Jan 17 (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.