The size of the stake that TCV is acquiring was not disclosed, but it is rumoured that FXall has agreed to sell a 20% share in the company to the private equity firm.

TCV is thought to have beaten off rival General Atlantic, which last year bought a 25% stake in forex specialist firm SaxoBank for $126.5m.

FXall says it will use the new funds to support its core business strategy and develop new products and services.

Phil Weisberg, CEO of FXall, says: "This investment will fuel continued development of new products and services, enabling us to deliver an even more comprehensive offering to our customers."

As part of the refinancing TCV partners Henry Feinberg and Robert Trudeau will join FXall's board of directors.

FXall launched in 2001 and trading volumes on the system have grown every quarter since. In Q2 this year, total trading on the platform surpassed $2.4 trillion, up 50% on Q2 2005.

The TCV transaction is expected to close next month.