According to Bloomberg, BC Partners has requested to receive offers from potential buyers for United Group in July, just as the company is attracting the interest of private equities.
According to the US news agency, Apax Partners and Warburg Pincus are considering submitting bids for some or all of United Group.
Saudi Telecom and Emirates Telecommunications Group will also likely submit bids.
Contacts have also been made with Orange, Telekom Austria, and Iliad, owned by French telecom billionaire Xavier Niel.
BC Partners is seeking a valuation of about €8 billion, including debt, for United Group, according to sources cited by Bloomberg.
Some of the interested parties may eventually bid for some of the group's assets in individual markets.
In addition to Greece, United Group also operates in countries such as Bulgaria, Serbia, Slovenia, Croatia, Bosnia-Herzegovina, and Montenegro.