Moments ago, the biggest single employer in the US after the Federal government, with 2.2 million workers, surprised its shareholders when it announced that Rob Walton, who had served as Chairman of the Board since 1992, was stepping down (he will stay on as a director) and would be replaced with vice-Chairman Greg Penner, grandson of founder Sam and son in law of Rob, who started his career at Goldman Sachs before joining WMT as a management trainee.

From the press release:

"This transition demonstrates Walmart's commitment to long-term succession planning and keeping high caliber, capable leaders at the head of our company," said Walton. "Greg's service to Walmart spans more than 15 years, and during that time he has had a significant impact, both as an associate and as a Board member the past seven years. Greg has done an outstanding job as our Vice Chairman over the past year, and he has provided strong leadership and guidance as the Chairman of our Technology and eCommerce Committee since it was formed in 2011. He brings an ideal blend of finance, technology and international business expertise – as well as a deep knowledge and love of Walmart – to this role."

"It would be impossible to overstate Rob Walton's impact on Walmart and how personally committed he has been over the years," said Penner. "I'm deeply honored to follow in his footsteps and recognize the deep responsibility I have to our associates, all shareholders and the Board. I've admired this company since my first Saturday morning meeting more than two decades ago. I believe in its mission and the positive role it plays throughout the world. I am excited about continuing to work with our outstanding senior management team and talented Walmart associates at all levels of the company."

Who is Penner:

Penner, 45, began his career at Goldman Sachs & Co. as an analyst specializing in corporate finance.