its proportionate share of such charge as a reduction of equity income (loss) — net in our consolidated income statements. However, the actual amount we record with respect to our proportionate share of such charges may be impacted by items such as basis differences, deferred taxes and deferred gains. 

Management's assessments of the recoverability and impairment tests of noncurrent assets involve critical accounting estimates. These estimates require significant management judgment, include inherent uncertainties and are often interdependent; therefore, they do not change in isolation. Factors that management must estimate include, among others, the economic life of the asset, sales volume, prices, inflation, cost of capital, marketing spending, foreign currency exchange rates, tax rates and capital spending. These factors are even more difficult to predict when global financial markets are highly volatile. The estimates we use when assessing the recoverability of noncurrent assets are consistent with those we use in our internal planning. When performing impairment tests, we estimate the fair values of the assets using management's best assumptions, which we believe would be consistent with what a hypothetical marketplace participant would use. Estimates and assumptions used in these tests are evaluated and updated as appropriate. The variability of these factors depends on a number of conditions, including uncertainty about future events, and thus our accounting estimates may change from period to period. If other assumptions and estimates had been used when these tests were performed, impairment charges could have resulted. As mentioned above, these factors do not change in isolation; and therefore, we do not believe it is practicable to present the impact of changing a single factor. Furthermore, if management uses different assumptions or if different conditions occur in future periods, future impairment charges could result. 

Our Company faces many uncertainties and risks related to various economic, political and regulatory environments in the countries in which we operate, particularly in developing or emerging markets. Refer to the heading "Our Business — Challenges and Risks," above, and "Item 1A. Risk Factors" in Part I of this report. As a result, management must make numerous assumptions which involve a significant amount of judgment when completing recoverability and impairment tests of noncurrent assets in various regions around the world. 

Investments in Equity and Debt Securities 

The carrying values of our investments in equity securities are determined using the equity method, the cost method or the fair value method. Refer to the heading "Basis of Presentation," above, for information related to how the carrying values of our equity method investments are determined. We account for investments in companies that we do not control or account for under the equity method either at fair value or under the cost method, as applicable. Investments in equity securities are carried at fair value, if the fair value of the security is readily determinable. Equity investments 

carried at fair value are classified as either