John Maynard Keynes 'a great economist but poor currency trader'

Study of Keynes's foreign exchange dealings between the first and second world wars reveals a chequered record

Markets can remain irrational longer than you can remain solvent. Such is the advice John Maynard Keynes is supposed to have given to would-be investors looking to make a killing in the period between the first and second world wars.

There is some dispute about whether Keynes ever delivered this warning. What is not at issue is that it was advice he did not always follow, especially when it came to his dabblings in the currency market.