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EXHIBIT 21.1

SUBSIDIARIES OF THE COMPANY

The following is a list of subsidiaries of IBG, Inc.:

Name		Jurisdiction of Organization
IBG LLC		Connecticut, U.S.A.

The following is a list of subsidiaries of IBG LLC:

Name		Jurisdiction of Organization
Timber Hill LLC(1)		Connecticut, U.S.A.
Interactive Brokers LLC(2)		Connecticut, U.S.A.
Interactive Brokers Canada Inc.		Canada
Interactive Brokers (U.K.) Limited		United Kingdom
Timber Hill Europe AG		Switzerland
Timber Hill Securities Hong Kong Limited		Hong Kong
Timber Hill Australia Pty Limited		Australia
Timber Hill Canada Company		Canada
Timber Hill Specialists Corp.		Delaware, U.S.A.
Interactive Brokers Hungary Kft		Hungary
IB Exchange Corp.		Delaware, U.S.A.
Interactive Brokers (India) Private Limited(3)		India
Interactive Brokers Financial Products S.A.		Luxembourg
Interactive Brokers Securities Japan, Inc.		Japan
Interactive Brokers Software Services Estonia		Estonia
Interactive Brokers Software Services Russia		Russia

(1)

IBG LLC owns 99.99% and Thomas Peterffy owns 0.01%.

(2)

IBG LLC owns 99.9% and Thomas Peterffy owns 0.1%.

(3)

IB Exchange Corp. owns 0.01%

The following is a list of subsidiaries of Timber Hill Europe AG:

Name		Jurisdiction of Organization
Timber Hill (U.K.) Limited		United Kingdom
Timber Hill (Mauritius) Limited		Mauritius

The following is a list of subsidiaries of Interactive Brokers LLC:

Name		Jurisdiction of Organization
Interactive Brokers Corp.		Connecticut, U.S.A.

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EXHIBIT 21.1

SUBSIDIARIES OF THE COMPANY