Apollo, Carlyle and KKR are eyeing Pension Insurance Corporation ahead of a deadline to submit bids for the firm this week.
London-based PIC has more than 300,000 policyholders and a growing portfolio of real estate investments.
The three US private equity groups are only at early stages of considering bids for the £5bn business, said the FT.
Canada’s Brookfield Asset Management also considered making an offer but decided not to move forward.
JP Morgan is advising on the deal.