X0306 5/A 2015-12-31 2016-02-12 0 0 0000719220 S&T BANCORP INC STBA 0001658977 Lazzari Melanie A 800 PHILADELPHIA STREET INDIANA PA 15701 1 Senior Vice President Common Stock 2015-12-31 5 J 0 8.213 30.82 A 2851.534 D Common Stock 2015-12-31 5 J 0 101.058 30.82 A 3273.484 I 401(k) Increase due to reinvested dividends in a dividend reinvestment plan. Dividends reinvested in 2015 were inadvertently double counted. Actual recorded amount as of 12/31/2015 should have been 8.213. These shares represent the YTD increase in shares held in a 401K plan. /s/Timothy P. McKee, attorney-in-fact for Melanie A. Lazzari 2016-03-30