asset, sales volume, pricing, cost of raw materials, delivery costs, inflation, cost of capital, marketing spending, foreign currency exchange rates, tax rates, capital spending and proceeds from the sale of assets. 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 or meaningful 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. Refer to the heading "Operations Review" below for additional information related to our present business environment. 

Certain factors discussed above are impacted by our current business environment and are discussed throughout this report, as appropriate. 

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. 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 trading or available-for-sale securities. Realized and unrealized gains and losses on trading securities and realized gains and losses on available-for-sale securities are included in net income. Unrealized gains and losses, net of deferred taxes, on available-for-sale securities are included in our consolidated balance sheets as a component of accumulated other comprehensive income (loss) ("AOCI"). Trading securities are reported as either marketable securities or other assets in our