The offer, pitched at 115p per share, values the group at £630mln and is a near 39% premium to the market price at the close last night.
The elderly have been especially vulnerable during the coronavirus outbreak and McCarthy & Stone was forced to close operations from March along with other building contractors.
In the six months to end April, 2020, the group posted a loss of £91.3mln and said that going forward it would switch its emphasis to be more of a service-led organisation.
Lone Star said it recognised the achievements of McCarthy so far and that the acquisition offered it an opportunity to move into the UK retirement living sector.
Donald Quintin, president of Lone Star Europe, said: “As a leading developer and manager of retirement communities in the UK, McCarthy & Stone represents an attractive opportunity in a market underpinned by clear fundamentals: a rapidly ageing population and a structural undersupply of suitable housing options for older people."
The US firm added it was a long-term and patient investor with significant experience in real estate investing,
McCarthy & Stone chairman Paul Lester said: “The offer represents a compelling and attractive opportunity for shareholders to crystallise their investment in the company in the near term."
Before the pandemic, the retirement homes group shares were trading above 150p and they jumped 40.5% today to 116.6p.
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