The Globe and Mail reports in its Saturday edition that Walmart's chief executive officer, Doug McMillon, has announced that he plans to retire early next year. An Associated Press dispatch to The Globe reports that Mr. McMillon, who has transformed America's largest retailer into a tech-driven powerhouse, has led a significant period of sales growth since taking on the role of CEO in 2014. The announcement came as a surprise on Friday. John Furner, 51, the head of Walmart's U.S. operations, will take over on Feb. 1, the day after Mr. McMillon's retirement becomes effective, the company said. Although Mr. McMillon is set to spend a year advising his successor, Walmart shares fell 3 per cent immediately in premarket trading after the news of the unexpected leadership change. Unlike Amazon's Jeff Bezos or Tesla's Elon Musk, Mr. McMillon is not a household name, but he played a key role in the U.S. economy. The pending CEO switch comes at a challenging time for retail companies and other employers that have spent almost 11 months navigating the Trump administration's volatile policies on tariffs and an immigration crackdown that threatens to shrink the supply of workers. Walmart is the country's largest private employer.