Stephens Investments SC 13D KNIGHT CAPITAL / Stephens Investments ownership change

CUSIP No. 499005106 EXHIBIT 7.1

AGREEMENT TO FILE JOINT SCHEDULE 13D

Each of the undersigned, being a record owner or “beneficial owner” of the common stock of Knight Capital Group, Inc. (“Common Stock”), hereby agrees to jointly file a Schedule 13D with respect to their respective holdings of the Common Stock and to include this agreement as an exhibit to such Schedule 13D.

IN WITNESS WHEREOF, each of the undersigned has executed and delivered this agreement as of the 16th day of August, 2012.

/s/ David A. Knight

David A. Knight, as attorney in fact for Stephens Investments Holdings LLC, Stephens KCG LLC, SIE KCG LLC, and Warren A. Stephens