NEW ALBANY, United States — Abercrombie & Fitch Co. Chief Executive Officer Mike Jeffries, who turned the retail chain into a hot teen-apparel company in the 1990s before it lost its cachet in recent years, is stepping down.

Jeffries will retire immediately as CEO and a member of the board, the New Albany, Ohio-based company said today in a statement. The board is now seeking a replacement for Jeffries and has enlisted an executive-search firm to identify both internal and external candidates.

Jeffries, 70, has come under fire as the Abercrombie and Hollister clothing lines lost their relevance with teenage shoppers, leading to declining same-store sales and tumbling profit.

Abercrombie had already stripped Jeffries of his chairman role earlier this year. It created a new chief operating officer job and named four new independent directors to its board as part of a deal with Engaged Capital LLC, an activist investor that sought changes at the company. The retailer has also named two new executives to head up the Abercrombie and Hollister brands.

Investors applauded Jeffries’s departure, sending the stock up as much as 9.8 percent to $28.94 in early trading. Through yesterday’s close, the retailer’s shares had fallen almost 20 percent this year so far.

As part of today’s changes, Abercrombie & Fitch’s nonexecutive chairman, Arthur Martinez, will become executive chairman.

By Lindsey Rupp; editors: Nick Turner, Cecile Daurat.