In select cases, investors were afforded access to the spot market by physically backed commodity offerings like SPDR Gold Shares ( GLD ) and iShares Silver Trust ( SLV ). As the Fed executed extremely loose monetary policy, hoping to prevent a deflationary spiral through the direct injection of capital to the economy, inflationary fears began to surface. click to enlarge The Theory The downfall of first-generation products was the fact that persistent and outsized levels of contango caused very poor tracking relative to the spot commodity over the longer term.