Volcker Rule: Q&A - Telegraph Why is it important? The Volcker Rule is the keystone in the most sweeping set of financial reform since the Great Depression, designed to prevent a repeat of the 2008 financial crash. It will go a large way to separating the investment and the commercial activities of banks - although it does not go quite the whole hog. Why don't banks like it? Many banks make a huge proportion of their profits from gambling with their own funds, a practice also known as proprietary trading. Once Volcker Rukes come into effect in 2015, that route will no longer be open to them. Critics claim that proprietary trading did not cause the financial crisis in any case, so it shouldn't be the focus for regulatory reform. They are also wary of the extra red tape the Volcker Rule will usher in. Why do regulators like the Volcker Rule? Proprietary trading does not always lead to profits. Many major banks have also chalked up enormous losses in recent years because of their own gambles. In 2007, Morgan Stanley lost $9bn on a massive bet related to mortgage derivatives. A year later, Merrill Lynch lost nearly $16bn and Deutsche Bank lost nearly $2bn in bets on risky securities. When will the Volcker Rule come into effect? The rule will come into force in 2015 - giving banks more than a year to acquaint themselves with the legislation, which runs to more than 1,000 pages.