Sotheby's (BID: sentiment, chart, options) shares have taken a dive today after the company reported a first-quarter earnings loss. The auction house lost $12.4 million, or 19 cents per share, reversing about half of its year-ago profit of $24.3 million, or 37 cents per share. Revenue slipped 12% lower to $129.3 million. Ahead of the report, analysts' expectations called for a profit of 10 cents per share on $141 million in revenue.

Revenue for the quarter was dented by lower auction-commission margins, while profits were pressured by a jump in salaries and administrative costs. President and CEO Bill Ruprecht noted that BID slashed its auction guarantee risk exposure in order to allow for "greater financial market uncertainty. This necessarily required our agreeing to thinner commission margins in order to win consignments." However, Ruprecht added, "The market continues to be strong, and the demand for great works of art remains high, as we have seen throughout the spring, and most recently on Wednesday night." (The auction house raked in $273 million from a New York Impressionist art sale earlier this week.)

At last check, BID is down more than 8% as investors react to the disappointing report. Today's plunge has effectively dashed BID's chances of closing a second consecutive week atop its 10-week moving average. This trendline, in tandem with its 20-week counterpart, has pressured the stock lower since last November.