NEW YORK ( TheStreet) -- Fannie Mae ( FNMA) and Freddie Mac ( FMCC) completed nearly 1.1 million mortgage loan refinances in 2012 under the Home Affordable Refinance Program (HARP), topping previous estimates. According to a report by the Federal Housing Finance Agency, the number of refinances in 2012 was more than double the 438,228 homes refinanced in 2011 and outpaced the number of loans refinanced through the program in previous years. The jump in volume followed changes to the program made in October 2011 that allowed more underwater borrowers access to refinancing options. About a quarter of the 2012 refinances were for borrowers whose loan balances exceeded the value of their homes by more than 125%. Borrowers need to have a loan-to-value greater than 80% in order to be eligible for HARP refinancing. HARP refinances in the fourth quarter represented 22% total refinancing volume. The program has been particularly successful in some states. In December 2012, HARP refinances accounted for 68% of refinances in Nevada and 58% in Florida. HARP got off to a disappointing start in April 2009, falling far short of the administration's targets. The program was criticized for being too stringent in its requirements for struggling borrowers. Since inception, Fannie and Freddie have refinanced nearly 2.2 million loans, but half the volume kicked in in 2012. Large banks, especially Wells Fargo ( WFC) and JPMorgan Chase ( JPM), have been profiting from the enhanced HARP, reporting strong mortgage origination volume and gains on loan sales during 2012. Analysts expect the refinancing wave to ebb somewhat in 2013. JPMorgan said in a recent Investor Day presentation that it expects HARP volume to fall 50% in 2013, but noted that it still has the opportunity to refinance $250 billion in loans, in its $1 trillion mortgage servicing book. According to FBR Capital analyst Paul Miller, there are still $2 trillion to $2.5 trillion in loans that are eligible for refinancing, which should keep mortgage origination volume strong. Read more on why the mortgage boom should continue, in Mortgage-Banking Boom Has Legs. HARP is set to expire in December 2013, though a bill in Congress aims to extend the program by one more year and expand it to help even more borrowers. -- Written by Shanthi Bharatwaj in New York. >To contact the writer of this article, click here: Shanthi Bharatwaj. >To follow the writer on Twitter, go to http://twitter.com/shavenk. >To submit a news tip, send an email to: email@example.com.