growth, profit margins, and our cost of capital. Declines in investment values that are deemed to be other than temporary may result in an impairment charge reducing the investments’ carrying value to fair value.
We retain risk relating to certain of our general liability insurance, workers’ compensation insurance, vehicle physical damage insurance, property insurance, employment practices liability insurance, directors and officers insurance and employee medical benefits in the U.S. As a result, we are likely to be responsible for a significant portion of the claims and losses incurred under these programs. The amount of risk we retain varies by program, and for certain exposures, we have pre-determined maximum loss limits for certain individual claims and/or insurance periods. Losses, if any, above the pre-determined loss limits are paid by third-party insurance carriers. Certain insurers have limited available property coverage in response to the natural catastrophes experienced in recent years. Our estimate of future losses is prepared by management using our historical loss experience and industry-based development factors. Aggregate reserves relating to retained risk were $29.8 million and $28.3 million as of September 30, 2017 and December 31, 2016, respectively.
Tax regulations may require items to be included in our tax returns at different times than the items are reflected in our financial statements. Some of these differences are permanent, such as expenses that are not deductible on our tax return, and some are temporary differences, such as the timing of depreciation expense. Temporary differences create deferred tax assets and liabilities. Deferred tax assets generally represent items that will be used as a tax deduction or credit in our tax returns in future years which we have already recorded in our financial statements. Deferred tax liabilities generally represent deductions taken on our tax returns that have not yet been recognized as expense in our financial statements. We establish valuation allowances for our deferred tax assets if the amount of expected future taxable income is not likely to allow for the use of the deduction or credit.
Classification in Continuing and Discontinued Operations
We classify the results of our operations in our consolidated financial statements based on generally accepted accounting principles relating to discontinued operations, which requires judgments, including whether a business will be divested, the period required to complete the divestiture, the likelihood of changes to the divestiture plans, and whether the divestiture represents a strategic shift that has, or will have, a major impact on our operations. If we determine that a business should be either reclassified from continuing operations to discontinued operations or from discontinued operations to continuing operations, our consolidated financial statements for prior periods are revised to reflect such reclassification. Refer to the disclosures provided under “Assets Held for Sale and Discontinued Operations” in Part I, Item 1, Note 1 of the Notes to our Consolidated Condensed Financial Statements for a detailed description of the factors we consider for classification in discontinued operations.
Recent Accounting Pronouncements
Please see the disclosures provided under “Recent Accounting Pronouncements” in Part I, Item 1, Note 1 of the Notes to our Consolidated Condensed Financial Statements which are incorporated by reference herein.