UPDATE 2-Wal-Mart seeks efficiency in new U.S. structure

* US logistics, real estate, store ops now all under COO

* Organizing U.S. into three geographic business units

* Each unit to have a president

* Shares close down 1.5 pct (Recasts with details of new structure, adds company comment, background on CEO Mike Duke, updates stock price, adds byline)

By Nicole Maestri

SAN FRANCISCO, Jan 28 (Reuters) - Wal-Mart Stores Inc (WMT.N) is consolidating some U.S. operations while dividing the country into three regions with separate presidents as the world's biggest retailer looks to more efficiently manage its more than 3,700 U.S. stores.

The company said on Thursday it is consolidating its logistics, real estate and store operations, now all to be overseen by Bill Simon, its U.S chief operating officer.

Andy Barron will oversee store merchandising execution, which will design merchandise strategies for its three new U.S. geographic business units: Walmart West, Walmart South and Walmart North.

Each unit will have its own president, who will be able to run the business in response to local market demands.

Eduardo Castro Wright, who oversees Wal-Mart's U.S operations, said in a memo that the structure would "facilitate our growth as we seek to enter new markets and develop new segments across the U.S."

The changes come nearly one year after Mike Duke became Wal-Mart's CEO, taking the helm on Feb. 1 from Lee Scott, who retired from the role.

At its analyst meeting in October, Duke said Wal-Mart was determined to become more efficient and cut costs, allowing it to offer lower prices, which would in turn drive sales.

The retailer has also been looking for ways to stock its stores with merchandise that is more tailored to local tastes, while also scouting ways to open stores in new markets after saturating many regions with large supercenters.

While Wal-Mart has gained market share amid the economic downturn, analysts are watching to see if customers will continue to shop in its stores as the economy improves.

"The big question mark is are they going to be able to keep these trade-down customers ... and this is a way to ensure that it does become a better place to shop," said Angie Lessuise, an analyst with Telsey Advisory Group, of the new structure.

Earlier on Thursday, Wal-Mart announced a $2 billion sourcing deal with Li & Fung Ltd (0494.HK), which it said should help drive "significant" savings across its supply chain.

Wal-Mart shares closed down 79 cents, or 1.5 percent, at $52.61 on the New York Stock Exchange. (Reporting by Nicole Maestri. Editing by Robert MacMillan, Gary Hill) ((nicole.maestri@thomsonreuters.com, +1-415-677-3975; Reuters Messaging: nicole.maestri.reuters.com@reuters.net))