The wealthy took a break from buying mansions in the Hamptons last quarter. The question is whether it signals a broader cool down in the luxury real estate market.
Average sale prices in the Hamptons fell 26 percent in the fourth quarter compared with the same quarter last year, according to a report from Douglas Elliman and Miller Samuel. The median sales price fell 15 percent and the number of sales fell 6 percent.
The top end of the Hamptons market fared the worst. Among the top 10 percent of sales, prices fell 27 percent and sales were down 7.5 percent.
(Read more: Hamptons beach home sales hit new record)
Don't go looking for bargains, however. The average sales price in the New York rich's beach playground was still $1,574,327. And Elliman said the fall off was more of a statistical anomaly than sign of a weaker market. The fourth quarter of 2012 saw a surge of buying as a result of the expected "fiscal cliff" tax hikes, as sellers rushed to close deals before the taxes went up.
"The current market shows stability," the report said.
(Read more: 10 of the most expensive views in America)
But the sudden rise in inventories in the Hamptons suggests there is also a risk of a broader chill in the high end—especially as the stock market starts to level off. Listing inventory jumped a whopping 53 percent in the fourth quarter, and the monthly absorption rate surged to 9.5 months from 5.8 months a year ago.
(Read more: Which state leads in millionaires per capita?)
"The Hamptons market is still healthy, but it's not going to set the world on fire," said Dorothy Herman, president and CEO of Douglas Elliman. "It will do well, but I don't think we'll see a lot of new records this year."
—By CNBC's Robert Frank. Follow him on Twitter @robtfrank.