US stocks plummet as investors warn banking situation could worsen

U.S. stocks plummeted Wednesday morning after bank concerns reached European markets, while investors are warning that the banking situation could worsen after the closures of Silicon Valley Bank and Signature Bank over the weekend.

The three major U.S. stock indexes – the NASDAQ Composite, the Dow Jones Industrial Average and the S&P 500 – all fell by more than 1% after the market opened Wednesday, according to Google Finance. 

The stocks were down in pre-market trading after several European banking stocks stopped trading due to severe losses. The market's tumble comes following the collapses of Silicon Valley Bank, in California, and Signature Bank, in New York, over the past week.

The CEO of Blackrock, one of the world's top asset management companies, warned Wednesday that the worst may be yet to come. 

"We don’t know yet whether the consequences of easy money and regulatory changes will cascade throughout the U.S. regional banking sector with more seizures and shutdowns coming," Larry Fink wrote in his annual letter to investors.