Put out a statement on Monday saying it has offered 200p per share and that it will be its final proposal.
“The fifth proposal is subject to a number of customary pre-conditions, including the satisfactory completion of due diligence,” said the US firm, which is in the process of buying retirement home builder McCarthy & Stone PLC and was in the running to buy Asda last year.
Lone Star said this proposal represents a premium of roughly 69% to Senior’s closing price of 118.3p per share on 27 May, which was the last closing price before the potential offer was made public on 28 May.
Senior’s said on that date that the proposed 176p offer at that time “fundamentally undervalued Senior and its future prospects” and so the board unanimously rejected it.
Shares in the company were up 14% to 172.7p on Monday morning.