Freddie Mac Senior Vice President Paul Mullings highlighted billions saved during the current refinancing boom in a blog post Monday, but the market and policymakers want more. "Pick up the paper or turn on the TV and you would think nobody can refinance a mortgage, when more than 10 million already have since 2009, saving billions of dollars in monthly payments," Mullings said. Mullings pointed out refinancing is dominating the government-sponsored enterprises business. Roughly 8 million Freddie and Fannie Mae borrowers made it through standard and streamlined refi programs from March 2009 through June 2011. Including Federal Housing Administration and Veterans Affairs programs, too, the number goes to 10 million. Mullings said the millions who've refinanced through these programs have saved a total $25 billion in mortgage interest payments. Roughly 70% of Freddie Mac business in the second quarter was a refinance, compared to 30% in purchase mortgages. Refis as a percentage of Freddie business peaked in the first quarter at 85% (see chart). The Obama administration began work on ushering in more in recent months, in an effort to help more borrowers who've been shut out of refinancing their mortgage, because it was worth more than the underlying property. The Federal Housing Finance Agency is considering changes to the Home Affordable Refinance Program in order to help more underwater borrowers take advantage of the current historically low rates. Possible changes include eliminating fees and any loan-to-value ratio caps. But the major hurdle in the way of boost even more refinancing opportunities for a struggling housing market are representation and warranty claims. "Risk of putbacks due to faulty reps and warranties remains the top concern for most originators, and many have suggested that rep and warranty risk is the single largest hurdle to meaningful refi reform," Bank of America (BAC) Merrill Lynch analysts said Monday. The talks now center around possibly introducing a supplementary guarantee fee on these refinanced loans that would protect originators against putback risk, but the analysts said even this common ground seems to be fading. "Reports out of the FHFA meeting suggest that this change is off the table. Although originators are gradually getting increased clarity around putback risk, the threat of putbacks continues to serve as a drag on full-scale refinancing efforts," the analysts said, adding they don't expect any changes before the end of the year. Write to Jon Prior. Follow him on Twitter @JonAPrior.