The inventory of resale homes jumped to 9.6 months in July, as the sales rate for that month dropped 9 percent compared to the same month last year, the National Association of Realtors reported today.

A for-sale inventory greater than six months is generally considered to indicate a buyer’s market — this statistic indicates the length of time it will take to deplete the for-sale inventory at the current sales pace. The existing-home inventory has climbed 31.5 percent since July 2006, when there was a 7.3-month supply.

The inventory of single-family resale homes was 9.2 months in July while the inventory of condominiums and cooperatives rose to 11.9 months.

Subprime mortgage loan defaults and excessive household and corporate debt represent a greater short-term threat to the U.S. economy than terrorism, energy prices or inflation, according to a new survey of economists.

Nearly one in three of members of the National Association for Business Economists surveyed in July and August said the housing boom can be described as “a serious national bubble.” Close to two in three economists surveyed cited easier credit standards as the number one or number two cause driving the housing boom.

In the span of a couple of weeks earlier this month, Tyler Nelson went from renting, to thinking he was a homeowner, back to renter, and finally, as of Friday, a homeowner again.

He hopes.

A few months ago, the North Dakota native started researching a home purchase - even after some friends and colleagues told him it would be virtually impossible for a 24-year-old to buy in pricey San Francisco.

An electrical engineer, Nelson found he enjoyed learning about tax laws and mortgages - that is, until earlier this month, when the application and approval process became a lot more complicated.

Selling or buying a home is more than a financial transaction. It’s a major life event, and often the gateway to a significant transition: starting a family, retiring, transferring jobs, moving closer to relatives.

With the real estate market softening and mortgages becoming harder to get, many home buyers and sellers are stymied, unable to progress with their plans because they cannot get their deals done.

In the Bay Area, sales volume has fallen to the lowest level in 12 years. Although prices in certain higher-end communities are holding steady, they are decreasing in neighborhoods with a large number of new or entry-level homes. Houses are lingering on the market much longer.

In some ways, the Sanchez family embodies a real estate success story.

Two brothers, Antonio and Pedro, and Antonio’s wife, Isabel, bought a three-bedroom home in the East Oakland flatlands five years ago. They saved up a 3 percent down payment from the brothers’ jobs at a vegetable market and Isabel’s part-time work cleaning houses.

They have lived together in the remodeled Craftsman on a street of tidy bungalows since then. They rent out a small apartment over the garage to help with the mortgage.

The house is now worth $425,000, $100,000 more than they owe on the mortgage.