PacWest Stock Continues to Tumble Amid Deposit Drop and Borrowing Capacity Boost.

PacWest Bancorp's shares fell 20% in premarket trading after the bank pledged more assets as collateral to the US Federal Reserve to increase its borrowing capacity and said deposits declined about 9.5% during the week ended May 5. The bank pledged an additional $5.1bn of its loans to the central bank on Wednesday, resulting in an additional borrowing capacity of $3.9bn. The slump dragged down other regional banks, with shares of Western Alliance Bancorp, KeyCorp and Zions Bancorp down between 2.4% and 8%.