$MKTX
MARKETAXESS HOLDINGS INC Stock $mktx

$mktx Overview Financials Valuation SEC Filings Company Website

2019 Q4 Form 10-K Financial Statement

#000156459021006981 Filed on February 19, 2021

Income Statement

Concept	2019 Q4	2019 Q3	2019 Q2
Revenue	$129.8M	$131.6M	$125.5M
YoY Change	15.48%	29.73%	17.32%
Cost Of Revenue	$7.200M	$7.400M	$6.500M
YoY Change	12.5%	25.42%	12.07%
Gross Profit	$122.6M	$124.2M	$119.0M
YoY Change	15.66%	29.92%	17.59%
Gross Profit Margin	94.45%	94.38%	94.83%
Selling, General & Admin	$50.70M	$48.80M	$49.20M
YoY Change	15.23%	18.45%	19.13%
% of Gross Profit	41.35%	39.29%	41.34%
Research & Development		$7.381M	$6.474M
YoY Change		25.55%
% of Gross Profit		5.94%	5.44%
Depreciation & Amortization	$7.800M	$6.700M	$6.300M
YoY Change	32.2%	9.84%	8.62%
% of Gross Profit	6.36%	5.39%	5.29%
Operating Expenses	$61.70M	$65.63M	$64.61M
YoY Change	18.43%	19.26%	31.59%
Operating Profit	$60.90M	$65.97M	$60.88M
YoY Change	12.99%	42.13%	16.99%
Interest Expense	$1.800M	$2.200M	$2.100M
YoY Change	-5.26%	37.5%	50.0%
% of Operating Profit	2.96%	3.34%	3.45%
Other Income/Expense, Net	-$700.0K	$1.373M	$2.032M
YoY Change	-450.0%	-0.87%	72.79%
Pretax Income	$62.00M	$67.34M	$62.91M
YoY Change	10.52%	40.88%	18.23%
Income Tax	$11.70M	$13.34M	$14.80M
% Of Pretax Income	18.87%	19.8%	23.53%
Net Earnings	$50.30M	$54.00M	$48.11M
YoY Change	9.83%	39.92%	18.82%
Net Earnings / Revenue	38.75%	41.04%	38.33%
Basic Earnings Per Share		$1.46	$1.30
Diluted Earnings Per Share	$1.320M	$1.42	$1.27
COMMON SHARES
Basic Shares Outstanding	37.78M	37.07M	37.05M
Diluted Shares Outstanding		38.00M	37.91M

Balance Sheet

Concept	2019 Q4	2019 Q3	2019 Q2
SHORT-TERM ASSETS
Cash & Short-Term Investments	$500.6M	$556.2M	$519.2M
YoY Change	2.91%	24.33%	204.16%
Cash & Equivalents	$270.1M	$320.5M	$287.3M
Short-Term Investments	$230.5M	$235.6M	$231.9M
Other Short-Term Assets	$30.80M	$18.60M	$22.60M
YoY Change	36.89%	0.0%	7.62%
Inventory
Prepaid Expenses
Receivables	$62.00M	$72.80M	$66.30M
Other Receivables	$0.00	$0.00	$0.00
Total Short-Term Assets	$362.9M	$411.9M	$375.1M
YoY Change	11.22%	41.69%	47.91%
LONG-TERM ASSETS
Property, Plant & Equipment	$71.80M	$66.53M	$64.21M
YoY Change	13.94%	22.52%	28.16%
Goodwill	$146.9M
YoY Change	145.94%
Intangibles	$60.99M
YoY Change	1958.95%
Long-Term Investments	$230.5M	$235.6M	$231.9M
YoY Change	-4.0%	-0.21%	-7.09%
Other Assets	$500.0K	$3.200M	$1.600M
YoY Change	-85.29%	39.13%	6.67%
Total Long-Term Assets	$592.0M	$443.1M	$436.9M
YoY Change	60.34%	24.68%	20.03%
TOTAL ASSETS
Total Short-Term Assets	$362.9M	$411.9M	$375.1M
Total Long-Term Assets	$592.0M	$443.1M	$436.9M
Total Assets	$954.9M	$855.0M	$812.0M
YoY Change	37.29%	32.34%	31.48%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$19.30M	$16.30M	$17.10M
YoY Change	-34.35%	-15.54%	-14.5%
Accrued Expenses	$145.4M	$127.1M	$116.4M
YoY Change	271.87%	303.49%	393.22%
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$181.4M	$156.7M	$146.4M
YoY Change	113.66%	146.0%	158.66%
LONG-TERM LIABILITIES
Long-Term Debt	$0.00	$0.00	$0.00
YoY Change
Other Long-Term Liabilities	$3.500M	$3.700M	$3.800M
YoY Change	25.0%	-2.63%	5.56%
Total Long-Term Liabilities	$3.500M	$3.700M	$3.800M
YoY Change	25.0%	-2.63%	5.56%
TOTAL LIABILITIES
Total Short-Term Liabilities	$181.4M	$156.7M	$146.4M
Total Long-Term Liabilities	$3.500M	$3.700M	$3.800M
Total Liabilities	$184.8M	$160.4M	$150.1M
YoY Change	110.86%	137.63%	149.34%
SHAREHOLDERS EQUITY
Retained Earnings	$591.1M	$560.2M
YoY Change	27.59%
Common Stock	$342.7M	$343.7M
YoY Change	0.2%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$153.4M	$196.4M
YoY Change	-17.07%
Treasury Stock Shares	$2.811M	$2.941M
Shareholders Equity	$770.1M	$694.6M	$661.9M
YoY Change
Total Liabilities & Shareholders Equity	$954.9M	$855.0M	$812.0M
YoY Change	37.29%	32.34%	31.48%

Cashflow Statement

Concept	2019 Q4	2019 Q3	2019 Q2
OPERATING ACTIVITIES
Net Income	$50.30M	$54.00M	$48.11M
YoY Change	9.83%	39.92%	18.82%
Depreciation, Depletion And Amortization	$7.800M	$6.700M	$6.300M
YoY Change	32.2%	9.84%	8.62%
Cash From Operating Activities	$89.10M	$67.70M	$69.70M
YoY Change	27.1%	-0.44%	28.12%
INVESTING ACTIVITIES
Capital Expenditures	-$12.20M	-$9.100M	-$9.600M
YoY Change	-16.44%	-12.5%	-42.51%
Acquisitions
YoY Change
Other Investing Activities	-$94.70M	$4.600M	-$11.70M
YoY Change	-7384.62%	64.29%	-11800.0%
Cash From Investing Activities	-$106.8M	-$4.600M	-$21.30M
YoY Change	703.01%	-39.47%	27.54%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-32.00M	-27.60M	-22.30M
YoY Change	57.64%	34.63%	-0.89%
NET CHANGE
Cash From Operating Activities	89.10M	67.70M	69.70M
Cash From Investing Activities	-106.8M	-4.600M	-21.30M
Cash From Financing Activities	-32.00M	-27.60M	-22.30M
Net Change In Cash	-49.70M	35.50M	26.10M
YoY Change	-236.16%	-11.03%	71.71%
FREE CASH FLOW
Cash From Operating Activities	$89.10M	$67.70M	$69.70M
Capital Expenditures	-$12.20M	-$9.100M	-$9.600M
Free Cash Flow	$101.3M	$76.80M	$79.30M
YoY Change	19.6%	-2.04%	11.53%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P5Y
CY2019	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P5Y
CY2018	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P5Y
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P2Y9M18D
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P1Y8M12D
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P12Y3M18D
CY2019Q4	us-gaap	Marketable Securities MarketableSecurities	230477000
CY2019Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P13Y3M18D
CY2020Q4	us-gaap	Accounts Receivable Net AccountsReceivableNet	79577000
CY2019Q4	us-gaap	Accounts Receivable Net AccountsReceivableNet	62017000
CY2020Q4	mktx	Receivables From Brokers Dealers Clearing Organizations And Customers ReceivablesFromBrokersDealersClearingOrganizationsAndCustomers	279915000
CY2020	us-gaap	Lessee Operating Lease Existence Of Option To Extend LesseeOperatingLeaseExistenceOfOptionToExtend	true
CY2020	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	1
CY2020	mktx	Hedge Derivative Expiration Period HedgeDerivativeExpirationPeriod	P1M
CY2020	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	1
CY2020	dei	Document Annual Report DocumentAnnualReport	true
CY2020	dei	Document Transition Report DocumentTransitionReport	false
CY2020	dei	Entity File Number EntityFileNumber	001-34091
CY2020	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	DE
CY2020	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	52-2230784
CY2020	dei	Entity Address Address Line1 EntityAddressAddressLine1	55 Hudson Yards
CY2020	dei	Entity Address City Or Town EntityAddressCityOrTown	New York
CY2020	dei	Entity Address State Or Province EntityAddressStateOrProvince	NY
CY2020	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	10001
CY2020	dei	City Area Code CityAreaCode	212
CY2020	dei	Local Phone Number LocalPhoneNumber	813-6000
CY2020	dei	Security12b Title Security12bTitle	Common Stock, $0.003 par value
CY2020	dei	Security Exchange Name SecurityExchangeName	NASDAQ
CY2020	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2020	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2020	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2020	dei	Entity Small Business EntitySmallBusiness	false
CY2020	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2020	dei	Icfr Auditor Attestation Flag IcfrAuditorAttestationFlag	true
CY2020	dei	Entity Shell Company EntityShellCompany	false
CY2020Q2	dei	Entity Public Float EntityPublicFloat	16300000000
CY2021Q1	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	37995877
CY2019Q4	us-gaap	Goodwill Goodwill	146861000
CY2019Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	60986000
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	71795000
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	270124000
CY2020Q4	us-gaap	Cash And Securities Segregated Under Federal And Other Regulations CashAndSecuritiesSegregatedUnderFederalAndOtherRegulations	50059000
CY2020Q4	us-gaap	Marketable Securities MarketableSecurities	28111000
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	81399000
CY2019Q4	us-gaap	Prepaid Expense And Other Assets PrepaidExpenseAndOtherAssets	31271000
CY2019Q4	us-gaap	Assets Assets	954930000
CY2019Q4	us-gaap	Employee Related Liabilities Current And Noncurrent EmployeeRelatedLiabilitiesCurrentAndNoncurrent	47365000
CY2019	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	511352000
CY2018	us-gaap	Labor And Related Expense LaborAndRelatedExpense	109117000
CY2019	us-gaap	Occupancy Net OccupancyNet	11639000
CY2019	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	11559000
CY2018	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	12114000
CY2019	mktx	Transaction Costs TransactionCosts	11314000
CY2018	mktx	Transaction Costs TransactionCosts	7754000
CY2019	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	15696000
CY2018	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	11353000
CY2020	us-gaap	Net Income Loss NetIncomeLoss	299377000
CY2019	us-gaap	Operating Expenses OperatingExpenses	260470000
CY2018	us-gaap	Operating Expenses OperatingExpenses	222981000
CY2019	us-gaap	Operating Income Loss OperatingIncomeLoss	250882000
CY2018	us-gaap	Operating Income Loss OperatingIncomeLoss	212584000
CY2019	us-gaap	Investment Income Nonoperating InvestmentIncomeNonoperating	8063000
CY2018	us-gaap	Investment Income Nonoperating InvestmentIncomeNonoperating	6112000
CY2020	us-gaap	Interest Expense InterestExpense	1142000
CY2020	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-1673000
CY2019	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-1521000
CY2018	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-610000
CY2020	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	-369000
CY2019	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	6542000
CY2018	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	5502000
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	374359000
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	257424000
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	218086000
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	74982000
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	52522000
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	45234000
CY2019	us-gaap	Net Income Loss NetIncomeLoss	204902000
CY2018	us-gaap	Net Income Loss NetIncomeLoss	172852000
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	8.01
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	5.53
CY2018	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.68
CY2017Q4	us-gaap	Stockholders Equity StockholdersEquity	514768000
CY2018	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-90000
CY2018	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	15850000
CY2018	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	2973000
CY2018	mktx	Adjustments Related To Tax Withholding Expense Benefit For Share Based Compensation AdjustmentsRelatedToTaxWithholdingExpenseBenefitForShareBasedCompensation	8043000
CY2018	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	25171000
CY2019	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	1207000
CY2019	mktx	Adjustments Related To Tax Withholding Expense Benefit For Share Based Compensation AdjustmentsRelatedToTaxWithholdingExpenseBenefitForShareBasedCompensation	25820000
CY2019	mktx	Treasury Stock Used For Acquisition Of Business TreasuryStockUsedForAcquisitionOfBusiness	48830000
CY2019	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	17256000
CY2019	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	77068000
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	770091000
CY2020	us-gaap	Net Income Loss NetIncomeLoss	299377000
CY2020	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	6164000
CY2020	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-544000
CY2020	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	4007000
CY2020	mktx	Adjustments Related To Tax Withholding Expense Benefit For Share Based Compensation AdjustmentsRelatedToTaxWithholdingExpenseBenefitForShareBasedCompensation	42418000
CY2020	us-gaap	Net Income Loss NetIncomeLoss	299377000
CY2019	us-gaap	Net Income Loss NetIncomeLoss	204902000
CY2020	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	35996000
CY2019	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	26857000
CY2018	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	23080000
CY2020	mktx	Amortization Of Operating Lease Right Of Use Assets AmortizationOfOperatingLeaseRightOfUseAssets	6842000
CY2019	mktx	Amortization Of Operating Lease Right Of Use Assets AmortizationOfOperatingLeaseRightOfUseAssets	5795000
CY2020	us-gaap	Share Based Compensation ShareBasedCompensation	25613000
CY2019	us-gaap	Share Based Compensation ShareBasedCompensation	25294000
CY2018	us-gaap	Share Based Compensation ShareBasedCompensation	15850000
CY2020	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	10099000
CY2019	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	2674000
CY2018	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	-1173000
CY2020	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	550000
CY2019	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	778000
CY2018	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-2253000
CY2020	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	18015000
CY2019	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	2962000
CY2018	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	5117000
CY2020	us-gaap	Increase Decrease In Brokerage Receivables IncreaseDecreaseInBrokerageReceivables	182871000
CY2020	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	1977000
CY2019	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	4624000
CY2018	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	3791000
CY2020	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	-67952000
CY2019	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	-4045000
CY2018	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	-856000
CY2020	us-gaap	Increase Decrease In Employee Related Liabilities IncreaseDecreaseInEmployeeRelatedLiabilities	14961000
CY2019	us-gaap	Increase Decrease In Employee Related Liabilities IncreaseDecreaseInEmployeeRelatedLiabilities	8312000
CY2018	us-gaap	Increase Decrease In Employee Related Liabilities IncreaseDecreaseInEmployeeRelatedLiabilities	2551000
CY2020	us-gaap	Increase Decrease In Payables To Broker Dealers IncreaseDecreaseInPayablesToBrokerDealers	133326000
CY2020	us-gaap	Increase Decrease In Income Taxes IncreaseDecreaseInIncomeTaxes	16189000
CY2019	us-gaap	Increase Decrease In Income Taxes IncreaseDecreaseInIncomeTaxes	187000
CY2018	us-gaap	Increase Decrease In Income Taxes IncreaseDecreaseInIncomeTaxes	2965000
CY2020	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	6006000
CY2019	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	-820000
CY2018	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	14524000
CY2020	mktx	Increase Decrease In Operating Lease Liabilities IncreaseDecreaseInOperatingLeaseLiabilities	-5788000
CY2019	mktx	Increase Decrease In Operating Lease Liabilities IncreaseDecreaseInOperatingLeaseLiabilities	-829000
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	404489000
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	265935000
CY2018	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	223917000
CY2020	mktx	Payments To Acquire Net Of Cash And Cash Equivalents Acquired PaymentsToAcquireNetOfCashAndCashEquivalentsAcquired	23297000
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CY2020	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	170657000
CY2019	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	170936000
CY2018	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	333791000
CY2020	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	32865000
CY2019	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	160827000
CY2018	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	336533000
CY2020	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	15010000
CY2019	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	12292000
CY2018	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	35888000
CY2020	us-gaap	Payments To Develop Software PaymentsToDevelopSoftware	30618000
CY2019	us-gaap	Payments To Develop Software PaymentsToDevelopSoftware	22408000
CY2018	us-gaap	Payments To Develop Software PaymentsToDevelopSoftware	11705000
CY2019	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	30000
CY2018	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-39000
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	68867000
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-122051000
CY2018	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-50296000
CY2020	us-gaap	Payments Of Ordinary Dividends PaymentsOfOrdinaryDividends	90566000
CY2019	us-gaap	Payments Of Ordinary Dividends PaymentsOfOrdinaryDividends	76231000
CY2018	us-gaap	Payments Of Ordinary Dividends PaymentsOfOrdinaryDividends	62432000
CY2020	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	4007000
CY2019	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	1207000
CY2018	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	2973000
CY2020	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	42418000
CY2019	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	25820000
CY2018	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	8043000
CY2020	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	16135000
CY2019	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	17256000
CY2018	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	25171000
CY2020	us-gaap	Proceeds From Short Term Debt ProceedsFromShortTermDebt	578356000
CY2020	us-gaap	Repayments Of Subordinated Debt RepaymentsOfSubordinatedDebt	578356000
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-145112000
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-118100000
CY2018	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-92673000
CY2020	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	5553000
CY2019	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	1011000
CY2018	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	-1640000
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	333797000
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	26795000
CY2018	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	79308000
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	274253000
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	247458000
CY2017Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	168150000
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	608050000
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	274253000
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	247458000
CY2020	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	45046000
CY2019	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	51766000
CY2018	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	47208000
CY2020	us-gaap	Interest Paid Net InterestPaidNet	1142000
CY2020	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	727000
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	7464000
CY2020	us-gaap	Stock Issued1 StockIssued1	10866000
CY2019	us-gaap	Stock Issued1 StockIssued1	1811000
CY2020	us-gaap	Noncash Or Part Noncash Acquisition Intangible Assets Acquired1 NoncashOrPartNoncashAcquisitionIntangibleAssetsAcquired1	14665000
CY2019	us-gaap	Fair Value Of Assets Acquired FairValueOfAssetsAcquired	148425000
CY2019	mktx	Payments To Acquire Businesses Net Of Cash And Cash Equivalents Acquired PaymentsToAcquireBusinessesNetOfCashAndCashEquivalentsAcquired	97430000
CY2019	mktx	Treasury Stock Used For Acquisition Of Business TreasuryStockUsedForAcquisitionOfBusiness	48830000
CY2019	us-gaap	Noncash Or Part Noncash Acquisition Net Nonmonetary Assets Acquired Liabilities Assumed1 NoncashOrPartNoncashAcquisitionNetNonmonetaryAssetsAcquiredLiabilitiesAssumed1	2165000
CY2020	dei	Entity Incorporation Date Of Incorporation EntityIncorporationDateOfIncorporation	2000-04-11
CY2020	mktx	Cash Equivalents Maximum Period CashEquivalentsMaximumPeriod	P3M
CY2019	us-gaap	Other Than Temporary Impairment Loss Debt Securities Available For Sale Recognized In Earnings OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarnings	0
CY2018	us-gaap	Other Than Temporary Impairment Loss Debt Securities Available For Sale Recognized In Earnings OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarnings	0
CY2020	us-gaap	Other Than Temporary Impairment Loss Debt Securities Available For Sale Recognized In Earnings OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarnings	0
CY2020Q4	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	200000
CY2019Q4	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	100000
CY2018Q4	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	100000
CY2020	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	500000
CY2019	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	300000
CY2018	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	200000
CY2020	us-gaap	Allowance For Doubtful Accounts Receivable Write Offs AllowanceForDoubtfulAccountsReceivableWriteOffs	100000
CY2019	us-gaap	Allowance For Doubtful Accounts Receivable Write Offs AllowanceForDoubtfulAccountsReceivableWriteOffs	100000
CY2018	us-gaap	Allowance For Doubtful Accounts Receivable Write Offs AllowanceForDoubtfulAccountsReceivableWriteOffs	200000
CY2020	mktx	Number Of Revenue Streams NumberOfRevenueStreams	4
CY2020	mktx	Description Of Commission Revenue DescriptionOfCommissionRevenue	For Open Trading trades that the Company executes between and among institutional investor and broker-dealer clients on a matched principal basis by serving as counterparty to both the buyer and the seller, the Company earns its commission through the difference in price between the two trades.
CY2020	mktx	Settlement Period Of Bond Transaction SettlementPeriodOfBondTransaction	within one to two trading days
CY2019Q4	us-gaap	Contract With Customer Liability ContractWithCustomerLiability	3499000
CY2020	mktx	Contract With Customer Liability Payments Received ContractWithCustomerLiabilityPaymentsReceived	25089000
CY2020	mktx	Contract With Customer Liability Revenue Recognized Including Additions ContractWithCustomerLiabilityRevenueRecognizedIncludingAdditions	24390000
CY2020	mktx	Contract With Customer Liability Foreign Currency Translation ContractWithCustomerLiabilityForeignCurrencyTranslation	-50000
CY2020Q4	us-gaap	Contract With Customer Liability ContractWithCustomerLiability	4248000
CY2020Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	21100000
CY2020Q4	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P33M
CY2020Q4	mktx	Marketable Securities Amortized Cost MarketableSecuritiesAmortizedCost	26761000
CY2020Q4	mktx	Marketable Securities Accumulated Gross Unrealized Gain Before Tax MarketableSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	1350000
CY2020	us-gaap	Use Of Estimates UseOfEstimates	<p style="margin-bottom:0pt;margin-top:18pt;margin-left:2.26%;text-indent:0.24%;font-weight:bold;font-style:italic;font-size:10pt;font-family:Times New Roman;text-transform:none;font-variant: normal;">Use of Estimates </p> <p style="text-align:justify;margin-bottom:0pt;margin-top:6pt;text-indent:4.54%;font-size:10pt;font-family:Times New Roman;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. </p>
CY2020Q4	srt	Alternative Excess Net Capital AlternativeExcessNetCapital	435400000
CY2020Q4	srt	Alternative Net Capital Requirement1 AlternativeNetCapitalRequirement1	21600000
CY2020Q4	us-gaap	Securities Reserve Deposit Required And Made SecuritiesReserveDepositRequiredAndMade	50100000
CY2020Q4	us-gaap	Assets Fair Value Disclosure AssetsFairValueDisclosure	48162000
CY2019Q4	mktx	Money Market Funds Fair Value Disclosure MoneyMarketFundsFairValueDisclosure	99755000
CY2019Q4	us-gaap	Assets Fair Value Disclosure AssetsFairValueDisclosure	327460000
CY2020Q4	us-gaap	Marketable Securities MarketableSecurities	28111000
CY2019Q4	us-gaap	Trading Securities Debt Amortized Cost TradingSecuritiesDebtAmortizedCost	91031000
CY2019Q4	mktx	Trading Securities Accumulated Gross Unrealized Gain Before Tax TradingSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	1625000
CY2019Q4	mktx	Trading Securities Accumulated Gross Unrealized Loss Before Tax TradingSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	14000
CY2019Q4	us-gaap	Trading Securities Debt TradingSecuritiesDebt	92642000
CY2019Q4	mktx	Marketable Securities Amortized Cost MarketableSecuritiesAmortizedCost	228150000
CY2019Q4	mktx	Marketable Securities Accumulated Gross Unrealized Gain Before Tax MarketableSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	2346000
CY2019Q4	mktx	Marketable Securities Accumulated Gross Unrealized Loss Before Tax MarketableSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	19000
CY2019Q4	us-gaap	Marketable Securities MarketableSecurities	230477000
CY2020Q4	mktx	Marketable Securities Within One Year Fair Value MarketableSecuritiesWithinOneYearFairValue	18290000
CY2019Q4	mktx	Marketable Securities Within One Year Fair Value MarketableSecuritiesWithinOneYearFairValue	120850000
CY2020Q4	mktx	Marketable Securities After One Through Five Years Fair Value MarketableSecuritiesAfterOneThroughFiveYearsFairValue	9821000
CY2019Q4	mktx	Marketable Securities After One Through Five Years Fair Value MarketableSecuritiesAfterOneThroughFiveYearsFairValue	109627000
CY2020Q4	us-gaap	Marketable Securities MarketableSecurities	28111000
CY2019Q4	us-gaap	Marketable Securities MarketableSecurities	230477000
CY2020	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	261600000
CY2019	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	262100000
CY2018	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	409300000
CY2020	us-gaap	Debt Securities Trading Unrealized Gain Loss DebtSecuritiesTradingUnrealizedGainLoss	-400000
CY2019	us-gaap	Debt Securities Trading Unrealized Gain Loss DebtSecuritiesTradingUnrealizedGainLoss	800000
CY2020	us-gaap	Debt Securities Trading Realized Gain Loss DebtSecuritiesTradingRealizedGainLoss	1700000
CY2020	us-gaap	Due To And From Broker Dealers And Clearing Organizations Disclosure DueToAndFromBrokerDealersAndClearingOrganizationsDisclosure	<p style="margin-bottom:0pt;margin-top:0pt;text-indent:0%;font-weight:bold;font-size:10pt;font-family:Times New Roman;font-style:normal;text-transform:none;font-variant: normal;">5. Receivables from and Payables to Broker-dealers, Clearing Organizations and Customers</p> <p style="margin-bottom:0pt;margin-top:0pt;text-indent:0%;font-size:10pt;"> </p> <p style="text-align:justify;margin-top:6pt;margin-bottom:0pt;text-indent:4.54%;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">As of December 31, 2020, receivables from and payables to broker-dealers, clearing organizations and customers consisted of the following:</p> <p style="text-align:justify;margin-top:6pt;margin-bottom:0pt;text-indent:4.54%;font-family:Times New Roman;font-size:10pt;"> </p> <div> <table border="0" cellpadding="0" cellspacing="0" style="margin:auto;border-collapse:collapse; width:97.8%;"> <tr> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;width:68.16%; border-bottom:solid 0.75pt transparent;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> <td colspan="2" style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:30.82%; border-bottom:solid 0.75pt #000000;" valign="bottom"> <p style="text-align:center;margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;font-weight:bold;color:#000000;font-family:Times New Roman;font-size:10pt;font-style:normal;text-transform:none;font-variant: normal;">December 31, 2020</p></td> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;width:1%;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;font-weight:bold;color:#000000;font-family:Times New Roman;font-size:10pt;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> </tr> <tr> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:68.16%;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">Receivables from broker-dealers, clearing organizations and customers:</p></td> <td colspan="2" style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:30.82%; border-top:solid 0.75pt #000000;" valign="bottom"> <p style="text-align:center;margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;font-weight:bold;color:#000000;font-family:Times New Roman;font-size:10pt;font-style:normal;text-transform:none;font-variant: normal;">(In thousands)</p></td> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:1%;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;font-weight:bold;color:#000000;font-family:Times New Roman;font-size:10pt;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> </tr> <tr> <td style="background-color:#DDEBF7;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:68.16%;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:13.7pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">Securities failed-to-deliver - broker-dealers</p></td> <td style="background-color:#DDEBF7;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:1.1%;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">$</p></td> <td style="background-color:#DDEBF7;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:29.72%;white-space:nowrap;" valign="bottom"> <p style="text-align:right;margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">93,294</p></td> <td style="background-color:#DDEBF7;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:1%;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> </tr> <tr> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:68.16%;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:13.7pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">Securities failed-to-deliver - customers</p></td> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:1.1%;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:29.72%;white-space:nowrap;" valign="bottom"> <p style="text-align:right;margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">87,685</p></td> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:1%;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> </tr> <tr> <td style="background-color:#DDEBF7;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:68.16%;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:13.7pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">Deposits with clearing organizations and broker-dealers</p></td> <td style="background-color:#DDEBF7;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:1.1%;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> <td style="background-color:#DDEBF7;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:29.72%;white-space:nowrap;" valign="bottom"> <p style="text-align:right;margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">97,043</p></td> <td style="background-color:#DDEBF7;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:1%;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> </tr> <tr> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;width:68.16%; border-bottom:solid 0.75pt transparent;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:13.7pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">Other</p></td> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:1.1%; border-bottom:solid 0.75pt #000000;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:29.72%; border-bottom:solid 0.75pt #000000;white-space:nowrap;" valign="bottom"> <p style="text-align:right;margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">1,893</p></td> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;width:1%; border-bottom:solid 0.75pt transparent;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> </tr> <tr> <td style="background-color:#DDEBF7;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;width:68.16%; border-bottom:double 2.5pt transparent;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:27.35pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">Total</p></td> <td style="background-color:#DDEBF7;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:1.1%; border-top:solid 0.75pt #000000; border-bottom:double 2.5pt #000000;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">$</p></td> <td style="background-color:#DDEBF7;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:29.72%; border-top:solid 0.75pt #000000; border-bottom:double 2.5pt #000000;white-space:nowrap;" valign="bottom"> <p style="text-align:right;margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">279,915</p></td> <td style="background-color:#DDEBF7;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;width:1%; border-bottom:double 2.5pt transparent;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> </tr> <tr> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:68.16%;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-size:11pt;font-family:Calibri;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:1.1%; border-top:double 2.5pt #000000;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:29.72%; border-top:double 2.5pt #000000;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:1%;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> </tr> <tr> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:68.16%;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">Payables to broker-dealers, clearing organizations and customers:</p></td> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:1.1%;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-size:11pt;font-family:Calibri;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:29.72%;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-size:11pt;font-family:Calibri;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:1%;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-size:11pt;font-family:Calibri;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> </tr> <tr> <td style="background-color:#DDEBF7;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:68.16%;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:13.7pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">Securities failed-to-receive - broker-dealers</p></td> <td style="background-color:#DDEBF7;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:1.1%;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> <td style="background-color:#DDEBF7;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:29.72%;white-space:nowrap;" valign="bottom"> <p style="text-align:right;margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">70,917</p></td> <td style="background-color:#DDEBF7;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:1%;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> </tr> <tr> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:68.16%;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:13.7pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">Securities failed-to-receive - customers</p></td> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:1.1%;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:29.72%;white-space:nowrap;" valign="bottom"> <p style="text-align:right;margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">60,784</p></td> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:1%;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> </tr> <tr> <td style="background-color:#DDEBF7;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;width:68.16%; border-bottom:solid 0.75pt transparent;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:13.7pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">Other</p></td> <td style="background-color:#DDEBF7;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:1.1%; border-bottom:solid 0.75pt #000000;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> <td style="background-color:#DDEBF7;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:29.72%; border-bottom:solid 0.75pt #000000;white-space:nowrap;" valign="bottom"> <p style="text-align:right;margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">1,625</p></td> <td style="background-color:#DDEBF7;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;width:1%; border-bottom:solid 0.75pt transparent;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> </tr> <tr> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;width:68.16%; border-bottom:double 2.5pt transparent;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:27.35pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">Total</p></td> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:1.1%; border-top:solid 0.75pt #000000; border-bottom:double 2.5pt #000000;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">$</p></td> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;padding-Bottom:0pt;width:29.72%; border-top:solid 0.75pt #000000; border-bottom:double 2.5pt #000000;white-space:nowrap;" valign="bottom"> <p style="text-align:right;margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-family:Times New Roman;font-size:10pt;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;">133,326</p></td> <td style="background-color:#FFFFFF;padding-left:0pt;padding-Right:0.75pt;padding-Top:0.75pt;width:1%; border-bottom:double 2.5pt transparent;white-space:nowrap;" valign="bottom"> <p style="margin-bottom:0pt;margin-top:0pt;margin-left:0pt;;text-indent:0pt;;color:#000000;font-size:1pt;font-family:Times New Roman;font-weight:normal;font-style:normal;text-transform:none;font-variant: normal;"> </p></td> </tr> </table></div> <p style="margin-bottom:0pt;margin-top:0pt;text-indent:0%;font-family:Times New Roman;font-size:10pt;"> </p>
CY2020Q4	mktx	Securities Failed To Deliver Broker Dealers SecuritiesFailedToDeliverBrokerDealers	93294000
CY2020Q4	mktx	Securities Failed To Deliver Customers SecuritiesFailedToDeliverCustomers	87685000
CY2020Q4	us-gaap	Deposits Paid For Securities Borrowed At Carrying Value DepositsPaidForSecuritiesBorrowedAtCarryingValue	97043000
CY2020Q4	us-gaap	Other Receivables From Broker Dealers And Clearing Organizations OtherReceivablesFromBrokerDealersAndClearingOrganizations	1893000
CY2020Q4	us-gaap	Receivables From Brokers Dealers And Clearing Organizations ReceivablesFromBrokersDealersAndClearingOrganizations	279915000
CY2020Q4	mktx	Securities Failed To Receive Broker Dealers SecuritiesFailedToReceiveBrokerDealers	70917000
CY2020Q4	mktx	Securities Failed To Receive Customers SecuritiesFailedToReceiveCustomers	60784000
CY2020Q4	us-gaap	Other Payables To Broker Dealers And Clearing Organizations OtherPayablesToBrokerDealersAndClearingOrganizations	1625000
CY2020Q4	srt	Payables To Broker Dealers And Clearing Organizations PayablesToBrokerDealersAndClearingOrganizations	133326000
CY2020Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	109246000
CY2020Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	13892000
CY2020Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	95354000
CY2019Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	70972000
CY2019Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	9986000
CY2019Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	60986000
CY2020	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	3900000
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	800000
CY2018	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	400000
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	5700000
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	6900000
CY2018	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	5928000
CY2020	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	15538000
CY2019	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	13234000
CY2018	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	8862000
CY2020	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	64883000
CY2019	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	49848000
CY2018	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	46407000
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	7900000
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	6700000
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	5700000
CY2019Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	135186000
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	85204000
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	71795000
CY2020	us-gaap	Capitalized Computer Software Additions CapitalizedComputerSoftwareAdditions	30600000
CY2019	us-gaap	Capitalized Computer Software Additions CapitalizedComputerSoftwareAdditions	22400000
CY2020	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	30215000
CY2019	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	28928000
CY2018	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	31617000
CY2020	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	19130000
CY2019	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	7686000
CY2020Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	248759000
CY2019Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	206981000
CY2020Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	163555000
CY2020	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	7474000
CY2019	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	2579000
CY2018	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-1416000
CY2020	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	1439000
CY2019	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	403000
CY2018	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-272000
CY2020	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	1186000
CY2019	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-308000
CY2018	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	515000
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	10099000
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	2674000
CY2018	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-1173000
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	74982000
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	52522000
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	45234000
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	288300000
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	190400000
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	168500000
CY2020	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.21
CY2020	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2019	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2018	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2020	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.044
CY2019	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.025
CY2018	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.020
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Research EffectiveIncomeTaxRateReconciliationTaxCreditsResearch	0.003
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Research EffectiveIncomeTaxRateReconciliationTaxCreditsResearch	0.003
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Research EffectiveIncomeTaxRateReconciliationTaxCreditsResearch	0.003
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	-0.004
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	-0.005
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	-0.005
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Share Based Compensation Cost EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost	0.054
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Share Based Compensation Cost EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost	0.035
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Share Based Compensation Cost EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost	0.021
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.007
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.012
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.006
CY2020Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Capitalized Software DeferredTaxLiabilitiesDeferredExpenseCapitalizedSoftware	7828000
CY2019Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Capitalized Software DeferredTaxLiabilitiesDeferredExpenseCapitalizedSoftware	5306000
CY2020Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssets	2852000
CY2020	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.200
CY2019	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.204
CY2018	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.207
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	3682000
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	4926000
CY2020Q4	mktx	Deferred Tax Assets Operating Lease Liabilities DeferredTaxAssetsOperatingLeaseLiabilities	19339000
CY2019Q4	mktx	Deferred Tax Assets Operating Lease Liabilities DeferredTaxAssetsOperatingLeaseLiabilities	20227000
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Other DeferredTaxAssetsTaxDeferredExpenseOther	1968000
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Other DeferredTaxAssetsTaxDeferredExpenseOther	892000
CY2020Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	24989000
CY2019Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	26045000
CY2020Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	24989000
CY2019Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	26045000
CY2020Q4	mktx	Deferred Tax Liabilities Depreciation And Amortization DeferredTaxLiabilitiesDepreciationAndAmortization	9729000
CY2019Q4	mktx	Deferred Tax Liabilities Depreciation And Amortization DeferredTaxLiabilitiesDepreciationAndAmortization	4085000
CY2019Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssets	1120000
CY2020Q4	mktx	Deferred Tax Liabilities Operating Lease Right Of Use Assets DeferredTaxLiabilitiesOperatingLeaseRightOfUseAssets	15600000
CY2019Q4	mktx	Deferred Tax Liabilities Operating Lease Right Of Use Assets DeferredTaxLiabilitiesOperatingLeaseRightOfUseAssets	16515000
CY2020Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	11020000
CY2019Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	981000
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	6831000
CY2018Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	4718000
CY2017Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	2650000
CY2020	mktx	Unrecognized Tax Benefits Increases Resulting From State And Local Apportionment UnrecognizedTaxBenefitsIncreasesResultingFromStateAndLocalApportionment	9486000
CY2019	mktx	Unrecognized Tax Benefits Increases Resulting From State And Local Apportionment UnrecognizedTaxBenefitsIncreasesResultingFromStateAndLocalApportionment	2113000
CY2018	mktx	Unrecognized Tax Benefits Increases Resulting From State And Local Apportionment UnrecognizedTaxBenefitsIncreasesResultingFromStateAndLocalApportionment	2068000
CY2020Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	16317000
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	6831000
CY2018Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	4718000
CY2020Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	16300000
CY2020	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	3700000
CY2019	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	600000
CY2018	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	400000
CY2020Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	4900000
CY2019Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	1200000
CY2020	us-gaap	Common Stock Voting Rights CommonStockVotingRights	one
CY2020Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.60
CY2020Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.60
CY2020Q4	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.60
CY2020Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.60
CY2019Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.51
CY2019Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.51
CY2019Q4	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.51
CY2019Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.51
CY2018Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.42
CY2018Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.42
CY2018Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.42
CY2018Q4	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.42
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant	2531199
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	91.43
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	58.37
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	56.11
CY2020Q4	mktx	Number Of Awards Excluded From Option Pricing Model NumberOfAwardsExcludedFromOptionPricingModel	2
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate Minimum ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMinimum	0.016
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate Minimum ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMinimum	0.026
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate Minimum ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMinimum	0.022
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate Minimum ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum	0.268
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate Minimum ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum	0.259
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate Minimum ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum	0.269
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.006
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.008
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.008
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	529611
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	67.60
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	168217
CY2018	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	261.19
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	1676
CY2018	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	142.69
CY2018	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	120588
CY2018	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	24.66
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	575564
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	132.93
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	82474
CY2019	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	279.57
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	548
CY2019	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	198.67
CY2019	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	106899
CY2019	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	28.24
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	550591
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	175.16
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	13900
CY2020Q4	mktx	Closing Price Of Common Stock ClosingPriceOfCommonStock	570.56
CY2020Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	5900000
CY2020	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1	P2Y4M24D
CY2020	mktx	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Performance Shares Payout Range Minimum ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsPerformanceSharesPayoutRangeMinimum	0
CY2020	mktx	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Performance Shares Payout Range Maximum ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsPerformanceSharesPayoutRangeMaximum	1.50
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	223.60
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	134401000
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	99415
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	137.78
CY2020Q4	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	43025000
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	387372
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	368.10
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	218
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	307.52
CY2020	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	176901
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	84.07
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	76709000
CY2020	us-gaap	Lease Cost LeaseCost	13465000
CY2019	us-gaap	Lease Cost LeaseCost	11044000
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	37359000
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	37083000
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	36958000
CY2020	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	785000
CY2019	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	873000
CY2018	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	897000
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	38144000
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	37956000
CY2018	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	37855000
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	8.01
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	5.53
CY2018	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.68
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	7.85
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	5.40
CY2018	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.57
CY2020	us-gaap	Lessee Operating Lease Option To Extend LesseeOperatingLeaseOptionToExtend	Certain leases contain options to extend the initial term at the Company’s discretion
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	85204000
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	71795000
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.059
CY2019Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.059
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	12131000
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	10516000
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	10270000
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	10937000
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	10937000
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	79003000
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	133794000
CY2020Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	40182000
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	93612000
CY2020Q4	mktx	Number Of Lease Agreements NumberOfLeaseAgreements	2
CY2020Q4	us-gaap	Contractual Obligation ContractualObligation	2100000
CY2020	mktx	Settlement Period Of Bond Transaction SettlementPeriodOfBondTransaction	within one to two trading days
CY2020	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	689125000
CY2019	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	511352000
CY2018	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	435565000
CY2020	us-gaap	Defined Contribution Plan Employer Discretionary Contribution Amount DefinedContributionPlanEmployerDiscretionaryContributionAmount	4000000.0
CY2019	us-gaap	Defined Contribution Plan Employer Discretionary Contribution Amount DefinedContributionPlanEmployerDiscretionaryContributionAmount	3300000
CY2018	us-gaap	Defined Contribution Plan Employer Discretionary Contribution Amount DefinedContributionPlanEmployerDiscretionaryContributionAmount	2600000
CY2020	mktx	Non Qualified Deferred Cash Incentive Plan Maximum Eligibility Percentage Of Employees NonQualifiedDeferredCashIncentivePlanMaximumEligibilityPercentageOfEmployees	1
CY2020Q4	mktx	Mutual Fund Investments And Deferred Compensation Obligation At Fair Value MutualFundInvestmentsAndDeferredCompensationObligationAtFairValue	8900000
CY2019Q4	mktx	Mutual Fund Investments And Deferred Compensation Obligation At Fair Value MutualFundInvestmentsAndDeferredCompensationObligationAtFairValue	6200000
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	608050000
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	274253000

Files In Submission

Name	View Source	Status
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0001564590-21-006981-index.html	Edgar Link	pending
0001564590-21-006981.txt	Edgar Link	pending
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$MKTX
MARKETAXESS HOLDINGS INC Stock $mktx

2019 Q4 Form 10-K Financial Statement

#000156459021006981 Filed on February 19, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$MKTX MARKETAXESS HOLDINGS INC Stock $mktx

2019 Q4 Form 10-K Financial Statement

#000156459021006981 Filed on February 19, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$MKTX
MARKETAXESS HOLDINGS INC Stock $mktx