Sotheby's auction house saw revenue increase during the third quarter of 2012, according to a quarterly report filed yesterday by the publicly traded company.

The house's net income declined 58 percent, or $57.7 million, during the first nine months over the same period last year, when, according to a press release, the house saw an unprecedented number of single-owner sales, typically more lucrative.

Partially offsetting that loss, the company saw an increase in private sale commission revenues of $8.2 million to $56 million, a 17 percent increase.

"The art market remains quite robust, especially at the high end," said CEO Bill Ruprecht on a Thursday afternoon conference call.

Third quarters typically represent a loss for the company, since its most profitable auctions take place in the second and fourth quarters.

But Sotheby's reported that revenue increased 18 percent in the third quarter, to $68.5 million. The increase was driven by a $4.9 million or 50% rise in private sale commission revenues and a $1.6 million or 56 percent increase in finance segment revenues.

In the conference call, analysts asked whether the company could expect such a growth rate to continue, but CEO Bill Ruprecht and CFO William Sheridan demurred, saying they have no crystal ball to determine what clients may choose to sell, or what estates will come on the market in any particular future quarter.