(Reuters) - Walmart's ( WMT ) Executive Vice President of Supply Chain Dave Guggina will become the retailer's U.S. chief e-commerce officer, replacing Tom Ward, according to a company memo seen by Reuters on Friday.

Ward will take on the role of chief operating officer of Sam's Club, Walmart's ( WMT ) warehouse chain.

In his prior role with the company, Guggina worked to implement automation in the supply chain.

The move comes as the Bentonville, Arkansas-based retailer is investing billions to expand its e-commerce business by providing more product choices online, and automating its supply chain to improve delivery times.

In November, Walmart ( WMT ) posted a 22% jump in third-quarter U.S. e-commerce sales, partly aided by increasing consumer preference for purchasing groceries online.