NEW YORK (Bloomberg) — Tremont Group Holdings Inc. and other feeder funds to Bernard Madoff's defunct investment advisory business sued insurers including a CNA Financial Corp. unit for failing to cover Madoff-related litigation.

Tremont, a fund of funds based in Rye, New York, that had about $3.3 billion invested with Madoff, is owned by OppenheimerFunds Inc., a unit of MassMutual Financial Group. Investors have filed more than a dozen lawsuits against MassMutual seeking to recoup Madoff-related losses.

Liability insurers for MassMutual's directors and officers, and its primary fidelity bond insurers, have ignored repeated requests to pay defence costs, lawyers for MassMutual and the funds said in a complaint filed yesterday in Delaware Chancery Court. MassMutual seeks a court order declaring that Madoff's theft, the biggest Ponzi scheme in US history, resulted in multiple losses that are covered under its insurance policies.

In addition to CNA's Continental Casualty Co., the complaint names some underwriters of the Lloyd's of London insurance market and American Financial Group Inc.'s Great American Insurance Co.