Monument Insurance Brokers is being sued for $6.2m (£3.4m) by members of Lloyd's Syndicate 957 in a breach of contract row.
In late 1996, syndicate 957 instructed Monument to act as its agent in the "arrangement, placement, renewal and ongoing administration" of reinsurance contracts.
Syndicate 957 alleges that, following the termination of the agency agreement in 2003, Monument has "failed to remit promptly to the syndicate" reinsurance claim payments totalling $6.2m (£3.4m), which the broker had collected on Syndicate 957's behalf.
A Monument spokeswoman said: "There is an unresolved disagreement with the run-off managers of Syndicate 957 concerning brokerage and other sums due to TCRU Ltd (previously called Monument Insurance Brokers Ltd)."
"The detail is complex and will probably take some time to resolve, both parties have engaged lawyers and the matter is in their hands," the spokeswoman said.