This excerpt taken from the NDAQ 10-K filed Mar 15, 2006.
NASD will continue to maintain voting control over us until we meet SEC conditions to operate as an exchange and may have interests that are different from yours and, therefore, may make decisions that are adverse to your interests.
The SEC requires that NASD retain greater than 50% of the voting control over us until we operate as an exchange and no longer rely on NASDs SRO license to operate The Nasdaq Stock Market. NASD maintains voting control through the single outstanding share of our series D preferred stock. Therefore, NASD will continue to retain voting control over us until we meet SEC conditions to operate as an exchange. As a result, until such time, NASD will continue to have the ability, if it so elects, to dictate the outcome of matters brought to a vote of our stockholders. NASD may have interests that conflict with the interests of holders of our common stock. NASDs voting control may delay or prevent a change in control, impede a merger, consolidation, takeover, or other business combination involving us or discourage a potential acquirer from making a tender offer or otherwise attempting to obtain control of us or result in actions that may be opposed by other stockholders.