Walmart Inc announced Monday that longtime executive Brett Biggs will step down as chief financial officer of the world’s largest retailer next year.

Biggs, CFO since 2015, has helped oversee a period of rapid change at Walmart as the physical retailer launched and expanded a number of initiatives to help fend off the competition from Amazon.com Inc.

Walmart made its biggest overseas investment in 2018 with a $ 16 billion deal to buy a controlling stake in Indian online marketplace Flipkart, and bolstered its e-commerce business in the United States by buying retailers of Modcloth and Bonobos clothing.

Monday’s announcement surprised some analysts who saw Biggs as the next vacancy at Walmart.

“Bret Biggs was a candidate to succeed Doug McMillon as CEO, given his long tenure with the company and his extensive experience in business units and functions outside of finance,” said Jason Benowitz, Senior Portfolio Manager at Roosevelt Investment Group.

“However, we expect McMillon to serve many more years at the helm,” added Benowitz.

Walmart shares were down 1% late in the morning.

Biggs has held a number of finance roles, including CFO of the company’s international division and US operations, since joining the company in 2000.

Biggs will remain in office until a successor is appointed next year, Walmart said, adding that he would continue to represent the company as a member of the board of directors of his fintech startup until January 2023. .

The startup, a joint venture with investment firm Ribbit Capital, aims to develop financial products for Walmart employees and customers.

Walmart said it was considering internal and external candidates to replace Biggs as the company faces rising labor and supply chain costs that have eaten away at its profit margins.