“And that’s just little bitty me,” he said.

Mr. Haupt is one of thousands of Americans who jumped into the raging housing market of the last decade, which was heralded in stories of neighbors’ windfalls and reality television shows like “Flip That House,” “Flip This House” and “Flipping Out.”

Driving past his empty house recently, Mr. Haupt considered how things had crashed so fast.

“I feel like, yes, I overextended myself,” he said. “But when do you know not to overextend yourself? If I had a crystal ball, I never would have built my house. But when do you know? That’s why we’re speculators.”

He added, “If the banks had a crystal ball, they might not be in this mess either.”

St. Charles County, an affluent, fast-growing neighbor of St. Louis, was a natural incubator for speculators like Mr. Haupt, with a construction boom that doubled the population from 1980 to 2001.

Subdivisions with names like Crimson Meadows, Spring Mill and Barton Creek, pushed the suburban frontier ever farther from St. Louis. For a young builder, the low price of credit drove down the costs of building and drove up the homes’ sale prices.

As long as the market kept going, Mr. Haupt felt he could not lose.

His million-dollar house now sits forlorn and unattended, a dead spot in an expensive subdivision that was once all cornfields. Asked to identify the architectural style, he said, “I call it ‘Bank Repossession’ now.”