With all the parties involved, it's hard to say definitively who should bear the cost of debt gone bad. But because banks serve as central clearinghouses for mortgage debt, and because they have the most cash in the till, they're an easy target for class-action attorneys. Josh Shein is a reformed mortgage broker of sorts whose Maryland-based company, Great Oak Lending, now keeps loans on its books. Shein says the banking industry has two "daunting tasks" ahead - figuring out who is liable for the trillions of dollars in lost home value and changing the culture of the business. Shein describes a typical mortgage transaction before lenders were facing the backlash of a mortgage bubble gone berserk: "This loan was sold three times. It was brokered by XYZ Company. At the time there was no licensing involved for that individual loan officer, so we don't even know who actually did this loan. Then there are servicing issues here and there, with a bunch of places handling them. They talked to a loan-modification company to try to work it out - and maybe it did or didn't get somewhere. Then the foreclosure issue comes up and it ends up getting passed to this other company to do that." "There's all these different players getting involved," Shein concludes. "It confuses and muddies the waters so no one really knows how to resolve this." -- Written by Lauren Tara LaCapra in New York. >To contact the writer of this article, click here: Lauren Tara LaCapra. >To follow the writer on Twitter, go to http://twitter.com/laurenlacapra. >To submit a news tip, send an email to: email@example.com.