Aon has put its claims consulting division Axiom up for sale with a price tag of £20m.
It is understood the decision to sell the claims services and run-off specialist is part of Aon UK's "rationalisation programme", according to industry sources.
Various Lloyd's and London market services companies that specialise in run-off and claims services are looking at the deal.
According to sources, these could include Cavell and Capita.
But one leading London market run-off specialist said: "They might find it hard to get a buyer. It has a lot of embedded Equitas claims and the company has struggled to pick up many new third party contracts in recent years."
Axiom is a separate company within Aon, providing added services to Aon's existing client base, especially its third party client base.
It offers specialist claims services for insurance and reinsurance risks; portfolio and risk transfer facilities; exit strategies for discontinued business; and fraud investigations.
An Aon spokesman said: "We are considering alternative strategies with potential investors regarding the future development and growth of Axiom's business."
He said no decisions had been taken to date.