You know the story: Last year we all learned that mortgage lenders were breaking the law and rushing foreclosures through by forging documents and signatures in what’s become known as the robosigning scandal.

In a deal with Federal investigators and states’ attorneys general, 14 of the largest banks in the country — as well as Lender Processing Services and Mortgage Electronic Registration Systems (MERS) — agreed to change their polices so they wouldn’t be breaking the law.

They also agreed to have an independent third party review 4.5 million foreclosure files to determine how much harm they did to borrowers, and then to contact those borrowers (presumably to apologize).

On Friday, acting comptroller of the currency John Walsh told The Institute for International Finance that the process would likely take more than a year. That’s because, when his office reviewed some sample loans it found

critical deficiencies in the way they were handled by the servicers – deficiencies in the
governance process, in document preparation, and in the oversight and monitoring of third party law firms and vendors.

So now his office has teams of examiners working full time in those banks (“as many as 80 in a single large bank, assisted over the course of the year by perhaps two dozen more”) to see what laws were broken, who was hurt, and to let the public know what remedies are available.

Walsho pointed out that “Every borrower who was subject to foreclosure in 2009 and 2010 has a right, under our orders, to request a review of their case if they believe they suffered financial harm because of deficient practices.” So you can bet that will add to the banks’ work load — and subtract from their balance sheets.

As Walsh put it:

These enforcement actions will be a complex and expensive undertaking for the banks,
and the amount of restitution is open-ended and will only be known when the process ends.