X0306 4/A 2017-12-31 2018-01-03 0 0001381197 Interactive Brokers Group, Inc. IBKR 0001665345 Mendonca Denis 1 PICKWICK PLAZA GREENWICH CT 06830 0 1 0 0 Chief Accounting Officer Class A common stock 2017-12-31 4 A 0 3350 0 A 10953 D This represents a grant of restricted stock units under the amended 2007 Stock Incentive Plan, pending stockholder approval, that will vest 10% on 5/9/2018 and 15% on each of the first six anniversaries of 5/9/2018. This amount includes (a) Class A common stock attributable to vested restricted stock units that were awarded under the 2007 Stock Incentive Plan ("Plan"), (b) unvested restricted stock units that were awarded under the Plan, and (c) 3,350 restricted stock units that will be issued under the amended 2007 Stock Incentive Plan ("Amended Plan") subject to shareholder approval of the Amended Plan. The original Form 4 incorrectly reported the restricted stock units of 3,350, to be issued under the Amended Plan, subject to shareholder approval of the Amended Plan, as restricted stock. /s/ Denis Mendonca 2018-04-06