Rob Walton, the eldest son of Walmart founder Sam Walton, will step down from the board on June 5, ending his 55 years at the company, the company announced in its annual report.

Walton, now 79, joined Walmart in 1969 and has served in various leadership positions, including SVP, corporate secretary, general counsel and vice chairman.

He has been on the company’s board of directors for more than 40 years and took over as chairman in 1992 following his father’s death. His son-in-law Greg Penner succeeded him as chair in 2015.

“His leadership has been critical as we’ve grown our business over so many years,” Penner said.

“There’s no doubt Sam would be very proud. On behalf of our associates and the Board, I’d like to thank him for his unparalleled and amazing service.”

The board has nominated the remaining 10 members, along with chairman and CEO of Chipotle Mexican Grill Brian Niccol, for election at the upcoming shareholders’ meeting. If elected, Brian will be the fifth new independent director of Walmart since 2017.

The retail giant posted nearly $650 billion in total revenues and more than $16 billion in net income last year. The store count stood at more than 10,500.