Recent accusations against speculators in general and long-only commodity index funds in particular include: increasing market volatility, distorting historical price relationships, and fueling a rapid increase and decrease in the level of commodity prices. Some researchers have argued that...

Despite extensive study, researchers continue to search for consistent and reliable measures of risk preferences to explain market behavior. We find that a measure, combining experiments rooted in expected utility theory and measures derived from surveys, explains spot and contractual sales, but...