Royal & Sun Alliance Insurance Group PLC is going to be penalised by the Financial Services Authority (FSA) as part of an on-going review on mis-sold pensions, according to reports in The Financial Times.
A spokesman for the insurer said: "We have been advised that we'll be fined for some aspects of the administration of the review."
However, the company has assured shareholders that any fines will "not be material" enough to impact its results.
Under the FSA's review, insurers were required to identify and compensate people claiming they were wrongly sold personal pensions between April 1988 and June 1994.
Since the beginning of the review, the FSA has taken disciplinary action against 345 firms, resulting in fines totalling about £10m.