Goodwill impairment is an earnings charge that companies record on their income statements after they identify that there is persuasive evidence that the asset associated with the goodwill can no longer demonstrate financial results that were expected from it at the time of its purchase. Because many companies acquire other firms and pay a price that exceeds the fair value of identifiable assets and liabilities that the acquired firm possesses, the difference between the purchase price and the fair value of acquired assets is recorded as a goodwill. However, if unforeseen circumstances arise that decrease expected cash flows from acquired assets, their fair value can be lower than what was originally paid for them, and a company must book a goodwill impairment.

U.S. accounting principles require companies to review their goodwill for impairment at least annually at a reporting unit level. Events that may trigger goodwill impairment include deterioration in economic conditions, increased competition, loss of key personnel and regulatory action. The definition of a reporting unit plays a crucial role during the test; it is defined as the business unit that a company's management reviews and evaluates as a separate segment. Reporting units typically represent distinct business lines, geographic units or subsidiaries.

Goodwill impairment is identified in two steps. First, a company must compare the fair value of a reporting unit to its carrying value on the balance sheet. Because observable market values are rarely present to determine the fair value of a reporting unit, management teams typically use financial models for fair value estimation. If the fair value exceeds the carrying value, no impairment exists, and companies are not allowed to write up their goodwill.