We build an equilibrium model of commodity markets in which speculators are capital constrained, and commodity producers have hedging demands for commodity futures. Increases in producers' hedging demand or speculators' capital constraints increase hedging costs via price-pressure on futures. These in turn affect producers' equilibrium hedging and supply decision inducing a link between a financial friction in the futures market and the commodity spot prices. Consistent with the model, measures of producers' propensity to hedge forecasts futures returns and spot prices in oil and gas market data from 1979 to 2010. The component of the commodity futures risk premium associated with producer hedging demand rises when speculative activity reduces. We conclude that limits to financial arbitrage generate limits to hedging by producers, and affect equilibrium commodity supply and prices

We present a model of equilibrium allocation of capital for arbitrage. If asset prices may fall low enough, it is profitable to carry liquid capital to acquire assets in such states. Set against this, keeping capital in liquid form entails costs in terms of foregone profitable investments. This trade-off generates occasional fire sales and limited arbitrage capital as robust phenomena. With learning-by-doing effects, arbitrage capital moves in to acquire assets only if fire sales are steep. However, once arbitrage capital finds it profitable to acquire assets, it requires similar returns elsewhere, inducing contagious fire-sale prices even for unrelated assets

This paper uses a unique data set of trades in a unique pair of securities that enables the precise identification of individual broker activity and the trade direction of that activity. We find direct evidence that the imposition (removal) of short-sale constraints limits (generates) trading activity consistent with brokers exploiting apparent mispricing