Source: Financial Times, 17th July 2011

Blaming speculators for rising commodity prices is a popular pursuit. It is also one with a long history. ''The cost of living in this country must not be a football to be kicked around by grain gamblers,'' is a quote with a very modern ring to it. In fact, the quote is from October 1947 and attributed to US President Truman, who hiked the margins on futures trading in an attempt to rein in soaring US wheat prices. But while getting the blame for more than half a century, what impact do speculators actually have on commodity prices?