Foreign exchange company Travelex could change hands after a mystery investor approached its private equity owners about a buyout.

An anonymous investor is thought to have approached Apax, which acquired the company in 2005, to hold talks with a view to buying the company – which could prompt the group to launch a formal sale process.

Both Apax and Travelex declined to comment on the weekend report.

Apax bought a majority stake in the firm eight years ago at an estimated enterprise value of more than £1 billion.

Its latest set of published results show the group turned over £586.7 million in 2011, a 9% increase on the previous year.

Travelex sold its global payments business to Western Union and its pre-paid card management division to Mastercard in the same year.