BENTONVILLE, Ark. (AP) – Wal-Mart Stores Inc. announced Tuesday that one of its key executives, Eduardo Castro-Wright, will retire in 2012.

The world's biggest retailer said that Castro-Wright, 56, will retire from his role as vice chairman of Wal-Mart and CEO of its global ecommerce and global sourcing business on July 1. Wal-Mart aims to name a replacement by the end of January and have Castro-Wright assist in the transition.

Castro-Wright joined Wal-Mart in 2001 and worked as the head of its business in Mexico before becoming president and CEO of its U.S. operations in 2005.

In June 2010, Wal-Mart appointed Bill Simon, who had been chief operating officer, to take over its U.S. operations, shifting Castro-Wright to lead the retailer's global ecommerce and sourcing business. Wal-Mart said at the time that the move allowed Castro-Wright to relocate to California to be with his family, including his wife who was recovering from a heart transplant. It also helped Wal-Mart increase its emphasis on building its international online business.

The executive moves occurred amid a slump at Wal-Mart's U.S. business as it grappled with tough economic times and mistakes it made in pricing and merchandising. Wal-Mart's U.S. business has had nine consecutive quarters of declines for a key revenue measure, the longest stretch in its history.

The company has been re-introducing merchandise it cut during an overzealous bid to reduce clutter in its stores and has returned to offering "everyday low prices" at its stores. In August, it told investors it expects to reverse the declines by the fourth quarter.

Wal-Mart has focused more on its international business from growth as sales in the U.S. have softened. The company's overseas business, which includes China, Brazil, Japan, Mexico and other countries, made up approximately 26 percent of the company's revenue in fiscal 2011.

Wal-Mart, based in Bentonville, Ark., has more than 9,700 stores under its various banners in 28 countries.

"(Castro-Wright) has been a strong advocate for our customers and in every assignment has brought passion and commitment to the job. He has also built talented teams wherever he has led," the company's CEO Mike Duke said in a statement.

Under Castro-Wright's leadership, Wal-Mart has notably expanded its online business overseas.

Wal-Mart bought a minority stake in online company Yihaodian in China in May. It has added online shopping for home delivery in a number of countries as well. The company says expanding this business has been crucial to Wal-Mart because it provides people outside the biggest cities the same opportunities that Wal-Mart stores did 50 years ago when the company first brought products to rural areas of the U.S.

Castro-Wright also has worked to help Wal-Mart to develop shopping opportunities for mobile devices and tapping into social networks. Under his stewardship, Wal-Mart bought social media company Kosmix in April to help strengthen its social and mobile commerce.

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