Four months after President Barack Obama pledged $275 billion to shore up home sales, the engine that powered every U.S. recovery since 1960 is stalled, Bloomberg reported.

Bankers’ reluctance to finance buyers who won’t live in the properties they purchase is one barrier to a turnaround. Stricter qualifying rules and a rise in the cost of residential loans to 5.42 percent have impeded new mortgage lending, which is at a 13-year low. An inventory of 2.1 million unoccupied houses on the market may be a drag on a revival.

The $8,000 first-time homebuyer tax credit in the economic stimulus package and a government program to subsidize some mortgage payments have had little effect, said Eric Belsky, executive director of Harvard University’s Joint Center for Housing Studies in Cambridge, Mass.

“It hasn’t been much more than a seesawing of data,” Belsky said in an interview. “Housing has led the U.S. economy out of every recession for at least 50 years, and for that to happen again more stimulus is going to be needed.”

The residential real estate market improved ahead of the end of the past seven contractions, with home construction starts beginning to climb an average of seven months before gross domestic product picked up and sales gaining about four months in advance, according to data compiled by David Berson, chief economist of PMI Group Inc., a mortgage insurer in Walnut Creek, Calif.

Existing U.S. home sales in May rose 2.4 percent to an annual rate of 4.77 million, lower than forecast, and the median price was down 16.8 percent from the same month in 2008, according to the Chicago-based National Association of Realtors.

There’s little chance the turnover will increase enough this year to end the housing recession, said Andres Carbacho-Burgos, an economist with Moody’s Economy.com in West Chester, Pa.