Fed Vice Chairman Donald L. Kohn in a speech yesterday, addressed a theory to which I am partial: the theory that low real interest rates have been a factor behind the continued rise in prices of agricultural and mineral commodities, including oil, over the last year.

The relevant excerpt: “Some observers have questioned whether the news on fundamentals affecting supply and demand in commodities markets has been sufficient to justify the sharp price increases in recent months. Some of these commentators have cited the actions of the Federal Reserve in reducing interest rates as an important consideration boosting commodity prices. To be sure, commodity prices did rise as interest rates fell. However, for many commodities, inventories have fallen to all-time lows, a development that casts doubt on the premise that speculative demand boosted by low interest rates has pushed prices above levels that would be consistent with the fundamentals of supply and demand. As interest rates in the United States fell relative to those abroad, the dollar declined, which could have boosted the prices of commodities commonly priced in dollars by reducing their cost in terms of other currencies, hence raising the amount demanded by people using those currencies. But the prices of commodities have risen substantially in terms of all currencies, not just the dollar. In sum, lower interest rates and the reduced foreign exchange value of the dollar may have played a role in the rise in the prices of oil and other commodities, but it probably has been a small one.” (Speech at the National Conference on Public Employee Retirement Systems, New Orleans, Louisiana, May 20, 2008). read more