Roberts was appointed COO in July 2011, when Marathon Oil split from its refining operations, now called Marathon Petroleum. A company statement said Roberts resigned “to pursue other interests.”
Roberts has been with Marathon since 2006, joining as senior vice president of business development. He rose to executive vice president in charge of worldwide upstream operations in 2008.
The sudden move was a surprise to some and sent the Marathon Oil stock price into decline. By late afternoon, shares were down 54 cents to $30.38.
“This seems a bit surprising, given the fact that Marathon has been improving their operations in the Lower 48 [states] and it’s been moving in a positive direction,” said Allen Good, Morningstar oil analyst.
Fadel Gheit, senior oil analyst for Oppenheimer & Co. said the move might have been the result of succession planning for CEO Clarence P. Cazalot. Cazalot orchestrated the company’s split and the new Marathon Oil could demand a new leadership plan, Gheit said.
“The board probably wanted someone of Clarence’s mold, focus and vision,” Gheit said. “There’s nothing wrong with the man. But he might not be perceived by the board as the right man to lead the company after Clarence.”
Prior to Marathon, Roberts worked for British natural gas corporation BG Group, where he served as executive vice president and managing director overseeing the Asian and Middle East operations. He also was adviser to the vice chairman of Chevron Corporation from 2001 to 2003, according to Marathon Oil.
Roberts earned a bachelor’s degree in mineral engineering from the University of Alabama in Tuscaloosa in 1983.