April 6 (Bloomberg) -- Wal-Mart Stores Inc., the world's largest retailer, named new chiefs of operations and human resources for its U.S. division, where sales last year grew at their slowest pace in at least 27 years.

Bill Simon will become U.S. chief operating officer and Pat Curran will be executive vice president for human resources, the Bentonville, Arkansas-based company said today in a statement.

The newly created positions are part of an increased focus on the U.S., where Wal-Mart gets about four-fifths of its sales, spokesman Kevin Thornton said. Sales at U.S. stores open at least a year rose 2.1 percent last year, trailing gains outside the U.S., such as a 5.9 percent increase in Mexico.

Simon previously led Wal-Mart's pharmacy division and spearheaded the company's introduction of $4 prescriptions for some generic drugs. He'll continue to oversee pharmacy and other services such as optical and also be responsible for security in stores.

Curran, who joined Wal-Mart in 1983 as an hourly worker in the pets department, was most recently senior vice president of operations on the U.S. East Coast.

As head of personnel at U.S. stores, she will face pressure from unions and politicians including presidential candidates Barack Obama and John Edwards. They have chastised Wal-Mart for its treatment of its 1.4 million U.S. employees, saying the company needs to boost pay and benefits.

Wal-Mart has also faced legislative attempts to mandate what it pays, including a law passed in Maryland last year that was later overturned by a federal judge and a measure in Chicago vetoed by the mayor.

Castro-Wright

Both Curran and Simon will continue to report to Eduardo Castro-Wright, chief executive officer of Wal-Mart's more than 4,000 U.S. stores. The new appointments bring the number of executive vice presidents under Castro-Wright to five. Thorton said today's appointments are part of Castro-Wright's three-year plan to reinvigorate U.S. stores.

Castro-Wright headed Wal-Mart's Mexico unit before becoming chief operating officer in February 2005, then CEO of U.S. stores in September of that year.

Shares of Wal-Mart didn't trade today because of the Good Friday holiday in the U.S. They rose 22 cents to $48.27 yesterday in New York Stock Exchange composite trading, and have gained 4.5 percent this year.

To contact the reporter on this story: Lauren Coleman-Lochner in New York at llochner@bloomberg.net

Last Updated: April 6, 2007 18:01 EDT