Competitive bidding for high value works combined with commissions from booming private transactions pushed Sotheby's consolidated sales to a record $3.4 billion in the first half of 2011. Sotheby's private sales were up 114% in the first half. Second-quarter earnings surged by 48%.

The publicly-traded auction house announced Wednesday that net income was $129.7 million for the first six months of the year, up 54% over 2010.

The net income improvement was offset by higher salaries, headcount increases, administrative cost increases, and consulting fees, says Sotheby's, even while a contract dispute with the company's unionized art handlers has boiled over into picketing this week.

Auction commission margin fell to 16.4% from 18.7%, due to competition for consignments.

“This is the best quarter in Sotheby’s history,” said Bill Ruprecht, President and Chief Executive
Officer. “Record first half consolidated sales (up by 44%) reflected the surge of activity from buyers and sellers across China as well as significant increases in auction sales in each of our four principal selling centers."

Among the year's highlights so far was the Contemporary Art Evening sale that brought $174.1 million, the highest total ever for the category in London.

The London Impressionist week was notable for Egon Schiele’s 1914 Cityscape Hauser mit bunter Waesche (Vorstadt II)/ Houses with Laundry (Suburb II) which sold for $40 million, almost double the previous record for the artist at auction.

Another stand-out sale was Guardi’s Venice, a View of the Rialto Bridge, Looking North, from the
Fondamenta del Carbon, which sold for $42.9 million, the second highest price achieved at auction for an Old Master painting, during the $76.5 million Old Master and British Paintings Evening Sale in July.

"As I look back on these extraordinary six months for our business, the global appeal of art was one of the few constants in a period of continued economic uncertainty," said Ruprecht.