HSBC has slapped a new redemption fee of up to three percent on one of its money funds.

But HSBC said the charge would only apply in “exceptional circumstances” to avoid to a run on the funds in a financial crisis.

But one customer, who asked not to be named, said: “I’ve had this account for a long time — I don’t see how they can spring this on us when we made these investments in good faith.”

The customer added: “They don’t make very much anyway — the interest has been negligible. Now they’re trying to hit us with three percent for withdrawals in circumstances they decide.

“The banks charge enough in fees at it is without adding another one.”

The HSBC client spoke out after the bank informed customers who had invested in their corporate money funds scheme of the new charge.

A spokeswoman for HSBC said the change was backed by the International Organisation of Securities Commissions and based on recommendations by the fund’s manager.

She added: “It should be noted it is not the intention of the directors to levy a redemption fee during normal market conditions and would only be a mechanism that could be invoked, during times of severe market stress, such as those that arose during the credit crisis in September 2008.”

She added: “While three percent is the maximum fee that can be charged, if it is imposed, it is not anticipated to be as high as three percent.”

Shareholders were told of the change in a letter from the bank last month.

The spokeswoman said: “Investors were provided with detailed information regarding the fee and how it would protect the price of the fund in two ways.

“First a redemption fee aims to price the cost of liquidity — that is, the cost to the funds resulting from the selling of assets in a distressed market, at the time when the redemption fee is levied.

“The charge for liquidity would minimise the impact on the fund, as redeeming shareholders would not pass on the cost of immediate liquidity to the funds, which in turn could impact the price of the fund.

“Second, the redemption fee is used to reduce the risk of a run on the funds, therefore minimising the potential for other investors having to realise market losses as a consequence of selling assets at distressed prices.”