Exhibit 99.1

13 February 2013

NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION, IN WHOLE OR IN PART, DIRECTLY OR INDIRECTLY, IN, INTO OR FROM ANY JURISDICTION WHERE TO DO SO WOULD CONSTITUTE A VIOLATION OF THE RELEVANT LAWS OR REGULATIONS OF SUCH JURISDICTION

13 February 2013

GAIN Capital Confirms Preliminary Takeover Discussions with London Capital Group

GAIN Capital Holdings, Inc. (“GAIN”) notes the announcement made by London Capital Group Holdings plc (“LCG”) on 12 February 2013. GAIN confirms that it is in early stage discussions with LCG regarding the possible acquisition by GAIN of the entire issued and to be issued share capital of LCG.

There can be no assurances that any agreement will be reached or that a transaction will be completed.

GAIN’s Board of Directors would only pursue a transaction if it believes, at the appropriate time, that it will be in the best interests of its shareholders.

GAIN will provide further comment if and when an agreement is reached, the discussions are terminated or such other material event occurs requiring additional disclosures.

Rule 2.10

In accordance with Rule 2.10 of the City Code on Takeovers and Mergers (the “Code”), GAIN confirms that, as at the close of business on 12 February 2013, the issued share capital of GAIN comprises 35,061,056 ordinary shares of $0.00001 each with International Securities Identification Number (ISIN) US36268W1009.

A copy of this announcement will be available at http://www.gaincapital.com/ by no later than 12 noon (London time) on 14 February 2013.

Under Rule 8.3(a) of the Code, any person who is interested in 1% or more of any class of relevant securities of an offeree company or of any paper offeror (being any offeror other than an offeror in respect of which it has been announced that its offer is, or is likely to be, solely in cash) must make an Opening Position Disclosure following the commencement of the offer period and, if later, following the announcement in which any paper offeror is first identified. An Opening Position Disclosure must contain details of the person’s interests and short positions in, and rights to subscribe for, any relevant securities of each of (i) the offeree company and (ii) any paper offeror(s). An Opening

Position Disclosure by a person to whom Rule 8.3(a) applies must be made by no later than 3.30 pm (London time) on the 10th business day following the commencement of the offer period and, if appropriate, by no later than 3.30 pm (London time) on the 10th business day following the announcement in which any paper offeror is first identified. Relevant persons who deal in the relevant securities of the offeree company or of a paper offeror prior to the deadline for making an Opening Position Disclosure must instead make a Dealing Disclosure.

Under Rule 8.3(b) of the Code, any person who is, or becomes, interested in 1% or more of any class of relevant securities of the offeree company or of any paper offeror must make a Dealing Disclosure if the person deals in any relevant securities of the offeree company or of any paper offeror. A Dealing Disclosure must contain details of the dealing concerned and of the person’s interests and short positions in, and rights to subscribe for, any relevant securities of each of (i) the offeree company and (ii) any paper offeror, save to the extent that these details have previously been disclosed under Rule 8. A Dealing Disclosure by a person to whom Rule 8.3(b) applies must be made by no later than 3.30 pm (London time) on the business day following the date of the relevant dealing.

If two or more persons act together pursuant to an agreement or understanding, whether formal or informal, to acquire or control an interest in relevant securities of an offeree company or a paper offeror, they will be deemed to be a single person for the purpose of Rule 8.3.

Opening Position Disclosures must also be made by the offeree company and by any offeror and Dealing Disclosures must also be made by the offeree company, by any offeror and by any persons acting in concert with any of them (see Rules 8.1, 8.2 and 8.4).

Details of the offeree and offeror companies in respect of whose relevant securities Opening Position Disclosures and Dealing Disclosures must be made can be found in the Disclosure Table on the Takeover Panel’s website at www.thetakeoverpanel.org.uk, including details of the number of relevant securities in issue, when the offer period commenced and when any offeror was first identified. You should contact the Panel’s Market Surveillance Unit on +44 (0)20 7638 0129 if you are in any doubt as to whether you are required to make an Opening Position Disclosure or a Dealing Disclosure.