In some cases, agents say, buyers who signed contracts before the market started to fall have managed to renegotiate the sales prices to reflect the current market more accurately.

Image FORFEITED A buyer for this Spring Street penthouse, with stunning river views, walked away from the deal, and a $780,000 deposit. Credit... Tina Fineberg for The New York Times

Frederick W. Peters, the president of Warburg Realty, said his agency had had two multimillion-dollar deals in which buyers had forfeited six-figure deposits. “In both cases,” he explained, “the buyers felt that any renegotiation wasn’t going to satisfy them and they preferred to remove themselves from the market for a while.”

Their decisions, he added, were “driven by the fact it’s a new world and they were not sure what they wanted to do with their resources in the face of that.” When they re-enter the market, Mr. Peters said, they will very likely be able to buy similar properties at prices low enough “that they will still have saved money, even after walking away from their deposits.”

Other walk-away buyers, though, have not given up on the current market and are already searching for other properties to buy.

Penny Toepfer-Guttman, an agent at Brown Harris Stevens, represented someone who gave up more than $1 million in a deposit on an apartment in a new development in Manhattan. She said her client had decided that the original apartment was too unusual a space and that he was now looking for something more conventional.

The first unit, she said, had a huge amount of outdoor space, and because it was priced above $10 million, “he would have been paying more per square foot than anyone else in the neighborhood.” The developer, whom Ms. Toepfer-Guttman would not name, refused to renegotiate the price, so the buyer walked.

Ms. Toepfer-Guttman, who has been an agent for 17 years, said, “I have never seen numbers like this being left in deposits; this is new territory.”