Marathon Oil Corporation

http://www.sec.gov/Archives/edgar/data/101778/000010177811000034/form8k2011july1.htm On June 30, 2011, Marathon Oil Corporation completed the spin-off of Marathon Petroleum Corporation (“MPC”) to its stockholders. MPC is now an independent public company and its common stock trades under the symbol “MPC” on the New York Stock Exchange. As part of the spin-off, Marathon Oil Corporation ceased to guarantee $3 billion of notes issued by MPC in February 2011 (i.e., MPC became the sole obligor on the notes). The obligations assumed by MPC represented approximately 37% of the long-term debt of Marathon Oil Corporation (as per page 2 of Marathon’s 10-Q for the quarter ended March 31, 2011: http://www.sec.gov/Archives/edgar/data/101778/000010177811000020/form10q2011q1.htm).