Marathon Oil Corp. to focus on upstream responsibilities, while new Marathon Petroleum Corp. handles downstream business for the company, effective June 30.

Marathon Oil Corp. plans to separate its upstream and downstream segments.

The new Marathon Petroleum Corp. (MPC), which will be headquartered in Findlay, Ohio, will operate the company’s refining, marketing, terminals and pipelines, as well as the Speedway gasoline and convenience store chain, which has more than 1,300 locations throughout the Midwest.

Marathon Oil Corp. (MRO) plans to continue operating the Exploration & Production, Oil Sands Mining and Integrated Gas business segments. The spin-off is expected to take effect on June 30, 2011. MPC is expected to be traded under the MPC ticker on the New York Stock Exchange.