Sotheby's announced last week that it would be increasing its buyer's premium, the commission paid the auction house above the hammer price, in a move already taken by rival Christie's earlier in the month.

Beginning March 15, auction buyers will pay 25% on the first $100,000 of the hammer price, 20% on the portion of hammer price above $100,000 up to and including $2 million and 12% on any remaining amount above $2 million. Sotheby's says this translates to an increase of 2% or less for 98% of buyers on the final purchase price.

Sotheby’s reported an 11% drop in auction commission revenue in 2012 and a 10% reduction in net auction sales.

Commission revenue decreased for big-ticket sales in the impressionist, modern and contemporary art categories where the top auction houses compete vigorously for high-end consignments.

Sotheby’s net income for 2012 was $108.3 million, down 37% from 2011, but private sales were up 11%.