Equiniti Group has received a revised offer from US private equity investor Siris Capital, to buy the outsourcer for around £661m in cash.
Siris revised its bid to 180 pence per share following discussions, London-listed Equiniti said.
In early April, Siris submitted a non-binding proposal for 170 pence per share, which Equiniti said it would evaluate “carefully in all respects”.
Rothschild & Co and Citi are acting as Equiniti’s advisers.
Equiniti, which manages pensions, employee share schemes and other back-office services for FTSE 100 companies, had a tough year last year, with the business recording reduced revenue, EBITDA and profit in its annual results.