Zurich-based Credit Suisse apparently warned its clients more than eight years ago to stay away from funds managed by disgraced United States investor Bernard Madoff.
Switzerland's second-largest bank issued the recommendation in 2000 after a meeting with the financier in New York, the Bloomberg news agency reported on Wednesday.
The bank, whose clients lost almost $1 billion (SFr1.13 billion) in Madoff's alleged $50-billion Ponzi scheme, could not figure out how the firm generated its returns.
Credit Suisse clients were taking in around 11 per cent per year, Bloomberg said, adding that the bank could not force is customers to withdraw their money.
The 70-year-old Madoff was arrested in December by authorities in the US and is free on bail.