Bank of America (BAC) is a leader in trial mortgage modifications stuck in the Home Affordable Modification Program. The bank has 32,495 trials that are more than six months old. The number may seem small, but it is still more than four times the next highest amount held by the mortgage servicing arm of JPMorgan Chase (JPM). The Treasury launched HAMP in March 2009. So far, the servicers participating in HAMP have started 519,648 permanent modifications and started roughly 1.4 million trials. A borrower is supposed to move out of a trial when it he or she has made three monthly payments under the new terms and has submitted all documentation. Over the last six months, servicers have averaged 37,000 permanent modifications per month. But they have been on the decline over the past quarter, dropping 16% in September and falling 26% in August. The Treasury reported 69,400 trials that have aged six months or more, meaning BofA holds nearly half of the backlog held by servicers. (click below to enlarge). The servicers working on loans held by the government-sponsored enterprises hold 10,009 backlogged trials, and JPMorgan Chase hold 7,075. CitiMortgage, the servicing arm of Citigroup (C) holds 4,815. When BofA released its numbers Thursday morning, ahead of the Treasury, it said 18,000 of its aged trials have already received permanent modification offers, and another 4,500 are pending cancellation. Rebecca Mairone, default servicing executive for BofA Home Loans, said the bank has set a priority of reviewing trial modifications that have lasted six months or more. "At this time, we anticipate substantially completing decisions on the remaining 'aged trials' by year's end," Mairone said. Write to Jon Prior.