Despite an uncertain art market, Sotheby’s announced this morning that it had earned $73.6 million in the final quarter of 2009, the second-highest earnings ever recorded by the company. That strong fourth-quarter figure helped mitigate some of Sotheby’s rougher patches earlier in the year, allowing the auctioneer to report an overall yearly loss of only $6.5 million.

Though net auction sales slipped seven percent, the auctioneer said it was able to improve margins on auction commissions by cutting internal costs by 28 percent and sharply limiting the use of guaranteed minimums on auction lots, which had hurt the company’s bottom line when demand in the art market declined over the course of the worldwide recession.

Among other good market news heralded by the auction house, private sales grew 27 percent in 2009, to $472.6 million, as sellers sought to sell work discreetly rather than risk a poor public showing. In its statement, Sotheby’s also championed its sale of the world’s most expensive work of art ever bought at auction, Giacomettis L’homme qui marche I, for £65 million ($103.4 million) earlier this month.