The Hamptons is drawing in big bucks, but from fewer buyers, a new report finds.

A second-quarter market report from Prudential Douglas Elliman shows that in the luxury market in the Hamptons and the North Fork of Long Island, the median sales price increased 10.3%, to $4,412,500, from the prior-year quarter, although inventory increased 46.8%, to 499 units, and the number of days a property sat on the market increased 92.4%, to 152 days. Sales dropped 11.5%, to 54 units.

“You’re really looking at a lower level of activity, expanding inventory, greater days on the market. The price indicators are dropping, as well,” the president of the appraisal firm Miller Samuel, which wrote the report, Jonathan Miller, said. “The exception to these weakening indicators has been the upper end of the market.”

The top three Hamptons locations for average sales price are Sagaponack, Shelter Island, and Quogue, with price tags of $8.275 million, $12.2 million, and $15.65 million, respectively.

The Hamptons have “a close linkage with Manhattan. A concern with lower bonuses next year and layoffs causes inventory to rise and market time to expand,” Mr. Miller said.

“Let’s say you’re losing your job, not sure of your future. The first property you’d put on the market would probably not be your primary residence,” the chief executive officer of Prudential Douglas Elliman, Dottie Herman, said. Because the Hamptons is a second home market, properties there are often sold first, she said.

According to the report, the median sales price fell 9.2% in the Hamptons and the North Fork market, to $817,500, from the prior-year quarter, with the number of sales falling 13.3%, to 541 units, and inventory increasing 30.7%, to 1,849 units.

“I think in some places prices have gone down, but I think it’s a listing-by-listing basis,” an associate broker with the Corcoran Group, Cathy Tweedy, said. “I don’t think it’s universal.”

The report shows some bright spots: The median sales price for Hamptons properties south of Route 27 increased 1%, to $1.55 million, largely because of the area’s many luxury homes with high prices and ocean views, and the scarcity of land there.

“Right now everything is in flux,” Ms. Herman said. “I think with the Hamptons, it’s a pretty safe bet. There is only so much land and oceanfront.”