Wal-Mart Stores’ second-highest executive, the vice chairman, Thomas Coughlin, will retire next month after more than 25 years at the world’s largest retailer amid sluggish same store sales.

Mr. Coughlin, 55, will leave January 24 and will serve on the board through June 3, the Bentonville, Ark.-based company said. His duties, which include overseeing all of Wal-Mart’s American divisions and operations such as logistics, will be divided among other executives.

Mr. Coughlin has overseen improving sales at the Sam’s Club chain during the last two years while gains at Wal-Mart stores have slowed as higher gasoline prices crimp consumer spending. After limited discounting resulted in tepid November sales, Wal-Mart last week took the unusual step of buying full-page newspaper ads to promote price cuts on about two dozen holiday items.

“This is someone who has such vast experience in all parts of the company,” said an analyst at National City Corp.’s private client group in Cleveland, Amy Bonkoski, whose $26 billion in assets include Wal-Mart shares. “His experience will certainly be a loss to Wal-Mart.”

Mr. Coughlin’s departure probably had nothing to do Wal-Mart’s disappointing comparable sales, which rose 0.7% in November, said New York-based Matrix USA analyst Ivan Feinseth, who doesn’t own Wal-Mart shares.

“He could have woken up this morning and said I don’t feel like working anymore,” Mr. Feinseth said. “He has plenty of money and may want to focus on other things.”

Mr. Coughlin received $3.86 million in salary and bonus last year.

Some investors disagree with that assessment.

“At Wal-Mart, they don’t tolerate errors,” said Marvin Roffman, president of Roffman Miller Associates, which manages $280 million in Philadelphia and owns Wal-Mart shares. “The competition is getting aggressive and they are paying the penalty. Wal-Mart doesn’t like to lose market share and they are losing some share right now, though the losses are small.”

Mr. Coughlin’s departure is his own choice, said a spokesman, Jay Allen.

Mr. Coughlin was treated for an arterial blockage in October of last year. He has recovered from the blockage and his decision to retire isn’t health-related, Mr. Allen said.

The president and chief executive of Wal-Mart Stores USA, Mike Duke, will take on responsibility for logistics and the finance and compliance office. Mr. Duke and the chief executive of Sam’s Club, Kevin Turner, who reports to Mr. Coughlin, will report directly to Wal-Mart’s chief executive, H. Lee Scott, the company said. Wal-Mart’s Internet operations will report to the chief financial officer, Tom Schoewe.

Mr. Coughlin was named vice chairman of the American business, a new position, in April 2003 to broaden his duties to include distribution and online sales. The position enabled the company’s divisions, including Wal-Mart Stores, Sam’s Club, andWalmart.com, to work more closely in merchandising and planning.

Under Mr. Coughlin and Mr. Turner, Sam’s Club refocused on small businesses, such as day-care centers that buy art supplies and restaurants that buy pots and pans, and added higher price merchandise such as wine to get customers to buy extra items when they shop. Profit at Sam’s Club has risen for six straight quarters after three quarters of declines.