This excerpt taken from the TESO 10-K filed Mar 29, 2007.
This Lease is and shall be subject and subordinate to any and all ground or similar leases affecting the Project, all mortgages which may now or hereafter encumber or affect the Project and to all renewals, modifications, consolidations, replacements and extensions of any such leases and/or mortgages; provided, however, that at the option of any Underlying Party (hereinafter defined), this Lease shall be superior to the lease or mortgage of such Underlying Party. The provisions of this Section 13.01 shall be self-operative and shall require no further consent or agreement by Tenant or any Underlying Party, but upon request of Landlord or any such Underlying Party Tenant shall, at Tenants expense, execute within ten (10) business days any appropriate certificate or instrument that Landlord or such Underlying Party may reasonably request confirming such subordination. As used in this Lease, the term Underlying Party shall mean the holder of the lessors interest under any ground or similar lease of all or part of the Building and/or the mortgagee or purchaser at foreclosure with respect to any mortgage of all or part of the Building. Tenant agrees that any Underlying Party may unilaterally subordinate its mortgage or lease to this Lease at any time by filing a notice of such subordination in the Official Public Records of Real Property of the county where the Building is located.