Common Stock Issuances Temporary Equity In 2011, we issued 584,432 shares of common stock to 31 limited partners in exchange for an equal number of units. We issued 324,720 shares of common stock related to employee and director stock options exercised during 2011. We used  the net proceeds from the option exercises of approximately $9.6 million to acquire additional units. The Operating Partnership  used the net proceeds for general business purposes. On December 9, 2011, the Operating Partnership issued 73,428 units in connection with the acquisition of a 50% interest in  two development properties as discussed in Note 3. We classify as temporary equity those securities for which there is the possibility that we could be required to redeem the  security for cash irrespective of the probability of such a possibility. As a result, we classify one series of preferred units of the  Operating Partnership and noncontrolling redeemable interests in properties in temporary equity. Each of these securities is  discussed further below. Limited Partners’ Preferred Interest in the Operating Partnership and Noncontrolling Redeemable Interests in Properties. The following table summarizes the preferred units of the Operating Partnership and the amount of the noncontrolling redeemable  interests in properties as of December 31. The redemption features the preferred units of the Operating Partnership contain  provisions which could require us to settle the redemption in cash. As a result, this series of preferred units in the Operating  Partnership remains classified outside permanent equity. The remaining interest in a property or portfolio of properties which  are redeemable at the option of the holder or in circumstances that may be outside our control, are accounted for as temporary  equity. The carrying amount of the noncontrolling interest is adjusted to the redemption amount assuming the instrument is  redeemable at the balance sheet date. Changes in the redemption value of the underlying noncontrolling interest are recorded  within accumulated deficit. There are no noncontrolling interests redeemable at amounts in excess of fair value. 2011 2010 7.50% Cumulative Redeemable Preferred Units, 260,000 units authorized,  255,373 issued and outstanding  $ 25,537 $ 25,537 Other noncontrolling redeemable interests in properties   242,408 59,932 Limited partners’ preferred interest in the Operating Partnership and other noncontrolling  redeemable interests in properties  $267,945 $ 85,469 2011 Annual Report 57