Interactive Brokers : Reports Brokerage Metrics for October 2018, includes Reg.-NMS Execution Statistics November 1, 2018

Interactive Brokers Group Reports Brokerage Metrics and Other Financial Information for October 2018, includes Reg.-NMS Execution Statistics

GREENWICH, CT, November 1, 2018-Interactive Brokers Group, Inc. (IEX: IBKR) an automated global electronic broker, today reported its Electronic Brokerage monthly performance metrics for October.

Brokerage highlights for the month included:

• 986 thousand Daily Average Revenue Trades (DARTs), 41% higher than prior year and 22% higher than prior month.

• Ending client equity of $133.9 billion, 11% higher than prior year and 6% lower than prior month.

• Ending client margin loan balances of $28.8 billion, 14% higher than prior year and 6% lower than prior month.

• Ending client credit balances of $50.9 billion, including $1.7 billion in insured bank deposit sweeps1, 7% higher than prior year and 0.2% higher than prior month.

• 585 thousand client accounts, 26% higher than prior year and 2% higher than prior month.

• 383 annualized average cleared DARTs per client account.

• Average commission per cleared client order of $3.79 including exchange, clearing and regulatory fees. Key products:

  October 2018	Average Commission per	Ave rage
  Cleared Client Order	Order Size
  Stocks	$2.24	1,347 shares
  Equity Options	$5.46	8.1 contracts
  Futures	$6.16	3.5 contracts

  Futures include options on futures. We estimate exchange, clearing and regulatory fees to be 58% of the futures commissions.

Other financial information for Interactive Brokers Group:

• GLOBAL2: The value of the GLOBAL, reported in U.S. dollars, decreased by 0.59% in October. Year to date, the value of the GLOBAL decreased 1.56%.

In the interest of transparency, wequantify our clients'all-in cost of trade execution below.

• In October, clients' total cost of executing and clearing U.S.Reg.-NMS stocks through IB was 2.1 basis points of trade money3, as measured against a daily VWAP4benchmark (1.1 basis points net cost for the rolling twelve months).

The above illustrates that the rolling twelve months'average all-in cost of a client U.S. Reg.-NMS stock trade was 1.1 basis points.

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Note 1:FDIC insured client bank deposit sweep program balances with participating banks. These deposits are not reported inthe Company'sstatement of financial condition.

Note 2:In connection with our currency diversification strategy, we have determined to base our net worth in GLOBALs, a basket of 14 major currencies in which we hold our equity. The total effect of the currency diversification strategy is reported in Comprehensive Income; the components are reported in (1)Other Income in the corporate segment and (2) Other Comprehensive Income ("OCI") on the balance sheet.The effect of the GLOBAL on our comprehensive income can be estimated by multiplying the total equity for the period by the change in the U.S. dollar value of the GLOBAL during the same period.

Note 3:Trade money is the total amount of money clients spent or received, including all commissions and fees.

Note 4:Consistent with the clients' trading activity,the computed VWAP benchmark includes extended trading hours.

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More information, including historical results for each of the above metrics, can be found on the investor relations pageof the Company's corporate web site,www.interactivebrokers.com/ir.

About Interactive Brokers Group, Inc.:Interactive Brokers Group affiliates provide automated trade execution and custody of securities, commodities and foreign exchange around the clock on over 120 markets in numerous countries and currencies, from a single IB UniversalAccountSMto clients worldwide. We service individual investors, hedge funds, proprietary trading groups, financial advisors and introducing brokers. Our four decades of focus on technology and automation has enabled us to equip our clients with a uniquely sophisticated platform to manage their investmentportfolios at the lowest cost according to Barron's Best Online Brokers review, March26, 2018. We strive to provide our

clients with advantageous execution prices and trading, risk and portfolio management tools, research facilities and investment products, all at low or no cost, positioning them to achieve superior returns on investments.

Cautionary Note Regarding Forward-Looking Statements:

The foregoing information contains certain forward-looking statements that reflect the company's current views with respect to certain current and future events and financial performance. These forward-looking statements are and will be, as the case may be, subject to many risks, uncertainties and factors relating to the company's operations and business environment which may cause the company's actual results to be materially different from any future results, expressed or implied, in these forward-looking statements. Any forward-looking statements in this release are based upon information available to the company on the date of this release. The company does not undertake to publicly update or revise its forward-looking statements even if experience or future changes make it clear that any statements expressed or implied therein will not be realized. Additional information on risk factors that could potentially affect the company's financial results may be found in the company's filings with the Securities and Exchange Commission.

For Interactive Brokers Group, Inc. Investors:Nancy Stuebe, 203-618-4070 orMedia:Kalen Holliday, 203-913-1369.