European investors face billions of dollars losses in the wake of disclosure of 'Ponzi' scheme run by Bernard Madoff, now being investigated by the American authorities.

European banks, including Spain's Grupo Santander SA and France's BNP Paribas, were quoted by the Wall Street Journal as saying that their clients and shareholders face billions of euros of losses on investments, underscoring the global reach of the alleged Ponzi scheme run by the veteran New York money manager.

A ponzi scheme is a type of securities fraud where the promoter makes some sort of false or misleading statement about an investment (often including a guaranteed high rate of return) and pays off older investors with newer investors money.

Santander, the eurozone's largest bank by market value, said its clients had an exposure of 2.33 billion euros ($3.1 billion) to Madoff's investment funds, mainly through its Optimal Strategic US Equity fund.

The company, which has been relatively unscathed from global financial crisis, said it had hired Madoff's firm to execute the Optimal fund's investments. Santander vowed to "undertake the legal actions which may be needed to defend the interests of investors."

The Journal reported that BNP, France's largest bank by market value, said it could lose as much as 350 million euros as a result of the alleged fraud.

However, the bank said it has no investment of its own in the hedge funds managed by Bernard Madoff Investment Services. BNP Paribas, however, said it is exposed to these funds through its trading business and lending to hedge funds that had invested in Madoff's funds.

The losses, the Journal said, could prove particularly embarrassing for banks' private-banking businesses, which charge high fees to wealthy investors in return for what is supposed to be superior advice and due diligence.

More than two billion euros belongs to institutional investors and international clients of Santander's private-banking business, which provides services to wealthy individuals, it was quoted as saying. The remaining 320 million euros belongs to private-banking customers in Spain, where the bank is based.

Most of the European banks' exposures were on client investments they managed, rather than on the banks' own balance sheets, it said, adding that it's not yet clear how much, if anything, investors in Madoff's funds may be able to recover.

Exposures to Madoff's funds have also emerged among a growing number of smaller European private banks.

In a letter posted on its website, the Swiss private bank Reichmuth and Co said its clients had an exposure of some 385 million Swiss francs to Madoff funds.

The bank said Reichmuth Matterhorn, a fund that invests in other hedge funds, faced a potential loss of about 8.6 per cent on its exposure to Madoff. That amount represented about 3.5 per cent of the 11 billion Swiss francs Reichmuth & Co. has under management, the bank said, the Journal reported.