Benfield Group has voiced "disappointment" at the decision by Lloyd's to commence legal action against it.
Benfield said it "is disappointed that Lloyd's has considered it necessary to take this action".
Benfield and Aon were responsible for placing the reinsurance of Lloyd's Central Fund.
Benfield added: "As previously disclosed in Benfield's financial statements, Benfield believes, based on professional advice, that these proceedings will not result in a material liability to Benfield, nor to its professional indemnity insurers. Benfield will defend any action vigorously."
