Siris, which agreed to a roughly $917 million deal to buy the British company earlier this year, plans to integrate Equiniti with U.S.-based firm AST, which it is also buying.

"It is possible that such integration could result in headcount reductions which are not expected to exceed approximately 10% of the enlarged workforce," Siris said in a statement.

Equiniti and AST employ about 5,750 people in total, Siris said.

Siris' purchase of Equiniti is among a raft of deals to buy British companies this year, reflecting private equity's appetite for cash-generating UK assets. However, these moves have created fears of job losses and prompted some suitors to provide assurances.

U.S.-based CD&R won a $10 billion auction to buy British supermarket Morrisons this month. The private equity firm has committed to retaining Morrisons' headquarters, its existing management team and maintain staff pay rates.

(Reporting by Priyanshi Mandhan and Sachin Ravikumar in Bengaluru; Editing by Amy Caren Daniel)