Sotheby's ( BID ) long-serving chief financial officer, William Sheridan, will step down from that role next month, a move that comes as the auctioneer faces pressure from activist investors calling for shareholder-friendly action.<br /><br /> Mr. Sheridan took on the CFO role 17 years ago, when he joined Sotheby's in 1996 after serving at accounting and consulting firm Deloitte & Touche. He will be succeeded by Patrick McClymont, a partner and managing director at Goldman Sachs Group Inc. ( GS ). Mr. McClymont's appointment is effective Oct. 7.<br /><br />"It has been a true pleasure to be part of Sotheby's and now I look forward to spending more time with my family and focusing on charitable work," Mr. Sheridan said in a prepared statement.<br /><br />The move comes as activist hedge-fund manager Richard "Mick" McGuire and Daniel Loeb's Third Point LLC disclosed they are engaged in dialogue with members of the auction house's board and management. Sotheby's has said it is in the process of looking into a variety of ways to return capital to shareholders, and plans to report the results of its review early next year.<br /><br />Sotheby's has seen its bottom line alternate between profits and losses in recent years, though revenue has improved in recent periods. The seasonality of the art-auction market tilts to favor its second and fourth quarters.<br /><br />On Monday, Sotheby's said Mr. Sheridan will remain with the company through the end of the year to support the CFO transition. Mr. McClymont, who worked in Goldman's investment banking division, first joined the financial firm in 1998.<br /><br />Sotheby's shares were up 0.8% to $47.60 in recent trading, while shares were broadly trading slightly lower. The stock has gained 42% in 2013.