Awards may be granted under the Plan in the form of undivided fractional limited partnership interests in the Operating Partnership of one or more classes (“ OP Units ”) established pursuant to the Operating Partnership’s agreement of limited partnership, as amended from time to time. Awards of OP Units shall be valued by reference to, or otherwise determined by reference to or based on, shares of Common Stock. OP Units awarded under the Plan may be (i) convertible, exchangeable or redeemable for other limited partnership interests in the Operating Partnership (including OP Units of a different class or series) or shares of Common Stock, or (ii) valued by reference to the book value, fair value or performance of the Operating Partnership. Awards of OP Units are intended to qualify as “profits interests” within the meaning of IRS Revenue Procedure 93-27, as clarified by IRS Revenue Procedure 2001-43, with respect to a Participant in the Plan who is rendering services to or for the benefit of the Operating Partnership, including its Subsidiaries.