(Bloomberg) -- Walmart Inc.’s top U.S. e-commerce executive is departing less than 18 months after joining the company. 

Casey Carl will leave at the end of February, the retail giant said in a memo to employees Thursday. Tom Ward, the senior vice president for last-mile deliveries, will replace Carl as the head of the company’s U.S. e-commerce operations, effective Feb. 1. 

“Continuing the growth of our e-commerce business is critical to our long-term success,” John Furner, the head of Walmart’s U.S. operations, said in the memo. “We have a strong foundation.”

Walmart is making the change while rushing to keep up with Amazon.com Inc. and other rivals in e-commerce sales as more consumer spending shifts online. Walmart’s U.S. e-commerce sales climbed 15% during the nine months ending Oct. 31. Amazon’s North American sales gained more than 20% during the nine months through Sept. 30. 

The exit of Walmart’s e-commerce chief, which was reported earlier by the Wall Street Journal, adds to a string of recent executive departures. The Bentonville, Arkansas-based retailer, which often makes leadership changes shortly before the end of its fiscal year in late January, last week announced the departure of two key U.S. executives: the chief merchandising officer and the chief customer officer.  

Carl, a former Target Corp. executive, joined Walmart in September 2020. He took on additional e-commerce responsibilities following the departure about a year ago of Marc Lore, who joined Walmart after the 2016 acquisition of his startup, Jet.com, for $3.3 billion. 

Walmart shares were down 0.1% at 11:04 a.m. in New York. The stock edged up 0.4% last year, far behind the 27% rise of the S&P 500 index.

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