The price risk in commodities is often more complex and volatile than that associated with currencies and interest rates. Commodity markets may also be less liquid than those for interest rates and currencies and, as a result, changes in supply and demand can have a more dramatic effect on price and volatility. Banks need also to guard against the risk that arises when a short position falls due before the long position. Owing to a shortage of liquidity in some markets, it might be difficult to close the short position and the bank might be "squeezed by the market". All these market characteristics of commodities can make price transparency and the effective hedging of risks more difficult.