As investors around the world size up losses on Bernard Madoff's alleged Ponzi scheme, one purveyor of investment services to the world's wealthy - Swiss private bank Union Bancaire Privée - is scrambling to explain its ties to the New York financier.

Half of UBP's 22 funds of funds, which channelled clients' money into other hedge funds, put at least some of that money into Madoff-related investment vehicles, including one run by J Ezra Merkin, chairman of car-loan company GMAC, according to a recent letter from the bank to investors. At the same time, UBP provided an array of services such as investment advice and loans to a division of Fairfield Greenwich Group, a New York firm that funnelled investors' money into Madoff funds. Some outside fund managers also looked to UBP, which said it had about $700m (€493m) in Madoff-related investments through its funds of funds and client portfolios, in making their own investments.