Bank of America reported better-than-expected earnings Wednesday but shares fell as investors worry that mortgage problems may continue to plague the bank.

So far Bank of America has set aside roughly $35 billion to service its delinquent mortgages and the potential costs and litigations from so-called putbacks, or what government agencies like Fannie Mae and Freddie Mac and private lenders including Blackrock (BLK, Fortune 500) and Pimco (PTTRX) can charge Bank of America for improperly underwriting mortgages.

Many analysts wonder whether that’s enough.

“It’s still really hard to model Bank of America’s expenses because of these mortgage costs,” said Jefferson Harralson, a banking analyst at Keefe, Bruyette & Woods.

Source: CNN