We analyze data from 2005 through 2009 that uniquely identify categories of traders to assess how speculators such as hedge funds and swap dealers relate to volatility and price changes. Examining various subperiods where price trends are strong, we find little evidence that speculators...

We employ data over 2005-2009 which uniquely identify categories of traders to test whether speculators like hedge funds and swap dealers cause price changes or volatility. We find little evidence that speculators destabilize financial markets. To the contrary, speculative trading activity...