FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * Galik Milan   2. Issuer Name and Ticker or Trading Symbol Interactive Brokers Group, Inc. [IBKR] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) President (Last) (First) (Middle) ONE PICKWICK PLAZA 3. Date of Earliest Transaction (Month/Day/Year) 09/20/2017 (Street) GREENWICH, CT 06830 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Class A common stock 09/20/2017   P   578 (1) A $ 43.32 (3) 850,329 (2) D   Class A common stock 12/15/2017   P   415 (1) A $ 60.4 (4) 850,744 (2) D   Class A common stock 03/15/2018   P   348 (1) A $ 72.29 (5) 926,466 (2) D   Class A common stock 06/15/2018   P   360 (1) A $ 69.96 (6) 860,566 (2) (8) D   Class A common stock 09/17/2018   P   427 (1) A $ 59.01 (7) 860,993 (2) D

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Galik Milan ONE PICKWICK PLAZA GREENWICH, CT 06830	X		President

Signatures

/s/ Raymond Bussiere as authorized signatory for Milan Galik		09/21/2018
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	These shares were purchased on behalf of the reporting person through a dividend reinvestment program, in which the reporting person is a participant. These shares were inadvertently excluded from Form 4 reporting.
(2)	This amount includes (a) Class A common stock attributable to vested restricted stock units that were awarded under the amended 2007 Stock Incentive Plan ("Plan"); (b) unvested restricted stock units that were awarded under the Plan; and (c) the cumulative shares purchased through the dividend investment program.
(3)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $43.22 to $43.50, inclusive. The reporting person undertakes to provide Interactive Brokers Group, Inc. (the "Company"), any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each price within the ranges set forth in footnotes (3) - (7) to this Form 4.
(4)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $60.26 to $60.50, inclusive.
(5)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $72.02 to $72.44, inclusive.
(6)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $69.73 to $70.13, inclusive.
(7)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $59.00 to $59.05, inclusive.
(8)	The decrease in securities beneficially owned gives effect to the shares that were withheld for tax purposes related to the May 9, 2018 vesting of restricted stock units awarded under the Plan. This withholding transaction was reported on Form 4, filed with the Securities Exchange Commission on May 22, 2018.
Remarks: This Form 4 is filed to report shares purchased through a dividend reinvestment program, in which the reporting person is a participant, on September 20, 2017, December 15, 2017, March 15, 2018, June 15, 2018 and September 17, 2018, that were inadvertently excluded from Form 4 reporting. Subsequently filed Form 4s through May 22, 2018 are hereby amended to reflect the number of shares beneficially owned at the end of the period reported on such form (which are shown in column 5) by the shares shown to be purchased in this report on September 20, 2017, December 15, 2017, March 15, 2018, June 15, 2018 and September 17, 2018.

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