(Reuters) - Marathon Oil (NYSE:MRO) Corp's shares fell as much as 8 percent on Monday, wiping about $1.14 billion from its market value, after the oil producer said Chief Financial Officer J.R. Sult had resigned.
Marathon said Lance Robertson, its vice president of resource plays, had also quit the company.
Sult, the company's CFO since September 2013, resigned for personal reasons and Pat Wagner will take over as interim CFO until a successor to Sult is found, Marathon said.
The company promoted Mitch Little to executive vice president of operations to oversee its oil and gas operations.
"(Sult and Robertson) were very high profile with the investment community and their replacements for the most part are not," Wells Fargo (NYSE:WFC) Securities analyst Roger Read wrote in a note.
Marathon shares were down 7.6 percent at $15.53 in afternoon trading, weighed down also by a nearly 3 percent fall in oil prices.