Wall Street tipped lower in premarket trading as anxiety over the stability of the U.S. banking system dragged on a day after the Federal Reserve announced another interest rate hike. Futures for the S&P 500 and the Dow Jones industrials each fell 0.3% before the bell Thursday. Concerns about a rush of withdrawals by customers of regional banks continues to roil the financial sector. PacWest Bancorp attempted to calm investors investors overnight as its shares plunged 45%. First Horizon shares tumbled 42% before the bell. Zions Bancorp slumped 10%, Comerica fell 7%, and KeyCorp fell 5%.