Freddie Mac said Thursday that rates on a 30-year fixed-rate mortgage fell to record lows again last week, averaging 4.36 percent with an average 0.7 point for the week ended Aug. 26. Rates fell from 4.42 percent one week earlier, and are well below the average of 5.14 percent recorded one year ago. “Existing home sales plunged 27 percent in July, while new homes fell 12 percent to a new all-time record low, which led to some market concerns that the housing market may slow the economic recovery," said Amy Crews Cutts, deputy chief economist at Freddie Mac. "As a result, long-term bond yields fell to the lowest levels since January 2009, allowing fixed mortgage rates to ease to new record lows this week." Rates on 5-year adjustable rate mortgages remained tied for all-time lows last week, as well, staying at 3.56 percent with an average 0.6 point. Despite record low rates, many borrowers are having a tough time qualifying and closing on purchase money and refinanced mortgages. Home prices declines have left more than 11 million borrowers underwater, according to CoreLogic (CLGX) and largely unable to sell their homes or refinance their mortgages. As testament to the difficulty borrowers face in taking advantage of low mortgage rates, researchers at Barclays Capital recently found that for every 100 borrowers that were 100bps in the money on their existing mortgage during 2000-2008, as many as 60% refinanced into a lower-rate mortgage when they could. By 2009-2010, that figure has fallen to just 20-25%. Paul Jackson is the publisher of HousingWire and