144 0001252518 XXXXXXXX LIVE 0000719220 S&T Bancorp, Inc. 000-12508 800 Philadelphia Street PO BOX 190 Indiana PA 15701 412-944-4707 William J. Hieb Director Common Stock Fidelity Brokerage Services LLC 245 Summer Street Boston MA 02110 10689 543749.43 34633 08/11/2026 Nasdaq Common Stock Equiniti c/o Apex Clearing 350 N St. Paul Street Suite 300 Dallas TX 75201 6600 335742 34633 08/11/2026 Nasdaq Common Stock 11/30/2019 Exchange of stock at time of merger DNB Financial Corporation N 10689 11/30/2019 N/A Common Stock 05/15/2023 Stock award S&T Bancorp, Inc. N 1832 05/15/2023 N/A Common Stock 05/14/2024 Stock award S&T Bancorp, Inc. N 1905 05/14/2024 N/A Common Stock 05/13/2025 Stock award S&T Bancorp, Inc. N 1573 05/13/2025 N/A Common Stock 05/12/2026 Stock award S&T Bancorp, Inc. N 1290 05/12/2026 N/A Y Shares are being sold from The Hieb Family Trust. 08/10/2026 /s/ Jackie Kennane, attorney-in-fact for William J. Hieb