PacWest Bancorp PACW.O fell 2.5%, while Zions Bancorporation ZION.O and Western Alliance Bank WAL.N inched up 0.7% and 0.6%, respectively. By Shreyashi Sanyal May 10 (Reuters) - U.S. stock index futures dipped on Wednesday as investors awaited a key reading on inflation to see whether the Federal Reserve's efforts were successful in cooling rising prices. "The direction of rates seems to depend on economic data again, the quasi-banking crisis and liquidity crunch hasn't yet been an active factor that changes Fed course."