Fewer borrowers entered into contracts to buy existing homes during March, the National Association of Realtors said Wednesday, as tougher underwriting guidelines and falling home prices continued to dampen buyer demand. The NAR said that its index of pending home sales edged down 1.0 percent in March compared to February levels, and was 20.1 percent lower than in March 2007. March is typically the start of the spring selling season, and pending contracts traditionally begin an upward swing in the month, analysts told HW — meaning that the 2008 selling season is likely to be significantly weaker than any seasonal sales cycle in recent memory. Bloomberg reported that the 1 percent drop matched economists’ median expectations. “Things are beginning to improve,” said NAR chief economist Lawrence Yun, “but the availability of affordable mortgages is uneven around the country and sometimes within metropolitan areas.” Yun said he expects to see improvement in pending sales numbers in the back half of this year. Regionally, three of four regions saw contract volume drop in March, with the Midwest leading the fall at 10.4 off versus February’s numbers; the Northeast saw a 12.5 percent monthly jump, but remains 15.4 percent below year ago levels, the NAR said. The NAR, somewhat surprisingly given recent history, left its forecast for annual existing home sales largely unchanged, although it significantly revised — downward — its expectations for new home sales. The realtors said they now expect 536,000 new home sales in 2008; one month ago, they forecast 576,000. For more information, visit http://www.realtor.org.