Did the Fed Asset Purchases Drive Commodity Prices

Via Mark Thoma, these guys say no:

In this Economic Letter from the FRBSF, Reuven Glick and Sylvain Leduc argue that the Fed did not cause the run-up in commodity prices:

Prices of commodities including metals, energy, and food have been rising at double-digit rates in recent months. Some critics argue that Federal Reserve purchases of long-term assets are fueling this rise by maintaining an excessively expansionary monetary stance. However, daily data indicate that Federal Reserve announcements of large-scale asset purchases tended to lower commodity prices even as long-term interest rates and the value of the dollar declined.