Cboe Global Markets (CBOE) 10-K 22 Feb 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2017	Feb. 15, 2018	Jun. 30, 2017
Document and Entity Information
Entity Registrant Name	Cboe Global Markets, Inc.
Entity Central Index Key	1,374,310
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Entity Current Reporting Status	Yes
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Amendment Flag	false
Entity Common Stock, Shares Outstanding		112,704,945
Entity Public Float			$ 11.4

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Current Assets:
Cash and cash equivalents	$ 143.5	$ 97.3
Financial investments	47.3
Accounts receivables, net	217.3	76.7
Income taxes receivable	17.2	53.7
Other current assets	9.4	7.4
Total Current Assets	434.7	235.1
Investments	82.7	72.9
Land	4.9	4.9
Property and equipment, net	73.9	55.9
Goodwill	2,707.4	26.5
Intangible assets, net	1,902.6	8.7
Other assets, net	59.5	72.7
Total Assets	5,265.7	476.7
Current Liabilities:
Accounts payable and accrued liabilities	153.8	82.4
Section 31 fees payable	105.6	4.4
Deferred revenue	15.4	3.1
Income taxes payable	2.6
Contingent consideration liability	56.6
Total Current Liabilities	334	89.9
Long-term debt	1,237.9
Income tax liability	78.8	52.1
Deferred income taxes	488.2
Other non-current liabilities	6.8	4.2
Redeemable Noncontrolling Interest	9.4	12.6
Stockholders’ Equity:
Preferred stock, $0.01 par value: 20,000,000 shares authorized, no shares issued and outstanding at December 31, 2017 and Decemner 31, 2016
Common stock, $0.01 par value: 325,000,000 shares authorized, 125,342,953 and 113,378,384 shares issued and outstanding, respectively at December 31, 2017 and 92,950,065 and 81,285,307 shares issued and outstanding, respectively at December 31, 2016	1.2	0.9
Common stock in treasury, at cost, 11,964,569 shares at December 31, 2017 and 11,664,758 shares at December 31, 2016	(558.3)	(532.2)
Additional paid-in capital	2,623.7	139.2
Retained earnings	993.3	710.8
Accumulated other comprehensive income (loss), net	50.7	(0.8)
Total stockholders’ equity	3,110.6	317.9
Total liabilities, redeemable noncontrolling interest, and stockholders’ equity	$ 5,265.7	$ 476.7

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Consolidated Balance Sheets
Preferred stock, par value (in USD per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	20,000,000	20,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	325,000,000	325,000,000
Common stock, shares issued (in shares)	124,705	92,950,065
Common stock, shares outstanding (in shares)	112,741,217	81,285,307
Treasury stock (in shares)	11,964,569	11,664,758

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues:
Transaction fees	$ 1,564.9	$ 509.3	$ 485.3
Access fees	106.8	52.4	53.3
Exchange services and other fees	74.8	46.3	42.2
Market data fees	164.5	33.2	30
Regulatory fees	291.5	48.3	33.5
Other revenue	26.6	13.6	19.5
Total revenues	2,229.1	703.1	663.8
Cost of revenues:
Liquidity payments	849.7	35.8	29.2
Routing and clearing	37.6	11.1	2.3
Section 31 fees	260	11.8
Royalty fees	86.2	78	70.6
Total cost of revenues	1,233.5	136.7	102.1
Revenues less cost of revenues	995.6	566.4	561.7
Operating expenses:
Compensation and benefits	201.4	113.2	105.9
Depreciation and amortization	192.2	44.4	46.3
Technology support services	42.1	22.5	20.7
Professional fees and outside services	66	53.1	50.1
Travel and promotional expenses	17.2	11	9
Facilities costs	10.3	5.7	5
Acquisition-related costs	84.4	13.6
Other expenses	10.1	4.7	4.8
Total operating expenses	623.7	268.2	241.8
Operating Income	371.9	298.2	319.9
Non-operating (expenses) income:
Interest expense, net	(41.3)	(5.7)
Other income	3.8	14.1	4.1
Income before income tax provision	334.4	306.6	324
Income tax provision	(66.2)	120.9	119
Net income	400.6	185.7	205
Net loss attributable to noncontrolling interests	1.1	1.1
Net income excluding noncontrolling interests	401.7	186.8	205
Change in redemption value of noncontrolling interests	(1.1)	(1.1)
Net income allocated to participating securities	(3.9)	(0.8)	(0.9)
Net Income allocated to common stockholders	$ 396.7	$ 184.9	$ 204.1
Basic earnings per share (in dollars per share)	$ 3.70	$ 2.27	$ 2.46
Diluted earnings per share (in dollars per share)	$ 3.69	$ 2.27	$ 2.46
Basic weighted average shares outstanding (in shares)	107.2	81.4	83.1
Diluted weighted average shares outstanding (in shares)	107.5	81.4	83.1

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Consolidated Statements of Comprehensive Income
Net income	$ 400.6	$ 185.7	$ 205
Other comprehensive (loss) income, before tax:
Foreign currency translation adjustments	51.3
Unrealized holding gains on available-for-sale investments	0.2
Post retirement benefit obligations			(0.1)
Comprehensive income	452.1	185.7	204.9
Comprehensive loss attributable to noncontrolling interest	1.1	1.1
Comprehensive income excluding noncontrolling interest	453.2	186.8	204.9
Change in redemption value of noncontrolling interests	(1.1)	(1.1)
Comprehensive income allocated to participating securities	(3.9)	(0.8)	(0.9)
Comprehensive income allocated to common stockholders, net of tax	$ 448.2	$ 184.9	$ 204

Consolidated Statement of Chang

Consolidated Statement of Changes in Stockholder's Equity - USD ($) $ in Millions	Common Stock	Treasury Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive (Loss) Income	Redeemable Noncontrolling Interests	Total
Beginning balance at Dec. 31, 2014	$ 0.9	$ (332.3)	$ 110.1	$ 472	$ (0.7)		$ 250
Increase (Decrease) in Stockholders' Equity
Stock-based compensation			12.2				12.2
Excess tax benefit from stock-based compensation			1.3				1.3
Purchase of common stock		(135.3)					(135.3)
Net income excluding noncontrolling interest				205			205
Post-retirement benefit obligations					(0.1)		(0.1)
Cash dividends on common stock				(73.4)			(73.4)
Ending balance at Dec. 31, 2015	0.9	(467.6)	123.6	603.6	(0.8)		259.7
Increase (Decrease) in Stockholders' Equity
Stock-based compensation			14.5				14.5
Excess tax benefit from stock-based compensation			1.1				1.1
Purchase of common stock		(64.6)					(64.6)
Net income excluding noncontrolling interest				186.8			186.8
Cash dividends on common stock				(78.5)			(78.5)
Increase due to acquiring majority of outstanding equity of Vest						$ 12.6
Net loss attributable to redeemable noncontrolling interest						(1.1)
Redemption value adjustment				(1.1)		1.1	(1.1)
Ending balance at Dec. 31, 2016	0.9	(532.2)	139.2	710.8	(0.8)	12.6	317.9
Increase (Decrease) in Stockholders' Equity
Issuance of stock for acquisition of Bats Global Markets, Inc.	0.3		2,424.4				2,424.7
Issuance of vested restricted stock granted to employees			0.3				0.3
Common stock issued from employee stock plans		(26.1)					(26.1)
Stock-based compensation			52.6				52.6
Exercise of common stock options			4				4
Net income excluding noncontrolling interest				401.7			401.7
Cash dividends on common stock				(118.1)			(118.1)
Purchase of additional equity interest from noncontrolling interest			3.2			(3.2)	3.2
Other comprehensive income					51.5		51.5
Net loss attributable to redeemable noncontrolling interest						(1.1)
Redemption value adjustment				(1.1)		1.1	(1.1)
Ending balance at Dec. 31, 2017	$ 1.2	$ (558.3)	$ 2,623.7	$ 993.3	$ 50.7	$ 9.4	$ 3,110.6

Consolidated Statement of Chan7

Consolidated Statement of Changes in Stockholder's Equity (Parenthetical) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)$ / shares
Consolidated Statements of Changes in Stockholders’ Equity
Dividends (in dollars per share) | $ / shares	$ 0.88
Post-retirement benefit obligation adjustment, tax expense (benefit) | $	$ (86)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows from Operating Activities:
Net income	$ 400.6	$ 185.7	$ 205
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	192.2	44.4	46.3
Amortization of debt issuance cost	3.6
Change in fair value of contingent consideration	1
Gain on settlement of contingent consideration		(1.4)
Realized gain on available-for-sale securities	(0.4)
Provision for uncollectable convertible notes receivable	3.8
Provision for deferred income taxes	(238.4)	(8.8)	(8.3)
Stock-based compensation expense	52.6	14.5	12.2
Loss on disposition of property			0.6
Impairment of data processing software	14.9
Equity in investments	(1.4)	(1.2)	(0.8)
Impairment of investment and other assets			0.1
Changes in assets and liabilities:
Accounts receivable	(20.6)	(8.4)	0.2
Income taxes receivable	42	(25.8)	(6.4)
Other prepaid expenses	(7.3)	(0.2)	(0.5)
Other current assets		0.5	0.8
Accounts payable and accrued liabilities	10.3	21	(3.5)
Section 31 fees payable	(42.4)
Deferred revenue	7.8	(1.5)	0.7
Income taxes payable	(50.5)	(1.6)	(0.1)
Income tax liability	6.3	12.4	(1)
Other liabilities	0.3
Net Cash Flows provided by Operating Activities	374.4	229.6	245.3
Cash Flows from Investing Activities:
Acquisitions, net of cash acquired	(1,414.1)	(14.3)	(3)
Purchases of available-for-sale financial investments	(136)
Proceeds from maturities of available-for-sale financial investments	155.1		0
Investments	(4)	(23.7)	(37.1)
Payment of contingent consideration from acquisition		(2)
Purchases of property and equipment	(37.5)	(44.4)	(39.3)
Net Cash Flows used in Investing Activities	(1,436.5)	(84.4)	(79.4)
Cash Flows from Financing Activities:
Proceeds from long-term debt	1,943.9
Principal payments of long term debt	(700)
Debt issuance costs	(2)	(8.2)
Dividends paid	(118.1)	(78.5)	(73.4)
Purchase of unrestricted stock from employees	(26.1)	(4.1)	(3.2)
Proceeds from exercise of stock-based compensation	2
Excess tax benefit from stock-based compensation		1.1	1.3
Payment of outstanding debt in conjunction with acquisition of a business			(4)
Purchase of common stock under announced program		(60.5)	(132.2)
Net Cash Flows provided by (used in) Financing Activities	1,099.7	(150.2)	(211.5)
Effect of Foreign Currency Exchange Rate Changes on Cash and Cash equivalents	8.6
Increase (Decrease) in Cash and Cash Equivalents	46.2	(5)	(45.6)
Beginning of Period	97.3	102.3	147.9
End of Period	143.5	97.3	102.3
Supplemental disclosure of cash transactions:
Cash paid for income taxes	177.4	142.1	133.5
Interest paid	27
Supplemental disclosure of noncash transactions:
Forfeiture of common stock for payment of exercise of stock options	3.7
Supplemental disclosure of noncash investing activities:
Change in post-retirement benefit obligation		$ (0.1)	0.2
Unpaid liability to acquire equipment and software			2.8
Contingent consideration - current	56.6		2
Contingent consideration - current			$ 1.4
Accounts receivable acquired	117.8
Financial investments acquired	66
Property and equipment acquired	21.8
Goodwill acquired	2,653.3
Intangible assets acquired	2,000
Other assets acquired	32.8
Accounts payable and accrued expenses assumed	(59.9)
Section 31 fees payable acquired	(143.6)
Deferred tax liability acquired	(722.6)
Other liabilities assumed	(135.5)
Issuance of common stock related to acquisition	$ (2,424.7)

Nature of Operations

Nature of Operations	12 Months Ended
	Dec. 31, 2017
Nature of Operations
Nature of Operations	(1) Nature of Operations Cboe Global Markets, Inc. is one of the world’s largest exchange holding companies, offering cutting-edge trading and investment solutions to investors around the world. The Company is committed to relentless innovation, connecting global markets with world-class technology, and providing seamless solutions that enhance the customer experience. Cboe offers trading across a diverse range of products in multiple asset classes and geographies, including options, futures, U.S. and European equities, exchange-traded products, global foreign exchange and multi-asset volatility products based on the VIX, the world’s barometer for equity market volatility. Cboe’s trading venues include the largest options exchange in the U.S. by volume and the largest stock exchange by value traded in Europe. In addition, the Company is the second-largest stock exchange operator by volume in the U.S. and a leading market globally for ETP trading. The Company is headquartered in Chicago with offices in Kansas City, New York, London, San Francisco, Singapore, Hong Kong, and Ecuador. In October 2017, the Company changed its legal name from CBOE Holdings, Inc. to Cboe Global Markets, Inc. The amendment to effect the name change was filed and became effective with the State of Delaware on October 16, 2017.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	(2) Summary of Significant Accounting Policies (a) These consolidated financial statements are prepared in conformity with accounting principles generally accepted in the United States (“GAAP”) as established by FASB. (b) The accompanying financial statements are presented on a consolidated basis to include the accounts and transactions of Cboe Global Markets, Inc. and its majority owned subsidiaries and all significant intercompany accounts and transactions have been eliminated. Certain prior period amounts have been reclassified to conform to current period presentation. The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosures of contingent assets and liabilities, valuation of redeemable noncontrolling interests and reported amounts of revenues and expenses. On an ongoing basis, management evaluates its estimates based upon historical experience, observance of trends, information available from outside sources and various other assumptions that management believes to be reasonable under the circumstances. Actual results may differ from these estimates under different conditions or assumptions. For those consolidated subsidiaries in which the Company's ownership is less than 100% and for which the Company has control over the assets and liabilities and the management of the entity, the outside stockholders' interest are shown as non-controlling interests. In 2017, the Company changed the presentation of liquidity payments to be a cost of revenues, which historically had been netted against transaction fees. The Company also changed the presentation of royalty fees to be a cost of revenues. The presentation of routing fees and costs were also changed. Routing fees were presented in transaction fees in total revenues and routing and clearing costs in total cost of revenues. These fees were previously presented as a net operating expense. These changes were made to conform to current presentation and the changes have been reflected in all periods presented. Segment information The Company previously operated as a single reportable business segment. As a result of the Bats acquisition on February 28, 2017 (Note 5), the Company is reporting five business segments: Options, U.S. Equities, Futures, European Equities, and Global FX, which is reflective of how the Company's chief operating decision-maker reviews and operates the business (Note 17). This change has been reflected in all periods presented. (c) The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities as well as disclosure of the amounts of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ materially from those estimates. Material estimates that are particularly susceptible to significant change in the near term include the receivable for market data fees, the valuation of goodwill and unrecognized tax benefits. (d) The Company’s cash and cash equivalents are exposed to concentrations of credit risk. The Company maintains cash at various financial institutions and brokerage firms which, at times, may be in excess of the federal depository insurance limit. The Company’s management regularly monitors these institutions and believes that the potential for future loss is remote. The Company considers all liquid investments with original or acquired maturities of three months or less to be cash equivalents. (e) Financial investments are classified as trading or available‑for‑sale. Trading financial investments represent financial investments held by the Company’s broker‑dealer subsidiary that retain the industry‑specific accounting classification required for broker‑dealers. These investments are recorded at fair value with changes in unrealized gains and losses reflected within interest expense, net in the consolidated statements of income. Available‑for‑sale financial investments are comprised of the financial investments not held by the broker‑dealer subsidiary. Unrealized gains and losses, net of income taxes, are included as a component of accumulated other comprehensive (loss) income in the accompanying consolidated balance sheets. Interest on financial investments, including amortization of premiums and accretion of discounts, is recognized as income when earned. Realized gains and losses on financial investments are calculated using the specific identification method and are included in interest expense, net in the accompanying consolidated statements of income. A decline in the fair value of any available‑for‑sale investment below carrying amount that is deemed to be other‑than‑temporary results in an impairment to reduce the carrying amount to realizable value. To determine whether an impairment is other‑than‑temporary, the Company considers all available information relevant to the collectability of the investment, including past events, current conditions, and reasonable and supportable forecasts when developing estimate of cash flows expected to be collected. Evidence considered in this assessment includes the reasons for the impairment, the severity and duration of the impairment, changes in value subsequent to year‑end, forecasted performance of the investee, and the general market condition in the geographic area or industry in which the investee operates. (f) Accounts receivable are concentrated with the Company’s member firms and market data distributors and are carried at cost. The Company nets transaction fees and liquidity payments for each member firm on a monthly basis and recognizes the total owed to a member firm as an asset and the total owed to a member firm as a liability. On a periodic basis, management evaluates the Company’s receivables and determines an appropriate allowance for uncollectible accounts receivable based on anticipated collections. In circumstances where a specific customer’s inability to meet its financial obligations is probable, the Company records a specific provision for uncollectible accounts against amounts due to reduce the receivable to the amount the Company estimates will be collected. Once the Company determines an allowance for an uncollectible account is necessary, interest on the receivable ceases to be accrued. (g) Property and equipment, net is stated at cost less accumulated depreciation. Depreciation is computed using the straight‑line method over the estimated lives of the assets, generally ranging from three to seven years. Expenditures for repairs and maintenance are charged to expense as incurred. Depreciation of leasehold improvements is calculated using the straight‑line method over the shorter of the related lease term or the estimated useful life of the assets. Long‑lived assets to be held and used are reviewed to determine whether any events or changes in circumstances indicate that the carrying amounts of the assets may not be recoverable. The Company bases this evaluation on such impairment indicators as the nature of the assets, the future economic benefit of the assets, any historical or future profitability measurements, as well as other external market conditions or factors that may be present. If such impairment indicators are present that would indicate that the carrying amount of any asset may not be recoverable, the Company determines whether an impairment has occurred through the use of an undiscounted cash flow analysis of the asset at the lowest level for which identifiable cash flows exist. In the event of impairment, the Company recognizes a loss for the difference between the carrying amount and the estimated value of the asset as measured using quoted market prices or, in the absence of quoted market prices, a discounted cash flow analysis. The Company accounts for software development costs under ASC Topic 350, Intangibles—Goodwill and Other . The Company expenses software development costs as incurred during the preliminary project stage, while capitalizing costs incurred during the application development stage, which includes design, coding, installation and testing activities. (h) Goodwill represents the excess of purchase price over the value assigned to the net tangible and identifiable intangible assets of a business acquired. Goodwill is allocated to the Company’s reporting units based on the assignment of the fair values of each reporting unit of the acquired company. The Company tests goodwill for impairment at the reporting unit level annually, or in interim periods if certain events occur indicating that the carrying value may be impaired. The impairment test is performed during the fourth quarter using October 1 st carrying values, and if the fair value of the reporting unit is found to be less than the carrying value, an impairment loss is recorded. The Company performed its 2017 annual goodwill impairment test and determined that no impairment existed. Intangible assets, net, primarily include acquired trademarks and trade names, customer relationships, strategic alliance agreements, licenses and registrations and non‑compete agreements. Intangible assets with finite lives are amortized based on the discounted cash flow method applied over the estimated useful lives of the intangible assets. Intangible assets deemed to have indefinite useful lives are not amortized, but instead are tested for impairment at least annually, usually concurrently with goodwill. Impairment exists if the fair value of the asset is less than the carrying amount, and in that case, an impairment loss is recorded. The Company performed its 2017 annual intangible assets impairment test using October 1, 2017 carrying values and determined that no impairment existed. (i) The financial statements of foreign subsidiaries where the functional currency is not the U.S. dollar are translated into U.S. dollars using the exchange rate in effect as of each balance sheet date. Statements of income and cash flow amounts are translated using the average exchange rate during the period. The cumulative effects of translating the balance sheet accounts from the functional currency into the U.S. dollar at the applicable exchange rates are included in accumulated other comprehensive income (loss), net in the balance sheet. Foreign currency gains and losses are recorded as other income, net in the consolidated statements of income. The Company’s operations in the United Kingdom, Singapore, and Hong Kong are recorded in Pounds sterling, Singapore dollars, and Hong Kong dollars, respectively. (j) Deferred taxes are recorded on a liability method whereby deferred tax assets are recognized for deductible temporary differences and operating loss and tax credit carryforwards, and deferred tax liabilities are recognized for taxable temporary differences. Temporary differences are the differences between the reported amounts of assets and liabilities and their tax bases. Deferred tax assets are reduced by a valuation allowance when, in the opinion of management, it is more likely than not that some portion or all of the deferred tax assets will not be realized. Deferred tax assets and liabilities are adjusted for the effects of changes in tax laws and rates on the date of enactment. The Company recognizes the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by the taxing authorities, based upon the technical merits of the position. The tax benefit recognized in the consolidated financial statements from such a position is measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. Also, interest and penalties expense is recognized on the full amount of deferred benefits for uncertain tax positions. The Company’s policy is to include interest and penalties related to unrecognized tax benefits in the income tax provision within the consolidated statements of income. (k) For further discussion related to revenue recognition of fees, such as transaction fees and liquidity payments, access fees, exchange services and other fees, market data fees, and regulation transaction and Section 31 fees, see Note 4. Concentrations of Revenue and Liquidity Payments For the years ended December 31, 2017, 2016, and 2015, two members accounted for 17%, 42% and 45%, respectively, of the Company’s transaction fees. No member accounted for more than 10% of the Company’s total revenue during the years ended December 31, 2017, 2016, and 2015. For the years ended December 31, 2017, 2016, and 2015, no member accounted for more than 10% of the Company’s liquidity payments. No member is contractually or otherwise obligated to continue to use the Company’s services. The loss of, or a significant reduction of, participation by these members may have a material adverse effect on the Company’s business, financial position, results of operations and cash flows. The two largest clearing members mentioned above clear the majority of the market-maker sides of transactions at all of the Company’s U.S. options exchanges. If either of these clearing members were to withdraw from the business of market-maker clearing and market-makers were unable to transfer to another clearing member, this could create significant disruption to the U.S. options markets, including ours. (l) The Company presents both basic and diluted earnings per share. Basic earnings per share is computed by dividing net income by the weighted average number of common shares outstanding during the period. Diluted earnings per share is computed by dividing net income by the sum of the weighted average number of common shares and dilutive common share equivalents outstanding. The dilutive effect is calculated using the more dilutive of the two-class or treasury stock method. (m) The Company grants stock‑based compensation to its employees through awards of restricted stock units. In connection with the acquisition of Bats, Bats previously awarded stock options and restricted stock awards. The Company records stock‑based compensation expense for all stock‑based compensation granted based on the grant‑date fair value. The Company recognizes compensation expense related to stock‑based compensation awards with graded vesting that have a service condition on a straight‑line basis over the requisite service period of the entire award. In connection with the acquisition of Bats, as discussed in Note 20 in further detail, each outstanding Bats stock option (defined below) granted under any of the Bats Plans (defined below) that was outstanding immediately prior to the effective time of the acquisition of Bats was converted into an option to purchase our common stock, on the same terms and conditions (including vesting schedule) as were applicable to such Bats stock option. In addition, each award of Bats restricted shares (defined below) granted under any of the Bats Plans that was unvested immediately prior to the effective time of the acquisition of Bats was assumed by the Company and converted into an award of restricted shares of our common stock, subject to the same terms and conditions (including vesting schedule) that applied to the applicable Bats restricted shares. The amount of stock‑based compensation expense related to awards of restricted stock and restricted stock units is based on the fair value of Cboe Global Markets, Inc. common stock at the date of grant. The fair value is based on a current market‑based transaction of the Company’s common stock. If a market‑based transaction of the Company’s common stock is not available, then the fair value is based on an independent third‑party valuation using equal weighting of two valuation analysis techniques, discounted cash flows and valuation multiples observed from publicly traded companies in a similar industry. The amount of future stock‑based compensation expense related to awards of stock options is based on the Black‑Scholes valuation model. Assumptions used to estimate the grant‑date fair value of stock options are determined as follows: · Expected term is determined using the simplified method, using the average between the contractual term and vesting period of the award. The simplified method was used due to the lack of historical information; · Expected volatility of award grants made under the Company’s plan is measured using the weighted average of historical daily changes in the market price of the common stock of comparable public companies over the period equal to the expected term of the award or a minimum of two years if comparable public company historical market prices are not available for the entire expected term; · Expected dividend rate is determined based on expected dividends to be declared; · Risk‑free interest rate is equivalent to the implied yield on zero‑coupon U.S. Treasury bonds with a maturity equal to the expected term of the awards; and · Forfeitures are based on the history of cancellations of awards. (n) The Company records identifiable assets, liabilities and goodwill acquired in a business combination at fair value at the acquisition date. Additionally, transaction‑related costs are expensed in the period incurred. (o) All costs incurred to issue debt are capitalized as a contra-liability and amortized over the life of the loan using the interest method. (p) The Company uses the cost method to account for a non-marketable equity investment in an entity that it does not control and for which it does not have the ability to exercise significant influence over an entity’s operating and financial policies. When it does not have a controlling financial interest in an entity but can exercise significant influence over the entity's operating and financial policies, such investment is accounted for using the equity method. The Company recognizes dividend income when declared. In general, the equity method of accounting is used when the Company owns 20% to 50% of the outstanding voting stock of a company and when it is able to exercise significant influence over the operating and financial policies of a company. The Company has an investment where it has significant influence and as such accounts for the investments under the equity method of accounting. For equity method investments, the Company records the pro‑rata share of earnings or losses each period and records any dividends received as a reduction in the investment balance. The equity method investment is evaluated for other‑than‑temporary declines in value by considering a variety of factors such as the earnings capacity of the investment and the fair value of the investment compared to its carrying amount. If the estimated fair value of the investment is less than the carrying amount and the decline in value is considered to be other than temporary, the excess of the carrying amount over the estimated fair value is recognized in the financial statements as an impairment.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	12 Months Ended
	Dec. 31, 2017
Recent Accounting Pronouncements
Recent Accounting Pronouncements	(3) Recent Accounting Pronouncements Recent Accounting Pronouncements – Adopted In the first quarter of 2017, the Company adopted Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers (Topic 606). Under the ASU, revenue is recognized when a customer obtains control of promised goods or services in an amount that reflects the consideration the entity expects to receive in exchange for those goods or services. In addition, the standard requires disclosure of the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. The Company applied the five-step method outlined in the ASU to all revenue streams and elected the full retrospective implementation method. The additional disclosures required by the ASU have been included in Note 4. In the first quarter of 2017, the Company adopted ASU 2016-09, Compensation — Stock Compensation . This ASU simplifies several aspects of the accounting for stock-based payment transactions, including the recognition of excess tax benefits and deficiencies, the classification of those excess tax benefits on the statement of cash flows, an accounting policy election for forfeitures, the amount an employer can withhold to cover income taxes and still qualify for equity classification and the classification of those taxes paid on the statement of cash flows. The Company has chosen to use the actual forfeiture rate and applied the prospective transition method for excess tax benefits and employees taxes paid. As of the adoption date, the Company did not have any awards classified as a liability under the previous guidance. In the first quarter of 2017, the Company adopted ASU 2016-16, Accounting for Income Taxes:Intra-Entity Transfers of Assets other than Inventory . The ASU requires that the income tax impact of intra-entity sales and transfers of property, except for inventory, be recognized when the transfer occurs. The Company applied the full retrospective application which did not result in any impact to the financial statements. Recent Accounting Pronouncements - Issued, not yet Adopted In May 2017, the FASB issued ASU 2017-09, Compensation - Stock Compensation (Topic 718) that provides additional guidance as to which changes to a share-based payment award requires an entity to apply modification accounting. Specifically, an entity is to account for the effects of a modification, unless all of the following are satisfied: (1) the fair value (or calculated value or intrinsic value, if such an alternative measurement method is used) of the modified award is the same as the fair value (or calculated value or intrinsic value, if such an alternative measurement method is used) of the original award immediately before the original award is modified; (2) the vesting conditions of the modified award are the same as the vesting conditions of the original award immediately before the original award is modified; and (3) the classification of the modified award as an equity instrument or as a liability instrument is the same as the classification of the original award immediately before the original award is modified. For public entities, the update is effective for fiscal years beginning after December 15, 2017. Early adoption is permitted. The Company is in the process of evaluating this guidance and assessing the impact the ASU could have on the consolidated financial statements. In March 2017, the FASB issued ASU 2017-07, Compensation - Retirement Benefits (Topic 715) . This ASU requires an employer to report the service cost component in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period. The other components are required to be presented in the income statement separately from the service cost component and outside a subtotal of income from operations. For public entities, the update is effective for fiscal years beginning after December 15, 2017. Early adoption is permitted. The Company is in the process of evaluating this guidance and assessing the impact the ASU could have on the consolidated financial statements. In January 2017, the FASB issued ASU 2017-01, Business Combinations (Topic 805)-Clarifying the Definition of a Business. ASU No. 2017-01 clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. There are three elements of a business: inputs, processes, and outputs. While an integrated set of assets and activities (collectively, a “set”) that is a business usually has outputs, outputs are not required to be present. Additionally, all of the inputs and processes that a seller uses in operating a set are not required if market participants can acquire the set and continue to produce outputs. ASU No. 2017-01 provides a screen to determine when a set is not a business. The screen requires that when substantially all of the fair value of the gross assets acquired (or disposed of) is concentrated in a single identifiable asset or a group of similar identifiable assets, the set is not a business. This screen reduces the number of transactions that need to be further evaluated. If, however, the screen is not met, then the amendments in this ASU (1) require that to be considered a business, a set must include, at a minimum, an input and a substantive process that together significantly contribute to the ability to create output and (2) remove the evaluation of whether a market participant could replace missing elements. Finally, the amendments in this ASU narrow the definition of the term “output” so that it is consistent with the manner in which outputs are described in Topic 606 - Revenue from Contracts with Customers . For public entities, the update is effective for annual or any interim goodwill impairment tests in fiscal years beginning after December 15, 2018. Early adoption is permitted under certain circumstances. The Company is in the process of evaluating this guidance and assessing the impact the ASU could have on the consolidated financial statements. In January 2017, the FASB issued ASU 2017-04, Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. This ASU simplifies the manner in which an entity is required to test goodwill for impairment by eliminating Step 2 from the goodwill impairment test. Step 2 measures a goodwill impairment loss by comparing the implied fair value of a reporting unit’s goodwill with the carrying amount of that goodwill. In computing the implied fair value of goodwill under Step 2, an entity, prior to the amendments in ASU No. 2017-04, had to perform procedures to determine the fair value at the impairment testing date of its assets and liabilities, including unrecognized assets and liabilities, in accordance with the procedure that would be required in determining the fair value of assets acquired and liabilities assumed in a business combination. However, under this ASU, an entity should (1) perform its annual or interim goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount, and (2) recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value, with the understanding that the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. Additionally, ASU No. 2017-04 removes the requirements for any reporting unit with a zero or negative carrying amount to perform a qualitative assessment and, if it fails such qualitative test, to perform Step 2 of the goodwill impairment test. For public entities, the update is effective for annual or any interim goodwill impairment tests in fiscal years beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The Company is in the process of evaluating this guidance and assessing the impact the ASU could have on the consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases . This update requires a lessee to recognize on the balance sheet a liability to make lease payments and a corresponding right-of-use asset. The guidance also requires certain qualitative and quantitative disclosures about the amount, timing and uncertainty of cash flows arising from leases. This update is effective for annual and interim periods beginning after December 15, 2018. Early adoption is permitted. The Company is in the process of evaluating this guidance and assessing the impact the ASU could have on the consolidated financial statements. In September 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230) — Classification of Certain Cash Receipts and Cash Payments (a consensus of the FASB Emerging Issues Task Force) . ASU No. 2016-15 addresses eight specific cash flow issues in an effort to reduce diversity in practice: (1) debt prepayment or debt extinguishment costs; (2) settlement of zero-coupon bonds; (3) contingent consideration payments made after a business combination; (4) proceeds from the settlement of insurance claims; (5) proceeds from the settlement of corporate-owned life insurance policies, including bank-owned life insurance policies; (6) distributions received from equity method investees; (7) beneficial interests in securitization transactions; and (8) separately identifiable cash flows and application of the predominance principle. The ASU is effective for the Company for fiscal years beginning after December 15, 2017, and for the interim periods within that fiscal year. Early adoption is permitted, including adoption during an interim period. The Company is in the process of evaluating this guidance and assessing the impact the ASU could have on the consolidated financial statements

Revenue Recognition

Revenue Recognition	12 Months Ended
	Dec. 31, 2017
Revenue Recognition
Revenue Recognition	(4) Revenue Recognition As of January 1, 2017, the Company adopted ASU 2014-09 Revenue from Contracts with Customers - Topic 606 and all subsequent ASUs that modified ASC 606. The Company has elected to apply the ASU and all related ASUs retrospectively to each prior reporting period presented. The implementation of the guidance had no material impact on the measurement or recognition of revenue of prior periods, however, additional disclosures have been added in accordance with the ASU. The main types of revenue contracts are: · Transaction fees - Transaction fees represent fees charged by the Company for the performance obligation of executing a trade on its markets. These fees can be variable based on trade volume tiered discounts, however, as all tiered discounts are calculated monthly, the actual discount is recorded on a monthly basis. Transaction fees, as well as any tiered volume discounts, are calculated and billed monthly in accordance with the Company’s published fee schedules. Transaction fees are recognized across all segments. The Company also pays liquidity payments to customers based on its published fee schedules. The Company uses these payments to improve the liquidity on its markets and therefore recognizes those payments as a cost of revenue. · Access fees - Access fees represent fees assessed for the opportunity to trade, including fees for trading-related functionality across all segments. These fees are billed monthly in accordance with the Company’s published fee schedules and recognized on a monthly basis when the performance obligation is met. There is no remaining performance obligation after revenue is recognized. · Exchange services and other fees - To facilitate trading, the Company offers technology services, terminal and other equipment rights, maintenance services, trading floor space and telecommunications services. Trading floor and equipment rights are generally on a month-to-month basis. Facilities, systems services and other fees are generally monthly fee-based, although certain services are influenced by trading volume or other defined metrics, while others are based solely on demand. All fees associated with the trading floor are recognized in the Options segment. · Market data fees - Market data fees represent the fees received by the Company from the U.S. tape plans and fees charged to customers for proprietary market data. Fees from the U.S. tape plans are collected monthly based on published fee schedules and distributed quarterly to the U.S. exchanges based on a known formula. A contract for proprietary market data is entered into and charged on a monthly basis in accordance with the Company’s published fee schedules as the service is provided. Both types of market data are satisfied over time, and revenue is recognized on a monthly basis as the customer receives and consumes the benefit as the Company provides the data. U.S. tape plan market data is recognized in the U.S. Equities and Options segments. Proprietary market data fees are recognized across all segments. · Regulatory fees - There are two types of regulatory fees that the Company recognizes. The first type represents fees collected by the Company to cover the Section 31 fees charged to the Exchanges by the SEC. The fees charged to customers are based on the fee set by the SEC per notional value of the transaction executed on the Company’s U.S. securities markets. These fees are calculated and billed monthly and are recognized in the U.S. Equities and Options segments. As the Exchanges are responsible for the ultimate payment to the SEC, the exchanges are considered the principal in these transactions. Regulatory fees also includes the options regulatory fee (ORF) which supports the Company’s regulatory oversight function in the Options segment and other miscellaneous regulatory fees and cannot be used for non-regulatory purposes. · Other revenue - Other revenue primarily includes revenue from various licensing agreements, all fees related to the trade reporting facility operated in the European Equities segment, and revenue associated with advertisements through the Company’s website. All revenue recognized in the income statement is considered to be revenue from contracts with customers. The following table depicts the disaggregation of revenue according to product line and segment (in millions): Corporate European items and Options U.S. Equities Futures Equities Global FX eliminations Total Year Ended December 31, 2017 Transaction fees $ 673.8 $ 659.4 $ 131.7 $ 66.2 $ 33.8 $ — $ 1,564.9 Access fees 54.7 41.3 1.9 6.4 2.5 — 106.8 Exchange services and other fees 42.6 19.2 7.2 4.2 1.6 — 74.8 Market data fees 41.1 111.0 2.5 9.6 0.3 — 164.5 Regulatory fees 55.4 236.1 — — — — 291.5 Other revenue 15.9 5.5 1.3 3.2 — 0.7 26.6 883.5 1,072.5 144.6 89.6 38.2 0.7 2,229.1 Timing of revenue recognition Services transferred at a point in time $ 745.1 $ 901.0 $ 133.0 $ 69.4 $ 33.8 $ 0.7 $ 1,883.0 Services transferred over time 138.4 171.5 11.6 20.2 4.4 — 346.1 883.5 1,072.5 144.6 89.6 38.2 0.7 2,229.1 Year Ended December 31, 2016 Transaction fees $ 408.2 $ — $ 101.1 $ — $ — $ — $ 509.3 Access fees 51.6 — 0.8 — — — 52.4 Exchange services and other fees 38.4 — 7.9 — — — 46.3 Market data fees 30.1 — 3.1 — — — 33.2 Regulatory fees 48.3 — — — — — 48.3 Other revenue 12.9 — 0.7 — — — 13.6 589.5 — 113.6 — — — 703.1 Year Ended December 31, 2015 Transaction fees $ 399.1 $ — $ 87.5 $ — $ — $ (1.3) $ 485.3 Access fees 52.6 — 0.7 — — — 53.3 Exchange services and other fees 42.2 — — — — — 42.2 Market data fees 30.0 — — — — — 30.0 Regulatory fees 45.0 — — — — (11.5) 33.5 Other revenue 17.2 — 2.3 — — — 19.5 586.1 — 90.5 — — (12.8) 663.8 Contract liabilities for the year ended December 31, 2017 primarily represent prepayments of transaction fees and certain access and market data fees to the Exchanges. The revenue recognized from contract liabilities and the remaining balance is shown below (in millions): Balance at January 1, 2017 Cash Additions Revenue Recognition Balance at December 31, 2017 Liquidity provider sliding scale (1) $ — $ 19.2 $ (14.4) $ 4.8 Other, net 3.1 20.4 (12.9) 10.6 Total deferred revenue $ 3.1 $ 39.6 $ (27.3) $ 15.4 (1) Liquidity providers are eligible to participate in the sliding scale program, which involves prepayment of transaction fees, and to receive reduced fees based on the achievement of certain volume thresholds within a calendar month. These transaction fees received are amortized and recorded as revenue ratably as the transactions occur over the period. asdflkj

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2017
Acquisitions
Acquisitions	(5) Acquisitions Bats Global Markets, Inc. On February 28, 2017, pursuant to the Agreement and Plan of Merger, dated as of September 25, 2016 (the “Merger Agreement”), by and among Cboe, Bats, CBOE Corporation, a Delaware corporation and a wholly-owned subsidiary of Cboe (“Merger Sub”), and Cboe Bats, LLC (formerly CBOE V, LLC), a Delaware limited liability company and a wholly-owned subsidiary of Cboe (“Merger LLC”), Cboe completed the merger of Merger Sub with and into Bats and the subsequent merger of Bats with and into Merger LLC. As a result of the Merger, Bats became a wholly-owned subsidiary of Cboe. The acquisition-date fair value of the consideration transferred totaled $4.0 billion, which consisted of the following (in millions): Cash consideration for Bats outstanding common stock $ 955.5 Common stock issued 2,387.3 Equity awards issued 37.4 3,380.2 Debt extinguished 580.0 Total consideration $ 3,960.2 As a result of the Merger, each share of voting common stock of Bats, par value of $0.01 per share (“Bats Voting Common Stock”), and each share of non-voting common stock of Bats, par value of $0.01 per share (“Bats Non-Voting Common Stock” and, together with the Bats Voting Common Stock, “Bats Common Stock”), issued and outstanding immediately prior to the effective time of the Merger (the “Effective Time”) (other than shares held by Cboe, Bats or any of their respective subsidiaries, shares held by any holder of Bats Common Stock who was entitled to demand and properly demanded appraisal of such shares under Delaware law and unvested restricted shares of Bats Common Stock granted under any Bats equity incentive plan (all such shares described in this parenthetical, “Excluded Shares”)) was converted into, at the election of the holder of such share, either (i) 0.3201 of a share of common stock, par value of $0.01 per share, of Cboe (“Cboe Common Stock”) and $10.00 in cash (the “Mixed Consideration”), (ii) $14.99 in cash and 0.2577 of a share of Cboe Common Stock (the “Cash Election Consideration”) or (iii) 0.4452 of a share of Cboe Common Stock (the “Stock Election Consideration”). Pursuant to the terms of the Merger Agreement, the Cash Election Consideration and Stock Election Consideration payable in the Merger were calculated based on the volume-weighted average price (rounded to four decimal places) of shares of Cboe Common Stock on The Nasdaq Stock Market LLC for the period of ten consecutive trading days ended on February 24, 2017, which was $79.9289. The Cash Election Consideration and the Stock Election Consideration were subject to automatic adjustment, as described in the Merger Agreement and in the definitive joint proxy statement/prospectus dated December 9, 2016, filed by Cboe with the SEC on December 12, 2016, as amended and supplemented from time to time (the “Prospectus”), to ensure that the total amount of cash paid and the total number of shares of Cboe Common Stock issued in the Merger were the same as what would have been paid and issued if all holders of Bats Common Stock received the Mixed Consideration at the Effective Time. The amounts in the table below represent the allocation of the purchase price. The following table summarizes the estimated fair values of the assets acquired and liabilities assumed at the acquisition date (in millions): Cash and cash equivalents $ 130.1 Accounts receivable 117.8 Financial investments 66.0 Property and equipment 21.8 Other assets 32.8 Goodwill Intangibles Accounts payable (33.7) Accrued expenses (26.2) Section 31 fees (143.6) Income tax payable (52.9) Deferred tax liability (722.6) Other liabilities (82.6) $ For tax purposes, no tax deductible goodwill was generated as a result of this acquisition. Goodwill was assigned to the Options, U.S. Equities, European Equities, and Global FX segments as further described in Note 17 and is attributable to the expansion of asset classes, broadening of geographic reach, and expected synergies of the combined workforce, products and technologies of the Company and Bats. The intangible assets were assigned to the Options, U.S. Equities, European Equities, and Global FX segments in the following manner and will be amortized over the following useful lives: U.S. European Options Equities Equities Global FX Useful life Trading registrations and licenses $ 95.5 $ 572.7 $ 171.8 $ — indefinite Customer relationships 37.1 222.9 160.0 140.0 years Market data customer relationships 53.6 322.0 60.0 64.4 years Technology 22.5 22.5 22.5 22.5 7 years Trademarks and tradenames 1.0 6.0 1.8 1.2 2 years Goodwill 226.4 1,738.1 419.3 267.2 $ 436.1 $ 2,884.2 $ 835.4 $ 495.3 There were no goodwill or intangible assets assigned to the Futures segment as a result of this transaction as Bats did not operate a Futures business and no synergies are attributable to this segment. The fair value of accounts receivable acquired was $117.8 million. The gross amount of accounts receivable was $118.0 million of which $0.2 million was deemed uncollectable. The Company expensed $84.4 million of acquisition-related costs during the year ended December 31, 2017 that included $44.2 million of compensation-related costs, $24.4 million of professional fees, $14.9 million of an impairment of capitalized data processing software, and $0.9 million of facilities expenses. These expenses are included in acquisition-related costs in the consolidated statements of income. The amounts of revenue, operating income and net income of Bats are included in the Company’s consolidated statements of income from the acquisition date to the year ended December 31, 2017 and are as follows (in millions): Revenue $ Revenue less cost of revenues 378.2 Operating income 73.4 Net income 88.4 The financial information in the table below summarizes the combined results of operations of the Company and Bats, on a pro forma basis, as though the companies had been combined as of January 1, 2016. The pro forma financial information is presented for informational purposes only and is not indicative of the results of operations that would have been achieved if the acquisition had taken place at the beginning of the period presented. Such pro forma financial information is based on the historical financial statements of the Company and Bats. This pro forma financial information is based on estimates and assumptions that have been made solely for purposes of developing such pro forma information, including, without limitation, preliminary purchase accounting adjustments. The pro forma financial information does not reflect any synergies or operating cost reductions that may be achieved from the combined operations. The pro forma financial information combines the historical results for the Company and Bats for the year ended December 31, 2017 and 2016 in the following table (in millions, except per share amounts): Fiscal Year ended December 31, 2017 2016 Revenue $ 2,502.0 $ 2,572.0 Revenue less cost of revenues 1,434.5 1,002.8 Operating income 471.9 406.3 Net income 271.1 231.6 Earnings per share: Basic $ 2.41 $ 2.06 Diluted 2.41 2.06 The supplemental 2017 and 2016 pro forma amounts have been calculated after applying the Company's accounting policies and adjusting the results to reflect the additional amortization that would have been charged assuming the adjusted fair values of acquired intangible assets had been applied on January 1, 2017 and on January 1, 2016. The supplemental 2017 pro forma financial information includes pro forma adjustments of $107.8 million for acquisition-related costs, such as fees to investment bankers, attorneys, accountants and other professional advisors, as well as severance to employees. Silexx Financial Systems In November 2017, the Company completed the acquisition of assets of Silexx Financial Systems, LLC (Silexx) for $9.0 million in cash. Silexx is a developer and operator of a multi-asset order and execution management system. Of the purchase price, $6.7 million was allocated to goodwill, $2.1 million was allocated to intangible assets, and $0.2 million was allocated to working capital. Silexx is included in the Options segment.

Severance

Severance	12 Months Ended
	Dec. 31, 2017
Severance
Severance	(6) Severance Subsequent to the Bats acquisition, the Company determined that certain employees' positions were redundant. As such, the Company communicated employee termination benefits to these employees. The following is a summary of the employee termination benefits recognized within compensation and benefits in the consolidated statements of income (in millions): Employee Termination Benefits Balance at December 31, 2016 $ 0.4 Termination benefits accrued 24.3 Termination payments made (19.9) Balance at December 31, 2017 $ 4.8

Investments

Investments	12 Months Ended
	Dec. 31, 2017
Financial Investments
Investments	(7) Investments As of December 31, 2017 and 2016, the Company's investments were comprised of the following (in millions): Year Ended December 31, 2017 2016 Equity Method: Investment in Signal Trading Systems, LLC $ 12.5 $ 12.4 Investment in EuroCCP 9.6 — Total equity method investments 22.1 12.4 Cost Method: Investment in OCC 30.3 30.3 Investment in Eris Exchange Holdings, LLC 20.0 20.0 Investment in American Financial Exchange, LLC 5.9 5.9 Other cost method investments 4.4 4.3 Total cost method investments 60.6 60.5 Total investments $ 82.7 $ 72.9 Equity Method Equity method investments include investments in Signal Trading Systems, LLC ("Signal"), a joint entity with FlexTrade System, Inc. to develop and market a multi-asset front-end order entry system, and EuroCCP, a Dutch domiciled clearing house. EuroCCP is one of three interoperable central counterparties, or CCPs, used to clear trades conducted on Cboe Europe Equities' markets. Cboe Europe Equities owns 20% of EuroCCP and can exercise significant influence over the entity as an equal shareholder with four other investors. Cost Method The carrying amount of cost method investments totaled $60.6 million and $60.5 million as of December 31, 2017 and 2016, respectively, and is included in investments in the consolidated balance sheets. The Company accounts for these investments using the cost-method of accounting primarily as a result of the Company's inability to exercise significant influence as the Company is a smaller shareholder of these investments. As of December 31, 2017, cost method investments primarily reflect a 20% investment in OCC and minority investments in American Financial Exchange, CurveGlobal and Eris Exchange Holdings, LLC. In December 2014, OCC announced a newly-formed capital plan. The OCC capital plan was designed to strengthen OCC's capital base and facilitate its compliance with proposed SEC regulations for Systemically Important Financial Market Utilities ("SIFMUs") as well as international standards applicable to financial market infrastructures. On February 26, 2015, the SEC issued a notice of no objection to OCC's advance notice filing regarding the capital plan, and OCC and OCC's existing exchange stockholders, which include Cboe Options, subsequently executed agreements effecting the capital plan. Under the plan, each of OCC's existing exchange stockholders agreed to contribute its pro-rata share, based on ownership percentage, of $150 million in equity capital, which would increase OCC's shareholders' equity, and to provide its pro rata share in replenishment capital, up to a maximum of $40 million per exchange stockholder, if certain capital thresholds are breached. OCC also adopted policies under the plan with respect to fees, customer refunds, and stockholder dividends, which envision an annual dividend payment to the exchange stockholders equal to the portion of OCC's after-tax income that exceeds OCC's capital requirements after payment of refunds to OCC's clearing members (with such customer refunds generally to constitute 50% of the portion of OCC's pre-tax income that exceeds OCC's capital requirements). On March 3, 2015, in accordance with the plan, Cboe Options contributed $30 million to OCC. That contribution has been recorded under investments in the consolidated balance sheets as of December 31, 2017. On March 6, 2015, OCC informed Cboe Options that the SEC, acting through delegated authority, had approved OCC's proposed rule filing for the capital plan. Following petitions to review the approval based on delegated authority, the SEC conducted its own review and then approved the proposed rule change implementing OCC's capital plan. Certain petitioners subsequently appealed the SEC approval order for the OCC capital plan to the U.S. Court of Appeals for the D.C. Circuit and moved to stay the SEC approval order. On February 23, 2016, the Court denied the petitioners' motion to stay. On August 8, 2017, the Court held that the SEC’s approval order lacked reasoned decision-making sufficient to support the SEC’s conclusion that the OCC capital plan complied with applicable statutory requirements. The Court declined to vacate the SEC’s approval order or to require the unwinding of actions taken under the OCC capital plan, but instead remanded the matter to the SEC for further proceedings concerning whether that capital plan complies with those statutory requirements. Petitioners requested a stay of dividend payments to the exchange stockholders until the SEC made a final decision about the OCC capital plan, but the SEC denied that request on September 14, 2017. The SEC allowed for and received information from interested parties for the SEC’s consideration in connection with its review of the OCC capital plan on remand from the Court. The SEC’s review of the OCC capital plan on remand from the Court remains pending.

Financial Investments

Financial Investments	12 Months Ended
	Dec. 31, 2017
Financial Investments
Financial Investments	(8) Financial Investments The Company’s financial investments with original or acquired maturities longer than three months, but that mature in less than one year from the balance sheet date and any money market funds that are considered cash and cash equivalents are classified as current assets and are summarized as follows (in millions): December 31, 2017 Cost basis Unrealized gains Unrealized losses Fair value Available-for-sale: U.S. Treasury securities $ 47.3 $ — $ — $ 47.3 Money market funds 2.5 — — 2.5 Total financial investments $ 49.8 $ — $ — $ 49.8 December 31, 2016 Cost basis Unrealized gains Unrealized losses Fair value Money market funds $ 67.5 $ — $ — $ 67.5 Total financial investments $ 67.5 $ — $ — $ 67.5

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2017
Property and Equipment, Net
Property and Equipment, Net	(9) Property and Equipment, Net Property and equipment consisted of the following as of December 31, 2017 and 2016 (in millions): December 31, December 31, 2017 2016 Construction in progress $ 5.9 $ 0.2 Building 77.4 77.0 Furniture and Equipment 139.7 138.8 Total property and equipment 223.0 216.0 Less accumulated depreciation (149.1) (160.1) Property and equipment, net $ 73.9 $ 55.9 Depreciation expense using the straight-line method was $31.3 million, $24.0 million and $46.1 million for the years ended December 31, 2017, 2016 and 2015, respectively.

Other Assets, Net

Other Assets, Net	12 Months Ended
	Dec. 31, 2017
Other Assets, Net
Other Assets, Net	(10) Other Assets, Other assets, net consisted of the following as of December 31, 2017 and 2016 (in millions): December 31, December 31, 2017 2016 Software development work in progress $ 10.2 $ 12.3 Data processing software 220.0 222.6 Less accumulated depreciation and amortization (189.6) (172.0) Data processing software, net 40.6 62.9 Other assets (1) 18.9 9.8 Data processing software and other assets, net $ 59.5 $ 72.7 (1) At December 31, 2016, other assets included $6.2 million of deferred financing costs and $3.5 million of deferred tax assets. The deferred financing costs were reclassified in 2017 and recorded as a reduction of long-term debt as a result of the issuance of long term debt. See Note 13 “Debt” of the consolidated financial statements for further information. At December 31, 2017, the majority of the balance included long-term prepaid assets and notes receivable. Amortization expense related to data processing software was $17.9 million, $18.7 million, and $0.0 million for the years ended December 31, 2017, 2016, and 2015.

Goodwill and Intangible Assets,

Goodwill and Intangible Assets, Net	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets, Net
Goodwill and Intangible Assets, Net	(11) Goodwill and Intangible Assets, Net The following table presents the details of goodwill by segment (in millions): U.S. European Corporate Options Equities Equities Global FX and Other Total Balance as of December 31, 2015 $ 7.7 $ — $ — $ — $ — $ 7.7 Additions — — — — 18.8 18.8 Dispositions — — — — — — Changes in foreign currency exchange rates — — — — — — Balance as of December 31, 2016 7.7 — — — 18.8 26.5 Additions 233.1 1,740.4 419.3 267.2 — 2,660.0 Dispositions (1.4) — — — — (1.4) Changes in foreign currency exchange rates — — 22.3 — — 22.3 Balance as of December 31, 2017 $ 239.4 $ 1,740.4 $ 441.6 $ 267.2 $ 18.8 $ 2,707.4 Goodwill has been allocated to specific reporting units for purposes of impairment testing - Options, U.S. Equities, European Equities and Global FX. No goodwill has been allocated to Futures. Goodwill and intangible asset annual impairment testing was performed as of October 1, 2017 and did not result in any impairment of goodwill or intangible assets. The allocation of the new goodwill did not impact the existing goodwill assignment to reporting units and there are no aggregate impairments of goodwill. The following table presents the details of the intangible assets (in millions): U.S. European Corporate Options Equities Equities Global FX and Other Total Balance as of December 31, 2015 $ 2.4 $ — $ — $ — $ — $ 2.4 Additions — — — — 8.0 8.0 Dispositions — — — — — — Amortization (0.4) — — — (1.3) (1.7) Changes in foreign currency exchange rates — — — — — — Balance as of December 31, 2016 2.0 — — — 6.7 8.7 Additions 212.0 1,146.1 416.1 228.1 — 2,002.3 Dispositions (0.2) — — — — (0.2) Amortization (15.1) (74.3) (23.8) (28.5) (1.2) (142.9) Changes in foreign currency exchange rates — — 34.7 — — 34.7 Balance as of December 31, 2017 $ 198.7 $ 1,071.8 $ 427.0 $ 199.6 $ 5.5 $ 1,902.6 For the years ended December 31, 2017, 2016 and 2015, amortization expense was $142.9 million, $1.7 million and $0.2 million, respectively. The estimated future amortization expense is $158.4 million for 2018, $137.5 million for 2019, $121.0 million for 2020, $105.7 million for 2021 and $93.5 million for 2022. The following table presents the categories of intangible assets at December 31, 2017 and 2016 (in millions): Weighted December 31, 2017 Average U.S. European Corporate Amortization Options Equities Equities Global FX and Other Period (in years) Trading registrations and licenses $ 95.5 $ 572.7 $ 186.5 $ — $ — Indefinite Customer relationships 38.8 222.9 173.7 140.0 3.0 19 Market data customer relationships 53.6 322.0 65.1 64.4 — 14 Technology 24.6 22.5 24.4 22.5 4.0 6 Trademarks and tradenames 1.7 6.0 2.0 1.2 1.0 2 Other 0.2 — — — — 2 Accumulated amortization (15.7) (74.3) (24.7) (28.5) (2.5) $ 198.7 $ 1,071.8 $ 427.0 $ 199.6 $ 5.5 Weighted December 31, 2016 Average U.S. European Corporate Amortization Options Equities Equities Global FX and Other Period (in years) Trading registrations and licenses $ — $ — $ — $ — $ — — Customer relationships 0.9 — — — 3.0 9 Market data customer relationships — — — — — — Technology 1.1 — — — 4.0 4 Trademarks and tradenames 0.4 — — — 1.0 6 Other 0.2 — — — — 2 Accumulated amortization (0.6) — — — (1.3) $ 2.0 $ — $ — $ — $ 6.7

Accounts Payable and Accrued Li

Accounts Payable and Accrued Liabilities	12 Months Ended
	Dec. 31, 2017
Accounts Payable and Accrued Liabilities
Accounts Payable and Accrued Liabilities	(12) Accounts Payable and Accrued Liabilities Accounts payable and accrued liabilities consisted of the following as of December 31, 2017 and 2016 (in millions): December 31, 2017 December 31, 2016 Compensation and benefit related liabilities $ 18.0 $ 25.1 Termination benefits 4.8 0.4 Royalties 20.3 17.8 Accrued liabilities 59.1 25.4 Marketing fee payable 8.4 7.2 Accounts payable 43.2 6.5 Total accounts payable and accrued liabilities $ 153.8 $ 82.4

Debt

Debt	12 Months Ended
	Dec. 31, 2017
Debt
Debt	(13) Debt The Company's long-term debt consisted of the following as of December 31, 2017 and 2016 (in millions): December 31, 2017 December 31, 2016 2017 Term Loan Agreement $ 294.9 $ — 3.650% Senior Notes 643.8 — 1.950% Senior Notes 299.2 — Total long-term debt $ 1,237.9 $ — In connection with the Merger, on December 15, 2016, the Company entered into the Term Loan Agreement (as defined below) providing for a $1.0 billion senior unsecured delayed draw term loan facility and on January 12, 2017, the Company issued $650 million aggregate principal amount of 3.650% Senior Notes due 2027 ("3.650% Senior Notes"). The proceeds from this delayed draw term loan facility and issuance of our senior notes, in addition to using cash on hand at Cboe and Bats, were used to finance a portion of the cash component of the Merger consideration, to refinance existing indebtedness of Bats and its subsidiaries and to pay related fees and expenses. In addition, on December 15, 2016, the Company entered into a $150 million revolving credit facility to be used for working capital and other general corporate purposes. On June 29, 2017, Cboe refinanced approximately $300 million of the amounts outstanding under the Term Loan Agreement through the issuance of $300 million in aggregate principal amount of 1.950% Senior Notes due 2019 ("1.950% Senior Notes" and, together with the 3.650% Senior Notes, the "Notes"). Term Loan Agreement On December 15, 2016, the Company, as borrower, entered into a Term Loan Credit Agreement (the “Term Loan Agreement”) with Bank of America, N.A., as administrative agent, certain lenders named therein (the “Term Lenders”), Merrill Lynch, Pierce, Fenner & Smith Incorporated, as sole lead arranger and sole bookrunner, Morgan Stanley MUFG Loan Partners, LLC, as syndication agent, and Citibank, N.A., PNC Bank, National Association and JPMorgan Chase Bank, N.A., as co-documentation agents. The Term Loan Agreement provided for a senior unsecured delayed draw term loan facility (the “Term Loan Facility”) in an aggregate principal amount of $1.0 billion. Loans under the Term Loan Agreement bear interest, at our option, at either (i) the London Interbank Offered Rate (“LIBOR”) periodically fixed for an interest period (as selected by us) of one, two, three or six months plus a margin (based on our public debt ratings) ranging from 1.00 percent per annum to 1.75 percent per annum or (ii) a daily floating rate based on the agent’s prime rate (subject to certain minimums based upon the federal funds effective rate or LIBOR) plus a margin (based on our public debt ratings) ranging from zero percent per annum to 0.75 percent per annum. The Company was required to pay a ticking fee to the agent for the account of the Term Lenders which initially accrued at a rate (based on our public debt ratings) ranging from 0.10 percent per annum to 0.30 percent per annum multiplied by the undrawn aggregate commitments of the Term Lenders in respect of the Term Loan Facility, accruing during the period commencing on December 15, 2016 and ending on the earlier of the date on which the loans are drawn. The Term Loan Agreement contains customary representations, warranties and affirmative and negative covenants for facilities of its type, including financial covenants, events of default and indemnification provisions in favor of the Term Lenders. The negative covenants include restrictions regarding the incurrence of liens, the incurrence of indebtedness by our subsidiaries and fundamental changes, subject to certain exceptions in each case. The financial covenants require us to meet a quarterly financial test with respect to a minimum consolidated interest coverage ratio of not less than 4.00 to 1.00 and a maximum consolidated leverage ratio of not greater than 3.50 to 1.00. At December 31, 2017, the Company was in compliance with these covenants. On February 28, 2017, Cboe made a draw under the Term Loan Agreement in the amount of $1.0 billion. Cboe used the proceeds to finance a portion of the cash component of the aggregate consideration for the Merger, repaid certain existing indebtedness of Bats, paid fees and expenses incurred in connection with the transactions contemplated by the Merger Agreement, funded working capital needs, and for other general corporate purposes. Loans under the Term Loan Agreement mature five years following the closing date of the Merger. 1.950% Senior Notes due 2019 On June 29, 2017, the Company issued $300 million aggregate principal amount of 1.950% Senior Notes. The form and terms of the 1.950% Senior Notes were established pursuant to an Officer’s Certificate, dated as of June 29, 2017, supplementing the Indenture (as defined below). Underwriter fees of $0.8 million were also capitalized and netted against long-term debt in the consolidated balance sheet, while other issuance fees of $0.9 million were expensed and are included in debt issuance costs on the consolidated statement of income for the year ended December 31, 2017. The Company used the net proceeds from the 1.950% Senior Notes to repay amounts under the Term Loan Agreement. The 1.950% Senior Notes mature on June 28, 2019 and bear interest at the rate of 1.950% per annum, payable semi-annually in arrears on June 28 and December 28 of each year, commencing December 28, 2017. The 1.950% Senior Notes are unsecured obligations of the Company and rank equally with all of the Company’s other existing and future unsecured, senior indebtedness, but are effectively junior to the Company’s secured indebtedness, to the extent of the value of the assets securing such indebtedness, and will be structurally subordinated to the secured and unsecured indebtedness of the Company’s subsidiaries. The Company has the option to redeem some or all of the 1.950% Senior Notes, at any time in whole or from time to time in part, at the redemption prices set forth in the Officer’s Certificate. The Company may also be required to offer to repurchase the 1.950% Senior Notes upon the occurrence of a Change of Control Triggering Event (as such term is defined in the Officer’s Certificate) at a repurchase price equal to 101% of the aggregate principal amount of 1.950% Senior Notes to be repurchased. 3.650% Senior Notes due 2027 On January 12, 2017, the Company entered into an indenture (the “Indenture”), by and between the Company and Wells Fargo Bank, National Association, as trustee, in connection with the issuance of $650 million aggregate principal amount of the Company’s 3.650% Senior Notes. The form and terms of the 3.650% Senior Notes were established pursuant to an Officer’s Certificate, dated as of January 12, 2017, supplementing the Indenture. The Company used a portion of the net proceeds from the 3.650% Senior Notes to fund, in part, the Merger, including the payment of related fees and expenses and the repayment of Bats’ existing indebtedness, and the remainder for general corporate purposes. The 3.650% Senior Notes mature on January 12, 2027 and bear interest at the rate of 3.650% per annum, payable semi-annually in arrears on January 12 and July 12 of each year, commencing July 12, 2017. The 3.650% Senior Notes are unsecured obligations of the Company and rank equally with all of the Company’s other existing and future unsecured, senior indebtedness, but are effectively junior to the Company’s secured indebtedness, to the extent of the value of the assets securing such indebtedness, and will be structurally subordinated to the secured and unsecured indebtedness of the Company’s subsidiaries. The Company has the option to redeem some or all of the 3.650% Senior Notes, at any time in whole or from time to time in part, at the redemption prices set forth in the Officer’s Certificate. The Company may also be required to offer to repurchase the 3.650% Senior Notes upon the occurrence of a Change of Control Triggering Event (as such term is defined in the Officer’s Certificate) at a repurchase price equal to 101% of the aggregate principal amount of 3.650% Senior Notes to be repurchased. Indenture Under the Indenture, the Company may issue debt securities, which includes the Notes, at any time and from time to time, in one or more series without limitation on the aggregate principal amount. The Indenture governing the Notes contains customary restrictions, including a limitation that restricts our ability and the ability of certain of our subsidiaries to create or incur secured debt. Such Indenture also limits certain sale and leaseback transactions and contains customary events of default. At December 31, 2017, the Company was in compliance with these covenants. Revolving Credit Agreement On December 15, 2016, the Company, as borrower, entered into a Credit Agreement (the “Revolving Credit Agreement”) with Bank of America, N.A., as administrative agent and as swing line lender, certain lenders named therein (the “Revolving Lenders”), Merrill Lynch, Pierce, Fenner & Smith Incorporated, as sole lead arranger and sole bookrunner, Morgan Stanley MUFG Loan Partners, LLC, as syndication agent, and Citibank, N.A., PNC Bank, National Association and JPMorgan Chase Bank, N.A., as co-documentation agents. The Revolving Credit Agreement provides for a senior unsecured $150 million five-year revolving credit facility (the “Revolving Credit Facility”) that includes a $25 million swing line sub-facility. The Company may also, subject to the agreement of the applicable lenders, increase the commitments under the Revolving Credit Facility by up to $100 million, for a total of $250 million. Subject to specified conditions, the Company may designate one or more of its subsidiaries as additional borrowers under the Revolving Credit Agreement provided that it guarantees all borrowings and other obligations of any such subsidiaries. As of December 31, 2017, no subsidiaries were designated as additional borrowers. Funds borrowed under the Revolving Credit Agreement may be used to fund working capital and for other general corporate purposes. As of December 31, 2017, no borrowings were outstanding under the Revolving Credit Agreement. Accordingly, at December 31, 2017, $150 million of borrowing capacity was available for the purposes permitted by the Revolving Credit Agreement. Loans under the Revolving Credit Agreement will bear interest, at our option, at either (i) LIBOR periodically fixed for an interest period (as selected by us) of one, two, three or six months plus a margin (based on our public debt ratings) ranging from 1.00 percent per annum to 1.75 percent per annum or (ii) a daily floating rate based on our prime rate (subject to certain minimums based upon the federal funds effective rate or LIBOR) plus a margin (based on our public debt ratings) ranging from zero percent per annum to 0.75 percent per annum. Subject to certain conditions stated in the Revolving Credit Agreement, the Company may borrow, prepay and reborrow amounts under the Revolving Credit Facility at any time during the term of the Revolving Credit Agreement. The Revolving Credit Agreement will terminate and all amounts owing thereunder will be due and payable on December 15, 2021, unless the commitments are terminated earlier, either at our request or, if an event of default occurs, by the Revolving Lenders (or automatically in the case of certain bankruptcy-related events). The Revolving Credit Agreement contains customary representations, warranties and affirmative and negative covenants for facilities of its type, including financial covenants, events of default and indemnification provisions in favor of the Revolving Lenders. The negative covenants include restrictions regarding the incurrence of liens, the incurrence of indebtedness by our subsidiaries and fundamental changes, subject to certain exceptions in each case. The financial covenants require us to meet a quarterly financial test with respect to a minimum consolidated interest coverage ratio of not less than 4.00 to 1.00 and a maximum consolidated leverage ratio of not greater than 3.50 to 1.00. At December 31, 2017, the Company was in compliance with these covenants. Bridge Facility In connection with entering into the Merger Agreement, the Company entered into a commitment letter with Bank of America, N.A. and Merrill Lynch, Pierce, Fenner & Smith Incorporated (or any of its designated affiliates) (Bank of America, N.A., and other such financial institutions that accede as lender to such debt commitment letter in accordance with its terms are referred to herein as the “Lenders”), which provides that, subject to the satisfaction and waiver of certain conditions which are usual and customary for financing of this type, the Lenders are committed to provide debt financing for the purposes of funding (i) the cash consideration to be paid in the transactions contemplated by the Merger Agreement, (ii) the refinancing of certain existing indebtedness of Bats and its subsidiaries and (iii) related fees and expenses, which debt financing consists of a senior unsecured 364-day bridge loan facility in an aggregate principal amount of up to $1.65 billion to the extent the Company fails to generate gross cash proceeds in an aggregate principal amount of up to $1.65 billion from permanent financing including in the form of a senior unsecured term loan facility and the issuance of senior unsecured notes on or prior to the consummation of the transaction contemplated by the Merger Agreement. The Company paid commitment and structuring fees of $6.0 million. Through December 31, 2017, the Company has amortized $6.0 million of these fees as a result of the Company entering into more permanent debt arrangements. The Company entered into a term loan agreement and completed a notes offering, as described above, securing $1.65 billion to finance the cash portion of its acquisition of Bats as well as the repayment of Bats' existing indebtedness. As a result of securing the financing discussed above, the bridge facility was terminated. Loan and Notes Payments and Contractual Interest The future expected loan repayments related to the Term Loan Agreement and the Notes as of December 31, 2017 is as follows (in millions): 2018 $ — 2019 2020 — 2021 — Thereafter 950.0 Principal amounts repayable 1,250.0 Debt issuance cost Unamortized discounts on notes Total debt outstanding $ 1,237.9 Interest expense recognized on the Term Loan Agreement and the Notes is included in interest expense, net in the consolidated statements of income, for the years ended December 31, 2017, 2016 and 2015 are as follows (in millions): Year Ended Year Ended Year Ended December 31, December 31, December 31, 2017 2016 2015 Components of interest expense: Contractual interest $ 39.0 $ 5.7 $ — Amortization of debt discount 0.6 — — Amortization of debt issuance cost 3.0 — — Interest expense $ 42.6 $ 5.7 $ — Interest income (1.3) — — Interest expense, net $ 41.3 $ 5.7 $ —

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss)	(14) Accumulated Other Comprehensive Income (Loss) The following represents the changes in accumulated other comprehensive income (loss) by component, before tax (in millions): Foreign currency Unrealized Total Other translation Investment Post-Retirement Comprehensive adjustment Gain/Loss Benefits Income Balance at December 31, 2015 $ — $ — $ (0.8) $ (0.8) Other comprehensive income (loss) — — — — Tax effect on other comprehensive income (loss) — — — — Balance at December 31, 2016 — — (0.8) (0.8) Other comprehensive income (loss) 51.3 0.2 — 51.5 Tax effect on other comprehensive income (loss) — — — — Balance at December 31, 2017 $ 51.3 $ 0.2 $ (0.8) $ 50.7

Fair Value Measurement

Fair Value Measurement	12 Months Ended
	Dec. 31, 2017
Fair Value Measurement
Fair Value Measurement	(15) Fair Value Measurement Fair value is the price that would be received upon the sale of an asset or paid upon the transfer of a liability in an orderly transaction between market participants at the measurement date and in the principal or most advantageous market for that asset or liability. The fair value should be calculated based on assumptions that market participants would use in pricing the asset or liability, not on assumptions specific to the entity. In addition, the fair value of liabilities should include consideration of non-performance risk, including the Company’s own credit risk. The Company applied FASB ASC 820, Fair Value Measurement and Disclosure , which provides guidance for using fair value to measure assets and liabilities by defining fair value and establishing the framework for measuring fair value. ASC 820 applies to financial and nonfinancial instruments that are measured and reported on a fair value basis. The three-level hierarchy of fair value measurements is based on whether the inputs to those measurements are observable or unobservable. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect the Company’s market assumptions. The fair-value hierarchy requires the use of observable market data when available and consists of the following levels: · Level 1—Unadjusted inputs based on quoted markets for identical assets or liabilities. · Level 2—Observable inputs, either direct or indirect, not including Level 1, corroborated by market data or based upon quoted prices in non-active markets. · Level 3—Unobservable inputs that reflect management’s best assumptions of what market participants would use in valuing the asset or liability. The Company has included a tabular disclosure for financial assets and liabilities that are measured at fair value on a recurring basis in the consolidated balance sheet as of December 31, 2017 and 2016, respectively. Instruments Measured at Fair Value on a Recurring Basis The following tables presents the Company’s fair value hierarchy for those assets measured at fair value on a recurring basis as of December 31, 2017 and 2016 (in millions): December 31, 2017 Total Level 1 Level 2 Level 3 Assets: Trading securities: U.S. Treasury securities $ 47.3 $ 47.3 $ — $ — Other securities — — — — Money market funds 2.5 2.5 — — Total assets $ 49.8 $ 49.8 $ — $ — Liabilities: Contingent consideration liability to related party $ 56.6 $ — $ — $ 56.6 Total Liabilities $ 56.6 $ — $ — $ 56.6 December 31, 2016 Total Level 1 Level 2 Level 3 Assets: Money market funds $ 67.5 $ 67.5 $ — $ — Total assets $ 67.5 $ 67.5 $ — $ — The following is a description of the Company’s valuation methodologies used for instruments measured at fair value on a recurring basis: Trading and Available‑for‑sale securities Financial investments classified as trading and available‑for‑sale consist of U.S. Treasury securities. These securities are valued by obtaining feeds from a number of live data sources, including active market makers and inter‑dealer brokers and therefore categorized as Level 1. Contingent Consideration Liability In connection with the acquisition of Bats, the Company acquired a contingent consideration arrangement with the former owners of Cboe FX. The fair value of this liability at December 31, 2017 was $56.6 million. That value is based on estimates of discounted future cash payments, a significant unobservable input, and is considered a Level 3 measurement. Instruments Measured at Fair Value on a Nonrecurring Basis Certain assets, such as goodwill and intangible assets, are measured at fair value on a non‑recurring basis. For goodwill, the process involves using a discounted cash flow method to determine the fair value of each reporting unit on a stand‑alone basis. That fair value is compared to the carrying amount of the reporting unit, including its recorded goodwill. Impairment is considered to have occurred if the fair value of the reporting unit is lower than the carrying amount of the reporting unit. For the intangible assets, the process also involves using a discounted cash flow method to determine the fair value of each intangible asset. Impairment is considered to have occurred if the fair value of the intangible asset is lower than the carrying amount. These measurements are considered Level 3 and these assets are recognized at fair value if they are deemed to be impaired. As of December 31, 2017 and 2016, none of these assets were required to be recorded at fair value since no impairment indicators were present. Fair Value of Financial Instruments The following table presents the Company’s fair value hierarchy for those financial instruments held by the Company as of December 31, 2017 and 2016 (in millions): December 31, 2017 Total Level 1 Level 2 Level 3 Assets: Cash and cash equivalents $ 143.5 $ 143.5 $ — $ — Trading investments 0.5 0.5 — — Available-for-sale investments 46.8 46.8 — — Accounts receivable 217.3 217.3 — — Income tax receivable 17.2 17.2 — — Total assets $ 425.3 $ 425.3 $ — $ — Liabilities: Accounts payable $ 43.2 $ — $ 43.2 $ — Section 31 fees payable 105.6 — 105.6 — Contingent consideration liability to related party 56.6 — — 56.6 Long-term debt 1,237.9 — 1,237.9 — Total liabilities $ 1,443.3 $ — $ 1,386.7 $ 56.6 December 31, 2016 Total Level 1 Level 2 Level 3 Assets: Cash and cash equivalents $ 97.3 $ 97.3 $ — $ — Accounts receivable 76.7 76.7 — — Income tax receivable 53.7 53.7 — — Total assets $ 227.7 $ 227.7 $ — $ — Liabilities: Accounts payable $ 6.5 $ — $ 6.5 $ — Total liabilities $ 6.5 $ — $ 6.5 $ — The carrying amounts of cash and cash equivalents, accounts receivable, income tax receivable, accounts payable, and Section 31 fees payable approximate fair value due to their liquid or short‑term nature. Long‑term debt The carrying amount of long‑term debt approximates its fair value based on quoted LIBOR at December 31, 2017 and 2016 and is considered a Level 2 measurement. Information on Level 3 Financial Liabilities The following table sets forth a summary of changes in the fair value of the Company’s level 3 financial liabilities during the year ended December 31, 2017 and 2016: Level 3 Financial Liabilities for the Year Ended December 31, 2017 Balance at Beginning of Balances at Period Additions Settlements End of Period Liabilities Contingent consideration liability to related party $ — $ 56.6 $ — $ 56.6 Total Liabilities $ — $ 56.6 $ — $ 56.6 Level 3 Financial Liabilities for the Year Ended December 31, 2016 Balance at Beginning of Balances at Period Additions Settlements End of Period Liabilities Contingent consideration liability to related party $ — $ — $ — $ — Total Liabilities $ — $ — $ — $ —

Redeemable Noncontrolling Inter

Redeemable Noncontrolling Interest	12 Months Ended
	Dec. 31, 2017
Redeemable Noncontrolling Interest
Redeemable Noncontrolling Interest	(16) Redeemable Noncontrolling Interest Redeemable noncontrolling interest are reported on the consolidated balance sheets in mezzanine equity in Redeemable Noncontrolling Interest. The Company recognizes changes to the redemption value of redeemable noncontrolling interest as they occur and adjust the carrying value to equal the redemption value at the end of each reporting period. The resulting increases or decreases in the estimated redemption amount are affected by corresponding charges or credits against retained earnings, or in the absence of retained earnings, additional paid in capital. The redemption amounts have been estimated based on the fair value of the majority-owned subsidiary, determined based on a weighting of the discounted cash flow and other economic factors. For the year ended December 31, 2017, the following reflects changes in our redeemable noncontrolling interest (in millions): Redeemable Balance as of December 31, 2016 $ 12.6 Decrease due to acquiring additional equity in Cboe Vest (3.2) Net loss attributable to redeemable noncontrolling interest (1.1) Redemption value adjustment 1.1 Balance as of December 31, 2017 $ 9.4

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2017
Segment Reporting
Segment Reporting	(17) Segment Reporting The Company previously operated as a single reportable business segment as of December 31, 2016. As a result of the Bats acquisition, beginning in 2017, the Company is reporting five segments: Options, U.S. Equities, Futures, European Equities, and Global FX, which is reflective of how the Company's chief operating decision-maker reviews and operates the business (Note 2). This change has been reflected in all periods presented. Segment performance is primarily based on operating income (loss). The Company has aggregated all of its corporate costs, acquisition-related costs, as well as other business ventures, within the Corporate Items and Eliminations unit based on the decision that those activities should not be used to evaluate the segment's operating performance; however, operating expenses that relate to activities of a specific segment have been allocated to that segment. The Options segment includes our options exchange business, which lists for trading options on market indexes (index options), mostly on an exclusive basis, as well as on non-exclusive "multiply-listed" options, such as options on the stocks of individual corporations (equity options) and options on other exchange-traded products (ETP options), such as exchange-traded funds (ETF options) and exchange-traded notes (ETN options) that occur on Cboe Options, C2, BZX and EDGX. It also includes the listed equity options routed transaction services that occur on Cboe Trading. The U.S. Equities segment includes listed cash equities and ETP transaction services that occur on BZX, BYX, EDGX and EDGA. It also includes market data revenue generated from the U.S. tape plans as well as revenue generated from the sale of proprietary market data ETP listing, listed cash equities and ETPs routed transaction services, connectivity fees, and advertising activity from ETF.com. The Futures segment includes the business of our futures exchange, CFE, which includes offering for trading futures on the VIX Index and bitcoin and other futures products. The European Equities segment includes the pan‑European listed cash equities transaction services, ETPs, exchange‑traded commodities, and international depository receipts that occur on the RIE, operated by Cboe Europe Equities. It also includes the listed cash equities and ETPs routed transaction services that occur on Cboe Chi-X Europe, as well as the listings business where ETPs can be listed on Cboe Europe Equities. The Global FX segment includes institutional FX trading services that occur on the Cboe FX platform, as well as non-deliverable forward FX transactions executed on Cboe SEF. Summarized financial data of reportable segments was as follows (in millions): Corporate European items and Options U.S. Equities Futures Equities Global FX eliminations Total Year ended December 31, 2017 Revenues $ 883.5 $ 1,072.5 $ 144.6 $ 89.6 $ 38.2 $ 0.7 $ 2,229.1 Operating income (loss) 252.2 103.2 126.8 8.9 (12.8) (106.4) 371.9 Year ended December 31, 2016 Revenues $ 589.5 $ — $ 113.6 $ — $ — $ — $ 703.1 Operating income (loss) 218.4 — 96.4 — — (16.6) 298.2 Year ended December 31, 2015 Revenues $ 586.1 $ — $ 90.5 $ — $ — $ (12.8) $ 663.8 Operating income (loss) 261.2 — 73.6 — — (14.9) 319.9

Employee Benefit Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2017
Employee Benefit Plan
Employee Benefit Plan	(18) Employee Benefit Plan Cboe employees are eligible to participate in the Cboe Options SMART Plan (“SMART Plan”). The SMART Plan is a defined contribution plan, which is qualified under Internal Revenue Code Section 401(k). In addition, eligible employees may participate in the Supplemental Employee Retirement Plan, Executive Retirement Plan and Deferred Compensation Plan. Effective January 1, 2017, the Executive Retirement Plan is closed to new executive officers and employees. Each plan is a defined contribution plan that is non-qualified under Internal Revenue Code. The Company contributed $6.2 million and $5.5 million to the defined contribution plans for the years ended December 31, 2017 and 2016, respectively. For the year ended December 31, 2017, $1.2 million of this expense was related to the acquisition of Bats and is included in acquisition-related costs in the consolidated statements of income. The remaining expense is included in compensation and benefits in the consolidated statements of income. Upon completion of the Merger, the Company assumed Bats' defined contribution plan that offers a 401(k) retirement plan eligible to legacy Bats U.S. employees. The Company’s contribution amounted to $1.5 million for the year ended December 31, 2017, respectively. This expense is included in compensation and benefits in the consolidated statements of income. The Bats plan merged into the SMART Plan as of January 1, 2018. The Company also assumed the Cboe Europe Equities employee‑selected stakeholder contribution plan upon completion of the Merger. The Company’s contribution amounted to $0.5 million year ended December 31, 2017, respectively. This expense is included in compensation and benefits in the consolidated statements of income.

Regulatory Capital

Regulatory Capital	12 Months Ended
	Dec. 31, 2017
Regulatory Capital
Regulatory Capital	(19) Regulatory Capital As a broker‑dealer registered with the SEC, Cboe Trading is subject to the SEC’s Uniform Net Capital Rule (Rule 15c3‑1), which requires the maintenance of minimum net capital, as defined therein. The SEC’s requirement also provides that equity capital may not be withdrawn or a cash dividend paid if certain minimum net capital requirements are not met. Cboe Trading computes the net capital requirements under the basic method provided for in Rule 15c3‑1. As of December 31, 2017, Cboe Trading is required to maintain net capital equal to the greater of 6.67% of aggregate indebtedness items, as defined, or $0.1 million. At December 31, 2017, Cboe Trading had net capital of $7.9 million, which was $7.6 million in excess of its required net capital of $0.3 million. As entities regulated by the FCA, Cboe Europe Equities is subject to the Financial Resource Requirement ("FRR") and Cboe Chi-X Europe is subject to the Capital Resources Requirement ("CRR"). As a RIE, Cboe Europe Equities computes its FRR in accordance with its Financial Risk Assessment, as agreed by the FCA. This FRR was $20.2 million at December 31, 2017. At December 31, 2017, Cboe Europe Equities had capital in excess of its required FRR of $25.6 million. As a Banks, Investment firms, PRUdential (BIPRU) 50k firm, as defined by the Markets in Financial Instruments Directive of the FCA, Cboe Chi‑X Europe computes its CRR as the greater of the base requirement of $0.1 million at December 31, 2017, or the summation of the credit risk, market risk and fixed overheads requirements, as defined. At December 31, 2017, Cboe Chi‑X Europe had capital in excess of its required CRR of $0.4 million. As a swap execution facility regulated by the CFTC, Cboe SEF is required to meet two capital adequacy tests: (i) its financial resources must be equal to at least twelve months of its projected operating costs and (ii) its unencumbered, liquid financial assets must be equal to at least six months of its projected operating costs. As of December 31, 2017, Cboe SEF had annual operating expenses of $1.5 million and had financial resources that exceeded this amount. Additionally, as of December 31, 2017, Cboe SEF had projected operating expenses for the upcoming 12 months of $1.4 million and had unencumbered, liquid financial assets that exceeded this amount. As a designated contract market regulated by the CFTC, CFE is required to meet two capital adequacy tests: (i) its financial resources must be equal to at least twelve months of its projected operating costs and (ii) its unencumbered, liquid financial assets must be equal to at least six months of its projected operating costs. As of December 31, 2017, CFE had annual projected operating expenses of $31.9 million and had financial resources that exceeded this amount. Additionally, as of December 31, 2017, CFE had projected operating expenses for six months of $16.0 million and had unencumbered, liquid financial assets that exceeded this amount.

Stock-based Compensation

Stock-based Compensation	12 Months Ended
	Dec. 31, 2017
Stock-based Compensation
Stock-based Compensation	(20) Stock-based Compensation Stock-based compensation is based on the fair value of the award on the date of grant, which is recognized over the related service period, net of actual forfeitures. The service period is the period over which the related service is performed, which is generally the same as the vesting period. In the first quarter of 2017, the Company adopted ASU 2016-09, Compensation — Stock Compensation . This ASU simplifies several aspects of the accounting for stock-based payment transactions (See Note 2). On February 19, 2017, the Company granted 251,273 restricted stock units ("RSUs"), each of which entitles the holder to one share of common stock upon vesting, to certain officers and employees at a fair value of $80.40 per share. The RSUs vest ratably over three years, with one-third vesting on each anniversary of the grant date, and vesting accelerates upon the occurrence of a change in control. Unvested RSUs will be forfeited if the officer or employee leaves the Company prior to the applicable vesting date, except in limited circumstances. The RSUs have no voting rights but entitle the holder to receive dividend equivalents. On February 28, 2017, the Company granted 68,254 RSUs, each of which entitles the holder to one share of common stock upon vesting, to certain officers and employees at a fair value of $78.05 per share. The RSUs vest ratably over three years, with one-third vesting on each anniversary of the grant date, and vesting accelerates upon the occurrence of a change in control. Unvested RSUs will be forfeited if the officer or employee leaves the Company prior to the applicable vesting date, except in limited circumstances. The RSUs have no voting rights but entitle the holder to receive dividend equivalents. On February 28, 2017, the Company granted 49,703 RSUs, each of which entitles the holder to one share of common stock upon vesting, to certain officers and employees at a fair value of $78.05 per share. The RSUs vest on the third anniversary of the grant date, and vesting accelerates upon the occurrence of a change in control. Unvested RSUs will be forfeited if the officer or employee leaves the Company prior to the applicable vesting date, except in limited circumstances. The RSUs have no voting rights but entitle the holder to receive dividend equivalents. The Merger Agreement provided that the number of shares of Cboe common stock into which each such award of Cboe Restricted Shares is converted will be equal to the number of shares of Bats common stock subject to the corresponding Bats Restricted Share award multiplied by the exchange ratio, which is the sum of (a) 0.3201 of a share of Cboe common stock and (b) the quotient obtained by dividing $10.00 by the volume-weighted average price, rounded to four decimal places, of shares of Cboe common stock on NASDAQ for the ten consecutive trading day period ending on the second full trading day prior to the Effective Time. The remaining service period will be completed post-merger and future vesting and expense will be recognized accordingly. Pursuant to the Merger Agreement, each award of restricted Bats common stock (“Bats restricted shares”) granted under any of the Bats Plans that was unvested immediately prior to the Effective Time was assumed by the Registrant and converted into awards of restricted shares totaling 622,527 of Common Stock at a fair value of $78.05 per share. In addition, on February 19, 2017 and February 28, 2017, the Company granted 41,481 and 19,255 RSUs, respectively, contingent on the achievement of performance conditions at a fair value of $111.00 and $102.00, respectively, per RSU, related to total shareholder return during the performance period. The Company used the Monte Carlo valuation model method to estimate the fair value of the total shareholder return RSUs which incorporated the following assumptions: risk-free interest rate (0.90)%, three-year volatility (21.1)% and three year correlation with S&P 500 Index (0.41).Each of these performance shares has a performance condition under which the number of units ultimately awarded will vary from 0% to 200% of the original grant, with each unit representing the contingent right to receive one share of our common stock. The vesting period for the RSUs contingent on the achievement of performance is three years. For each of the performance awards, the RSUs will be settled in shares of our common stock following vesting of the RSU assuming that the participant has been continuously employed during the vesting period, subject to acceleration in the event of a change in control of the Company or in the event of a participant’s earlier death or disability. Participants have no voting rights with respect to the RSUs until the issuance of the shares of stock. Dividends are accrued by the Company and will be paid once the RSUs contingent on the achievement of performance conditions vest. On May 15, 2017, the Company granted 2,655 RSUs, each of which entitles the holder to one share of common stock upon vesting, to certain officers and employees at a fair value $85.00 per share. On August 15, 2017, the Company granted 1,612 RSUs at a fair value of $97.54 per share. The RSUs vest ratably over three-years, with one-third vesting on each anniversary of the grant date, and vesting accelerates upon the occurrence of a change in control. Unvested RSUs will be forfeited if the officer or employee leaves the Company prior to the applicable vesting date, except in limited circumstances. The RSUs have no voting rights but entitle the holder to receive dividend equivalents. On May 18, 2017, the Company granted 15,405 shares of stock, at a fair value of $84.41 per share, to non employee members of the board of directors. The shares have a one-year vesting period and vesting accelerates upon the occurrence of a change in control of the Company. Unvested portions of the stock will be forfeited if the director leaves the Company prior to the applicable vesting date. The Company recognized stock-based compensation expense of $52.6 million, $14.5 million, and $12.1 million for the years ended December 31, 2017, 2016, and 2015 respectively. Stock-based compensation expense includes $9.0 million of accelerated expense recorded in the first quarter for certain officers and employees as a result of attaining certain age and service based requirements in our long-term incentive plan and award agreements. Stock-based compensation expense is included in compensation and benefits and acquisition-related costs in the consolidated statements of income. Pursuant to the Merger Agreement, each outstanding option to purchase Bats common stock (each, a “Bats stock option”) granted under any of the Bats Global Markets, Inc. 2009 Stock Option Plan, the Bats Global Markets, Inc. Third Amended and Restated 2012 Equity Incentive Plan and the Bats Global Markets, Inc. 2016 Omnibus Incentive Plan (collectively, the “Bats Plans”) that was outstanding immediately prior to the Effective Time was converted into an option to purchase Common Stock, on the same terms and conditions (including vesting schedule) as were applicable to such Bats stock option (but taking into account any changes, including any acceleration of vesting of such Bats stock option occurring by reason of the transactions contemplated by the Merger Agreement). The number of shares of Common Stock subject to each such converted stock option equals the number of shares of Bats common stock subject to the corresponding Bats stock option immediately prior to the Effective Time, multiplied by the exchange ratio (as defined below) (subject to certain adjustments and rounding). The exercise price per share for each such converted stock option equals the per share exercise price specified in the corresponding Bats stock option divided by the exchange ratio (rounded up to the nearest cent). The “exchange ratio” is equal to 0.4452, which equals the sum of 0.3201 plus the fraction obtained by dividing $10.00 by the volume-weighted average price, rounded to four decimal points, of a share of Common Stock on NASDAQ for the ten consecutive trading days ended February 24, 2017. Pursuant to the Merger Agreement, each award of restricted Bats common stock (“Bats restricted shares”) granted under any of the Bats Plans that was unvested immediately prior to the Effective Time was assumed by the Company and converted into an award of restricted shares of Common Stock, subject to the same terms and conditions (including vesting schedule) that applied to the applicable Bats restricted shares immediately prior to the Effective Time (but taking into account any changes, including any acceleration of vesting of such Bats restricted shares, occurring by reason provided for in the Merger Agreement). The number of shares of Common Stock subject to each such converted award of Bats restricted shares equals the number of shares of Bats common stock subject to the corresponding Bats restricted share award multiplied by the exchange ratio (as defined above). The activity in the Company's stock options, restricted stock and restricted stock units for the years ended December 31, 2017, 2016 and 2015 was as follows: Stock Options Summary stock option activity is presented below: Weighted Weighted Average Average Remaining Aggregate Number of Exercise Contractual Intrinsic Value Shares Price Term (years) (in millions) Outstanding, December 31, 2015 — $ — — $ — Granted — — — — Exercised — — Outstanding, December 31, 2016 — $ — — $ — Granted 683,390 22.45 — — Exercised (241,348) Outstanding and expected to vest at December 31, 2017 442,042 $ 25.36 1.0 $ 17.5 Exercisable at December 31, 2017 401,507 $ 25.08 5.0 $ 40.0 The Company estimated the grant date fair value of options awarded during 2017 using the Black‑Scholes valuation model with the following assumptions: 2017 Expected term (in years) 4.2 Expected volatility 19.8 % Expected dividend yield 1.3 % Risk-free rate 1.78 % Forfeiture rate — % Summary of the status of nonvested options is presented below: Weighted Average Grant- Nonvested options Options Date Fair Value December 31, 2015—Nonvested — $ — Granted — — Vested — — Forfeited — — December 31, 2016—Nonvested — $ — Granted 81,068 49.17 Vested — — Forfeited — — December 31, 2017—Nonvested 81,068 $ 49.17 In the year ended December 31, 2017, to satisfy employee's tax obligations and cash exercise payment due upon the election to exercise 241,348 stock options, the Company purchased 65,305 shares at a cost of $5.9 million. As of December 31, 2017, there were $1.7 million in total unrecognized compensation costs related to stock options. These costs are expected to be recognized over a weighted average period of 1.0 years as the stock options vest. Restricted Stock and Restricted Stock Units Summary restricted stock activity is presented below: Weighted Number of average grant shares date fair value Nonvested stock at December 31, 2015 456,570 $ 55.70 Granted 241,681 64.10 Vested (211,235) 48.14 Forfeited (6,421) 64.50 Nonvested stock at December 31, 2016 480,595 $ 63.64 Granted 1,091,843 78.94 Vested (498,540) 67.83 Forfeited (5,506) 71.68 Nonvested stock at December 31, 2017 1,068,392 $ 77.19 In the year ended December 31, 2017, to satisfy employees' tax obligations upon the vesting of restricted stock, the Company purchased 197,746 shares totaling $18.6 million as the result of the vesting of 498,540 shares of restricted stock. As of December 31, 2017, there were $47.0 million in total unrecognized compensation costs related to restricted stock and restricted stock units. These costs are expected to be recognized over a weighted average period of 1.8 years.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Taxes
Income Taxes	(21) Income Taxes Net deferred tax assets and liabilities consist of the following as of December 31, 2017 and 2016 (in millions): 2017 2016 Deferred tax assets: Accrued compensation and benefits $ 14.1 $ 16.3 Property, equipment and technology, net 2.4 0.6 Investment in affiliates — 4.7 Other 20.2 17.1 Subtotal 36.7 38.7 Valuation allowance (1.6) — Total deferred tax assets 35.1 38.7 Deferred tax liabilities: Intangibles (429.6) — Property, equipment and technology, net (17.1) (32.3) Investment in affiliates (75.0) (1.7) Prepaid expenses or assets (1.6) (1.2) Total deferred tax liabilities (523.3) (35.2) Net deferred tax assets/(liabilities) $ (488.2) $ 3.5 The Company provides a valuation allowance against deferred tax assets if, based on management’s assessment of historical and projected future operating results and other available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. A valuation allowance of $1.6 million was recorded against gross deferred tax assets for net operating losses as of December 31, 2017. As of December 31, 2017, we have state net operating loss carryforwards of $24.9 million, which, if unused, will expire beginning in 2029. The provision for income taxes for the years ended December 31, 2017, 2016 and 2015 consists of the following (in millions): Year Ended December 31 2017 2016 2015 Current tax expense: Federal $ 141.0 $ 107.1 $ 103.3 State 25.8 22.6 23.9 Foreign 5.4 — — Total current tax expense 172.2 129.7 127.3 Deferred income tax expense: Federal (227.5) (7.6) (6.4) State (6.5) (1.2) (1.9) Foreign (4.4) — — Total deferred income tax expense (238.4) (8.8) (8.3) Total $ (66.2) $ 120.9 $ 119.0 The Company considers a portion of its non-U.S. earnings to be indefinitely reinvested outside of the U.S. to the extent these earnings are not subject to U.S. income tax under an anti-deferral tax regime. As of December 31, 2017, all non-U.S. undistributed earnings were subject to a transition tax in the U.S. due to the Jobs Act. A distribution of these earnings is not expected to result in additional income tax. For the years ended December 31, 2017, 2016, and 2015, income from continuing operations before taxes consists of the following (in millions): 2017 2016 2015 U.S. operations $ 326.7 $ 306.6 $ 324.0 Foreign operations 7.7 — — $ 334.4 $ 306.6 $ 324.0 A reconciliation of the statutory federal income tax rate to the effective income tax rate for the years ended December 31, 2017, 2016, and 2015 is as follows: 2017 2016 2015 Statutory U.S. federal income tax rate 35.0 % 35.0 % 35.0 % Impact of federal, state and local tax law & rate changes, net (55.1) % - % - % State taxes, net of federal benefit 4.3 % 4.5 % 4.4 % Section 199 deduction (2.6) % (2.6) % (1.9) % Other, net (1.4) % 2.5 % (0.8) % Effective income tax rate (19.8) % 39.4 % 36.7 % The effective tax rate for 2017 was (19.8)% compared to 39.4% in 2016 and 36.7% in 2015. The effective tax rate increased from 2015 to 2016 primarily due to changes in unrecognized tax benefits and decreased from 2016 to 2017 primarily due to the tax benefit associated with re-measuring net deferred tax liabilities as a result of the Jobs Act. A reconciliation of the beginning and ending uncertain tax positions, excluding interest and penalties, is as follows (in thousands): 2017 2016 2015 Balance as of January 1 $ 41.9 $ 31.9 $ 35.4 Acquired unrecognized tax benefits 23.2 — — Gross increases on tax positions in prior period 6.2 8.8 — Gross decreases on tax positions in prior period (14.7) (0.6) (4.2) Gross increases on tax positions in current period 12.7 3.6 1.9 Lapse of statute of limitations (1.5) (1.8) (1.2) Balance as of December 31 $ 67.8 $ 41.9 $ 31.9 As of December 31, 2017, 2016 and 2015, the Company had $68.2 million, $40.5 million, and $29.7 million, respectively, of uncertain tax positions, net of federal benefit, which, if recognized in the future, would affect the effective income tax rate. Reductions to uncertain tax positions from the lapse of the applicable statutes of limitations and potential audit settlements during the next twelve months are estimated to be approximately $1.8 million and $6.5 million, respectively. Estimated interest costs and penalties are classified as part of the provision for income taxes in the Company's consolidated statements of income and were $(1.5) million, $2.5 million, and $2.5 million for the periods ended December 31, 2017, 2016 and 2015, respectively. Accrued interest and penalties were $11.1 million, $10.2 million and $7.7 million as of December 31, 2017, 2016 and 2015, respectively. The following table summarizes the tax years that are either currently under audit or remain open and subject to examination by the tax authorities in the most significant jurisdictions in which Cboe operates: U.S. Federal 2008-2017 Illinois 2015-2017 Kansas 2015-2017 New York 2007-2017 The Company has petitioned the Tax Court for a redetermination of an IRS deficiency for tax years 2011 through 2013 related to the Section 199 claims of Bats and certain of its subsidiaries. Management anticipates that in 2018 the IRS will determine a deficiency for tax years 2008-2013 relating to the Section 199 claims of Cboe and certain of its subsidiaries. The Company believes the aggregate amount of any additional liabilities that may result from these examinations, if any, will not have a material adverse effect on the financial position, results of operations, or cash flows of the Company. On December 22, 2017 the U.S. enacted the Tax Cuts and Jobs Act (the “Jobs Act”). The Jobs Act significantly changes U.S. corporate income tax laws by, among other things, reducing the U.S. corporate income tax rate to 21% starting in 2018 and creating a territorial tax system with a one-time mandatory tax on previously deferred foreign earnings of U.S. subsidiaries. Given the predominance of our U.S. earnings contribution, we expect a significant reduction in our overall effective tax rate in 2018. The change in the effective tax rate was due to the tax benefit associated with re-measuring net deferred tax liabilities as a result of the Jobs Act. Due to the timing of the enactment and the complexity involved in applying the provisions of the Jobs Act, we have made reasonable estimates of the effects and recorded provisional amounts in our financial statements as of December 31, 2017. As we collect and prepare necessary data and interpret the Jobs Act and any additional guidance issued by the U.S. Treasury Department, the Internal Revenue Service, and other standard-setting bodies, we may make adjustments to the provisional amounts.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Earnings Per Share	(22) Earnings Per Share The computation of basic net income allocated to common stockholders is calculated by reducing net income for the period by dividends paid or declared and undistributed net income for the period that are allocated to participating securities to arrive at net income allocated to common stockholders. Net income allocated to common stockholders is divided by the weighted average number of common shares outstanding during the period to determine net income per share allocated to common stockholders. The computation of diluted earnings per share is calculated by dividing net income allocated to common stockholders by the sum of the weighted average number of common shares outstanding plus all additional common shares that would have been outstanding if the potentially dilutive common shares had been issued. The dilutive effect is calculated using the more dilutive of the two-class or treasury stock method. Additionally, the change in the redemption value for the noncontrolling interest reduces net income allocated to common shareholders. Net income and diluted earnings per share for the year ended December 31, 2017 include a substantial benefit associated with the enactment of the Jobs Act. The enactment of the Jobs Act resulted in an estimated net income increase of $191.3 million primarily due to a one-time revaluation of our net deferred tax liability based on a U.S. federal tax rate of 21 percent. The following table sets forth the computation of basic and diluted earnings per share (in millions, except per share data): Year Ended December 31, (in thousands, except per share amounts) 2017 2016 2015 Basic EPS Numerator: Net Income $ 400.6 $ 185.7 $ 205.0 Loss attributable to noncontrolling interests 1.1 1.1 — Net Income excluding noncontrolling interests 401.7 186.8 205.0 Change in redemption value of noncontrolling interests (1.1) (1.1) — Earnings allocated to participating securities (3.9) (0.8) (0.9) Net Income allocated to common stockholders $ 396.7 $ 184.9 $ 204.1 Basic EPS Denominator: Weighted average shares outstanding 107.2 81.4 83.1 Basic Net Income Per Common Share $ 3.70 $ 2.27 $ 2.46 Diluted EPS Numerator: Net Income $ 400.6 $ 185.7 $ 205.0 Loss attributable to noncontrolling interests 1.1 1.1 — Net Income excluding noncontrolling interests 401.7 186.8 205.0 Change in redemption value of noncontrolling interests (1.1) (1.1) — Earnings allocated to participating securities (3.9) (0.8) (0.9) Net Income allocated to common stockholders $ 396.7 $ 184.9 $ 204.1 Diluted EPS Denominator: Weighted average shares outstanding 107.2 81.4 83.1 Dilutive common shares issued under stock program 0.3 — — Total dilutive weighted average shares 107.5 81.4 83.1 Diluted Net Income Per Common Share $ 3.69 $ 2.27 $ 2.46 For the periods presented, the Company did not have shares of stock-based compensation that would have an antidilutive effect on the computation of diluted net income per common share.

Commitments, Contingencies and

Commitments, Contingencies and Guarantees	12 Months Ended
	Dec. 31, 2017
Commitments, Contingencies and Guarantees
Commitments, Contingencies and Guarantees	(23) Commitments, Contingencies and Guarantees Legal Proceedings As of December 31, 2017, the Company was subject to the various legal proceedings and claims discussed below, as well as certain other legal proceedings and claims that have not been fully resolved and that have arisen in the ordinary course of business. The Company reviews its legal proceedings and claims, regulatory reviews and inspections and other legal proceedings on an ongoing basis and follows appropriate accounting guidance when making accrual and disclosure decisions. The Company establishes accruals for those contingencies where the incurrence of a loss is probable and can be reasonably estimated, and the Company discloses the amount accrued and the amount of a reasonably possible loss in excess of the amount accrued, if such disclosure is necessary for our financial statements to not be misleading. The Company does not record liabilities when the likelihood that the liability has been incurred is probable, but the amount cannot be reasonably estimated, or when the liability is believed to be only reasonably possible or remote. The Company's assessment of whether a loss is reasonably possible or probable is based on its assessment of the ultimate outcome of the matter following all appeals. As of December 31, 2017, the Company does not believe that there is a reasonable possibility that any material loss exceeding the amounts already recognized for these reviews, inspections or other legal proceedings, if any, has been incurred. While the consequences of certain unresolved proceedings are not presently determinable, the outcome of any litigation is inherently uncertain and an adverse outcome from certain matters could have a material effect on our earnings in any given reporting period. However, in the opinion of management, the ultimate liability is not expected to have a material effect on our financial position, liquidity or capital resources. City of Providence On April 18, 2014, the City of Providence, Rhode Island filed a securities class action lawsuit in the Southern District of New York against Bats and Direct Edge Holdings LLC, as well as 14 other securities exchanges. The action purports to be brought on behalf of all public investors who purchased and/or sold shares of stock in the United States since April 18, 2009 on a registered public stock exchange (“Exchange Defendants”) or a U.S.-based alternate trading venue and were injured as a result of the alleged misconduct detailed in the complaint, which includes allegations that the Exchange Defendants committed fraud through a variety of business practices associated with, among other things, what is commonly referred to as high frequency trading. On May 2, 2014 and May 20, 2014, American European Insurance Company and Harel Insurance Co., Ltd. each filed substantially similar class action lawsuits against the Exchange Defendants which were ultimately consolidated with the City of Providence, Rhode Island securities class action lawsuit. On June 18, 2015, the Southern District of New York (the “Court”) held oral argument on the pending Motion to Dismiss and thereafter, on August 26, 2015, the Court issued an Opinion and Order granting Exchange Defendants’ Motion to Dismiss, dismissing the complaint in full. Plaintiff filed a Notice of Appeal of the dismissal on September 24, 2015 and its appeal brief on January 7, 2016. Respondent's brief was filed on April 7, 2016 and oral argument was held on August 24, 2016. Following oral argument, the Court of Appeals issued an order requesting that the SEC submit an amicus brief on whether the Court had jurisdiction and whether the Exchange Defendants have immunity in the claims alleged. The SEC filed its amicus brief with the Court of Appeals on November 28, 2016 and Plaintiff and the Exchange Defendants filed their respective supplemental response briefs on December 12, 2016. On December 19, 2017, the Court of Appeals reversed the Court’s dismissal and remanded the case back to the Court. On January 31, 2018, the Exchange Defendants filed a motion for re-hearing with the Court of Appeals. Given the preliminary nature of the proceedings, the Company is unable to estimate what, if any, liability may result from this litigation. However, the Company believes that the claims are without merit and intend to litigate the matter vigorously. SIFMA Securities Industry Financial Markets Association (“SIFMA”) has filed a number of denial of access applications with the SEC to set aside proposed rule changes to establish or modify fees for Cboe Options, C2, BZX, BYX, EDGX and EDGA market data products and related services. Each application is being held in abeyance pending a decision on a separate SIFMA denial of access application held before an SEC's administrative law judge (“ALJ”) regarding fees proposed by NASDAQ and the NYSE for their respective market data products. On June 1, 2016, the ALJ issued a decision rejecting SIFMA's denial of access challenge to the NASDAQ and NYSE fees at issue. On July 19, 2016, SIFMA petitioned the SEC for review of the ALJ decision. An adverse ruling in that matter or a subsequent appeal could adversely affect exchange market data fees. Other As self-regulatory organizations under the jurisdiction of the SEC, Cboe Options, C2, BZX, BYX, EDGX and EDGA are subject to routine reviews and inspections by the SEC. As a designated contract market under the jurisdiction of the CFTC, CFE is subject to routine reviews and inspections by the CFTC. Cboe SEF, LLC is a swap execution facility registered with the CFTC and subject to routine reviews and inspections by the CFTC. Cboe Trading is subject to reviews and inspections by FINRA. The Company has from time to time received inquiries and investigative requests from the SEC's Office of Compliance Inspections and Examinations as well as the Division of Enforcement seeking information about our compliance with our obligations as a self-regulatory organization, the federal securities laws as well as our members’ compliance with the federal securities laws. In addition, while Cboe Europe Limited and Cboe Chi-X Europe have not been the subject of any material litigation or regulatory investigation in the past, there is always the possibility of such action in the future. As both companies are domiciled in the U.K., it is likely that any action would be taken in the U.K. courts in relation to litigation or by the FCA in relation to any regulatory enforcement action. The Company is also currently a party to various other legal proceedings in addition to those already mentioned. Management does not believe that the outcome of any of these other reviews, inspections, investigations or other legal proceedings will have a material impact on our consolidated financial position, results of operations or cash flows. Contractual Obligations The Company currently leases office space, data centers and remote network operations centers, with lease terms remaining ranging from three months to one hundred months as of December 31, 2017. Total rent expense related to these lease obligations, reflected in technology support services and facilities costs line items on the consolidated statements of income, for the years ended December 31, 2017, 2016, and 2015 were $7.6 million, $4.4 million and $4.1 million, respectively.

Quarterly Data (unaudited)

Quarterly Data (unaudited)	12 Months Ended
	Dec. 31, 2017
Quarterly Data (unaudited)
Quarterly Data (unaudited)	(24) Quarterly Data (unaudited) First Second Third Fourth Year ended December 31, 2017 (in millions, except per share data) Quarter Quarter Quarter Quarter Revenue less cost of revenues $ 193.4 $ 266.9 $ 269.7 $ 265.6 Operating income 26.1 117.8 119.3 108.7 Net income 15.2 68.0 60.3 257.1 Net income allocated to common stockholders 15.1 67.3 59.7 254.6 Basic earnings per share $ 0.16 $ 0.60 $ 0.53 $ 2.41 Diluted earnings per share $ 0.16 $ 0.60 $ 0.53 $ 2.40 First Second Third Fourth Year ended December 31, 2016 (in millions, except per share data) Quarter Quarter Quarter Quarter Revenue less cost of revenues $ 143.1 $ 144.1 $ 136.2 $ 143.0 Operating income 79.5 78.0 65.8 74.9 Net income 49.2 50.9 40.5 45.1 Net income allocated to common stockholders 49.2 50.7 40.3 44.7 Basic earnings per share $ 0.60 $ 0.62 $ 0.50 $ 0.55 Diluted earnings per share $ 0.60 $ 0.62 $ 0.50 $ 0.55

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2017
Subsequent Events
Subsequent Events	(25) Subsequent Events On February 15, 2018, the Company's board of directors declared a quarterly cash dividend of $0.27 per share. The dividend is payable on March 16, 2018 to stockholders of record at the close of business on March 2, 2018. On February 19, 2018, the Company granted 188,575 RSUs to certain officers and employees at a fair value of $111.45 per share, the closing price of the Company's stock on the grant date. The shares have a three year vesting period based on achievement of certain service, performance and/or market conditions and vesting accelerates upon the occurrence of a change in control of the Company or in the event of earlier death, disability or qualified retirement.

Summary of Significant Accoun34

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Summary of Significant Accounting Policies
Basis of Presentation	(b) The accompanying financial statements are presented on a consolidated basis to include the accounts and transactions of Cboe Global Markets, Inc. and its majority owned subsidiaries and all significant intercompany accounts and transactions have been eliminated. Certain prior period amounts have been reclassified to conform to current period presentation. The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosures of contingent assets and liabilities, valuation of redeemable noncontrolling interests and reported amounts of revenues and expenses. On an ongoing basis, management evaluates its estimates based upon historical experience, observance of trends, information available from outside sources and various other assumptions that management believes to be reasonable under the circumstances. Actual results may differ from these estimates under different conditions or assumptions. For those consolidated subsidiaries in which the Company's ownership is less than 100% and for which the Company has control over the assets and liabilities and the management of the entity, the outside stockholders' interest are shown as non-controlling interests. In 2017, the Company changed the presentation of liquidity payments to be a cost of revenues, which historically had been netted against transaction fees. The Company also changed the presentation of royalty fees to be a cost of revenues. The presentation of routing fees and costs were also changed. Routing fees were presented in transaction fees in total revenues and routing and clearing costs in total cost of revenues. These fees were previously presented as a net operating expense. These changes were made to conform to current presentation and the changes have been reflected in all periods presented.
Segment information	Segment information The Company previously operated as a single reportable business segment. As a result of the Bats acquisition on February 28, 2017 (Note 5), the Company is reporting five business segments: Options, U.S. Equities, Futures, European Equities, and Global FX, which is reflective of how the Company's chief operating decision-maker reviews and operates the business (Note 17). This change has been reflected in all periods presented.
Use of Estimates	(c) The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities as well as disclosure of the amounts of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ materially from those estimates. Material estimates that are particularly susceptible to significant change in the near term include the receivable for market data fees, the valuation of goodwill and unrecognized tax benefits.
Cash and Cash Equivalents	(d) The Company’s cash and cash equivalents are exposed to concentrations of credit risk. The Company maintains cash at various financial institutions and brokerage firms which, at times, may be in excess of the federal depository insurance limit. The Company’s management regularly monitors these institutions and believes that the potential for future loss is remote. The Company considers all liquid investments with original or acquired maturities of three months or less to be cash equivalents.
Financial Investments	(e) Financial investments are classified as trading or available‑for‑sale. Trading financial investments represent financial investments held by the Company’s broker‑dealer subsidiary that retain the industry‑specific accounting classification required for broker‑dealers. These investments are recorded at fair value with changes in unrealized gains and losses reflected within interest expense, net in the consolidated statements of income. Available‑for‑sale financial investments are comprised of the financial investments not held by the broker‑dealer subsidiary. Unrealized gains and losses, net of income taxes, are included as a component of accumulated other comprehensive (loss) income in the accompanying consolidated balance sheets. Interest on financial investments, including amortization of premiums and accretion of discounts, is recognized as income when earned. Realized gains and losses on financial investments are calculated using the specific identification method and are included in interest expense, net in the accompanying consolidated statements of income. A decline in the fair value of any available‑for‑sale investment below carrying amount that is deemed to be other‑than‑temporary results in an impairment to reduce the carrying amount to realizable value. To determine whether an impairment is other‑than‑temporary, the Company considers all available information relevant to the collectability of the investment, including past events, current conditions, and reasonable and supportable forecasts when developing estimate of cash flows expected to be collected. Evidence considered in this assessment includes the reasons for the impairment, the severity and duration of the impairment, changes in value subsequent to year‑end, forecasted performance of the investee, and the general market condition in the geographic area or industry in which the investee operates.
Accounts Receivable, Net	(f) Accounts receivable are concentrated with the Company’s member firms and market data distributors and are carried at cost. The Company nets transaction fees and liquidity payments for each member firm on a monthly basis and recognizes the total owed to a member firm as an asset and the total owed to a member firm as a liability. On a periodic basis, management evaluates the Company’s receivables and determines an appropriate allowance for uncollectible accounts receivable based on anticipated collections. In circumstances where a specific customer’s inability to meet its financial obligations is probable, the Company records a specific provision for uncollectible accounts against amounts due to reduce the receivable to the amount the Company estimates will be collected. Once the Company determines an allowance for an uncollectible account is necessary, interest on the receivable ceases to be accrued.
Property and Equipment, Net	(g) Property and equipment, net is stated at cost less accumulated depreciation. Depreciation is computed using the straight‑line method over the estimated lives of the assets, generally ranging from three to seven years. Expenditures for repairs and maintenance are charged to expense as incurred. Depreciation of leasehold improvements is calculated using the straight‑line method over the shorter of the related lease term or the estimated useful life of the assets. Long‑lived assets to be held and used are reviewed to determine whether any events or changes in circumstances indicate that the carrying amounts of the assets may not be recoverable. The Company bases this evaluation on such impairment indicators as the nature of the assets, the future economic benefit of the assets, any historical or future profitability measurements, as well as other external market conditions or factors that may be present. If such impairment indicators are present that would indicate that the carrying amount of any asset may not be recoverable, the Company determines whether an impairment has occurred through the use of an undiscounted cash flow analysis of the asset at the lowest level for which identifiable cash flows exist. In the event of impairment, the Company recognizes a loss for the difference between the carrying amount and the estimated value of the asset as measured using quoted market prices or, in the absence of quoted market prices, a discounted cash flow analysis. The Company accounts for software development costs under ASC Topic 350, Intangibles—Goodwill and Other . The Company expenses software development costs as incurred during the preliminary project stage, while capitalizing costs incurred during the application development stage, which includes design, coding, installation and testing activities.
Goodwill and Intangible Assets, Net	(h) Goodwill represents the excess of purchase price over the value assigned to the net tangible and identifiable intangible assets of a business acquired. Goodwill is allocated to the Company’s reporting units based on the assignment of the fair values of each reporting unit of the acquired company. The Company tests goodwill for impairment at the reporting unit level annually, or in interim periods if certain events occur indicating that the carrying value may be impaired. The impairment test is performed during the fourth quarter using October 1 st carrying values, and if the fair value of the reporting unit is found to be less than the carrying value, an impairment loss is recorded. The Company performed its 2017 annual goodwill impairment test and determined that no impairment existed. Intangible assets, net, primarily include acquired trademarks and trade names, customer relationships, strategic alliance agreements, licenses and registrations and non‑compete agreements. Intangible assets with finite lives are amortized based on the discounted cash flow method applied over the estimated useful lives of the intangible assets. Intangible assets deemed to have indefinite useful lives are not amortized, but instead are tested for impairment at least annually, usually concurrently with goodwill. Impairment exists if the fair value of the asset is less than the carrying amount, and in that case, an impairment loss is recorded. The Company performed its 2017 annual intangible assets impairment test using October 1, 2017 carrying values and determined that no impairment existed.
Foreign Currency	(i) The financial statements of foreign subsidiaries where the functional currency is not the U.S. dollar are translated into U.S. dollars using the exchange rate in effect as of each balance sheet date. Statements of income and cash flow amounts are translated using the average exchange rate during the period. The cumulative effects of translating the balance sheet accounts from the functional currency into the U.S. dollar at the applicable exchange rates are included in accumulated other comprehensive income (loss), net in the balance sheet. Foreign currency gains and losses are recorded as other income, net in the consolidated statements of income. The Company’s operations in the United Kingdom, Singapore, and Hong Kong are recorded in Pounds sterling, Singapore dollars, and Hong Kong dollars, respectively.
Income Taxes	(j) Deferred taxes are recorded on a liability method whereby deferred tax assets are recognized for deductible temporary differences and operating loss and tax credit carryforwards, and deferred tax liabilities are recognized for taxable temporary differences. Temporary differences are the differences between the reported amounts of assets and liabilities and their tax bases. Deferred tax assets are reduced by a valuation allowance when, in the opinion of management, it is more likely than not that some portion or all of the deferred tax assets will not be realized. Deferred tax assets and liabilities are adjusted for the effects of changes in tax laws and rates on the date of enactment. The Company recognizes the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by the taxing authorities, based upon the technical merits of the position. The tax benefit recognized in the consolidated financial statements from such a position is measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. Also, interest and penalties expense is recognized on the full amount of deferred benefits for uncertain tax positions. The Company’s policy is to include interest and penalties related to unrecognized tax benefits in the income tax provision within the consolidated statements of income.
Revenue Recognition	(k) For further discussion related to revenue recognition of fees, such as transaction fees and liquidity payments, access fees, exchange services and other fees, market data fees, and regulation transaction and Section 31 fees, see Note 4.
Concentrations of Revenue and Liquidity Payments	Concentrations of Revenue and Liquidity Payments For the years ended December 31, 2017, 2016, and 2015, two members accounted for 17%, 42% and 45%, respectively, of the Company’s transaction fees. No member accounted for more than 10% of the Company’s total revenue during the years ended December 31, 2017, 2016, and 2015. For the years ended December 31, 2017, 2016, and 2015, no member accounted for more than 10% of the Company’s liquidity payments. No member is contractually or otherwise obligated to continue to use the Company’s services. The loss of, or a significant reduction of, participation by these members may have a material adverse effect on the Company’s business, financial position, results of operations and cash flows. The two largest clearing members mentioned above clear the majority of the market-maker sides of transactions at all of the Company’s U.S. options exchanges. If either of these clearing members were to withdraw from the business of market-maker clearing and market-makers were unable to transfer to another clearing member, this could create significant disruption to the U.S. options markets, including ours.
Earnings Per Share	(l) The Company presents both basic and diluted earnings per share. Basic earnings per share is computed by dividing net income by the weighted average number of common shares outstanding during the period. Diluted earnings per share is computed by dividing net income by the sum of the weighted average number of common shares and dilutive common share equivalents outstanding.
Stock Based Compensation	(m) The Company grants stock‑based compensation to its employees through awards of restricted stock units. In connection with the acquisition of Bats, Bats previously awarded stock options and restricted stock awards. The Company records stock‑based compensation expense for all stock‑based compensation granted based on the grant‑date fair value. The Company recognizes compensation expense related to stock‑based compensation awards with graded vesting that have a service condition on a straight‑line basis over the requisite service period of the entire award. In connection with the acquisition of Bats, as discussed in Note 20 in further detail, each outstanding Bats stock option (defined below) granted under any of the Bats Plans (defined below) that was outstanding immediately prior to the effective time of the acquisition of Bats was converted into an option to purchase our common stock, on the same terms and conditions (including vesting schedule) as were applicable to such Bats stock option. In addition, each award of Bats restricted shares (defined below) granted under any of the Bats Plans that was unvested immediately prior to the effective time of the acquisition of Bats was assumed by the Company and converted into an award of restricted shares of our common stock, subject to the same terms and conditions (including vesting schedule) that applied to the applicable Bats restricted shares. The amount of stock‑based compensation expense related to awards of restricted stock and restricted stock units is based on the fair value of Cboe Global Markets, Inc. common stock at the date of grant. The fair value is based on a current market‑based transaction of the Company’s common stock. If a market‑based transaction of the Company’s common stock is not available, then the fair value is based on an independent third‑party valuation using equal weighting of two valuation analysis techniques, discounted cash flows and valuation multiples observed from publicly traded companies in a similar industry. The amount of future stock‑based compensation expense related to awards of stock options is based on the Black‑Scholes valuation model. Assumptions used to estimate the grant‑date fair value of stock options are determined as follows: · Expected term is determined using the simplified method, using the average between the contractual term and vesting period of the award. The simplified method was used due to the lack of historical information; · Expected volatility of award grants made under the Company’s plan is measured using the weighted average of historical daily changes in the market price of the common stock of comparable public companies over the period equal to the expected term of the award or a minimum of two years if comparable public company historical market prices are not available for the entire expected term; · Expected dividend rate is determined based on expected dividends to be declared; · Risk‑free interest rate is equivalent to the implied yield on zero‑coupon U.S. Treasury bonds with a maturity equal to the expected term of the awards; and · Forfeitures are based on the history of cancellations of awards.
Business Combinations	(n) The Company records identifiable assets, liabilities and goodwill acquired in a business combination at fair value at the acquisition date. Additionally, transaction‑related costs are expensed in the period incurred.
Debt Issuance Costs	(o) All costs incurred to issue debt are capitalized as a contra-liability and amortized over the life of the loan using the interest method.
Cost and Equity Method Investments	(p) The Company uses the cost method to account for a non-marketable equity investment in an entity that it does not control and for which it does not have the ability to exercise significant influence over an entity’s operating and financial policies. When it does not have a controlling financial interest in an entity but can exercise significant influence over the entity's operating and financial policies, such investment is accounted for using the equity method. The Company recognizes dividend income when declared. In general, the equity method of accounting is used when the Company owns 20% to 50% of the outstanding voting stock of a company and when it is able to exercise significant influence over the operating and financial policies of a company. The Company has an investment where it has significant influence and as such accounts for the investments under the equity method of accounting. For equity method investments, the Company records the pro‑rata share of earnings or losses each period and records any dividends received as a reduction in the investment balance. The equity method investment is evaluated for other‑than‑temporary declines in value by considering a variety of factors such as the earnings capacity of the investment and the fair value of the investment compared to its carrying amount. If the estimated fair value of the investment is less than the carrying amount and the decline in value is considered to be other than temporary, the excess of the carrying amount over the estimated fair value is recognized in the financial statements as an impairment.

Revenue Recognition (Tables)

Revenue Recognition (Tables)	12 Months Ended
	Dec. 31, 2017
Revenue Recognition
Schedule of the disaggregation of revenue according to product line and segment	The following table depicts the disaggregation of revenue according to product line and segment (in millions): Corporate European items and Options U.S. Equities Futures Equities Global FX eliminations Total Year Ended December 31, 2017 Transaction fees $ 673.8 $ 659.4 $ 131.7 $ 66.2 $ 33.8 $ — $ 1,564.9 Access fees 54.7 41.3 1.9 6.4 2.5 — 106.8 Exchange services and other fees 42.6 19.2 7.2 4.2 1.6 — 74.8 Market data fees 41.1 111.0 2.5 9.6 0.3 — 164.5 Regulatory fees 55.4 236.1 — — — — 291.5 Other revenue 15.9 5.5 1.3 3.2 — 0.7 26.6 883.5 1,072.5 144.6 89.6 38.2 0.7 2,229.1 Timing of revenue recognition Services transferred at a point in time $ 745.1 $ 901.0 $ 133.0 $ 69.4 $ 33.8 $ 0.7 $ 1,883.0 Services transferred over time 138.4 171.5 11.6 20.2 4.4 — 346.1 883.5 1,072.5 144.6 89.6 38.2 0.7 2,229.1 Year Ended December 31, 2016 Transaction fees $ 408.2 $ — $ 101.1 $ — $ — $ — $ 509.3 Access fees 51.6 — 0.8 — — — 52.4 Exchange services and other fees 38.4 — 7.9 — — — 46.3 Market data fees 30.1 — 3.1 — — — 33.2 Regulatory fees 48.3 — — — — — 48.3 Other revenue 12.9 — 0.7 — — — 13.6 589.5 — 113.6 — — — 703.1 Year Ended December 31, 2015 Transaction fees $ 399.1 $ — $ 87.5 $ — $ — $ (1.3) $ 485.3 Access fees 52.6 — 0.7 — — — 53.3 Exchange services and other fees 42.2 — — — — — 42.2 Market data fees 30.0 — — — — — 30.0 Regulatory fees 45.0 — — — — (11.5) 33.5 Other revenue 17.2 — 2.3 — — — 19.5 586.1 — 90.5 — — (12.8) 663.8
Schedule of revenue recognized from contract liabilities and the remaining balance	The revenue recognized from contract liabilities and the remaining balance is shown below (in millions): Balance at January 1, 2017 Cash Additions Revenue Recognition Balance at December 31, 2017 Liquidity provider sliding scale (1) $ — $ 19.2 $ (14.4) $ 4.8 Other, net 3.1 20.4 (12.9) 10.6 Total deferred revenue $ 3.1 $ 39.6 $ (27.3) $ 15.4 Liquidity providers are eligible to participate in the sliding scale program, which involves prepayment of transaction fees, and to receive reduced fees based on the achievement of certain volume thresholds within a calendar month. These transaction fees received are amortized and recorded as revenue ratably as the transactions occur over the period.

Acquisitions (Tables)

Acquisitions (Tables) - Bats Global Markets, Inc.	12 Months Ended
	Dec. 31, 2017
Acquisitions
Schedule of acquisition-date fair value of consideration transferred	The acquisition-date fair value of the consideration transferred totaled $4.0 billion, which consisted of the following (in millions): Cash consideration for Bats outstanding common stock $ 955.5 Common stock issued 2,387.3 Equity awards issued 37.4 3,380.2 Debt extinguished 580.0 Total consideration $ 3,960.2
Schedule of estimated fair values of the assets acquired and liabilities assumed	The amounts in the table below represent the allocation of the purchase price. The following table summarizes the estimated fair values of the assets acquired and liabilities assumed at the acquisition date (in millions): Cash and cash equivalents $ 130.1 Accounts receivable 117.8 Financial investments 66.0 Property and equipment 21.8 Other assets 32.8 Goodwill Intangibles Accounts payable (33.7) Accrued expenses (26.2) Section 31 fees (143.6) Income tax payable (52.9) Deferred tax liability (722.6) Other liabilities (82.6) $
Schedule of finite-lived and indefinite-lived intangible assets acquired	U.S. European Options Equities Equities Global FX Useful life Trading registrations and licenses $ 95.5 $ 572.7 $ 171.8 $ — indefinite Customer relationships 37.1 222.9 160.0 140.0 years Market data customer relationships 53.6 322.0 60.0 64.4 years Technology 22.5 22.5 22.5 22.5 7 years Trademarks and tradenames 1.0 6.0 1.8 1.2 2 years Goodwill 226.4 1,738.1 419.3 267.2 $ 436.1 $ 2,884.2 $ 835.4 $ 495.3
Schedule of pro forma information	The pro forma financial information combines the historical results for the Company and Bats for the year ended December 31, 2017 and 2016 in the following table (in millions, except per share amounts): Fiscal Year ended December 31, 2017 2016 Revenue $ 2,502.0 $ 2,572.0 Revenue less cost of revenues 1,434.5 1,002.8 Operating income 471.9 406.3 Net income 271.1 231.6 Earnings per share: Basic $ 2.41 $ 2.06 Diluted 2.41 2.06

Severance (Tables)

Severance (Tables)	12 Months Ended
	Dec. 31, 2017
Severance
Summary of employee termination benefits recognized	The following is a summary of the employee termination benefits recognized within compensation and benefits in the consolidated statements of income (in millions): Employee Termination Benefits Balance at December 31, 2016 $ 0.4 Termination benefits accrued 24.3 Termination payments made (19.9) Balance at December 31, 2017 $ 4.8

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2017
Financial Investments
Schedule of equity and cost method investments	As of December 31, 2017 and 2016, the Company's investments were comprised of the following (in millions): Year Ended December 31, 2017 2016 Equity Method: Investment in Signal Trading Systems, LLC $ 12.5 $ 12.4 Investment in EuroCCP 9.6 — Total equity method investments 22.1 12.4 Cost Method: Investment in OCC 30.3 30.3 Investment in Eris Exchange Holdings, LLC 20.0 20.0 Investment in American Financial Exchange, LLC 5.9 5.9 Other cost method investments 4.4 4.3 Total cost method investments 60.6 60.5 Total investments $ 82.7 $ 72.9

Financial Investments (Tables)

Financial Investments (Tables)	12 Months Ended
	Dec. 31, 2017
Financial Investments
Schedule of Financial Investments	The Company’s financial investments with original or acquired maturities longer than three months, but that mature in less than one year from the balance sheet date and any money market funds that are considered cash and cash equivalents are classified as current assets and are summarized as follows (in millions): December 31, 2017 Cost basis Unrealized gains Unrealized losses Fair value Available-for-sale: U.S. Treasury securities $ 47.3 $ — $ — $ 47.3 Money market funds 2.5 — — 2.5 Total financial investments $ 49.8 $ — $ — $ 49.8 December 31, 2016 Cost basis Unrealized gains Unrealized losses Fair value Money market funds $ 67.5 $ — $ — $ 67.5 Total financial investments $ 67.5 $ — $ — $ 67.5

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2017
Property and Equipment, Net
Schedule of Property and Equipment, Net	Property and equipment consisted of the following as of December 31, 2017 and 2016 (in millions): December 31, December 31, 2017 2016 Construction in progress $ 5.9 $ 0.2 Building 77.4 77.0 Furniture and Equipment 139.7 138.8 Total property and equipment 223.0 216.0 Less accumulated depreciation (149.1) (160.1) Property and equipment, net $ 73.9 $ 55.9

Goodwill and Intangible Asset41

Goodwill and Intangible Assets, Net (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets, Net
Schedule of goodwill details by segment	The following table presents the details of goodwill by segment (in millions): U.S. European Corporate Options Equities Equities Global FX and Other Total Balance as of December 31, 2015 $ 7.7 $ — $ — $ — $ — $ 7.7 Additions — — — — 18.8 18.8 Dispositions — — — — — — Changes in foreign currency exchange rates — — — — — — Balance as of December 31, 2016 7.7 — — — 18.8 26.5 Additions 233.1 1,740.4 419.3 267.2 — 2,660.0 Dispositions (1.4) — — — — (1.4) Changes in foreign currency exchange rates — — 22.3 — — 22.3 Balance as of December 31, 2017 $ 239.4 $ 1,740.4 $ 441.6 $ 267.2 $ 18.8 $ 2,707.4
Schedule of details of intangible assets	The following table presents the details of the intangible assets (in millions): U.S. European Corporate Options Equities Equities Global FX and Other Total Balance as of December 31, 2015 $ 2.4 $ — $ — $ — $ — $ 2.4 Additions — — — — 8.0 8.0 Dispositions — — — — — — Amortization (0.4) — — — (1.3) (1.7) Changes in foreign currency exchange rates — — — — — — Balance as of December 31, 2016 2.0 — — — 6.7 8.7 Additions 212.0 1,146.1 416.1 228.1 — 2,002.3 Dispositions (0.2) — — — — (0.2) Amortization (15.1) (74.3) (23.8) (28.5) (1.2) (142.9) Changes in foreign currency exchange rates — — 34.7 — — 34.7 Balance as of December 31, 2017 $ 198.7 $ 1,071.8 $ 427.0 $ 199.6 $ 5.5 $ 1,902.6
Schedule of categories of intangible assets	The following table presents the categories of intangible assets at December 31, 2017 and 2016 (in millions): Weighted December 31, 2017 Average U.S. European Corporate Amortization Options Equities Equities Global FX and Other Period (in years) Trading registrations and licenses $ 95.5 $ 572.7 $ 186.5 $ — $ — Indefinite Customer relationships 38.8 222.9 173.7 140.0 3.0 19 Market data customer relationships 53.6 322.0 65.1 64.4 — 14 Technology 24.6 22.5 24.4 22.5 4.0 6 Trademarks and tradenames 1.7 6.0 2.0 1.2 1.0 2 Other 0.2 — — — — 2 Accumulated amortization (15.7) (74.3) (24.7) (28.5) (2.5) $ 198.7 $ 1,071.8 $ 427.0 $ 199.6 $ 5.5 Weighted December 31, 2016 Average U.S. European Corporate Amortization Options Equities Equities Global FX and Other Period (in years) Trading registrations and licenses $ — $ — $ — $ — $ — — Customer relationships 0.9 — — — 3.0 9 Market data customer relationships — — — — — — Technology 1.1 — — — 4.0 4 Trademarks and tradenames 0.4 — — — 1.0 6 Other 0.2 — — — — 2 Accumulated amortization (0.6) — — — (1.3) $ 2.0 $ — $ — $ — $ 6.7

Accounts Payable and Accrued 42

Accounts Payable and Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2017
Accounts Payable and Accrued Liabilities
Schedule of Accounts Payable and Accrued Liabilities	Accounts payable and accrued liabilities consisted of the following as of December 31, 2017 and 2016 (in millions): December 31, 2017 December 31, 2016 Compensation and benefit related liabilities $ 18.0 $ 25.1 Termination benefits 4.8 0.4 Royalties 20.3 17.8 Accrued liabilities 59.1 25.4 Marketing fee payable 8.4 7.2 Accounts payable 43.2 6.5 Total accounts payable and accrued liabilities $ 153.8 $ 82.4

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2017
Debt
Schedule of long-term debt	The Company's long-term debt consisted of the following as of December 31, 2017 and 2016 (in millions): December 31, 2017 December 31, 2016 2017 Term Loan Agreement $ 294.9 $ — 3.650% Senior Notes 643.8 — 1.950% Senior Notes 299.2 — Total long-term debt $ 1,237.9 $ —
Schedule of maturities of long-term debt	The future expected loan repayments related to the Term Loan Agreement and the Notes as of December 31, 2017 is as follows (in millions): 2018 $ — 2019 2020 — 2021 — Thereafter 950.0 Principal amounts repayable 1,250.0 Debt issuance cost Unamortized discounts on notes Total debt outstanding $ 1,237.9
Schedule of interest expense	Interest expense recognized on the Term Loan Agreement and the Notes is included in interest expense, net in the consolidated statements of income, for the years ended December 31, 2017, 2016 and 2015 are as follows (in millions): Year Ended Year Ended Year Ended December 31, December 31, December 31, 2017 2016 2015 Components of interest expense: Contractual interest $ 39.0 $ 5.7 $ — Amortization of debt discount 0.6 — — Amortization of debt issuance cost 3.0 — — Interest expense $ 42.6 $ 5.7 $ — Interest income (1.3) — — Interest expense, net $ 41.3 $ 5.7 $ —

Accumulated Other Comprehensi44

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss)
Schedule of Accumulated Other Comprehensive Income, Net	The following represents the changes in accumulated other comprehensive income (loss) by component, before tax (in millions): Foreign currency Unrealized Total Other translation Investment Post-Retirement Comprehensive adjustment Gain/Loss Benefits Income Balance at December 31, 2015 $ — $ — $ (0.8) $ (0.8) Other comprehensive income (loss) — — — — Tax effect on other comprehensive income (loss) — — — — Balance at December 31, 2016 — — (0.8) (0.8) Other comprehensive income (loss) 51.3 0.2 — 51.5 Tax effect on other comprehensive income (loss) — — — — Balance at December 31, 2017 $ 51.3 $ 0.2 $ (0.8) $ 50.7

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Measurement
Schedule of fair value hierarchy for assets measured at fair value on a recurring basis	The following tables presents the Company’s fair value hierarchy for those assets measured at fair value on a recurring basis as of December 31, 2017 and 2016 (in millions): December 31, 2017 Total Level 1 Level 2 Level 3 Assets: Trading securities: U.S. Treasury securities $ 47.3 $ 47.3 $ — $ — Other securities — — — — Money market funds 2.5 2.5 — — Total assets $ 49.8 $ 49.8 $ — $ — Liabilities: Contingent consideration liability to related party $ 56.6 $ — $ — $ 56.6 Total Liabilities $ 56.6 $ — $ — $ 56.6 December 31, 2016 Total Level 1 Level 2 Level 3 Assets: Money market funds $ 67.5 $ 67.5 $ — $ — Total assets $ 67.5 $ 67.5 $ — $ —
Schedule of fair value hierarchy of financial instruments held	The following table presents the Company’s fair value hierarchy for those financial instruments held by the Company as of December 31, 2017 and 2016 (in millions): December 31, 2017 Total Level 1 Level 2 Level 3 Assets: Cash and cash equivalents $ 143.5 $ 143.5 $ — $ — Trading investments 0.5 0.5 — — Available-for-sale investments 46.8 46.8 — — Accounts receivable 217.3 217.3 — — Income tax receivable 17.2 17.2 — — Total assets $ 425.3 $ 425.3 $ — $ — Liabilities: Accounts payable $ 43.2 $ — $ 43.2 $ — Section 31 fees payable 105.6 — 105.6 — Contingent consideration liability to related party 56.6 — — 56.6 Long-term debt 1,237.9 — 1,237.9 — Total liabilities $ 1,443.3 $ — $ 1,386.7 $ 56.6 December 31, 2016 Total Level 1 Level 2 Level 3 Assets: Cash and cash equivalents $ 97.3 $ 97.3 $ — $ — Accounts receivable 76.7 76.7 — — Income tax receivable 53.7 53.7 — — Total assets $ 227.7 $ 227.7 $ — $ — Liabilities: Accounts payable $ 6.5 $ — $ 6.5 $ — Total liabilities $ 6.5 $ — $ 6.5 $ —
Summary of changes in the fair value of level 3 financial liabilities	Level 3 Financial Liabilities for the Year Ended December 31, 2017 Balance at Beginning of Balances at Period Additions Settlements End of Period Liabilities Contingent consideration liability to related party $ — $ 56.6 $ — $ 56.6 Total Liabilities $ — $ 56.6 $ — $ 56.6 Level 3 Financial Liabilities for the Year Ended December 31, 2016 Balance at Beginning of Balances at Period Additions Settlements End of Period Liabilities Contingent consideration liability to related party $ — $ — $ — $ — Total Liabilities $ — $ — $ — $ —

Redeemable Noncontrolling Int46

Redeemable Noncontrolling Interest (Tables)	12 Months Ended
	Dec. 31, 2017
Redeemable Noncontrolling Interest
Schedule of Redeemable Noncontrolling Interest	For the year ended December 31, 2017, the following reflects changes in our redeemable noncontrolling interest (in millions): Redeemable Balance as of December 31, 2016 $ 12.6 Decrease due to acquiring additional equity in Cboe Vest (3.2) Net loss attributable to redeemable noncontrolling interest (1.1) Redemption value adjustment 1.1 Balance as of December 31, 2017 $ 9.4

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting
Summarized Financial Information by Reportable Segment	Summarized financial data of reportable segments was as follows (in millions): Corporate European items and Options U.S. Equities Futures Equities Global FX eliminations Total Year ended December 31, 2017 Revenues $ 883.5 $ 1,072.5 $ 144.6 $ 89.6 $ 38.2 $ 0.7 $ 2,229.1 Operating income (loss) 252.2 103.2 126.8 8.9 (12.8) (106.4) 371.9 Year ended December 31, 2016 Revenues $ 589.5 $ — $ 113.6 $ — $ — $ — $ 703.1 Operating income (loss) 218.4 — 96.4 — — (16.6) 298.2 Year ended December 31, 2015 Revenues $ 586.1 $ — $ 90.5 $ — $ — $ (12.8) $ 663.8 Operating income (loss) 261.2 — 73.6 — — (14.9) 319.9

Stock-based Compensation (Table

Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Stock-based Compensation
Summary of stock option activity	Summary stock option activity is presented below: Weighted Weighted Average Average Remaining Aggregate Number of Exercise Contractual Intrinsic Value Shares Price Term (years) (in millions) Outstanding, December 31, 2015 — $ — — $ — Granted — — — — Exercised — — Outstanding, December 31, 2016 — $ — — $ — Granted 683,390 22.45 — — Exercised (241,348) Outstanding and expected to vest at December 31, 2017 442,042 $ 25.36 1.0 $ 17.5 Exercisable at December 31, 2017 401,507 $ 25.08 5.0 $ 40.0
Summary of fair value assumptions	The Company estimated the grant date fair value of options awarded during 2017 using the Black‑Scholes valuation model with the following assumptions: 2017 Expected term (in years) 4.2 Expected volatility 19.8 % Expected dividend yield 1.3 % Risk-free rate 1.78 % Forfeiture rate — %
Summary of nonvested options	Summary of the status of nonvested options is presented below: Weighted Average Grant- Nonvested options Options Date Fair Value December 31, 2015—Nonvested — $ — Granted — — Vested — — Forfeited — — December 31, 2016—Nonvested — $ — Granted 81,068 49.17 Vested — — Forfeited — — December 31, 2017—Nonvested 81,068 $ 49.17
Summary of restricted stock activity	Summary restricted stock activity is presented below: Weighted Number of average grant shares date fair value Nonvested stock at December 31, 2015 456,570 $ 55.70 Granted 241,681 64.10 Vested (211,235) 48.14 Forfeited (6,421) 64.50 Nonvested stock at December 31, 2016 480,595 $ 63.64 Granted 1,091,843 78.94 Vested (498,540) 67.83 Forfeited (5,506) 71.68 Nonvested stock at December 31, 2017 1,068,392 $ 77.19

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Taxes
Schedule of net deferred tax liabilities	Net deferred tax assets and liabilities consist of the following as of December 31, 2017 and 2016 (in millions): 2017 2016 Deferred tax assets: Accrued compensation and benefits $ 14.1 $ 16.3 Property, equipment and technology, net 2.4 0.6 Investment in affiliates — 4.7 Other 20.2 17.1 Subtotal 36.7 38.7 Valuation allowance (1.6) — Total deferred tax assets 35.1 38.7 Deferred tax liabilities: Intangibles (429.6) — Property, equipment and technology, net (17.1) (32.3) Investment in affiliates (75.0) (1.7) Prepaid expenses or assets (1.6) (1.2) Total deferred tax liabilities (523.3) (35.2) Net deferred tax assets/(liabilities) $ (488.2) $ 3.5
Schedule of provision for income taxes	The provision for income taxes for the years ended December 31, 2017, 2016 and 2015 consists of the following (in millions): Year Ended December 31 2017 2016 2015 Current tax expense: Federal $ 141.0 $ 107.1 $ 103.3 State 25.8 22.6 23.9 Foreign 5.4 — — Total current tax expense 172.2 129.7 127.3 Deferred income tax expense: Federal (227.5) (7.6) (6.4) State (6.5) (1.2) (1.9) Foreign (4.4) — — Total deferred income tax expense (238.4) (8.8) (8.3) Total $ (66.2) $ 120.9 $ 119.0
Schedule of income from continuing operations before taxes	For the years ended December 31, 2017, 2016, and 2015, income from continuing operations before taxes consists of the following (in millions): 2017 2016 2015 U.S. operations $ 326.7 $ 306.6 $ 324.0 Foreign operations 7.7 — — $ 334.4 $ 306.6 $ 324.0
Schedule of reconciliation of the statutory federal income tax rate to the effective income tax rate	A reconciliation of the statutory federal income tax rate to the effective income tax rate for the years ended December 31, 2017, 2016, and 2015 is as follows: 2017 2016 2015 Statutory U.S. federal income tax rate 35.0 % 35.0 % 35.0 % Impact of federal, state and local tax law & rate changes, net (55.1) % - % - % State taxes, net of federal benefit 4.3 % 4.5 % 4.4 % Section 199 deduction (2.6) % (2.6) % (1.9) % Other, net (1.4) % 2.5 % (0.8) % Effective income tax rate (19.8) % 39.4 % 36.7 %
Schedule of reconciliation of beginning and ending uncertain tax positions	A reconciliation of the beginning and ending uncertain tax positions, excluding interest and penalties, is as follows (in thousands): 2017 2016 2015 Balance as of January 1 $ 41.9 $ 31.9 $ 35.4 Acquired unrecognized tax benefits 23.2 — — Gross increases on tax positions in prior period 6.2 8.8 — Gross decreases on tax positions in prior period (14.7) (0.6) (4.2) Gross increases on tax positions in current period 12.7 3.6 1.9 Lapse of statute of limitations (1.5) (1.8) (1.2) Balance as of December 31 $ 67.8 $ 41.9 $ 31.9

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Reconciliation of basic and diluted net income per common share	(22) Earnings Per Share The computation of basic net income allocated to common stockholders is calculated by reducing net income for the period by dividends paid or declared and undistributed net income for the period that are allocated to participating securities to arrive at net income allocated to common stockholders. Net income allocated to common stockholders is divided by the weighted average number of common shares outstanding during the period to determine net income per share allocated to common stockholders. The computation of diluted earnings per share is calculated by dividing net income allocated to common stockholders by the sum of the weighted average number of common shares outstanding plus all additional common shares that would have been outstanding if the potentially dilutive common shares had been issued. The dilutive effect is calculated using the more dilutive of the two-class or treasury stock method. Additionally, the change in the redemption value for the noncontrolling interest reduces net income allocated to common shareholders. Net income and diluted earnings per share for the year ended December 31, 2017 include a substantial benefit associated with the enactment of the Jobs Act. The enactment of the Jobs Act resulted in an estimated net income increase of $191.3 million primarily due to a one-time revaluation of our net deferred tax liability based on a U.S. federal tax rate of 21 percent. The following table sets forth the computation of basic and diluted earnings per share (in millions, except per share data): Year Ended December 31, (in thousands, except per share amounts) 2017 2016 2015 Basic EPS Numerator: Net Income $ 400.6 $ 185.7 $ 205.0 Loss attributable to noncontrolling interests 1.1 1.1 — Net Income excluding noncontrolling interests 401.7 186.8 205.0 Change in redemption value of noncontrolling interests (1.1) (1.1) — Earnings allocated to participating securities (3.9) (0.8) (0.9) Net Income allocated to common stockholders $ 396.7 $ 184.9 $ 204.1 Basic EPS Denominator: Weighted average shares outstanding 107.2 81.4 83.1 Basic Net Income Per Common Share $ 3.70 $ 2.27 $ 2.46 Diluted EPS Numerator: Net Income $ 400.6 $ 185.7 $ 205.0 Loss attributable to noncontrolling interests 1.1 1.1 — Net Income excluding noncontrolling interests 401.7 186.8 205.0 Change in redemption value of noncontrolling interests (1.1) (1.1) — Earnings allocated to participating securities (3.9) (0.8) (0.9) Net Income allocated to common stockholders $ 396.7 $ 184.9 $ 204.1 Diluted EPS Denominator: Weighted average shares outstanding 107.2 81.4 83.1 Dilutive common shares issued under stock program 0.3 — — Total dilutive weighted average shares 107.5 81.4 83.1 Diluted Net Income Per Common Share $ 3.69 $ 2.27 $ 2.46

Quarterly Data (unaudited) (Tab

Quarterly Data (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Data (unaudited)
Summary of quarterly data	First Second Third Fourth Year ended December 31, 2017 (in millions, except per share data) Quarter Quarter Quarter Quarter Revenue less cost of revenues $ 193.4 $ 266.9 $ 269.7 $ 265.6 Operating income 26.1 117.8 119.3 108.7 Net income 15.2 68.0 60.3 257.1 Net income allocated to common stockholders 15.1 67.3 59.7 254.6 Basic earnings per share $ 0.16 $ 0.60 $ 0.53 $ 2.41 Diluted earnings per share $ 0.16 $ 0.60 $ 0.53 $ 2.40 First Second Third Fourth Year ended December 31, 2016 (in millions, except per share data) Quarter Quarter Quarter Quarter Revenue less cost of revenues $ 143.1 $ 144.1 $ 136.2 $ 143.0 Operating income 79.5 78.0 65.8 74.9 Net income 49.2 50.9 40.5 45.1 Net income allocated to common stockholders 49.2 50.7 40.3 44.7 Basic earnings per share $ 0.60 $ 0.62 $ 0.50 $ 0.55 Diluted earnings per share $ 0.60 $ 0.62 $ 0.50 $ 0.55

Summary of Significant Accoun52

Summary of Significant Accounting Policies (Details) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 31, 2017segmentitem	Dec. 31, 2016item	Dec. 31, 2015item
Property and Equipment, Net
Number of reportable segments | segment		5
Goodwill impairment loss | $	$ 0
Minimum
Property and Equipment, Net
Useful life (in years)		3 years
Expected term (in years)		2 years
Maximum
Property and Equipment, Net
Useful life (in years)		7 years
Transaction fees | Customer Risk
Property and Equipment, Net
Number of concentration risk		2	2	2
Concentration risk (as a percent)		17.00%	42.00%	45.00%
Revenue | Customer Risk
Property and Equipment, Net
Number of concentration risk		0	0	0
Concentration risk (as a percent)		10.00%	10.00%	10.00%
Liquidity payments | Customer Risk
Property and Equipment, Net
Number of concentration risk		0	0	0
Concentration risk (as a percent)		10.00%	10.00%	10.00%

Revenue Recognition - Schedule

Revenue Recognition - Schedule of revenue by product line and Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information
Revenues	$ 2,229.1	$ 703.1	$ 663.8
Services transferred at a point in time
Segment Reporting Information
Revenues	1,883
Services transferred over time
Segment Reporting Information
Revenues	346.1
Corporate Items and Eliminations
Segment Reporting Information
Revenues	0.7		(12.8)
Corporate Items and Eliminations | Services transferred at a point in time
Segment Reporting Information
Revenues	0.7
Options | Operating Segments
Segment Reporting Information
Revenues	883.5	589.5	586.1
Options | Operating Segments | Services transferred at a point in time
Segment Reporting Information
Revenues	745.1
Options | Operating Segments | Services transferred over time
Segment Reporting Information
Revenues	138.4
U.S. Equities | Operating Segments
Segment Reporting Information
Revenues	1,072.5
U.S. Equities | Operating Segments | Services transferred at a point in time
Segment Reporting Information
Revenues	901
U.S. Equities | Operating Segments | Services transferred over time
Segment Reporting Information
Revenues	171.5
Futures | Operating Segments
Segment Reporting Information
Revenues	144.6	113.6	90.5
Futures | Operating Segments | Services transferred at a point in time
Segment Reporting Information
Revenues	133
Futures | Operating Segments | Services transferred over time
Segment Reporting Information
Revenues	11.6
European Equities | Operating Segments
Segment Reporting Information
Revenues	89.6
European Equities | Operating Segments | Services transferred at a point in time
Segment Reporting Information
Revenues	69.4
European Equities | Operating Segments | Services transferred over time
Segment Reporting Information
Revenues	20.2
Global FX | Operating Segments
Segment Reporting Information
Revenues	38.2
Global FX | Operating Segments | Services transferred at a point in time
Segment Reporting Information
Revenues	33.8
Global FX | Operating Segments | Services transferred over time
Segment Reporting Information
Revenues	4.4
Transaction fees
Segment Reporting Information
Revenues	1,564.9	509.3	485.3
Transaction fees | Corporate Items and Eliminations
Segment Reporting Information
Revenues			(1.3)
Transaction fees | Options | Operating Segments
Segment Reporting Information
Revenues	673.8	408.2	399.1
Transaction fees | U.S. Equities | Operating Segments
Segment Reporting Information
Revenues	659.4
Transaction fees | Futures | Operating Segments
Segment Reporting Information
Revenues	131.7	101.1	87.5
Transaction fees | European Equities | Operating Segments
Segment Reporting Information
Revenues	66.2
Transaction fees | Global FX | Operating Segments
Segment Reporting Information
Revenues	33.8
Access fees
Segment Reporting Information
Revenues	106.8	52.4	53.3
Access fees | Options | Operating Segments
Segment Reporting Information
Revenues	54.7	51.6	52.6
Access fees | U.S. Equities | Operating Segments
Segment Reporting Information
Revenues	41.3
Access fees | Futures | Operating Segments
Segment Reporting Information
Revenues	1.9	0.8	0.7
Access fees | European Equities | Operating Segments
Segment Reporting Information
Revenues	6.4
Access fees | Global FX | Operating Segments
Segment Reporting Information
Revenues	2.5
Exchange services and other fees
Segment Reporting Information
Revenues	74.8	46.3	42.2
Exchange services and other fees | Options | Operating Segments
Segment Reporting Information
Revenues	42.6	38.4	42.2
Exchange services and other fees | U.S. Equities | Operating Segments
Segment Reporting Information
Revenues	19.2
Exchange services and other fees | Futures | Operating Segments
Segment Reporting Information
Revenues	7.2	7.9
Exchange services and other fees | European Equities | Operating Segments
Segment Reporting Information
Revenues	4.2
Exchange services and other fees | Global FX | Operating Segments
Segment Reporting Information
Revenues	1.6
Market data fees
Segment Reporting Information
Revenues	164.5	33.2	30
Market data fees | Options | Operating Segments
Segment Reporting Information
Revenues	41.1	30.1	30
Market data fees | U.S. Equities | Operating Segments
Segment Reporting Information
Revenues	111
Market data fees | Futures | Operating Segments
Segment Reporting Information
Revenues	2.5	3.1
Market data fees | European Equities | Operating Segments
Segment Reporting Information
Revenues	9.6
Market data fees | Global FX | Operating Segments
Segment Reporting Information
Revenues	0.3
Regulatory fees
Segment Reporting Information
Revenues	291.5	48.3	33.5
Regulatory fees | Corporate Items and Eliminations
Segment Reporting Information
Revenues			(11.5)
Regulatory fees | Options | Operating Segments
Segment Reporting Information
Revenues	55.4	48.3	45
Regulatory fees | U.S. Equities | Operating Segments
Segment Reporting Information
Revenues	236.1
Other revenue
Segment Reporting Information
Revenues	26.6	13.6	19.5
Other revenue | Corporate Items and Eliminations
Segment Reporting Information
Revenues	0.7
Other revenue | Options | Operating Segments
Segment Reporting Information
Revenues	15.9	12.9	17.2
Other revenue | U.S. Equities | Operating Segments
Segment Reporting Information
Revenues	5.5
Other revenue | Futures | Operating Segments
Segment Reporting Information
Revenues	1.3	$ 0.7	$ 2.3
Other revenue | European Equities | Operating Segments
Segment Reporting Information
Revenues	$ 3.2

Revenue Recognition - Rollforwa

Revenue Recognition - Rollforward of contract liabilities (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Movement in Deferred Revenue
Beginning balance	$ 3.1
Cash Additions	39.6
Revenue Recognition	(27.3)
Ending balance	15.4
Liquidity provider sliding scale
Movement in Deferred Revenue
Cash Additions	19.2
Revenue Recognition	(14.4)
Ending balance	4.8
Other, net
Movement in Deferred Revenue
Beginning balance	3.1
Cash Additions	20.4
Revenue Recognition	(12.9)
Ending balance	$ 10.6

Acquisitions (Details)

Acquisitions (Details) $ / shares in Units, $ in Millions	Feb. 28, 2017USD ($)item$ / sharesshares	Nov. 30, 2017USD ($)	Dec. 31, 2017USD ($)$ / shares	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)$ / shares	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2017USD ($)$ / shares	Dec. 31, 2016USD ($)$ / shares	Dec. 31, 2015USD ($)	Feb. 27, 2017$ / shares
Acquisitions
Common stock, par value (in dollars per share) | $ / shares			$ 0.01				$ 0.01				$ 0.01	$ 0.01
Goodwill expected to be deductible for tax purposes			$ 0								$ 0
Goodwill											2,660	$ 18.8
Acquisition-related costs											84.4	13.6
Compensation and benefits											201.4	113.2	$ 105.9
Professional fees and outside services											66	53.1	50.1
Facilities expenses											10.3	5.7	5
Impact on net income (loss)			$ (257.1)	$ (60.3)	$ (68)	$ (15.2)	$ (45.1)	$ (40.5)	$ (50.9)	$ (49.2)	(400.6)	(185.7)	$ (205)
Operating Segments | Futures
Acquisitions
Goodwill	$ 0
Intangibles	$ 0
Bats Global Markets, Inc. | Voting Common Stock
Acquisitions
Common stock, par value (in dollars per share) | $ / shares	$ 0.01
Bats Global Markets, Inc. | Non-voting Common Stock
Acquisitions
Common stock, par value (in dollars per share) | $ / shares	$ 0.01
Bats Global Markets, Inc.
Acquisitions
Consideration transferred	$ 3,960.2
Number of decimal places that the volume-weighted average price of shares of Cboe Common Stock was rounded to | item	4
Share price, measurement period	10 days
Share price (in dollars per share) | $ / shares														$ 79.9289
Intangibles	$ 2,000
Fair value of accounts receivable acquired	117.8
Gross value of accounts receivable acquired	118
Allowance for doubtful accounts	$ 0.2
Acquisition-related costs											84.4	$ (107)
Compensation and benefits											44.2
Professional fees and outside services											24.4
Impairment of capitalized data processing software											14.9
Facilities expenses											$ 0.9
Bats Global Markets, Inc. | Consideration Option One
Acquisitions
Equity interests issuable per share owned by acquiree (in shares) | shares	0.3201
Cash consideration (in dollars per share) | $ / shares	$ 10
Bats Global Markets, Inc. | Consideration Option Two
Acquisitions
Equity interests issuable per share owned by acquiree (in shares) | shares	0.2577
Cash consideration (in dollars per share) | $ / shares	$ 14.99
Bats Global Markets, Inc. | Consideration Option Three
Acquisitions
Equity interests issuable per share owned by acquiree (in shares) | shares	0.4452
Silexx Financial Systems
Acquisitions
Consideration transferred		$ 9
Goodwill		6.7
Intangibles		2.1
Working capital		$ 0.2

Acquisitions - Acquisition date

Acquisitions - Acquisition date fair value of consideration transferred (Details) - USD ($) $ in Millions	Feb. 28, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Acquisitions
Cash		$ 1,414.1	$ 14.3	$ 3
Bats Global Markets, Inc.
Acquisitions
Cash	$ 955.5
Common stock issued	2,387.3
Equity awards issued	37.4
Total consideration paid, excluding debt extinguished	3,380.2
Debt extinguished	580
Total consideration paid	$ 3,960.2

Acquisitions - Fair values of a

Acquisitions - Fair values of assets acquired and liabilities assumed (Details) - USD ($) $ in Millions	Dec. 31, 2017	Feb. 28, 2017	Dec. 31, 2016	Dec. 31, 2015
Acquisitions
Goodwill	$ 2,707.4		$ 26.5	$ 7.7
Bats Global Markets, Inc.
Acquisitions
Cash and cash equivalents		$ 130.1
Accounts receivable		117.8
Financial investments		66
Property and equipment		21.8
Other assets		32.8
Goodwill		2,653.3
Intangibles		2,000
Accounts payable		(33.7)
Accrued expenses		(26.2)
Section 31 fees payable		(143.6)
Income tax payable		(52.9)
Deferred tax liability		(722.6)
Other liabilities		(82.6)
Fair value of assets acquired and liabilities assumed		$ 3,960.2

Acquisitions - Intangible asset

Acquisitions - Intangible assets acquired (Details) - USD ($) $ in Millions	Feb. 28, 2017	Dec. 31, 2017	Dec. 31, 2016
Acquisitions
Goodwill		$ 2,660	$ 18.8
Options
Acquisitions
Goodwill	$ 226.4	233.1
Finite-lived and indefinite-lived intangible assets acquired	436.1
U.S. Equities
Acquisitions
Goodwill	1,738.1	1,740.4
Finite-lived and indefinite-lived intangible assets acquired	2,884.2
European Equities
Acquisitions
Goodwill	419.3	419.3
Finite-lived and indefinite-lived intangible assets acquired	$ 835.4
Global FX
Acquisitions
Goodwill		267.2
Finite-lived and indefinite-lived intangible assets acquired		495.3
Customer relationships
Acquisitions
Useful life	20 years
Customer relationships | Options
Acquisitions
Finite-lived intangible assets acquired	$ 37.1
Customer relationships | U.S. Equities
Acquisitions
Finite-lived intangible assets acquired	222.9
Customer relationships | European Equities
Acquisitions
Finite-lived intangible assets acquired	$ 160
Customer relationships | Global FX
Acquisitions
Finite-lived intangible assets acquired		140
Market data customer relationships
Acquisitions
Useful life	15 years
Market data customer relationships | Options
Acquisitions
Finite-lived intangible assets acquired	$ 53.6
Market data customer relationships | U.S. Equities
Acquisitions
Finite-lived intangible assets acquired	322
Market data customer relationships | European Equities
Acquisitions
Finite-lived intangible assets acquired	$ 60
Market data customer relationships | Global FX
Acquisitions
Finite-lived intangible assets acquired		64.4
Technology
Acquisitions
Useful life	7 years
Technology | Options
Acquisitions
Finite-lived intangible assets acquired	$ 22.5
Technology | U.S. Equities
Acquisitions
Finite-lived intangible assets acquired	22.5
Technology | European Equities
Acquisitions
Finite-lived intangible assets acquired	$ 22.5
Technology | Global FX
Acquisitions
Finite-lived intangible assets acquired		22.5
Trademarks and tradenames
Acquisitions
Useful life	2 years
Trademarks and tradenames | Options
Acquisitions
Finite-lived intangible assets acquired	$ 1
Trademarks and tradenames | U.S. Equities
Acquisitions
Finite-lived intangible assets acquired	6
Trademarks and tradenames | European Equities
Acquisitions
Finite-lived intangible assets acquired	1.8
Trademarks and tradenames | Global FX
Acquisitions
Finite-lived intangible assets acquired		$ 1.2
Trading registrations and licenses | Options
Acquisitions
Indefinite-lived intangible assets acquired	95.5
Trading registrations and licenses | U.S. Equities
Acquisitions
Indefinite-lived intangible assets acquired	572.7
Trading registrations and licenses | European Equities
Acquisitions
Indefinite-lived intangible assets acquired	$ 171.8

Acquisitions - Revenue and inco

Acquisitions - Revenue and income since acquisition date (Details) - Bats Global Markets, Inc. $ in Millions	10 Months Ended
	Dec. 31, 2017USD ($)
Acquisitions
Revenue	$ 1,439.8
Revenue less cost of revenues	378.2
Operating income	73.4
Net income	$ 88.4

Acquisitions - Pro forma financ

Acquisitions - Pro forma financial information (Details) - Bats Global Markets, Inc. - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Acquisitions
Revenue	$ 2,502	$ 2,572
Revenue less cost of revenues	1,434.5	1,002.8
Operating income	471.9	406.3
Net income	$ 271.1	$ 231.6
Earnings per share:
Basic (in dollars per share)	$ 2.41	$ 2.06
Diluted (in dollars per share)	$ 2.41	$ 2.06

Severance (Details)

Severance (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Restructuring Reserve
Beginning balance	$ 0.4
Termination benefits accrued	24.3
Termination payments made	(19.9)
Ending balance	$ 4.8

Investments - Schedule of inves

Investments - Schedule of investments (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Schedule of Cost and Equity Method Investments
Equity Method	$ 22.1	$ 12.4
Cost Method	60.6	60.5
Total Investments	82.7	72.9
Investment in Signal Trading Systems, LLC
Schedule of Cost and Equity Method Investments
Equity Method	12.5	12.4
Investment in EuroCCP
Schedule of Cost and Equity Method Investments
Equity Method	9.6
Investment in OCC
Schedule of Cost and Equity Method Investments
Cost Method	30.3	30.3
Other cost method investments
Schedule of Cost and Equity Method Investments
Cost Method	$ 4.4	$ 4.3

Investments - Equity method inv

Investments - Equity method investments (Details)	Dec. 31, 2017item
Schedule of Equity Method Investments
Number of central counterparties	3
Investment in EuroCCP | Cboe Europe Equities
Schedule of Equity Method Investments
Ownership percentage	20.00%
Number of other investors	4

Investments - Cost method inves

Investments - Cost method investments (Details) - USD ($) $ in Millions	Mar. 03, 2015	Feb. 26, 2015	Dec. 31, 2017	Dec. 31, 2016
Cost-method investments
Cost method investments			$ 60.6	$ 60.5
Investment in OCC
Cost-method investments
Cost method investments			$ 30.3	30.3
Ownership percentage			20.00%
Contribution requirement		$ 150
Contribution requirement, shareholder cap		$ 40
Customer refunds, percent of pre-tax income exceeding capital requirements		50.00%
Contributions	$ 30
Eris Exchange Holdings, LLC
Cost-method investments
Cost method investments			$ 20	20
Loan Markets, LLC
Cost-method investments
Cost method investments			$ 5.9	$ 5.9

Financial Investments (Details)

Financial Investments (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Available-for-sale:
Fair value	$ 46.8
Money market funds
Cost basis	143.5	$ 97.3	$ 102.3	$ 147.9
Money market funds	143.5	97.3
Financial Investments
Cost basis	49.8	67.5
Fair Value	49.8	67.5
Money market funds
Money market funds
Cost basis	2.5	67.5
Money market funds	2.5	$ 67.5
U.S. Treasury securities
Available-for-sale:
Cost basis	47.3
Fair value	$ 47.3

Property and Equipment, Net (De

Property and Equipment, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property and Equipment, Net
Total property and equipment	$ 223	$ 216
Less accumulated depreciation	(149.1)	(160.1)
Property and equipment, net	73.9	55.9
Depreciation expense	31.3	24	$ 46.1
Construction in progress
Property and Equipment, Net
Total property and equipment	5.9	0.2
Building
Property and Equipment, Net
Total property and equipment	77.4	77
Furniture and equipment
Property and Equipment, Net
Total property and equipment	$ 139.7	$ 138.8

Other Assets, Net - Schedule of

Other Assets, Net - Schedule of other assets, net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets
Less accumulated depreciation and amortization	$ (189.6)	$ (172)
Data processing software, net	40.6	62.9
Other assets	18.9	9.8
Data processing software and other assets, net	59.5	72.7
Deferred financing costs	6.6	6.2
Deferred tax assets		3.5
Amortization	142.9	1.7	$ 0.2
Software development work in progress
Finite-Lived Intangible Assets
Software	10.2	12.3
Data processing software
Finite-Lived Intangible Assets
Software	220	222.6
Amortization	$ 17.9	$ 18.7	$ 0

Goodwill and Intangible Asset68

Goodwill and Intangible Assets, Net - Goodwill by segment (Details) - USD ($) $ in Millions	Feb. 28, 2017	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Goodwill
Balance at beginning of the year			$ 26.5	$ 7.7
Additions			2,660	18.8
Dispositions			(1.4)
Changes in foreign currency exchange rates			22.3
Balance at end of the year		$ 2,707.4	2,707.4	26.5
Goodwill impairment loss		0
Options
Goodwill
Balance at beginning of the year			7.7	7.7
Additions	$ 226.4		233.1
Dispositions			(1.4)
Balance at end of the year		239.4	239.4	7.7
U.S. Equities
Goodwill
Additions	1,738.1		1,740.4
Balance at end of the year		1,740.4	1,740.4
European Equities
Goodwill
Additions	$ 419.3		419.3
Changes in foreign currency exchange rates			22.3
Balance at end of the year		441.6	441.6
Global FX
Goodwill
Additions			267.2
Balance at end of the year		267.2	267.2
Corporate and Other
Goodwill
Balance at beginning of the year			18.8
Additions				18.8
Balance at end of the year		$ 18.8	$ 18.8	$ 18.8

Goodwill and Intangible Asset69

Goodwill and Intangible Assets, Net - Schedule of intangible assets by segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-lived Intangible Assets
Balance at beginning of the year	$ 8.7	$ 2.4
Additions	2,002.3	8
Dispositions	(0.2)
Amortization	(142.9)	(1.7)	$ (0.2)
Changes in foreign currency exchange rates	34.7
Balance at end of the year	1,902.6	8.7	2.4
Options
Finite-lived Intangible Assets
Balance at beginning of the year	2	2.4
Additions	212
Dispositions	(0.2)
Amortization	(15.1)	(0.4)
Balance at end of the year	198.7	2	2.4
U.S. Equities
Finite-lived Intangible Assets
Balance at beginning of the year		0
Additions	1,146.1
Amortization	(74.3)
Balance at end of the year	1,071.8		0
European Equities
Finite-lived Intangible Assets
Balance at beginning of the year		0
Additions	416.1
Amortization	(23.8)
Changes in foreign currency exchange rates	34.7
Balance at end of the year	427		0
Global FX
Finite-lived Intangible Assets
Balance at beginning of the year		0
Additions	228.1
Amortization	(28.5)
Balance at end of the year	199.6		0
Corporate and Other
Finite-lived Intangible Assets
Balance at beginning of the year	6.7	0
Additions		8
Amortization	(1.2)	(1.3)
Balance at end of the year	5.5	$ 6.7	$ 0
Futures
Finite-lived Intangible Assets
Balance at end of the year	$ 0

Goodwill and Intangible Asset70

Goodwill and Intangible Assets, Net - Estimated Future Amortization (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets, Net
Amortization	$ 142.9	$ 1.7	$ 0.2
Amortization expense
2,018	158.4
2,019	137.5
2,020	121
2,021	105.7
2,022	$ 93.5

Goodwill and Intangible Asset71

Goodwill and Intangible Assets, Net - Schedule of intangible assets by category (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets
Intangible assets, net	$ 1,902.6	$ 8.7	$ 2.4
Customer relationships
Finite-Lived Intangible Assets
Weighted average amortization period (in years)	19 years
Customer relationships | Weighted Average
Finite-Lived Intangible Assets
Weighted average amortization period (in years)		9 years
Market data customer relationships
Finite-Lived Intangible Assets
Weighted average amortization period (in years)	14 years
Technology
Finite-Lived Intangible Assets
Weighted average amortization period (in years)	6 years
Technology | Weighted Average
Finite-Lived Intangible Assets
Weighted average amortization period (in years)		4 years
Trademarks and tradenames
Finite-Lived Intangible Assets
Weighted average amortization period (in years)	2 years
Trademarks and tradenames | Weighted Average
Finite-Lived Intangible Assets
Weighted average amortization period (in years)		6 years
Other
Finite-Lived Intangible Assets
Weighted average amortization period (in years)	2 years
Other | Weighted Average
Finite-Lived Intangible Assets
Weighted average amortization period (in years)		2 years
Options
Finite-Lived Intangible Assets
Accumulated amortization	$ (15.7)	$ (0.6)
Intangible assets, net	198.7	2	2.4
Options | Customer relationships
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	38.8	0.9
Options | Market data customer relationships
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	53.6
Options | Technology
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	24.6	1.1
Options | Trademarks and tradenames
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	1.7	0.4
Options | Other
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	0.2	0.2
Options | Trading registrations and licenses
Finite-Lived Intangible Assets
Indefinite-lived intangible assets, gross	95.5
U.S. Equities
Finite-Lived Intangible Assets
Indefinite-lived intangible assets, gross	572.7
Accumulated amortization	(74.3)
Intangible assets, net	1,071.8		0
U.S. Equities | Customer relationships
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	222.9
U.S. Equities | Market data customer relationships
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	322
U.S. Equities | Technology
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	22.5
U.S. Equities | Trademarks and tradenames
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	6
European Equities
Finite-Lived Intangible Assets
Accumulated amortization	(24.7)
Intangible assets, net	427		0
European Equities | Customer relationships
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	173.7
European Equities | Market data customer relationships
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	65.1
European Equities | Technology
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	24.4
European Equities | Trademarks and tradenames
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	2
European Equities | Trading registrations and licenses
Finite-Lived Intangible Assets
Indefinite-lived intangible assets, gross	186.5
Global FX
Finite-Lived Intangible Assets
Accumulated amortization	(28.5)
Intangible assets, net	199.6		0
Global FX | Customer relationships
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	140
Global FX | Market data customer relationships
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	64.4
Global FX | Technology
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	22.5
Global FX | Trademarks and tradenames
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	1.2
Corporate and Other
Finite-Lived Intangible Assets
Accumulated amortization	(2.5)	(1.3)
Intangible assets, net	5.5	6.7	$ 0
Corporate and Other | Customer relationships
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	3	3
Corporate and Other | Technology
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	4	4
Corporate and Other | Trademarks and tradenames
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	$ 1	$ 1

Accounts Payable and Accrued 72

Accounts Payable and Accrued Liabilities - Schedule of accounts payable and accrued liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Accounts Payable and Accrued Liabilities
Compensation and benefit-related liabilities	$ 18	$ 25.1
Termination benefits	4.8	0.4
Royalties	20.3	17.8
Accrued liabilities	59.1	25.4
Marketing fee payable	8.4	7.2
Accounts payable	43.2	6.5
Total accounts payable and accrued liabilities	$ 153.8	$ 82.4

Debt - Schedule of long-term de

Debt - Schedule of long-term debt (Details) - USD ($) $ in Millions	Dec. 31, 2017	Jun. 29, 2017	Jan. 12, 2017
Debt Instrument
Total long-term debt	$ 1,237.9
2017 Term Loan Agreement
Debt Instrument
Total long-term debt	294.9
3.650% Senior Notes
Debt Instrument
Total long-term debt	$ 643.8
Interest rate	3.65%		3.65%
1.950% Senior Notes
Debt Instrument
Total long-term debt	$ 299.2
Interest rate	1.95%	1.95%

Debt (Details)

Debt (Details) $ in Millions	Feb. 28, 2017USD ($)	Dec. 15, 2016USD ($)subsidiary	Sep. 25, 2016USD ($)	Dec. 31, 2017USD ($)subsidiary	Jun. 29, 2017USD ($)	Jan. 12, 2017USD ($)	Dec. 31, 2016USD ($)
Debt Instrument
Proceeds from long-term debt				$ 1,943.9
Deferred financing costs				6.6			$ 6.2
Borrowings outstanding				$ 1,237.9
Bats Global Markets, Inc.
Debt Instrument
Amount secured to finance the cash portion of pending acquisition		$ 1,650
Line of Credit
Debt Instrument
Credit facility, maximum borrowing capacity		25
Term Loan Agreement
Debt Instrument
Debt instrument face amount		1,000
Minimum consolidated interest ratio				4
Maximum consolidated leverage ratio				3.50
Proceeds from long-term debt	$ 1,000
Term of facility	5 years
Term Loan Agreement | Minimum
Debt Instrument
Ticking fee				0.10%
Term Loan Agreement | Maximum
Debt Instrument
Ticking fee				0.30%
Term Loan Agreement | LIBOR | Minimum
Debt Instrument
Variable interest rate				1.00%
Term Loan Agreement | LIBOR | Maximum
Debt Instrument
Variable interest rate				1.75%
Term Loan Agreement | Prime Rate | Minimum
Debt Instrument
Variable interest rate				0.00%
Term Loan Agreement | Prime Rate | Maximum
Debt Instrument
Variable interest rate				0.75%
3.650% Senior Notes
Debt Instrument
Debt instrument face amount					$ 300	$ 650
Interest rate				3.65%		3.65%
Redemption price				101.00%
Revolving Credit Agreement
Debt Instrument
Credit facility, maximum borrowing capacity		$ 150
Number of subsidiaries designated as additional borrowers | subsidiary				0
Minimum consolidated interest ratio				4
Maximum consolidated leverage ratio				3.50
Term of facility		5 years
Maximum borrowing capacity, increase limit		$ 100
Maximum borrowing capacity, total with increase		$ 250
Borrowings outstanding				$ 0
Borrowing capacity available				$ 150
Revolving Credit Agreement | Minimum
Debt Instrument
Number of subsidiaries that may be designated as additional borrowers | subsidiary		1
Revolving Credit Agreement | LIBOR | Minimum
Debt Instrument
Variable interest rate				1.00%
Revolving Credit Agreement | LIBOR | Maximum
Debt Instrument
Variable interest rate				1.75%
Revolving Credit Agreement | Prime Rate | Minimum
Debt Instrument
Variable interest rate				0.00%
Revolving Credit Agreement | Prime Rate | Maximum
Debt Instrument
Variable interest rate				0.75%
1.950% Senior Notes
Debt Instrument
Debt instrument face amount					$ 300
Interest rate				1.95%	1.95%
Deferred financing costs					$ 0.8
Debt issuance costs				$ 0.9
Redemption price				101.00%
Bridge Facility
Debt Instrument
Credit facility, maximum borrowing capacity			$ 1,650
Term of facility			364 days
Payments of commitment and structuring fees				$ 6
Amortization of commitment and structuring fees				$ 6

Debt - Schedule of debt repayme

Debt - Schedule of debt repayments (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Long-term Debt
2,019	$ 300
Thereafter	950
Principal amounts repayable	1,250
Debt issuance cost	(6.6)	$ (6.2)
Unamortized discount on notes	(5.5)
Total debt outstanding	$ 1,237.9

Debt - Schedule of Interest Exp

Debt - Schedule of Interest Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Debt
Contractual interest	$ 39	$ 5.7
Amortization of debt discount	0.6
Amortization of debt issuance cost.	3
Interest expense	42.6	5.7
Interest income	(1.3)
Interest expense, net	$ 41.3	$ 5.7

Accumulated Other Comprehensi77

Accumulated Other Comprehensive Income (Loss) - Schedule of accumulated other comprehensive loss, net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
AOCI Attributable to Parent, Net of Tax
Beginning balance	$ 317.9	$ 259.7
Other comprehensive loss	51.5
Ending balance	3,110.6	317.9
Accumulated Other Comprehensive (Loss) Income
AOCI Attributable to Parent, Net of Tax
Beginning balance	(0.8)	(0.8)
Other comprehensive loss	51.5
Tax effect on other comprehensive loss		0
Ending balance	50.7	(0.8)
Foreign Currency Translation
AOCI Attributable to Parent, Net of Tax
Other comprehensive loss	51.3
Tax effect on other comprehensive loss		0
Ending balance	51.3
Unrealized Investment Gain/Loss
AOCI Attributable to Parent, Net of Tax
Other comprehensive loss	0.2
Tax effect on other comprehensive loss		0
Ending balance	0.2
Post-Retirement Benefits
AOCI Attributable to Parent, Net of Tax
Beginning balance	(0.8)	(0.8)
Tax effect on other comprehensive loss		0
Ending balance	$ (0.8)	$ (0.8)

Fair Value Measurement - Schedu

Fair Value Measurement - Schedule of fair value hierarchy for assets measured at fair value on a recurring basis (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Assets:
Trading investments	$ 0.5
Money market funds	143.5	$ 97.3
Total assets	425.3	227.7
Liabilities:
Contingent consideration liability	56.6
Total liabilities	1,443.3	6.5
Money market funds
Assets:
Money market funds	2.5	67.5
Level 1
Assets:
Trading investments	0.5
Money market funds	143.5	97.3
Total assets	425.3	227.7
Level 2
Liabilities:
Total liabilities	1,386.7	6.5
Level 3
Liabilities:
Contingent consideration liability	56.6
Total liabilities	56.6
Recurring
Assets:
Total assets	49.8	67.5
Liabilities:
Contingent consideration liability	56.6
Total liabilities	56.6
Recurring | Money market funds
Assets:
Money market funds	2.5
Recurring | U.S. Treasury securities
Assets:
Trading investments	47.3
Recurring | U.S. Treasury securities | Money market funds
Assets:
Money market funds		67.5
Recurring | Level 1
Assets:
Total assets	49.8	67.5
Recurring | Level 1 | Money market funds
Assets:
Money market funds	2.5
Recurring | Level 1 | U.S. Treasury securities
Assets:
Trading investments	47.3
Recurring | Level 1 | U.S. Treasury securities | Money market funds
Assets:
Money market funds		$ 67.5
Recurring | Level 3
Liabilities:
Contingent consideration liability	56.6
Total liabilities	$ 56.6

Fair Value Measurement (Details

Fair Value Measurement (Details) $ in Millions	Dec. 31, 2017USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration agreement	$ 56.6
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration agreement	56.6
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration agreement	56.6
Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration agreement	$ 56.6

Fair Value Measurement - Sche80

Fair Value Measurement - Schedule of fair value hierarchy of financial instruments held (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Assets:
Cash and cash equivalents	$ 143.5	$ 97.3
Trading investments	0.5
Available-for-sale investments	46.8
Accounts receivable	217.3	76.7
Income tax receivable	17.2	53.7
Total assets	425.3	227.7
Liabilities:
Accounts payable	43.2	6.5
Section 31 fees payable	105.6
Contingent consideration liability	56.6
Long-term debt	1,237.9
Total liabilities	1,443.3	6.5
Level 1
Assets:
Cash and cash equivalents	143.5	97.3
Trading investments	0.5
Available-for-sale investments	46.8
Accounts receivable	217.3	76.7
Income tax receivable	17.2	53.7
Total assets	425.3	227.7
Level 2
Liabilities:
Accounts payable	43.2	6.5
Section 31 fees payable	105.6
Long-term debt	1,237.9
Total liabilities	1,386.7	$ 6.5
Level 3
Liabilities:
Contingent consideration liability	56.6
Total liabilities	$ 56.6

Fair Value Measurement - Summar

Fair Value Measurement - Summary of changes in the fair value of the company's Level 3 financial liabilities (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Additions	$ 56.6
Balance at the end of the period	56.6
Contingent consideration liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Additions	56.6
Balance at the end of the period	$ 56.6

Redeemable Noncontrolling Int82

Redeemable Noncontrolling Interest (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Increase (Decrease) in Redeemable Noncontrolling Interest
Beginning balance	$ 12.6
Ending balance	9.4	$ 12.6
Redeemable Noncontrolling Interests
Increase (Decrease) in Redeemable Noncontrolling Interest
Beginning balance	12.6
Decrease due to acquiring additional equity in Cboe Vest	(3.2)
Net loss attributable to redeemable noncontrolling interest	(1.1)	(1.1)
Redemption value adjustment	1.1
Ending balance	$ 9.4	$ 12.6

Segment Reporting - Summarized

Segment Reporting - Summarized financial information by reportable segment (Details) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2017USD ($)segment	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Segment Reporting Information
Number of reportable segments | segment									5
Revenues									$ 2,229.1	$ 703.1	$ 663.8
Operating income (loss)	$ 108.7	$ 119.3	$ 117.8	$ 26.1	$ 74.9	$ 65.8	$ 78	$ 79.5	371.9	298.2	319.9
Operating Segments | Options
Segment Reporting Information
Revenues									883.5	589.5	586.1
Operating income (loss)									252.2	218.4	261.2
Operating Segments | U.S. Equities
Segment Reporting Information
Revenues									1,072.5
Operating income (loss)									103.2
Operating Segments | Futures
Segment Reporting Information
Revenues									144.6	113.6	90.5
Operating income (loss)									126.8	96.4	73.6
Operating Segments | European Equities
Segment Reporting Information
Revenues									89.6
Operating income (loss)									8.9
Operating Segments | Global FX
Segment Reporting Information
Revenues									38.2
Operating income (loss)									(12.8)
Corporate Items and Eliminations
Segment Reporting Information
Revenues									0.7		(12.8)
Operating income (loss)									$ (106.4)	$ (16.6)	$ (14.9)

Employee Benefit Plan (Details)

Employee Benefit Plan (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
SMART Plan
Defined Contribution Plan
Company contribution amount	$ 6.2	$ 5.5
SMART Plan | Acquisition Related Costs
Defined Contribution Plan
Company contribution amount	1.2
Legacy BATS Employee 401k Plan
Defined Contribution Plan
Company contribution amount	1.5
Cboe Europe Equities Employee Selected Stakeholder Contribution Plan
Defined Contribution Plan
Company contribution amount	$ 0.5

Regulatory Capital (Details)

Regulatory Capital (Details)	12 Months Ended
	Dec. 31, 2017USD ($)
Cboe Trading
Regulatory Requirement
Minimum net capital required to be maintained, option 1 - percentage of aggregate indebtedness items	$ 6.67
Minimum net capital required to be maintained, option 2 - amount	100,000
Net capital	7,900,000
Excess net capital	7,600,000
Required net capital	300,000
Cboe Europe Equities
Regulatory Requirement
Financial resources requirement	20,200,000
Capital in excess of financial resources requirement	25,600,000
Cboe Chi-X Europe
Regulatory Requirement
Capital resources requirement	100,000
Capital in excess of capital resources requirement	400,000
Cboe SEF
Regulatory Requirement
Annual operating expenses for swap execution facility capital adequacy tests	1,500,000
XX month operating expenses for swap execution facility capital adequacy tests	1,400,000
CFE
Regulatory Requirement
Annual operating expenses for registered futures exchange capital adequacy tests	31,900,000
XX month operating expenses for registered futures exchange capital adequacy tests	$ 16,000,000

Stock-based Compensation (Detai

Stock-based Compensation (Details)	Aug. 15, 2017$ / sharesshares	May 18, 2017$ / sharesshares	May 15, 2017$ / sharesshares	Feb. 28, 2017USD ($)item$ / sharesshares	Feb. 27, 2017shares	Feb. 19, 2017$ / sharesshares	Dec. 31, 2017USD ($)item$ / sharesshares	Dec. 31, 2016USD ($)$ / sharesshares	Dec. 31, 2015USD ($)
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation expense | $							$ 52,600,000	$ 14,500,000	$ 12,100,000
Accelerated stock-based compensation expense | $							$ 9,000,000
Options exercised (in shares)							241,348
Payments for the purchase of shares to satisfy the employee income tax withholdings (in shares) | $							$ 26,100,000	$ 4,100,000	$ 3,200,000
Bats Global Markets, Inc.
Share-based Compensation Arrangement by Share-based Payment Award
Number of decimal places that the volume-weighted average price of shares of Cboe Common Stock was rounded to | item				4
Share price, measurement period				10 days
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award
Equity instruments granted (in shares)	1,612	15,405	2,655	68,254	49,703	251,273
Number of shares of common stock of which unit is convertible (in shares)		1	1	1		1
Fair value of equity instruments granted (in dollars per share) | $ / shares	$ 97.54	$ 84.41	$ 85	$ 78.05		$ 80.40
Vesting period	3 years			3 years		3 years
Vesting percentage	33.33%			33.33%		33.33%
Restricted Stock Units | Bats Global Markets, Inc.
Share-based Compensation Arrangement by Share-based Payment Award
Equity instruments granted (in shares)				622,527
Fair value of equity instruments granted (in dollars per share) | $ / shares				$ 78.05
Shares used for conversion ratio (in shares)				0.3201
Factor used for conversion of shares | $				$ 10
Number of decimal places that the volume-weighted average price of shares of Cboe Common Stock was rounded to | item				4
Share price, measurement period				10 years
Performance Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award
Equity instruments granted (in shares)				19,255		41,481
Number of shares of common stock of which unit is convertible (in shares)				1
Fair value of equity instruments granted (in dollars per share) | $ / shares				$ 102		$ 111
Vesting period				3 years
Risk-free rate				0.90%		0.90%
Expected volatility				21.10%		21.10%
Correlation with S&P index				0.41%		0.41%
Performance Based Restricted Stock Units | Minimum
Share-based Compensation Arrangement by Share-based Payment Award
Units ultimately expected to be awarded				0.00%
Performance Based Restricted Stock Units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award
Units ultimately expected to be awarded				200.00%
Stock options
Share-based Compensation Arrangement by Share-based Payment Award
Risk-free rate							1.78%
Expected volatility							19.80%
Options exercised (in shares)							241,348
Shares purchased to satisfy the employee income tax withholdings (in shares)							65,305
Payments for the purchase of shares to satisfy the employee income tax withholdings (in shares) | $							$ 5,900,000
Unrecognized compensation expense | $							$ 1,700,000
Unrecognized compensation expense, period for recognition							1 year
Stock options | Bats Global Markets, Inc.
Share-based Compensation Arrangement by Share-based Payment Award
Factor used for conversion of shares | $							$ 10
Number of decimal places that the volume-weighted average price of shares of Cboe Common Stock was rounded to | item							4
Acquisition, exchange ratio							0.4452
Acquisition, exchange ratio basis							0.3201
Acquisition, number of consecutive trading days for volume-weighted average price							10 years
Restricted Stock and Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award
Equity instruments granted (in shares)							1,091,843	241,681
Fair value of equity instruments granted (in dollars per share) | $ / shares							$ 78.94	$ 64.10
Shares purchased to satisfy the employee income tax withholdings (in shares)							197,746
Payments for the purchase of shares to satisfy the employee income tax withholdings (in shares) | $							$ 18,600,000
Unrecognized compensation expense | $							$ 47,000,000
Unrecognized compensation expense, period for recognition							1 year 9 months 18 days
Vested (in shares)							498,540	211,235

Stock-based Compensation - Stoc

Stock-based Compensation - Stock option activity (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)$ / sharesshares
Number of Shares
Granted (in shares) | shares	683,390
Exercised (in shares) | shares	(241,348)
Ending balance (in shares) | shares	442,042
Weighted Average Exercise Price
Granted (in dollars per share) | $ / shares	$ 22.45
Exercised (in dollars per share) | $ / shares	17.13
Ending balance (in dollars per share) | $ / shares	$ 25.36
Weighted Average Remaining Contractual Term (years)
Outstanding	1 year
Aggregate Intrinsic Value (in millions)
Ending balance | $	$ 17.5
Exercisable
Number of shares (in shares) | shares	401,507
Weighted average exercise price (in dollars per share) | $ / shares	$ 25.08
Weighted average remaining contractual term (years)	5 years
Aggregate intrinsic value | $	$ 40

Stock-based Compensation - Fair

Stock-based Compensation - Fair value of assumptions for options granted (Details) - Stock options	12 Months Ended
	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award
Expected term (in years)	4 years 2 months 12 days
Expected volatility	19.80%
Expected dividend yield	1.30%
Risk-free rate	1.78%

Stock-based Compensation - Nonv

Stock-based Compensation - Nonvested options activity (Details)	12 Months Ended
	Dec. 31, 2017$ / sharesshares
Options
Granted (in shares) | shares	81,068
Ending balance (in shares) | shares	81,068
Weighted Average Grant-Date Fair Value
Granted (in USD per share) | $ / shares	$ 49.17
Ending balance (in USD per share) | $ / shares	$ 49.17

Stock-based Compensation - Rest

Stock-based Compensation - Restricted stock activity (Details) - Restricted Stock and Restricted Stock Units - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Number of shares
Beginning balance (in shares)	480,595	456,570
Granted (in shares)	1,091,843	241,681
Vested (in shares)	(498,540)	(211,235)
Forfeited (in shares)	(5,506)	(6,421)
Ending balance (in shares)	1,068,392	480,595
Weighted average grant date fair value
Beginning balance (in USD per share)	$ 63.64	$ 55.70
Granted (in dollars per share)	78.94	64.10
Vested (in USD per share)	67.83	48.14
Forfeited (in USD per share)	71.68	64.50
Ending balance (in USD per share)	$ 77.19	$ 63.64

Income Taxes - Deferred tax ass

Income Taxes - Deferred tax assets and liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Accrued compensation and benefits	$ 14.1	$ 16.3
Property, equipment and technology, net	2.4	0.6
Investment in affiliates		4.7
Other	20.2	17.1
Subtotal	36.7	38.7
Valuation allowance	(1.6)
Total deferred tax assets	35.1	38.7
Deferred tax liabilities:
Intangibles	(429.6)
Property, equipment and technology, net	(17.1)	(32.3)
Investment in affiliates	(75)	(1.7)
Prepaid	(1.6)	(1.2)
Total deferred tax liabilities	(523.3)	(35.2)
Net deferred tax assets/(liabilities)		$ 3.5
Net deferred tax assets/(liabilities)	$ (488.2)

Income Taxes - Components of in

Income Taxes - Components of income tax expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current tax expense:
Federal	$ 141	$ 107.1	$ 103.3
State	25.8	22.6	23.9
Foreign	5.4
Total current tax expense	172.2	129.7	127.3
Deferred income tax expense:
Federal	(227.5)	(7.6)	(6.4)
State	(6.5)	(1.2)	(1.9)
Foreign	(4.4)
Total deferred income tax expense	(238.4)	(8.8)	(8.3)
Total	$ (66.2)	$ 120.9	$ 119

Income Taxes - Deferred income

Income Taxes - Deferred income tax liability, net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes
U.S. operations	$ 326.7	$ 306.6	$ 324
Foreign operations	7.7
Income before income tax provision	$ 334.4	$ 306.6	$ 324

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of the statutory federal income tax rate to the effective income tax rate (Details)	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statutory federal income tax rate		35.00%	35.00%	35.00%
Impact of federal, state and local tax law and rate changes, net		(55.10%)
State income tax rate, net of federal income tax effect		4.30%	4.50%	4.40%
Section 199 deductions		(2.60%)	(2.60%)	(1.90%)
Other, net		(1.40%)	2.50%	(0.80%)
Effective income tax rate		(19.80%)	39.40%	36.70%
Forecast
Statutory federal income tax rate	21.00%

Income Taxes - Reconciliation95

Income Taxes - Reconciliation of the beginning and ending uncertain tax positions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes
Unrecognized Tax Benefits, Beginning Balance	$ 41.9	$ 31.9	$ 35.4
Acquired unrecognized tax benefits	23.2
Gross increases on tax positions in prior period	6.2	8.8
Gross decreases on tax positions in prior period	(14.7)	(0.6)	(4.2)
Gross increases on tax positions in current period	12.7	3.6	1.9
Lapse of statute of limitations	(1.5)	(1.8)	(1.2)
Unrecognized Tax Benefits, Ending Balance	$ 67.8	$ 41.9	$ 31.9

Income Taxes - (Details)

Income Taxes - (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Contingency [Line Items]
Valuation allowance		$ 1.6
Operating loss carryforwards		24.9
Unrecognized tax positions that would affect the annual effective tax rate		68.2	$ 40.5	$ 29.7
Lapse of statute of limitations		1.5	1.8	1.2
Estimated interest costs and penalties		(1.5)	2.5	2.5
Accrued interest and penalties		$ 11.1	$ 10.2	$ 7.7
Forecast
Income Tax Contingency [Line Items]
Lapse of statute of limitations	$ 1.8
Potential audit settlements	$ 6.5

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	Jan. 01, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Jobs Act
Increase in estimated net income due to Jobs Act										$ 191.3
Statutory federal income tax rate										35.00%	35.00%	35.00%
Basic and Diluted EPS Numerator:
Net income		$ 257.1	$ 60.3	$ 68	$ 15.2	$ 45.1	$ 40.5	$ 50.9	$ 49.2	$ 400.6	$ 185.7	$ 205
Net loss attributable to noncontrolling interests										1.1	1.1
Net income excluding noncontrolling interests										401.7	186.8	205
Change in redemption value of noncontrolling interests										(1.1)	(1.1)
Net income allocated to participating securities										(3.9)	(0.8)	(0.9)
Net Income allocated to common stockholders		$ 254.6	$ 59.7	$ 67.3	$ 15.1	$ 44.7	$ 40.3	$ 50.7	$ 49.2	$ 396.7	$ 184.9	$ 204.1
Basic EPS Denominator:
Weighted average shares outstanding (in shares)										107.2	81.4	83.1
Basic Net Income Per Common Share (in dollars per share)		$ 2.41	$ 0.53	$ 0.60	$ 0.16	$ 0.55	$ 0.50	$ 0.62	$ 0.60	$ 3.70	$ 2.27	$ 2.46
Diluted EPS Denominator:
Weighted average shares outstanding (in shares)										107.2	81.4	83.1
Dilutive common shares issued under stock program (in shares)										0.3
Total dilutive weighted average shares (in shares)										107.5	81.4	83.1
Diluted Net Income Per Common Share (in dollars per share)		$ 2.40	$ 0.53	$ 0.60	$ 0.16	$ 0.55	$ 0.50	$ 0.62	$ 0.60	$ 3.69	$ 2.27	$ 2.46
Forecast
Jobs Act
Statutory federal income tax rate	21.00%

Commitments, Contingencies an98

Commitments, Contingencies and Guarantees (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Apr. 18, 2014item
Loss Contingencies
Rent expense | $	$ 7.6	$ 4.4	$ 4.1
Pending Litigation | City of Providence
Loss Contingencies
The number of other securities exchanges a lawsuit has been filed against | item				14
Minimum
Loss Contingencies
Lease terms	3 months
Maximum
Loss Contingencies
Lease terms	100 months

Quarterly Data (unaudited) (Det

Quarterly Data (unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Data (unaudited)
Revenues less cost of revenues	$ 265.6	$ 269.7	$ 266.9	$ 193.4	$ 143	$ 136.2	$ 144.1	$ 143.1	$ 995.6	$ 566.4	$ 561.7
Operating income	108.7	119.3	117.8	26.1	74.9	65.8	78	79.5	371.9	298.2	319.9
Net income	257.1	60.3	68	15.2	45.1	40.5	50.9	49.2	400.6	185.7	205
Net Income allocated to common stockholders	$ 254.6	$ 59.7	$ 67.3	$ 15.1	$ 44.7	$ 40.3	$ 50.7	$ 49.2	$ 396.7	$ 184.9	$ 204.1
Basic earnings per share (in dollars per share)	$ 2.41	$ 0.53	$ 0.60	$ 0.16	$ 0.55	$ 0.50	$ 0.62	$ 0.60	$ 3.70	$ 2.27	$ 2.46
Diluted earnings per share (in dollars per share)	$ 2.40	$ 0.53	$ 0.60	$ 0.16	$ 0.55	$ 0.50	$ 0.62	$ 0.60	$ 3.69	$ 2.27	$ 2.46

Subsequent Events (Details)

Subsequent Events (Details) - $ / shares	Feb. 19, 2018	Feb. 15, 2018	Aug. 15, 2017	May 18, 2017	May 15, 2017	Feb. 28, 2017	Feb. 27, 2017	Feb. 19, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Subsequent Events
Dividends (in dollars per share)									$ 1.04	$ 0.96	$ 0.88
Subsequent Event
Subsequent Events
Dividends (in dollars per share)		$ 0.27
Restricted Stock Units
Subsequent Events
Granted (in shares)			1,612	15,405	2,655	68,254	49,703	251,273
Granted (in dollars per share)			$ 97.54	$ 84.41	$ 85	$ 78.05		$ 80.40
Vesting period			3 years			3 years		3 years
Restricted Stock Units | Subsequent Event
Subsequent Events
Granted (in shares)	188,575
Granted (in dollars per share)	$ 111.45
Vesting period	3 years