SoftBank Group is in talks to acquire Graphcore, a struggling British semiconductor startup once valued at $2.8 billion (¥435.9 billion), according to people familiar with the deals.

The two companies have held discussions over several months but entered into more advanced deal talks recently, said the people, who asked not to be identified discussing private matters. Financial terms haven’t yet been decided and the talks could still unravel, they said. A final agreement isn’t imminent, one person said.

The talks come amid a surge in sales for SoftBank, thanks largely to its majority stake in another U.K.-based chip designer, Arm Holdings. On Feb. 7, Arm reported a strong outlook for its expansion beyond smartphones into more artificial intelligence applications. Arm shares have soared by about 40% since.