X0306 4 2012-12-19 1 0001381197 Interactive Brokers Group, Inc. IBKR 0001346000 TCV VI L P C/O TECHNOLOGY CROSSOVER VENTURES 528 RAMONA STREET PALO ALTO CA 94301 0 0 0 1 May be part of a 13(d) group 0001370400 Technology Crossover Management VI, L.L.C. C/O TECHNOLOGY CROSSOVER VENTURES 528 RAMONA STREET PALO ALTO CA 94301 0 0 0 1 May be part of a 13(d) group 0001082906 HOAG JAY C C/O TECHNOLOGY CROSSOVER VENTURES 528 RAMONA STREET PALO ALTO CA 94301 0 0 1 1 May be part of a 13(d) group 0001197937 KIMBALL RICK C/O TECHNOLOGY CROSSOVER VENTURES 528 RAMONA STREET PALO ALTO CA 94301 0 0 1 1 May be part of a 13(d) group 0001188456 DREW JOHN C/O TECHNOLOGY CROSSOVER VENTURES 528 RAMONA STREET PALO ALTO CA 94301 0 0 1 1 May be part of a 13(d) group 0001188444 REYNOLDS JON Q JR C/O TECHNOLOGY CROSSOVER VENTURES 528 RAMONA STREET PALO ALTO CA 94301 0 0 1 1 May be part of a 13(d) group 0001343722 Trudeau Robert C/O TECHNOLOGY CROSSOVER VENTURES 528 RAMONA STREET PALO ALTO CA 94301 0 0 1 1 May be part of a 13(d) group Common Stock 2012-12-19 4 S 0 29759 14.1613 D 1458211 I TCV VI, L.P. Common Stock 2012-12-20 4 S 0 59519 14.1166 D 1398692 I TCV VI, L.P. Common Stock 2540 I Robert W. Trudeau The price reported reflects the weighted average sale price. This transaction was executed in multiple trades at prices ranging from $14.0900 to $14.3650. The Reporting Persons hereby undertake to provide upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. This Form 4 is filed by more than one Reporting Person and is a joint filing with the Form 4 filed by TCV VII, L.P., TCV VII (A), L.P., Technology Crossover Management VII, Ltd., Technology Crossover Management VII, L.P., TCV Member Fund, L.P., Christopher P. Marshall, Timothy P. McAdam, John C. Rosenberg and David L. Yuan on December 21, 2012. These securities are directly held by TCV VI, L.P. Jay C. Hoag, Richard H. Kimball, John L. Drew, Jon Q. Reynolds, Jr. and Robert W. Trudeau (collectively, the "TCM VI Members") are Class A Members of Technology Crossover Management VI, L.L.C. ("TCM VI"), which is the sole general partner of TCV VI, L.P. The TCM VI Members and TCM VI may be deemed to beneficially own the securities held by TCV VI, L.P., but the TCM VI Members and TCM VI disclaim beneficial ownership of such securities except to the extent of their pecuniary interest therein. The price reported reflects the weighted average sale price. This transaction was executed in multiple trades at prices ranging from $13.9700 to $14.2300. The Reporting Persons hereby undertake to provide upon request by the staff of the Securities and Exchange Commission, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price. These shares consist of 847 shares of restricted stock and 1,693 shares of common stock held directly by Mr. Trudeau. Mr. Trudeau has sole dispositive power over the shares; however, TCV VI Management, LLC ("TCV VI Management") and TCV VII Managment, LLC ("TCV VII Management"),own 100% of the pecuniary interest therein and Mr. Trudeau disclaims beneficial ownership of such shares. Jay C. Hoag, Richard H. Kimball, John L. Drew, Jon Q. Reynolds, Jr., and Robert W. Trudeau (the "TCV VI Management Members") are members of TCV VI Management, but each disclaims beneficial ownership of such shares except to the extent of his pecuniary interest therein. The TCV VI Management Members, along with Christoher P. Marshall (the "TCV VII Management Members") are members of TCV VII Management, but each disclaims beneficial ownership of such shares except to the extent of his pecuniary interest therein. Frederic D. Fenton, Authorized signatory for TCV VI, L.P. 2012-12-21 Frederic D. Fenton, Authorized signatory for Technology Crossover Management VI, L.L.C. 2012-12-21 Frederic D. Fenton, Authorized signatory for Jay C. Hoag 2012-12-21 Frederic D. Fenton, Authorized signatory for Richard H. Kimball 2012-12-21 Frederic D. Fenton, Authorized signatory for John L. Drew 2012-12-21 Frederic D. Fenton, Authorized signatory for Jon Q. Reynolds, Jr. 2012-12-21 Frederic D. Fenton, Authorized signatory for Robert W. Trudeau 2012-12-21