The state of California announced today that it is suing Wells Fargo, accusing it of falsely assuring investors that their investments were as safe as cash, Reuters and the Associated Press are reporting.

The lawsuit was filed in San Francisco today, and a press conference by California Attorney General Edmund Brown was expected later this afternoon.

The investments in question were “auction-rate securities,” often municipal or corporate bonds with long-term maturities, Reuters reports. About 2,400 Californians were unable to access their investments after the market seized up in February 2008, the lawsuit says.

Wells Fargo has issued a statement disputing the allegations:

“We fully understand and deeply regret the effects this prolonged liquidity crisis has had on our clients. Wells Fargo could not have predicted these extraordinary circumstances, and even with the benefit of hindsight is not responsible for them.”