T-Mobile is the fourth-largest mobile operator in the UK
Vodafone, France Telecom and Telefonica are all in talks with Deutsche Telekom over buying its T-Mobile UK unit, the Financial Times (FT) has reported.
The FT said people familiar with the situation had told it that all three were eyeing the UK mobile operator, although talks were at an early stage.
The recent stock market rally meant a sale could raise about 4bn euros ($5.7bn; £3.5bn), the paper said.
France Telecom owns Orange UK, while Telefonica owns O2.
T-Mobile is currently the fourth-largest mobile operator in the UK, with a 15% share of the market.
O2 is the largest UK operator, with a 27% share, followed by Vodafone (25%) and Orange (22%).