Volcker rules are trading restrictions placed on financial institutions. The Volcker rule separates investment banking, private equity and proprietary trading sections of financial institutions from their consumer lending arms. Banks are not allowed to simultaneously enter into an advisory and creditor role with clients. The rule aims to minimize conflicts of interest between banks and their clients by separating the various types of business practices financial institutions engage in. It was proposed by the American economist and former United States Federal Reserve Chairman Paul Volcker to restrict the U.S. banks from making certain kinds of speculative investments if they are not on behalf of their customers. Volcker has argued that such speculative activity played a key role in the financial crisis of 2007–2010. Volcker rule is also known as Volcker plan.