Amount. Contemporaneously with the execution of this Lease, Tenant shall deliver to Landlord either # cash in the amount specified in the Lease Summary Sheet (the “Cash Security Deposit”), which shall be held by Landlord in accordance with Section 7.5 below, or # an irrevocable letter of credit (the “Letter of Credit”) that shall # be in the initial amount of $622,421.90; # be issued on the form attached hereto as Exhibit 6; # name Landlord as its beneficiary; # be drawn on an FDIC insured financial institution reasonably satisfactory to Landlord that both # has an office in the greater Boston metropolitan area that will accept presentation of, and pay against, the Letter of Credit and # satisfies both the Minimum Rating Agency Threshold and the Minimum Capital Threshold (as those terms are defined below). The “Minimum Rating Agency Threshold” shall mean that the issuing bank has outstanding unsecured, uninsured and unguaranteed senior long-term indebtedness that is then rated (without regard to qualification of such rating by symbols such as “+” or “-” or numerical notation) “Baa” or better by Moody’s Investors Service, Inc. and/or “BBB” or better by Standard & Poor’s Rating Services, or a comparable rating by a comparable national rating agency designated by Landlord in its discretion. The “Minimum Capital Threshold” shall mean that the issuing bank has combined capital, surplus and undivided profits of not less than $10,000,000,000. The Letter of Credit (and any renewals or replacements thereof) shall be for a term of not less than one (1) year. If the issuer of the Letter of Credit gives notice of its election not to renew such Letter of Credit for any additional period, Tenant shall be required to deliver a substitute Letter of Credit satisfying the conditions hereof at least thirty (30) days prior to the expiration of the term of such Letter of Credit. If the issuer of the Letter of Credit fails to satisfy either or both of the Minimum Rating Agency Threshold or the Minimum Capital Threshold, Tenant shall be required to deliver a substitute letter of credit from another issuer reasonably satisfactory to the Landlord and that satisfies both the Minimum Rating Agency Threshold and the Minimum Capital Threshold not later than ten (10) business days after Landlord notifies Tenant of such failure. Tenant agrees that it shall from time to time, as necessary, whether as a result of a draw on the Letter of Credit by Landlord pursuant to the terms hereof or as a result of the expiration of the Letter of Credit then in effect, renew or replace the original and any subsequent Letter of Credit so that a Letter of Credit, in the amount required hereunder, is in effect until a date which is at least ninety (90) days after the Expiration Date. If Tenant fails to furnish such renewal or replacement at least sixty (60) days prior to the stated expiration date of the Letter of Credit then held by Landlord, Landlord may draw upon such Letter of Credit and hold the proceeds thereof (and such proceeds need not be segregated) as a Security Deposit pursuant to the terms of this Article 7 until such time as a renewal or replacement Letter of Credit is furnished. Any renewal or replacement of the original or any subsequent Letter of Credit shall meet the requirements for the original Letter of Credit as set forth above, except that such replacement or renewal shall be issued by a national bank reasonably satisfactory to Landlord at the time of the issuance thereof.