Sotheby’s, the publicly traded auction house, said its third-quarter loss widened as art sales contracted with the global economy.

Its net loss was $57.8 million, or 89 cents a share, up from $47 million, or 73 cents a share, a year earlier. Three analysts surveyed by Bloomberg had estimated a loss of 29 cents a share.

The New York-based auctioneer reported that third-quarter revenue fell 41 percent to $44.9 million.

The auctioneer said most collecting categories were adversely affected by turmoil in the world economy. In addition, Sotheby’s moved its London contemporary-art auction to the second quarter this year from the third quarter of 2008. Last year, those sales were $208 million.

Its New York Impressionist and modern art auction last night totaled $181.8 million, nearly triple the equivalent sale in May.

“The art market is clearly in a better place than it was last autumn and the early spring of this year,” Chief Executive William F. Ruprecht said in a statement.

Before the release, the shares rose $2.32, or 15 percent, to $18.21 today in New York Stock Exchange trading, their biggest rally since March. They’ve doubled this year but remain below their closing high of $57.64, set two years ago.

Sotheby’s helped improve its third-quarter performance by sharply reducing the number of guarantees it offered to win consignments. At the end of 2008, the auctioneer said it lost more than $50 million on guaranteed deals as art prices tumbled with the overall economy.