Goodwill and intangible assets are primarily the result of business acquisitions.

The Company performs its annual impairment assessment of goodwill and indefinite life intangible assets as of November 30 of each year.

During the year ended December 31, 2023, the Company's China reporting unit experienced adverse impacts as a result of changes in market conditions and increases in interest rates which contributed to reduced forecasted revenues and reduced projected future cash flows.

As a result of these adverse impacts, the Company performed an interim quantitative assessment of goodwill impairment by comparing the fair value of its China reporting unit to its carrying value, including goodwill. When performing the assessment, the Company determined the fair value of its China reporting unit based on forecasted future cash flows. Based on the Company's forecast of the future cash flows of its China reporting unit, it was determined the carrying value of goodwill for its China reporting unit was impaired and the Company recorded a goodwill impairment charge of $77.4 million during the three months ended June 30, 2023.

The Company used a quantitative approach to measure the fair value of its China reporting unit using a discounted cash flow approach, which is a Level 3 measurement. The discounted cash flow analysis requires significant judgments, including estimates of future cash flows, which are dependent on internal forecasts and determination of the Company’s weighted average cost of capital, which is risk-adjusted to reflect the specific risk profile of the reporting unit being tested. The weighted average cost of capital used for the China reporting unit in the Company’s analysis was 12.5%.

During the year ended December 31, 2023, the Company performed a qualitative assessment for its remaining reporting unit with goodwill and its trademark indefinite life intangible assets. For the qualitative analysis performed as of November 30, 2023, the Company assessed several events and circumstances that could affect the significant inputs used to determine the fair values of the reporting unit and trademarks, including the significance of the amount of excess fair value over carrying value, consistency of operating margins and cash flows, budgeted-to-actual performance from prior year, no significant changes to projected forecasts, overall change in economic climate, changes in the industry and competitive environment, key management turnover, and earnings quality and sustainability. There were no unanticipated changes or negative indicators in the above qualitative factors that would impact the fair values as of the annual impairment date. As such, the Company determined there were no indicators of impairment and that it is more likely than not that the fair value of the reporting unit and trademarks are greater than their carrying values and therefore performing the next step of the impairment test was unnecessary.

For the years ended December 31, 2022 and 2021 the Company performed a quantitative impairment test which indicated no impairment and there was no change to the carrying amount of goodwill or trademarks due to impairment.

The accumulated impairment loss as of December 31, 2022 was recognized during the year ended December 31, 2019.

The intangible assets balance as of December 31, 2023, is reflected below (in thousands):


		Weighted-
		Average
	Estimated	Remaining		Gross					Net
	Useful Life	Useful Life		Carrying		Accumulated			Carrying
	(Years)	(Years)		Amount		Amortization			Amount

Intangible assets:
Customer relationships	16–18		11.3	$	1,291,830	$	(479,054	)	$	812,776
Acquired technologies	3–7		1.7		184,640		(172,840	)		11,800
Subtotal					1,476,470		(651,894	)		824,576
Trademarks—indefinite life					190,470		—			190,470
Total intangible assets				$	1,666,940	$	(651,894	)	$	1,015,046

The intangible assets balance as of December 31, 2022, is reflected below (in thousands):


		Weighted-
		Average
	Estimated	Remaining		Gross					Net
	Useful Life	Useful Life		Carrying		Accumulated			Carrying
	(Years)	(Years)		Amount		Amortization			Amount

Intangible assets:
Customer relationships	16–18		12.3	$	1,299,750	$	(410,095	)	$	889,655
Acquired technologies	3–7		1.8		187,950		(149,256	)		38,694
Subtotal					1,487,700		(559,351	)		928,349
Trademarks—indefinite life					190,470		—			190,470
Total intangible assets				$	1,678,170	$	(559,351	)	$	1,118,819

During the year ended December 31, 2023, the Company recorded an impairment charge to its China reporting unit's customer relationships and acquired technologies intangible assets. The Company's forecast of the China reporting unit's expected cash flows indicated the carrying amounts of the intangible assets were not recoverable and therefore the Company recorded an impairment charge of $5.3 million.

As a result of the impairment charge, the Company recorded a write off of the gross carrying amount and accumulated amortization of the associated intangible assets during the year ended December 31, 2023.

No intangible asset impairments were recorded during the years ended December 31, 2022 and 2021.

During February 2022, the Company recorded $4.8 million of acquired technology intangible assets as a result of the acquisition of Safekeep (see Note 4).

Amortization expense for intangible assets was $98.4 million, $99.2 million and $98.7 million for the years ended December 31, 2023, 2022 and 2021, respectively.