NEW YORK (CNNMoney) -- Bank of America shares plunged 20% Monday, fueled in part by a steep sell-off in the broader market and news that insurer American International Group is suing it for billions of dollars over alleged mortgage securities fraud.
Bank of America , the nation's largest bank, tumbled more than 20% while shares of AIG fell 10% on Monday. Bank of America has already lost nearly 49% of its value this year, while AIG has tumbled more than 59%.
Richard Staite, analyst with Atlantic Equities, said there were two main catalysts for Monday's selloff in Bank of America's stock.
First, the slump in Bank of America's stock is being triggered by more than just the AIG news. It's part of a broader market selloff that took other banking stocks down with it.
Citigroup shares fell 15.7%, JP Morgan Chase slumped almost 8.7%, Wells Fargo fell 9% while shares of Regions Financial tumbled 13.5%.
Second, investors are losing confidence in Bank of America, he said.
"Management has tried to reassure investors over the course of the last six months that they are getting on top of the mortgage problem but investors are very skeptical," he said, adding that there's really nothing that Bank of America can do to stop its stock price from falling.
There was more bad news for Bank of America. Credit default swaps (CDS) tied to its debt were at their highest level since May 2009.
Credit default swaps reflect the interest rates that Bank of America has to pay to borrow money. If they keep rising, Staite said it would exacerbate investor concerns about whether the company has enough liquidity to run its business.