Royal & SunAlliance said the US Federal District Court has issued a ruling granting partial summary judgement to MBIA Insurance Corp and Wells Fargo Bank Minnesota against its US-based subsidiary, Royal Indemnity.
R&SA said in a statement that it planned to appeal the decision.
According to R&SA, the court issued a preliminary document on 30 September, which is to be followed by the court's opinion at a future date.
Royal Indemnity is in dispute over credit risk insurance policies issued on the trade school student loan portfolios originated or purchased by Student Finance Corps.
Royal Indemnity has asserted that it was the victim of fraud, misrepresentation and cover-up related to the underlying loans and is seeking rescission of the policies and damages for fraud and breach of contract.
MBIA Insurance, which issued financial guarantees to institutional investors in securities backed by the loan portfolio, and Wells Fargo Bank, the trustee for the securitisation of the loan, have sued Royal Indemnity seeking to enforce the policies.
R&SA said the ruling had not changed its view of the situation in any way.