Assura PLC surged on Monday after news broke it had rejected four takeover advances from US private equity giant KKR, including a £1.56 billion bid last week.
KKR on Monday announced a 48p per share offer had been rebuffed over the weekend, following three proposals over the last six months.
Bids for the FTSE 250 healthcare real estate investment trust had been tabled alongside Universities Superannuation Scheme, which subsequently said it would not table a further offer "as part of the consortium or otherwise".
The latest marked a 28.8% premium to its closing share price as of February 13, when the last approach was made, KKR added.
"KKR believes that the terms of the latest proposal offer a highly attractive opportunity for Assura shareholders to realise their investment in cash at a significant premium to prevailing market prices,” it said.
"KKR is considering whether there is any merit in continuing to try and engage with the board.
"There can be no certainty that any firm offer for the company will be made. A further announcement will be made as and when appropriate."
Assura jumped 15.4% to 45p on Monday.