This excerpt taken from the C DEF 14A filed Jun 18, 2009.
Effect of the Preferred Stock Change on Stockholders
Currently, Citigroups restated certificate of incorporation provides that the holders of outstanding shares of common stock have voting power for the election of directors and for all other purposes. Pursuant to Section 242(b)(1) of the Delaware General Corporation Law, any changes to Citigroups restated certificate of incorporation must be approved by a majority of the outstanding stock entitled to vote thereon, and a majority of the outstanding stock of each class entitled to vote thereon as a class.
If the Preferred Stock Change is approved, we would file a certificate of amendment to our restated certificate of incorporation with the Secretary of State of the State of Delaware providing that the holders of common stock will not be entitled to vote with respect to any amendment to the restated certificate of incorporation (including any certificate of designation related to any series of preferred stock) that relates solely to the terms of one or more outstanding series of preferred stock, if such series of preferred stock is entitled to vote, either separately or together as a class with the holders of one or more other such series of affected preferred stock.
Therefore, holders of common stock would no longer be entitled to vote on or consent to, and we would not be required to seek their vote on or consent to, any changes to our restated certificate of incorporation or certificates of designation that relate solely to the terms of the preferred stock, so long as the holders of affected preferred stock are entitled to vote or consent to such changes. Holders of common stock would retain the power to vote on or consent to all other matters that they are currently entitled to vote or consent on, including the election of directors.