Sec Form 4 Filing - Blackstone Group L.P. @ KNIGHT CAPITAL GROUP, INC. - 2012-08-17

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 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 Blackstone Group L.P. 2. Issuer Name and Ticker or Trading Symbol KNIGHT CAPITAL GROUP, INC. [ KCG] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O THE BLACKSTONE GROUP, 345 PARK AVENUE 3. Date of Earliest Transaction (MM/DD/YY) 08/17/2012 (Street) NEW YORK, NY10154 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ 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 (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 Series A-2 Non-Voting Cumulative Perpetual Conv Pref Stock 08/17/2012 S 1,741 D $ 1,500 67,888 I ( 1 ) ( 2 ) (See Footnotes) ( 3 ) ( 6 ) ( 7 ) ( 8 ) ( 9 ) Series A-2 Non-Voting Cumulative Perpetual Conv Pref Stock 08/17/2012 S 1 D $ 1,500 35 I ( 1 ) ( 2 ) (See Footnotes) ( 4 ) ( 6 ) ( 7 ) ( 8 ) ( 9 ) Series A-2 Non-Voting Cumulative Perpetual Conv Pref Stock 08/17/2012 S 10 D $ 1,500 414 I ( 1 ) ( 2 ) (See Footnotes) ( 5 ) ( 6 ) ( 7 ) ( 8 ) ( 9 )

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Deriv ative 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 Series A-1 Cumulative Perpetual Convertible Preferred Stock ( 1 ) ( 2 ) 08/17/2012 S 432 ( 1 )( 2 ) ( 1 )( 2 ) Class A Common Stock 288,000 $ 1,500 16,866 I (See Footnotes) ( 3 ) ( 6 ) ( 7 ) ( 8 ) ( 9 ) Series A-1 Cumulative Perpetual Convertible Preferred Stock ( 1 ) ( 2 ) ( 1 )( 2 ) ( 1 )( 2 ) Class A Common Stock 5,333 8 I (See Footnotes) ( 4 ) ( 6 ) ( 7 ) ( 8 ) ( 9 ) Series A-1 Cumulative Perpetual Convertible Preferred Stock ( 1 ) ( 2 ) 08/17/2012 S 3 ( 1 )( 2 ) ( 1 )( 2 ) Class A Common Stock 2,000 $ 1,500 102 I (See Footnotes) ( 5 ) ( 6 ) ( 7 ) ( 8 ) ( 9 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Blackstone Group L.P. C/O THE BLACKSTONE GROUP 345 PARK AVENUE NEW YORK, NY10154 X Blackstone Holdings III L.P. C/O THE BLACKSTONE GROUP L.P. 345 PARK AVENUE NEW YORK, NY10154 X Blackstone Holdings III GP L.P. C/O THE BLACKSTONE GROUP L.P. 345 PARK AVENUE NEW YORK, NY10154 X Blackstone Holdings III GP Management L.L.C. C/O THE BLACKSTONE GROUP L.P. 345 PARK AVENUE NEW YORK, NY10154 X Blackstone Group Management L.L.C. C/O THE BLACKSTONE GROUP L.P. 345 PARK AVENUE NEW YORK, NY10154 X SCHWARZMAN STEPHEN A C/O THE BLACKSTONE GROUP L.P. 345 PARK AVENUE NEW YORK, NY10154 X Signatures BLACKSTONE HOLDINGS III L.P., By: Blackstone Holdings III GP L.P., its general partner, By: Blackstone Holdings III GP Management L.L.C., its general partner, By: /s/ John G. Finley, Name: John G. Finley, Title: Chief Legal Officer 08/21/2012 Signature of Reporting Person Date BLACKSTONE HOLDINGS III GP L.P., By: Blackstone Holdings III GP Management L.L.C., its general partner, By: /s/ John G. Finley, Name: John G. Finley, Title: Chief Legal Officer 08/21/2012 Signature of Reporting Person Date BLACKSTONE HOLDINGS III GP MANAGEMENT L.L.C, By: /s/ John G. Finley, Name: John G. Finley, Title: Chief Legal Officer 08/21/2012 Signature of Reporting Person Date THE BLACKSTONE GROUP L.P., By: Blackstone Group Management L.L.C., its general partner, By: /s/ John G. Finley, Name: John G. Finley, Title: Chief Legal Officer 08/21/2012 Signature of Reporting Person Date BLACKSTONE GROUP MANAGEMENT L.L.C., By: /s/ John G. Finley, Name: John G. Finley, Title: Chief Legal Officer 08/21/2012 Signature of Reporting Person Date STEPHEN A. SCHWARZMAN, By: /s/ Stephen A. Schwarzman, Name: Stephen A. Schwarzman 08/21/2012 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Following the reported transactions, Blackstone Funds (as defined below) beneficially own, in the aggregate, 16,976 shares of Series A-1 Cumulative Perpetual Convertible Preferred Stock, par value $0.01 per share (the "Series A-1 Preferred Stock") (convertible in accordance with the terms thereof at an initial conversion rate of 666.667 shares of Class A Common Stock, par value $0.01 per share (the "Common Stock"), per $1,000 of stated value of Series A-1 Preferred Stock, equal to an equivalent conversion price of $1.50 per share, into approximately 11,317,338 shares of Class A Common Stock, subject to certain adjustments), and 68,337 shares of Series A-2 Non-Voting Cumulative Perpetual Convertible Preferred Stock, par value $0.01 per share (the "Series A-2 Preferred Stock," and, with the Series A-1 Preferred Stock, the "Preferred Stock") (Continued in footnote 2) ( 2 )(convertible in accordance with the terms thereof, upon the occurrence of certain regulatory approvals, on a one-for-one basis into Series A-1 Preferred Stock or, at an initial conversion rate of 666.667 shares of Class A Common Stock per $1,000 of stated value of Series A-2 Preferred Stock, equal to an equivalent conversion price of $1.50 per share, into approximately 45,558,022 shares of Class A Common Stock, subject to certain adjustments). For further information on the events that trigger conversions and other details regarding the conversions, see the terms of the Certificate of Designations of Preferences and Rights of the Series A-1 Cumulative Perpetual Convertible Preferred Stock and Series A-2 Non-Voting Cumulative Perpetual Convertible Preferred Stock of Knight Capital Group, Inc. (attached as Exhibit 3.1 to Form 8-K filed with the Securities and Exchange Commission by the Issuer on August 6, 2012). ( 3 )Represents securities directly held by Blackstone Capital Partners VI L.P. ( 4 )Represents securities directly held by Blackstone Family Investment Partnership VI L.P. ( 5 )Represents securities directly held by Blackstone Family Investment Partnership VI ESC L.P. (collectively, with Blackstone Capital Partners VI L.P. and Blackstone Family Investment Partnership VI L.P., the "Blackstone Funds"). ( 6 )Blackstone Management Associates VI L.L.C. is the general partner of Blackstone Capital Partners VI L.P. BMA VI L.L.C. is the sole member of Blackstone Management Associates VI L.L.C. BCP VI Side-By-Side GP L.L.C. is the general partner of Blackstone Family Investment Partnership VI L.P. and Blackstone Family Investment Partnership VI ESC L.P. ( 7 )Blackstone Holdings III L.P. is the managing member and the owner of a majority in interest of BMA VI L.L.C. and the sole member of BCP VI Side-By-Side GP L.L.C. Blackstone Holdings III GP L.P. is the general partner of Blackstone Holdings III L.P. The general partner of Blackstone Holdings III GP L.P. is Blackstone Holdings III GP Management L.L.C. The sole member of Blackstone Holdings III GP Management L.L.C. is The Blackstone Group L.P. The general partner of The Blackstone Group L.P. is Blackstone Group Management L.L.C. Blackstone Group Management L.L.C. is wholly owned by Blackstone's senior managing directors and controlled by its founder, Stephen A. Schwarzman. ( 8 )Due to the limitations of the electronic filing system, Blackstone Capital Partners VI L.P., Blackstone Family Investment Partnership VI L.P., Blackstone Family Investment Partnership VI ESC L.P., Blackstone Management Associates VI L.L.C., BMA VI L.L.C. and BCP VI Side-By-Side GP L.L.C. are filing a separate Form 4. ( 9 )Each of the Reporting Persons, other than the Blackstone Funds to the extent of their direct holdings, disclaims beneficial ownership of such Preferred Stock, except to the extent of such Reporting Person's pecuniary interest therein, and, pursuant to Rule 16a-1(a)(4) under the Securities Exchange Act of 1934, each of the Reporting Persons, including the Blackstone Funds, states that the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of all of the reported shares for purposes of Section 16 or for any other purpose.

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