Sec Form 4 Filing - Calhoun Christopher Warren @ GAIN Capital Holdings, Inc. - 2012-03-01

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 Calhoun Christopher Warren 2. Issuer Name and Ticker or Trading Symbol GAIN Capital Holdings, Inc. [ GCAP] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O GAIN CAPITAL HOLDINGS, INC., 135 US HIGHWAY 202/206 3. Date of Earliest Transaction (MM/DD/YY) 03/01/2012 (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 ( 3 ) 03/01/2012 M 16,000 A $ 2.43 39,503 ( 2 ) ( 3 ) D Common Stock ( 1 ) 03/01/2012 S 16,000 D $ 5.3148 23,503 ( 2 ) D Common Stock ( 3 ) 04/02/2012 M 16,000 A $ 2.43 39,503 ( 2 ) ( 3 ) D Common Stock ( 1 ) 04/02/2012 S 16,000 D $ 5.277 23,503 ( 2 ) 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 Stock Option (Right to Buy) $ 2.43 03/01/2012 M 16,000 ( 4 ) ( 4 ) Common Stock 16,000 $ 0 48,496 D Stock Option (Right to Buy) $ 2.43 04/02/2012 M 16,000 ( 4 ) ( 4 ) Common Stock 16,000 $ 0 32,496 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Calhoun Christopher Warren C/O GAIN CAPITAL HOLDINGS, INC. 135 US HIGHWAY 202/206 BEDMINSTER, NJ07921 X Signatures /s/ Christopher W. Calhoun 04/04/2012 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The shares were sold pursuant to a sales plan dated May 31, 2011, which complies with the requirements of Rule 10b5-1(c)(1) under the Securities and Exchange Act of 1934, as amended. ( 2 )Includes 14,151 shares acquired through a restricted stock unit grant on March 1, 2011, which shares vest on a monthly basis beginning on the first day following Company's 2012 annual meeting of shareholders, and 9,352 shares acquired through a restricted stock award on March 23, 2011, which shares vest on a monthly basis beginning on the first day following the Company's 2011 annual meeting of shareholders, or June 16, 2011. As of the date of this report, of such restricted stock units and restricted stock awards, 7,014 shares are vested and 2,338 shares are unvested. ( 3 )Reflects shares acquired upon exercise of stock options listed in Table II below pursuant to a sales plan dated May 31, 2011, which complies with the requirements of Rule 10b5-1(c)(1) under the Securities and Exchange Act of 1934, as amended. ( 4 )Such stock options were granted on December 30, 2005 and vest ratably over three years, with one-third of the options vesting on each of the first three anniversaries of the grant date. The options have term of ten years. As of the date of this report, 32,496 are vested and 0 are unvested.

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