Sec Form 4 Filing - Rotsztain Diego @ GAIN Capital Holdings, Inc. - 2020-07-31

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 Rotsztain Diego 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) General Counsel and Secretary (Last) (First) (Middle) C/O GAIN CAPITAL HOLDINGS, INC., BEDMINSTER ONE, 135 US HWY. 202/206 3. Date of Earliest Transaction (MM/DD/YY) 07/31/2020 (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 ) 07/31/2020 D( 2 ) 91,010 D $ 6 46,268 D Common Stock ( 1 ) 07/31/2020 D( 3 ) 40,388 D $ 6 5,880 D Common Stock ( 1 ) 07/31/2020 D( 4 ) 5,880 D $ 6 0 D Common Stock ( 1 ) 07/31/2020 A( 5 ) 30,581 A $ 6 30,581 D Common Stock ( 1 ) 07/31/2020 D( 6 ) 30,581 D $ 6 0 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 Dispos ed 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

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Rotsztain Diego C/O GAIN CAPITAL HOLDINGS, INC. BEDMINSTER ONE, 135 US HWY. 202/206 BEDMINSTER, NJ07921 General Counsel and Secretary Signatures /s/ Diego Rotsztain 08/04/2020 Signature of Reporting Person Date

Explanation of Responses:

( 1 )On July 31, 2020, Gain Capital holdings, Inc. (the "Issuer") and StoneX Group Inc. (f/k/a INTL FCStone Inc.) completed the merger (the "Merger") contemplated by the Agreement and Plan of Merger among the parties thereto, dated as of February 26, 2020 (the "Merger Agreement"). ( 2 )Pursuant to the terms of the Merger Agreement, each share of Issuer common stock reported in Table I above was converted into the right to receive $6.00 in cash (the "Merger Consideration"). ( 3 )Disposed of pursuant to the terms of the Merger Agreement under which each restricted stock unit ("RSU") that is subject to time-based vesting was canceled in exchange for a cash payment representing a number of shares of common stock subject to such RSU, multiplied by the Merger Consideration. ( 4 )Disposed of pursuant to the terms of the Merger Agreement under which each performance-based RSU ("PRSU") for which the performance period has ended was canceled in exchange for a cash payment representing a number of shares of common stock subject to such PRSU determined based on actual performance during the performance period, multiplied by the Merger Consideration. ( 5 )On March 14, 2019, the reporting person received a compensatory grant of PRSUs for which vesting was dependent on the Issuer's performance. Pursuant to the Merger Agreement, such PRSUs for which the performance period has not ended were vested at target performance as of the Merger. ( 6 )Disposed of pursuant to the terms of the Merger Agreement under which each PRSU for which the performance period has not ended was canceled in exchange for a cash payment representing a number of shares of common stock subject to such PRSU determined based on target performance, multiplied by the Merger Consideration.

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