Marathon Oil (MRO)

F-7

Notes to Consolidated Financial Statements

1. Summary of Principal Accounting Policies

Marathon Oil Corporation ("Marathon" or the "Company") is engaged in worldwide exploration, production and marketing of crude oil and natural gas; domestic refining, marketing and transportation of crude oil and petroleum products; and worldwide marketing and transportation of products manufactured from natural gas, such as liquefied natural gas ("LNG") and methanol, and development of other projects to link stranded natural gas resources with key demand areas.

Principles applied in consolidation  –  These consolidated financial statements include the accounts of the businesses comprising Marathon.

        Prior to June 30, 2005, Marathon owned a 62 percent interest in Marathon Petroleum Company LLC ("MPC"). After Marathon acquired the remaining 38 percent interest as described in Note 6, MPC became a wholly owned subsidiary of Marathon. The accounts of MPC are consolidated in these financial statements for all periods presented and the applicable minority interest has been recognized for activity prior to the acquisition date.

        Investments in unincorporated oil and natural gas joint ventures and undivided interests in certain pipelines, natural gas processing plants and LNG tankers are consolidated on a pro rata basis.

        Investments in variable interest entities ("VIEs") for which Marathon is the primary beneficiary are consolidated.

        Investments in entities over which Marathon has significant influence, but not control, are accounted for using the equity method of accounting and are carried at Marathon's share of net assets plus loans and advances. This includes entities in which Marathon holds majority ownership but the minority shareholders have substantive participating rights in the investee. Differences in the basis of the investments and the separate net asset values of the investees, if any, are amortized into net income over the remaining useful lives of the underlying assets, except for the excess related to goodwill. Income from equity method investments represents Marathon's proportionate share of net income generated by the equity method investees.

        Gains or losses from a change in ownership of a consolidated subsidiary or an unconsolidated investee are recognized in net income in the period of change.

Use of estimates  –  The preparation of financial statements in accordance with generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amounts of revenues and expenses during the respective reporting periods.

Income per common share  –  Basic income per share is calculated based on the weighted average number of common shares outstanding. Diluted income per share assumes exercise of stock options and warrants and conversion of convertible debt and preferred securities, provided the effect is not antidilutive.

Segment information  –  Marathon's operations consist of three reportable operating segments:

•

Exploration and Production ("E&P") – explores for, produces and markets crude oil and natural gas on a worldwide basis;

•

Refining, Marketing and Transportation ("RM&T") – refines, markets and transports crude oil and petroleum products, primarily in the Midwest, the upper Great Plains and southeastern United States; and

•

Integrated Gas ("IG") – markets and transports products manufactured from natural gas, such as LNG and methanol, on a worldwide basis, and is developing other projects to link stranded natural gas resources with key demand areas.

        Management has determined that these are its operating segments because these are the components of Marathon (1) that engage in business activities from which revenues are earned and expenses are incurred, (2) whose operating results are regularly reviewed by Marathon's chief operating decision maker ("CODM") to make decisions about resources to be allocated and to assess performance and (3) for which discrete financial information is available. The CODM is responsible for allocating resources to and assessing performance of Marathon's operating segments. Information regarding assets by segment is not presented because it is not reviewed by the CODM. The CODM is the manager over the E&P and IG segments and the manager of the RM&T segment reports to the CODM. The segment managers are responsible for allocating resources within the segments, reviewing financial results of components within the segments and assessing the performance of the components. The components within the segments that are separately reviewed and assessed by the CODM in his role as segment manager are aggregable because they have similar economic characteristics. The CODM reviews the financial results of the RM&T segment at the segment level.

        Segment income represents income from continuing operations, net of minority interests and income taxes, attributable to the operating segments. Marathon's corporate general and administrative costs are not allocated to the operating segments. These costs primarily consist of employment costs (including pension effects), professional services, facilities and other costs associated with corporate activities. Non-cash gains and losses on two long-term natural gas sales contracts in the United Kingdom accounted for as derivative instruments, gains and losses on ownership changes in subsidiaries and certain non-operating or infrequently occurring items (as determined by the CODM) also are not allocated to operating segments. See the reconciliation of segment income to consolidated net income in Note 9.

Revenue recognition  –  Revenues are recognized when products are shipped or services are provided to customers, title is transferred, the sales price is fixed or determinable and collectibility is reasonably assured. Costs associated with revenues are recorded in cost of revenues.

F-7

Notes to Consolidated Financial Statements

1. Summary of Principal Accounting Policies

Marathon Oil Corporation ("Marathon" or the "Company") is engaged in worldwide exploration, production and marketing of crude oil and natural gas; domestic refining, marketing and transportation of crude oil and petroleum products; and worldwide marketing and transportation of products manufactured from natural gas, such as liquefied natural gas ("LNG") and methanol, and development of other projects to link stranded natural gas resources with key demand areas.

Principles applied in consolidation  –  These consolidated financial statements include the accounts of the businesses comprising Marathon.

        Prior to June 30, 2005, Marathon owned a 62 percent interest in Marathon Petroleum Company LLC ("MPC"). After Marathon acquired the remaining 38 percent interest as described in Note 6, MPC became a wholly owned subsidiary of Marathon. The accounts of MPC are consolidated in these financial statements for all periods presented and the applicable minority interest has been recognized for activity prior to the acquisition date.

        Investments in unincorporated oil and natural gas joint ventures and undivided interests in certain pipelines, natural gas processing plants and LNG tankers are consolidated on a pro rata basis.

        Investments in variable interest entities ("VIEs") for which Marathon is the primary beneficiary are consolidated.

        Investments in entities over which Marathon has significant influence, but not control, are accounted for using the equity method of accounting and are carried at Marathon's share of net assets plus loans and advances. This includes entities in which Marathon holds majority ownership but the minority shareholders have substantive participating rights in the investee. Differences in the basis of the investments and the separate net asset values of the investees, if any, are amortized into net income over the remaining useful lives of the underlying assets, except for the excess related to goodwill. Income from equity method investments represents Marathon's proportionate share of net income generated by the equity method investees.

        Gains or losses from a change in ownership of a consolidated subsidiary or an unconsolidated investee are recognized in net income in the period of change.

Use of estimates  –  The preparation of financial statements in accordance with generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amounts of revenues and expenses during the respective reporting periods.

Income per common share  –  Basic income per share is calculated based on the weighted average number of common shares outstanding. Diluted income per share assumes exercise of stock options and warrants and conversion of convertible debt and preferred securities, provided the effect is not antidilutive.

Segment information  –  Marathon's operations consist of three reportable operating segments:

•

Exploration and Production ("E&P") – explores for, produces and markets crude oil and natural gas on a worldwide basis;

•

Refining, Marketing and Transportation ("RM&T") – refines, markets and transports crude oil and petroleum products, primarily in the Midwest, the upper Great Plains and southeastern United States; and

•

Integrated Gas ("IG") – markets and transports products manufactured from natural gas, such as LNG and methanol, on a worldwide basis, and is developing other projects to link stranded natural gas resources with key demand areas.

        Management has determined that these are its operating segments because these are the components of Marathon (1) that engage in business activities from which revenues are earned and expenses are incurred, (2) whose operating results are regularly reviewed by Marathon's chief operating decision maker ("CODM") to make decisions about resources to be allocated and to assess performance and (3) for which discrete financial information is available. The CODM is responsible for allocating resources to and assessing performance of Marathon's operating segments. Information regarding assets by segment is not presented because it is not reviewed by the CODM. The CODM is the manager over the E&P and IG segments and the manager of the RM&T segment reports to the CODM. The segment managers are responsible for allocating resources within the segments, reviewing financial results of components within the segments and assessing the performance of the components. The components within the segments that are separately reviewed and assessed by the CODM in his role as segment manager are aggregable because they have similar economic characteristics. The CODM reviews the financial results of the RM&T segment at the segment level.

        Segment income represents income from continuing operations, net of minority interests and income taxes, attributable to the operating segments. Marathon's corporate general and administrative costs are not allocated to the operating segments. These costs primarily consist of employment costs (including pension effects), professional services, facilities and other costs associated with corporate activities. Non-cash gains and losses on two long-term natural gas sales contracts in the United Kingdom accounted for as derivative instruments, gains and losses on ownership changes in subsidiaries and certain non-operating or infrequently occurring items (as determined by the CODM) also are not allocated to operating segments. See the reconciliation of segment income to consolidated net income in Note 9.

Revenue recognition  –  Revenues are recognized when products are shipped or services are provided to customers, title is transferred, the sales price is fixed or determinable and collectibility is reasonably assured. Costs associated with revenues are recorded in cost of revenues.