By Anna Irrera

NEW YORK, Jan 31 (Reuters) - Japan Exchange Group Inc (JPX) , the operator of the Tokyo Stock Exchange, has taken a minority stake in UK-based fintech company OpenGamma Limited, as corporate investors account for a growing share of venture funding in fintech.

OpenGamma, which provides software to help derivatives traders better calculate risk, said that the strategic investment will help it expand in the Japanese market. The companies did not disclose the size of the investment.

The JPX funding round follows a $13.3 million investment in OpenGamma in October by venture capital firm Accel Partners, Euclid Opportunities, the fintech venture arm of electronic trading and post trade company NEX Group Plc, formerly known as Icap Plc, and ex-SunGard chief executive Cristóbal Conde.

"Having a strategic investor like JPX is really important, it really helps us in terms of credibility," said Peter Rippon, chief executive of OpenGamma. He added that the JPX's established presence in capital markets "makes them ideal partners" in achieving its objectives.

Launched in 2009 OpenGamma provides an open-source analytics and risk management platform for derivatives trading, to hedge funds, banks, clearing houses and asset managers.

One of the UK's most well known capital markets fintech startups, its services include a tool that allows financial institutions to make margin calculations for the major clearing houses.

The company aims to capitalize on post-crisis regulations around the world that have pushed more over-the-counter derivatives onto electronic platforms and through clearing houses, raising the demand for tools that can help manage the process.

"We've followed OpenGamma's transformation from an innovator in the development of open source software into an important risk analytics provider for institutional finance," Takeshi Hirano, executive officer of JPX, said in a statement.

Headquartered in Tokyo, JPX also runs the Osaka Securities Exchange and the Japan Securities Clearing Corporation.

OpenGamma's latest round of funding comes as investments from corporations constitute an increasingly significant share of venture funding for fintech startups. In the third quarter of 2016, corporates participated in 30 percent of global VC-backed fintech deals for the second consecutive quarter, according to a report from data provider CB Insights and KPMG.

(Reporting by Anna Irrera; Editing by Bernard Orr)