GAIN Capital Holdings Announces Pricing of Its Initial Public Offering

NEW YORK, December 15, 2010 - GAIN Capital Holdings Inc., a global provider of online foreign exchange
(forex or FX) trading and related services, including
contracts-for-difference (CFDs) trading, announced today its initial public
offering of 9,000,000 shares of its common stock at a price to the public of
$9.00 per share. The shares will begin trading today, December 15, 2010, on
the New York Stock Exchange under the ticker symbol "GCAP."

GAIN Capital Holdings Inc. is offering 407,692 shares of common stock and
its selling stockholders are offering 8,592,308 shares of common stock. In
addition, certain selling stockholders have granted the underwriters an
option to purchase up to 1,350,000 additional shares of common stock to cover
over-allotments, if any. GAIN Capital Holdings Inc. will not receive any
proceeds from the sale of shares by the selling stockholders.

Morgan Stanley and Deutsche Bank Securities are acting as joint
book-running managers for the offering. JMP Securities LLC, Raymond James and
Sandler O'Neill + Partners, L.P. are acting as co-managers.

The offering of these securities will be made only by means of a
prospectus, which may be obtained from Morgan Stanley, Attention: Prospectus
Department, 180 Varick Street, 2nd Floor, New York, NY 10014, telephone:
(866)718-1649 or by emailing prospectus@morganstanley.com; and Deutsche Bank
Securities, 100 Plaza One, Jersey City, New Jersey 07311, telephone:
(800)503-4611, or by emailing prospectusrequest@list.db.com. The prospectus
also may be obtained on the Securities and Exchange Commission's Web site at
www.sec.gov.

A registration statement relating to these securities has been declared
effective by the Securities and Exchange Commission. This press release shall
not constitute an offer to sell or a solicitation of an offer to buy, nor
shall there be any sale of these securities in any state or jurisdiction in
which such an offer, solicitation pr sale would be unlawful prior to
registration or qualification under the securities laws of any such state or
jurisdiction.

About GAIN Capital

GAIN Capital Holdings, Inc. is a global provider of online foreign
exchange (forex or FX) trading and related services, including
contracts-for-difference (CFDs) trading. Customers and trading partners in
more than 140 countries have utilized the company's award-winning trading
platform.

GAIN Capital provides execution, clearing, custody and technology
products and services to an institutional client base including asset
managers, broker/dealers and other financial services firms. GAIN also
operates FOREX.com, one of the largest and best-known brands in the retail
forex industry.

With offices in New York City; Bedminster, New Jersey; London; Sydney;
Hong Kong; Tokyo and Seoul, GAIN Capital and its affiliates are regulated by
the Commodity Futures Trading Commission (CFTC) in the United States, the
Financial Services Authority (FSA) in the United Kingdom, the Financial
Services Agency (FSA) in Japan, the Securities and Futures Commission (SFC)
in Hong Kong, and the Australian Securities and Investments Commission (ASIC)
in Australia.

For company information, visit www.gaincapital.com or
www.forex.com.

Investor, Miri Segal of GAIN Capital Holdings, Inc., +1-917-607-8654, ir at gaincapital.com; Media, In North America: Henry Feintuch, +1-212-808-4901, Savannah Tikotsky, +1-212-808-4903, both of Feintuch Communications, gain at feintuchpr.com; or In UK & Europe: Laura Cocker, +44(0)20-3047-2365, Laura Crooks, +44(0)20-3047-2366, both of Edelman, gain at edelman.com