This excerpt taken from the MWE 8-K filed Jul 5, 2006.
No Preemptive Rights, Registration Rights or Options. Except as described in the Pricing Prospectus and the Prospectus or in the organizational documents of the MarkWest Entities other than the General Partner, there are no preemptive rights or other rights to subscribe for or to purchase, nor any restriction upon the voting or transfer of, any partnership or member interests of the Partnership Entities, in each case pursuant to the partnership agreement or limited liability company agreement of such entity or the certificates of limited partnership or formation and other organizational documents or any other agreement or instrument to which any of such entities is a party or by which any one of them may be bound. Neither the filing of the Registration Statement nor the offering or sale of the Units as contemplated by this Agreement gives rise to any rights for or relating to the registration of any Units or other securities of the Partnership, other than the Units to be sold hereunder by the Selling Unitholders and other than as have been waived or deemed waived. Except as described in the Pricing Prospectus and the Prospectus, there are no outstanding options or warrants to purchase any partnership or member interests in any Partnership Entity.