The following table summarizes Other income (expense), net for the years ended December 31, 2022, 2021 and 2020 (in thousands):


	Year Ended December 31,
	2022		2021		2020
Interest income	$	9,533	$	5,116	$	6,351
Interest expense	(14,380)		(17,206)		(33,192)
Changes in fair value of investments (1)	—		95,623		(8,089)
Loss on extinguishment of debt	—		(5,090)		—
Foreign currency gains (losses), net and other (2)	(19,308)		14,237		17,962
Other income (expense), net	$	(24,155)	$	92,680	$	(16,968)

(1)Includes an $89.1 million unrealized gain due to an upward adjustment for an observable price change of SumUp for the year ended December 31, 2021.

(2)Includes a $32.3 million cumulative foreign currency translation adjustment gain that was reclassified into earnings for the year ended December 31, 2021 as a result of the substantial liquidation of our subsidiary in Japan as part of our 2020 Restructuring Plan.

The following table summarizes Prepaid expenses and other current assets as of December 31, 2022 and 2021 (in thousands):


	December 31,
	2022		2021
Prepaid expenses	$	16,048	$	28,550
Income taxes receivable	6,691		7,711
Deferred cloud implementation cost	9,362		6,476
Other	9,000		9,833
Total prepaid expenses and other current assets	$	41,101	$	52,570

The following table summarizes Other non-current assets as of December 31, 2022 and 2021 (in thousands):


	December 31,
	2022		2021
Deferred contract acquisition costs	$	4,815	$	7,080
Deferred cloud implementation costs	17,684		11,986
Other	4,992		6,036
Total other non-current assets	$	27,491	$	25,102

The following table summarizes Accrued expenses and other current liabilities as of December 31, 2022 and 2021 (in thousands):


	December 31,
	2022		2021
Refund reserve	$	11,072	$	19,601
Compensation and benefits	15,005		30,367
Accrued marketing	19,596		37,900
Restructuring-related liabilities	4,782		11,349
Customer credits	36,220		56,558
Operating lease obligations	37,525		32,062
Other (1)	47,252		51,476
Total accrued expenses and other current liabilities	$	171,452	$	239,313

(1)Includes certain payroll taxes deferred under the Coronavirus Aid, Relief and Economic Security ("CARES") Act of $2.7 million as of December 31, 2021 and 2022. This balance was paid in January 2023.

The following table summarizes Other non-current liabilities as of December 31, 2022 and 2021 (in thousands):


	December 31,
	2022		2021
Contingent income tax liabilities	$	11,213	$	24,213
Deferred income taxes	3,100		2,802
Other	4,273		7,433
Total other non-current liabilities	$	18,586	$	34,448