Exhibit 99.3

Frequently Used Terms

Listed below are definitions of several of ExxonMobil’s key business and financial performance measures and other terms. These definitions are provided to facilitate understanding of the terms and their calculation. In the case of financial measures that we believe constitute “non-GAAP financial measures” under Securities and Exchange Commission Regulation G, we provide a reconciliation to the most comparable Generally Accepted Accounting Principles (GAAP) measure and other information required by that rule.

EARNINGS EXCLUDING SPECIAL ITEMS

In addition to reporting U.S. GAAP defined net income, ExxonMobil also presents a measure of earnings that excludes earnings from special items quantified and described in our quarterly and annual earnings press releases. Earnings excluding special items is a non-GAAP financial measure, and is included to facilitate comparisons of base business performance across periods. A reconciliation to net income is shown on page 5. We also refer to earnings excluding special items as normalized earnings. Earnings per share amounts use the same average common shares outstanding as used for the calculation of net income per common share and net income per common share – assuming dilution.

OPERATING COSTS

Operating costs are the combined total of production, manufacturing, selling, general, administrative, exploration, depreciation, and depletion expenses from the Consolidated Statement of Income and ExxonMobil’s share of similar costs for equity companies. Operating costs are the costs during the period to produce, manufacture, and otherwise prepare the company’s products for sale – including energy costs, staffing, maintenance, and other costs to explore for and produce oil and gas, and operate refining and chemical plants. Distribution and marketing expenses are also included. Operating costs exclude the cost of raw materials, taxes, and interest expense. These expenses are on a before-tax basis. While ExxonMobil’s management is responsible for all revenue and expense elements of net income, operating costs, as defined below, represent the expenses most directly under management’s control. Information regarding these costs is therefore useful for investors and ExxonMobil management in evaluating management’s performance.

TOTAL SHAREHOLDER RETURN

Shareholder return measures the change in value of an investment in stock over a specified period of time, assuming dividend reinvestment. We calculate shareholder return over a particular measurement period by: dividing (1) the sum of (a) the cumulative value of dividends received during the measurement period, assuming reinvestment, plus (b) the difference between the stock price at the end

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and at the beginning of the measurement period; by (2) the stock price at the beginning of the measurement period. For this purpose, we assume dividends are reinvested in stock at market prices at approximately the same time actual dividends are paid. Shareholder return is usually quoted on an annualized basis.

CAPITAL AND EXPLORATION EXPENDITURES (Capex)

Capital and exploration expenditures are the combined total of additions at cost to property, plant, and equipment and exploration expenses on a before-tax basis from the Summary Statement of Income. ExxonMobil’s Capex includes its share of similar costs for equity companies. Capex excludes depreciation on the cost of exploration support equipment and facilities recorded to property, plant, and equipment when acquired. While ExxonMobil’s management is responsible for all investments and elements of net income, particular focus is placed on managing the controllable aspects of this group of expenditures.

CAPITAL EMPLOYED

Capital employed is a measure of net investment. When viewed from the perspective of how the capital is used by the businesses, it includes ExxonMobil’s net share of property, plant, and equipment and other assets less liabilities, excluding both short-term and long-term debt. When viewed from the perspective of the sources of capital employed in total for the Corporation, it includes ExxonMobil’s share of total debt and shareholders’ equity. Both of these views include ExxonMobil’s share of amounts applicable to equity companies, which the Corporation believes should be included to provide a more comprehensive measure of capital employed.

RETURN ON AVERAGE CAPITAL EMPLOYED (ROCE)

Return on average capital employed is a performance measure ratio. From the perspective of the business segments, ROCE is annual business segment earnings divided by average business segment capital employed (average of beginning- and end-of-year amounts). These segment earnings include ExxonMobil’s share of segment earnings of equity companies, consistent with our capital employed definition, and exclude the cost of financing. The Corporation’s total ROCE is net income excluding the after-tax cost of financing, divided by total corporate average capital employed. The Corporation has consistently applied its ROCE definition for many years and views it as the best measure of historical capital productivity in our capital-intensive, long-term industry, both to evaluate management’s performance and to demonstrate to shareholders that capital has been used wisely over the long term. Additional measures, which are more cash-flow based, are used to make investment decisions.

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ENTITLEMENT VOLUME EFFECTS

PRODUCTION SHARING CONTRACT NET INTEREST REDUCTIONS

Production Sharing Contract (PSC) net interest reductions are contractual reductions in ExxonMobil’s share of production volumes covered by PSCs. These reductions typically occur when cumulative investment returns or production volumes achieve thresholds as specified in the PSCs. Once a net interest reduction has occurred, it typically will not be reversed by subsequent events, such as lower crude oil prices.

PRICE AND SPEND IMPACTS ON VOLUMES

Price and spend impacts on volumes are fluctuations in ExxonMobil’s share of production volumes caused by changes in oil and gas prices or spending levels from one period to another. For example, at higher prices fewer barrels are required for ExxonMobil to recover its costs. According to the terms of contractual arrangements or government royalty regimes, price or spending variability can increase or decrease royalty burdens and/or volumes attributable to ExxonMobil. These effects generally vary from period to period with field spending patterns or market prices for crude oil or natural gas.

FINDING AND RESOURCE-ACQUISITION COSTS

Finding and resource-acquisition costs per oil-equivalent barrel is a performance measure that is calculated using the Exploration portion of Upstream capital and exploration expenditures and proved property acquisition costs divided by resource additions (in oil-equivalent barrels). ExxonMobil refers to new discoveries and acquisitions of discovered resources as resource additions. In addition to proved reserves, resource additions include quantities of oil and gas that are not yet classified as proved reserves, but which ExxonMobil believes will likely be moved into the proved reserves category and produced in the future.

LIQUIDS AND NATURAL GAS PROVED RESERVES

In this report, we use the term “proved reserves” to mean quantities of oil and gas that ExxonMobil has determined to be reasonably certain of recovery under existing economic and operating conditions on the basis of our long-standing, rigorous management review process. We book proved reserves when we have made significant funding commitments for the related projects. In this report, we aggregate proved reserves of consolidated and equity companies, excluding royalties and quantities due others, since ExxonMobil does not view these reserves differently from a management perspective. To reflect management’s view of ExxonMobil’s total liquids reserves, proved reserves in this report also include oil sands reserves from the Canadian Syncrude and Kearl operations, which are reported separately as mining reserves in our Form 10-K and proxy statement. Oil sands reserves included in this report totaled 1,871 million barrels at year-end 2008, 694 million barrels at year-end 2007, 718 million barrels at year-end 2006, 738 million barrels at year-end 2005, and 757 million barrels at year-end 2004. For our own management purposes and as discussed in this report, we determine proved reserves based on price and cost assumptions that are consistent with those used to make investment decisions. Therefore, the proved reserves in this report are not directly comparable to the data reported in our Form 10-K and proxy statement. Based on regulatory guidance, ExxonMobil began in 2004 to state our results in the Form 10-K and proxy statement to reflect the impacts on proved reserves of utilizing December 31 liquids and natural gas prices (“year-end price/cost effects”). On this basis, year-end proved reserves, including year-end price/cost effects totaled 23.0 billion oil-equivalent barrels in 2008, 22.5 billion oil-equivalent barrels in 2007, 22.8 billion oil-equivalent barrels in 2006, 22.4 billion oil-equivalent barrels in 2005, and 21.7 billion oil-equivalent barrels in 2004. Excluding year-end price/cost effects, 2008 proved reserves totaled 22.8 billion oil-equivalent barrels, 2007 proved reserves totaled 22.7 billion oil-equivalent barrels, 2006 proved reserves totaled 22.7 billion oil-equivalent barrels, 2005 proved reserves totaled 22.4 billion oil-equivalent barrels, while 2004 proved reserves totaled 22.2 billion oil-equivalent barrels.

RESOURCES, RESOURCE BASE, AND RECOVERABLE RESOURCES

Resources, resource base, recoverable oil, recoverable hydrocarbons, recoverable resources, and similar terms used in this report are the total remaining estimated quantities of oil and gas that are expected to be ultimately recoverable. In addition to proved reserves, the resource base includes quantities of oil and gas that are not yet classified as proved reserves, but which ExxonMobil believes will likely be moved into the proved reserves category and produced in the future.

PROVED RESERVES REPLACEMENT RATIO

Proved reserves replacement ratio is a performance measure that is calculated using proved oil-equivalent reserves additions divided by oil-equivalent production. Both proved reserves additions and production include amounts applicable to equity companies. The ratio usually reported by ExxonMobil excludes year-end price/cost effects, and includes Canadian oil sands mining operations in both additions and production volumes. See the definition of “liquids and natural gas proved reserves” above. When reporting the ratio, the listing of inclusions and exclusions is noted as appropriate.

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PROVED RESERVES REPLACEMENT COSTS

Proved reserves replacement costs per oil-equivalent barrel is a performance measure ratio. Proved reserves replacement costs per barrel are costs incurred in property acquisition and exploration, plus costs incurred in development activities, divided by proved oil-equivalent reserves additions, excluding sales. Both the costs incurred and the proved reserves additions include amounts applicable to equity companies as well as Canadian oil sands operations and exclude year-end price/cost effects. See the definition of “liquids and natural gas proved reserves” on the preceding page.

HEAVY OIL

Heavy oil, for the purpose of this report, includes heavy oil, extra heavy oil, and bitumen, as defined by the World Petroleum Congress in 1987 based on API gravity and viscosity at reservoir conditions. Heavy oil has an API gravity between 10 and 22.3 degrees. The API gravity of extra heavy oil and bitumen is less than 10 degrees. Extra heavy oil has a viscosity less than 10 thousand centipoise, whereas the viscosity of bitumen is greater than 10 thousand centipoise. The term “oil sands” is used to indicate heavy oil (generally bitumen) that is recovered in a mining operation.

CASH FLOW FROM OPERATIONS AND ASSET SALES

Cash flow from operations and asset sales is the sum of the net cash provided by operating activities and proceeds from sales of subsidiaries, investments, and property, plant, and equipment from the Summary Statement of Cash Flows. This cash flow is the total sources of cash from both operating the Corporation’s assets and from the divesting of assets. The Corporation employs a long-standing and regular disciplined review process to ensure that all assets are contributing to the Corporation’s strategic objectives. Assets are divested when they are no longer meeting these objectives or are worth considerably more to others. Because of the regular nature of this activity, we believe it is useful for investors to consider sales proceeds together with cash provided by operating activities when evaluating cash available for investment in the business and financing activities, including shareholder distributions.

DISTRIBUTIONS TO SHAREHOLDERS

The Corporation distributes cash to shareholders in the form of both dividends and share purchases. Shares are purchased both to reduce shares outstanding and to offset shares issued in conjunction with company benefit plans and programs. For purposes of calculating distributions to shareholders, the Corporation only includes the cost of those shares purchased to reduce shares outstanding.

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FUNCTIONAL EARNINGS

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RETURN ON AVERAGE CAPITAL EMPLOYED⁽¹⁾ BY BUSINESS

AVERAGE CAPITAL EMPLOYED⁽¹⁾ BY BUSINESS

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