X0609 4 2026-10-05 0 0001990354 Waystar Holding Corp. WAY 0002091511 Chan William false 1550 DIGITAL DRIVE #300 LEHI UT 84043 0 1 0 0 Chief Product & AI Officer 0 Common Stock 2026-10-05 4 F 0 9560 26.07 D 1571252 D The transaction represents shares of common stock withheld to pay taxes upon vesting of restricted stock units (RSUs) granted to the Reporting Person on October 2, 2025. The number of shares withheld was determined based on the actual sale price of shares sold on October 5, 2026 pursuant to a "sell-to-cover" transaction. Includes unvested RSUs. /s/ Gregory R. Packer, as Attorney-in-Fact 2026-10-06