Walmart US has appointed Duncan Mac Naughton as chief merchandising officer for its US stores.

Naughton will oversee all merchandise categories across more than 3,700 stores in Walmart's US business. He will continue to report to Bill Simon, Walmart US president and CEO.

"We are fortunate to have outstanding, seasoned leadership across our merchant organisation. Duncan has distinguished himself with a proven record of success in every organisation that he has worked in, including Walmart in the United States and Canada," said Simon.

"He is a strong steward of our culture and he understands that merchandising is at the very core of our business. Duncan is committed to giving our customers a breadth of assortment, national brands and every day low prices."

Mac Naughton joined the company in 2009 as chief merchandising officer for Walmart Canada. In October 2010, he was named executive vice president of merchandising for Walmart US, where he was responsible for consumables, health and wellness, and Walmart.com.