Tim Makowski's Stock Transactions and Performance Award Vesting at Advanced Drainage Systems

This Form 4 filing reports stock transactions by Tim A. Makowski, Vice President, Controller and Chief Accounting Officer of Advanced Drainage Systems, Inc. (WMS). The filing covers transactions from May 19-20, 2026, including the sale of 192 shares to cover tax obligations on vested restricted stock (104 shares at $131.59 on May 19 and 88 shares at $136.83 on May 20). More significantly, the filing reports the vesting of 3,729 performance-based units on May 20, which were earned after the company determined that performance goals for the period ended March 31, 2026 had been met. This award includes 53 dividend equivalents settled in common stock. Following these transactions, Makowski directly holds 6,004 shares and indirectly holds 17,556.8712 shares through the company's KSOP plan. The transactions reflect routine tax withholding on vested equity awards and the achievement of performance-based compensation targets.