[finance.yahoo.com]

Wall Street's credit worries are intensifying after a warning from JPMorgan Chase (JPM) CEO Jamie Dimon about cockroaches in the US economy. Investors on Thursday punished the stocks of regional banks and an investment bank exposed to the bankruptcy of an auto parts maker.

The regional banks that plummeted Thursday were Phoenix-based Western Alliance Bancorporation (WAL) and Salt Lake City's Zions Bancorporation (ZION). Zions' stock fell 13% and Western Alliance's stock fell nearly 10%.