(6) Goodwill and Other Intangible Assets

Goodwill and Indefinite Lived Intangible Assets

Changes in the carrying amount of goodwill are as follows:

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As presented in the accompanying consolidated balance sheets, trademarks are the other significant indefinite lived intangible asset. See the disclosure below for information related to the 2020 and 2019 impairments of the Company’s trademarks. Other fluctuations in the trademark balance from the prior year were due to the change in foreign exchange rates.

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Intangible Assets subject to amortization

Intangible assets subject to amortization are comprised of the following:

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Intangible assets are being amortized generally on an accelerated basis as reflected in amortization expense and in the future amortization table below.

Amortization expense was $136 million, $139 million and $137 million for the years ended December 31, 2020, 2019 and 2018, respectively.

The estimated future amortization expense for the next five years related to intangible assets with definite lives as of December 31, 2020, assuming no subsequent impairment of the underlying assets, is as follows (amounts in millions):

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Impairments

Due to the current and expected impact of COVID-19 on Tripadvisor’s operating results, and a sustained decline in Tripadvisor’s stock price, impairments of $250 million of trademarks and $279 million of goodwill were recorded during the year ended December 31, 2020, respectively, related to the Hotels, Media & Platform reporting unit. The fair value of the trademarks was determined using the relief from royalty method. The fair value of the reporting unit was determined using a combination of market multiples (market approach) and discounted cash flow (income approach) calculations (Level 3). 

Based on the quantitative assessment performed during the second quarter of 2020 and the resulting impairment losses recorded, the estimated fair values of the trademark and Hotels, Media & Platform reporting unit approximate their respective carrying values. Additionally, due to the COVID-19 environment and our inability to predict the expected duration and ultimate severity of the impact of COVID-19, the Company believes its reporting units and trademark are at an elevated risk of impairment in future periods. TripCo will continue to monitor Tripadvisor’s financial performance, stock price and other events and circumstances that may negatively impact the estimated fair values to determine if future impairment assessments may be necessary.

Due to deteriorations in revenue, impairment losses of $288 million were recorded during the year ended December 31, 2019 related to trademarks.  The trademarks were related to the hotels, media & platform reporting unit in 2019.  The fair value of the trademarks was determined using the relief from royalty method.

As of December 31, 2020, accumulated goodwill impairment losses for Tripadvisor totaled $1,571 million.