As banks have extended their range of activities and involvement in new markets, they must be particularly mindful of potential for concentrations of risk to arise for a number of reasons. First, any new activity will be less familiar and involve less data and experience for evaluating risk compared with long-standing activities or markets.
Second, risk concentrations can be hidden during normal times and may only manifest themselves during times of stress when activities or instruments that might in normal times have little or negative correlation suddenly become correlated, such as with a market-wide increase in the demand for liquidity as we have seen recently.