Union Bank now faces "hundreds of millions of dollars" in potential damages, according to plaintiffs lawyer Aaron Podhurst of Podhurst Orseck. But recent appellate rulings may have given other defendants the ammunition they need to avoid the same fate.

The appeals court concluded that plaintiffs didn't have to show they were directly overcharged to claim damages from an alleged scheme requiring private mortgage insurers to pay kickbacks to Countrywide. In three other cases, Barroway makes similar allegations against GMAC, Wells Fargo, and WaMu.

Do banks have the right to charge huge penalty fees for checking account overdrafts? A senior judge in Florida ruled that 15 cases raising such allegations can proceed to discovery in litigation that could cost the banks hundreds of millions of dollars.