EXHIBIT 21.1

Significant Subsidiaries of the Registrant

The following are significant subsidiaries of Knight Capital Group, Inc. as of December 31, 2011 and the states in which they are organized. Indentation indicates the principal parent of each subsidiary. Except as otherwise specified, in each case Knight Capital Group, Inc. owns, directly or indirectly, at least 99% of the voting securities of each subsidiary. The names of particular subsidiaries have been omitted because, considered in the aggregate as a single subsidiary, they would not constitute, as of December 31, 2011, a “significant subsidiary” as that term is defined in Rule 1-02(w) of Regulation S-X under the Securities Exchange Act of 1934.