Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2020

The following table presents commission revenue by fee type:

	Year Ended December 31,
	2020		2019		2018
	(In thousands)

Commission revenue by fee type
Variable transaction fees
Disclosed trading	$	343,427	$	266,916	$	228,004
Open Trading - matched principal trading		170,537		98,080		65,932
U.S. Treasuries - matched principal trading		12,372		2,184		—
Total variable transaction fees		526,337		367,180		293,936
Distribution fees and unused minimum fees		108,108		96,676		96,898
Total commissions	$	634,445	$	463,856	$	390,834

The following table presents information services revenue by timing of recognition:

	Year Ended December 31,
	2020		2019		2018
	(In thousands)

Information services revenue by timing of recognition
Services transferred over time	$	32,425	$	29,619	$	27,475
Services transferred at a point in time		1,916		1,111		752
Total information services revenues	$	34,341	$	30,730	$	28,227

The following table presents post-trade services revenue by timing of recognition:

	Year Ended December 31,
	2020		2019		2018
	(In thousands)
Post-trade services revenue by timing of recognition
Services transferred over time	$	19,158	$	15,669	$	15,013
Services transferred at a point in time		302		94		333
Total post-trade services revenues	$	19,460	$	15,763	$	15,346

The revenue recognized from contract liabilities and the remaining balance is shown below:

	December 31, 2019		Payments received in advance of services to be performed		Revenue recognized for services performed during the period			Foreign Currency Translation		December 31, 2020
	(In thousands)
Information services	$	2,138	$	9,593	$	(8,528	)	$	—	$	3,203
Post-trade services		1,361		15,496		(15,862	)		50		1,045
Total deferred revenue	$	3,499	$	25,089	$	(24,390	)	$	50	$	4,248