(Adds detail on company, deal)
LONDON, Sept 30 (Reuters) - Waypoint Capital is to buy astake of around 30 percent in Euromedic held by private equityfirm Montagu, valuing the healthcare business at between 800million and 1 billion euros ($1-$1.3 billion), two sourcesfamiliar with negotiations said.
Waypoint, the European investment vehicle backed by Swissbillionaire Ernesto Bertarelli, already owns around 60 percentof Euromedic through its investment partnership Ares LifeSciences. Bertarelli inherited his father's biotech empire andis the chairman of Waypoint.
Euromedic, which has its operational headquarters inBudapest, says it is the largest pan-European provider ofhealthcare services, with a focus on cancer care and advanceddiagnostic imaging.
Montagu owns around 30 percent of Euromedic and expects tomake twice its money on the deal as it exits its investment, oneof the sources said.
The transaction, on which UBS and HSBC acted as advisers, is expected to be announced later on Tuesday.
Ares and Montagu co-invested in Euromedic in 2008 in a dealvaluing the firm at around 800 million euros. Euromedic hassince sold off its dialysis care unit for 485 million euros in2011.
Montagu declined to comment. (1 US dollar = 0.7940 euro) (Reporting by Freya Berry; editing by Kirstin Ridley/KeithWeir)