Sec Form 4 Filing - Haines Andrew @ GAIN Capital Holdings, Inc. - 2011-08-31

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 Haines Andrew 2. Issuer Name and Ticker or Trading Symbol GAIN Capital Holdings, Inc. [ GCAP] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chief Information Officer (Last) (First) (Middle) C/O GAIN CAPITAL HOLDINGS, INC., 135 US HIGHWAY 202/206 3. Date of Earliest Transaction (MM/DD/YY) 08/31/2011 (Street) BEDMINSTER, NJ07921 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ 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 Common Stock ( 1 ) 08/31/2011 M 565 A $ 0 ( 2 ) 10,826 ( 3 ) D Common Stock ( 1 ) 08/31/2011 M 2,261 A $ 0 ( 2 ) 13,087 ( 3 ) D

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 Derivative 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 Restricted Stock Unit ( 1 ) ( 4 ) $ 0 ( 2 ) 08/31/2011 M 565 ( 4 ) ( 4 ) Common Stock 565 $ 0 ( 2 ) 2,827 D Restricted Stock Unit ( 1 ) ( 5 ) $ 0 ( 2 ) 08/31/2011 M 2,261 ( 5 ) ( 5 ) Common Stock 2,261 $ 0 ( 2 ) 3,393 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Haines Andrew C/O GAIN CAPITAL HOLDINGS, INC. 135 US HIGHWAY 202/206 BEDMINSTER, NJ07921 Chief Information Officer Signatures /s/ Andrew Haines 09/02/2011 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Reflects shares acquired as payment for the vested restricted units listed in Table II. ( 2 )Restricted stock units are a contingent right to receive one share of common stock for no consideration. ( 3 )Includes 8,000 shares acquired through a restricted on March 23, 2011. Such shares vest 25% per year on each of the first four anniversaries of the grant date. As of the date of this report 0 shares are vested and 8,000 remain unvested. ( 4 )Such restricted stock units were granted on June 30, 2007 and vested ratably over four years, with one-fourth of the restricted units vesting on each of the first four anniversaries of the grant date. There is no expiration date. Payment for vested restricted stock units in the form of common stock occurs on August 31, 2011, July 1, 2012, July 1, 2013 and December 31, 2014. ( 5 )Such restricted stock units were granted on December 31, 2006 and vested ratably over four years, with one-fourth of the restricted units vesting on each of the first four anniversaries of the grant date. There is no expiration date. Payment for vested restricted stock units in the form of common stock occurs on July 1, 2010, August 31, 2011, July 1, 2012 and December 31, 2014.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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