Capita Eastgate will be forced to redeploy or make redundant 25 staff after losing Axa's back office motor work.
The workers were based at Capita's Sittingbourne office, which does back office processing, call and help lines.
A Capita spokesman said Axa outsourced most of its back office work but had decided to take a small piece of its motor insurance business back in-house.
He said Capita was still in discussion with the workers and could not guarantee all would keep their jobs, but said the aim was to find them new jobs within the company.
About 100 staff work at the branch.