Banks will soon face a test of whether they have learned a big lesson of the financial crisis. From the middle of next month, the market volatility resulting from last year's collapse of Lehman Brothers will stop showing up in a commonly used measure banks use to determine how much risk they can take.

The result is that the models will give a green light to start taking chances again. If banks act on this, a range of markets could see a boost in both trading volumes and volatility. If they don't, it will be a sign that they are no longer relying on the oversimplified risk-valuation models that blinded so many to the risks exposed by the crisis. "I think this will be a good test of banks' risk-management areas," said Peter Rothwell, senior manager in the financial-risk-management group at KPMG in London, who said banks should now have reviewed the assumptions in their models.