This paper evaluates how different types of speculation affect the volatility of commodities' futures prices. We adopt …-2010 analyzed at weekly frequency. Using GARCH models we find that speculation significantly affects volatility of returns: short … term speculation has a positive and significant impact on volatility, while long term speculation generally has a negative …

This paper studies the information content of the S&P 500 and VIX markets on the volatility of the S&P 500 returns. We … risk-neutral distributions as well as the term structure of volatility smiles and of variance risk premia. We find that the …