Yet again the results underline just how important this growing source of business is to the auction house and its chief rival, Christie's. The two are now also thought to be the world's largest dealers as a result of this activity.
Overall, Sotheby's revenues grew 18%, reaching $68.5m, largely thanks to the $4.9m private sales revenues and a $1.6m boost in finance segment revenues.
The third quarter which runs to the end of September traditionally returns a loss as it covers the relatively inactive summer period. This year was no exception, with Sotheby's declaring a pre-tax loss of $46.4m, but that was $11.5m less of a loss than for the third quarter of 2011.
However, the net loss was up $2.8m largely, says Sotheby's, because last year the company benefited from a favourable reassessment of their tax liability.
It is likely to be the markets themselves rather than internal tweaking that will have the most significant impact on the company's performance by the end of the year.
The weakening Far Eastern market has been evident in the comparison of results from the October sales in Hong Kong: $261.9m in 2012 as opposed to $410.8m in 2011.
Overall, the first nine months of 2012 saw a 58% ($57.7m) fall in profits year on year. Again, Sotheby's point to 2011 as a boom year, with a large number of single-owner sales, as the reason for this year's decline, adding that this has partially been offset by strengthening private treaty sales revenues.
Seasonal highlights have boosted revenues, however, including Gerhard Richter's Abstraktes Bild, which set a record for a work by a living artists when it took £19m in London on October 12.
Chief executive Bill Ruprecht also announced that Sotheby's had been able to restructure the company's debt at far more favourable rates to contribute significantly to the bottom line. The resulting savings will allow the company to settle convertible notes, which form part of their debt security, by the time they mature in June next year.
