This excerpt taken from the NDAQ 8-K filed Feb 20, 2008.
2. Exercise of warrants
In January 2006, Citadel Derivatives Group, LLC met all of their performance criteria under the warrants issued to them on June 15, 2005 (see Strategic Partners under Note Q). Citadel Derivatives Group, LLC exercised their warrant on February 14, 2006 and the Exchange issued to them 10,334 shares of Class B Common Stock.