Alan Greenspan, former Federal Reserve chairman, continues to argue that even financial products that led to the economic crisis should not be banned, affirming his belief that markets should be the final arbiter over which tools work.

Mr Greenspan, who has faced criticism for making decisions that allowed the economic crisis, maintains that the market should judge these products. He disagrees with those, such as George Soros, who has called for an outright ban on tools that may have led to the crisis, and Dominique Strauss-Kahn, director of the International Monetary Fund, who has called for tougher regulation.