Now, agents say their biggest challenge is potential sellers who are wary of putting their home on the market because they fear they cannot find a place to buy.

Jeff and Lorena Leininger considered moving from their suburban Los Angeles home over the last several years, but they feared they would not get as much as they paid for it. But this year, with their youngest child getting ready for kindergarten, they decided it was time. Three days after showing the home, they had nine offers.

“It felt as crazy as it was back when we bought 10 years ago,” Mr. Leininger said. “But it was much worse on the other side. We would show up to an open house, and it was already sold. The clear message was: be ready to move fast or just get left out.”

Even in Florida, where the market was once swamped with foreclosures, there are signs of the latest boom, with cash purchases fueled in part by international investors and retirees awash in cash after selling their homes elsewhere.

Don Faught, a manager with Alain Pinel Realtors near San Francisco, said the current market is turning buyers to desperation, particularly because the turnaround has come so quickly.

“A year ago, people didn’t want a deal, they wanted a steal,” he said. “Sellers were listing homes for less than what they originally paid for them and offering all these concessions. Now, the only concessions are coming from the buyers.”

His office has begun to track the number of offers clients make before landing a property. The current record: 27 offers, nearly all at or above asking price.