US existing home sales increased nearly 10% from August to September, and sales activity is at its highest level since July 2007, the National Association of Realtors (NAR) said. September marks the fifth month to post a month-over-month gain out of the last six months, NAR said. September’s 9.4% increase brings existing sales to a seasonally adjusted annual rate of 5.57m units, up from 5.1m in August. September 2009’s rate is 9.2% higher than the same month a year ago. July 2007’s rate was 5.73m. NAR chief economist Lawrence Yun said the increase in market movement is due to low prices and mortgage rates and a surge in first-time homebuyers. “Much of the momentum is from people responding to the first-time buyer tax credit, which is freeing many sellers to make a trade and buy another home,” he said. But Yun warned, the market is still underperforming, and while there are indications of price stabilization, there is a need for more buyers in the market. NAR said the total housing inventory at the end of September fell 7.5% to 3.63m existing homes available for sale, representing an 7.8-month supply at the current sales pace, down from an 9.3-month supply in August. Unsold inventory totals are 15% below a year ago. The national median existing-home price for all housing types was $174,900 in September, 8.5% lower than September 2008. NAR’s measure of existing home sales includes single-family, townhomes, condominiums and co-ops. Write to Austin Kilgore.