Two of Walmart (WMT)'s executives are leaving the company less than four months after John Furner became CEO, CNBC reported Friday.

Tom Ward, chief operating officer of Sam's Club, is retiring, while Cedric Clark, Walmart's executive vice president of U.S. store operations, is departing, according to internal memos viewed by CNBC.

Walmart expects to announce Clark's replacement in the coming weeks, while timing for Ward's successor remains unclear, the report said.

Furner took over during a period of sustained growth for Walmart, driven by gains among higher-income shoppers and expansion in e-commerce.