Warren Buffett's letters to shareholders at times read like scripts from The Waltons TV show. But the billionaire fund manager's folksy style is a breath of fresh air for currency investors used to the obfuscation of Alan Greenspan, chairman of the Federal Reserve.

Mr Buffett believes the dollar has further to fall and the US trade deficit risks turning America into a “sharecropper's society”. It is only fair to point out that the chairman of Berkshire Hathaway is talking his own book. The value of the group's foreign exchange contracts mostly short positions against the dollar increased to $21.4bn at December 31 2004 from $12bn the previous year. That caveat aside, Mr Buffett's reasoning has merit.