0000719220-00-000004 DEF 14A 1 19991231 20000315 S&T BANCORP INC 0000719220 6022 251434426 PA 1231 DEF 14A 34 000-12508 570133 43 SOUTH NINTH ST P O BOX 190 INDIANA PA 15701 7244651466 800 PHILADELPHIA STREET INDIANA PA 15701 DEF 14A 1 000071922000000004-001-seq1-def-14a.txt 1999 PROXY