Exchange-set limits on the total number of positions a trader or a group of traders can hold in options contracts on the same side (call or put) of the market. Their objective is to prevent the control and manipulation of the market by a few players, and limit excessive speculation that may destabilize the market. Depending on the exchange, position limits may be set as number of contracts or as total units of the commodity. In stock markets, the limit depends on the option's trading volume and the number of outstanding shares of the underlying stock. For heavily traded stocks the limit is commonly 25,000 call or put contracts, but some index options have much higher limits, and trading in less active stocks may be limited to as low as 4,500 contracts. Some commodity exchanges allow exemptions from these limits in cases of bona fide hedges and certain risk management positions to qualified traders and arbitrageurs.