Wal-Mart Stores Inc. is seeking an executive to evaluate possible acquisitions and new store formats as it faces slowing sales growth and new competition in America.

The retailer, which hasn’t acquired an American company in at least 13 years, wants someone to “assess the strategic implications of any possible M&A on our overall portfolio,” according to a job posting on the Bentonville, Ark.-based company’s Web site. Wal-Mart’s American sales growth at stores open at least 12 months last year was 2.1%, the slowest since it began reporting the data in 1980. Wal-Mart is bracing for the entry of Tesco Plc, the largest British retailer, to America this year. Tesco plans to open a chain of convenience stores, called Fresh & Easy Neighborhood Markets, featuring prepared foods.

“The company should be focusing on improving its core stores,” an analyst at Banc of America Securities, David Strasser, wrote in a report yesterday. “We believe they need to fix this business before diversifying further.”

Wal-Mart spokesman John Simley called the posting “one of several middle-management-level positions that really was aimed at evaluating our existing formats with the aim of achieving better customer relevance.”