NEW ALBANY, United States — Abercrombie & Fitch Co. executive chairman Arthur Martinez is retiring, signalling that a long quest to set the clothing chain on a new course is wrapping up.Martinez will step down on February 3 when the fiscal year ends, the company said on Monday. The 78-year-old has been chairman since 2014, the year when long-time chief executive Mike Jeffries departed and the once-hip clothing brand set out to regain its cachet with shoppers.The company also boosted its fourth-quarter forecast on Monday, sending the shares up as much as 6.3 percent in early trading.Abercrombie struggled for years with tumbling sales and a leadership void. It had no permanent chief executive until its chief merchandising officer, Fran Horowitz, stepped into the role last year. Since then, the company’s Hollister chain has helped fuel a turnaround at the New Albany, Ohio-based company.Martinez, the former chief executive of Sears Roebuck & Co., will hand the chairman role to Terry Burman, who already serves as lead independent director.Abercrombie now expects same-store sales to grow in the high single digits, up from a previous projection in the low single digits. The company will report its results on March 7.The stock climbed as high as $21.18 in premarket hours. It was up 45 percent last year, rebounding from six straight years of declines.By Nick Turner; editors: Nick Turner and Lisa Wolfson.