Healthcare REIT BioMed Realty Trust said it had agreed to be bought by Blackstone in a deal valued at $8 billion.
The all-cash offer of $23.75 per share represents a premium of 10 percent to BioMed's close of $21.59 on Wednesday.
BioMed, which owns office buildings catering to pharma and biotech companies, has interests in properties comprising about 18.8 million rentable square feet.
The offer, which has been approved by BioMed's board, represents a premium of 24 percent to BioMed's closing price on Sept. 22, when Bloomberg first reported of Blackstone's interest.
The deal is expected to close in the first quarter of 2016.
Morgan Stanley is lead financial adviser to BioMed Realty. Citigroup Global Markets, J.P. Morgan Securities and Bank of America/Merrill Lynch are advising Blackstone.