The Chicago Board Options Exchange is getting tougher on market makers as competition from other options exchanges continues to increase. CBOE typically allots business to market-makers and designated, remote and electronic MMs to make sure they are meeting their respective obligations of balancing trading in their respective options. Starting this month, CBOE will require market makers in any given trading crowd to maintain at least 18% market share in their allotted issues over a three-month period in addition to their regular obligations, such as maintaining a certain quoted size and width. Traders at the CBOE believe the exchange is getting tougher to make sure that it is able to maintain the tightest markets in most widely traded options classes. "It has to do with the exchange fighting tooth and nail for miniscule amounts of market share. The slightest difference in the quality of markets can make a difference," one market maker said. CBOE's Equity Market Performance Committee is already reviewing the market makers for the 600 most actively traded classes. If any market maker is not meeting his obligation, the committee can revoke the appointment, and the market maker will lose the business.