Taiwan-based Cathay Life is about to buy the Walbrook Building in London for £580m ($877m), according to a report in the Sunday Times.
The office block has been home to broker Arthur J Gallagher's London headquarters since August 2013 and is located opposite Cannon Street railway station.
According to the report Cathay Life saw off more than 30 bidders for the building, which was put up for sale by its owners, Ares Private Equity and Delancey, in January.
None of the parties involved have confirmed the sale as yet.
If the transaction is confirmed this will be Cathay Life's second London property purchase in a year. In August 2014 it bought its first property in London, the Woolgate Exchange, for £320m (IAR, 27 August 2014, Cathay Life buys London office).