PacWest, Western Alliance Stocks Lead Renewed Regional Bank Selloff

Trading in both firms triggered multiple volatility halts after PacWest fell as much as 42% while Western Alliance plunged 27%. The KBW Regional Banking Index dropped as much as 7%, the most since the crisis that engulfed Silicon Valley Bank in March. 

Charles Schwab Corp., a brokerage with a banking arm that's come under pressure in the recent rout, sank 5.3%. Comerica Inc. and Zions Bancorp. each fell more than 10%.

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Part of what's driving bank shares down is the fact that many regional bank investors assumed the Federal Deposit Insurance Corp. would announce a change to deposit insurance alongside its announcements about the First Republic receivership process, said Gary Tenner, an analyst at DA Davidson. The level of uninsured deposits at Silicon Valley Bank and Signature played a key role in the bank runs that led to their downfall.