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Accepted by SEC EDGAR 05/27/2026 - 04:05 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)
05/22/2026

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	05/22/2026		F		129(1)	D	$133	5,875	D
Common Stock								17,556.8712	I	By KSOP(2)

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. 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	05/27/2026
	** 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)