CRESTPOINTE CORPORATE CENTER STANDARD OFFICE LEASE AGREEMENT

EXHIBIT 10.13

CRESTPOINTE CORPORATE CENTER
STANDARD OFFICE LEASE AGREEMENT

     THIS LEASE is made and entered into this 23 ^rd day of February, 2005, by and between CRESTPOINTE III, LLC, a Maryland limited liability company (“Landlord”) and COSTAR REALTY INFORMATION, INC., a Delaware corporation (“Tenant”).

     In consideration of the rents hereinafter reserved and the agreements hereinafter set forth, Landlord and Tenant mutually agree as follows:

     1.  SUMMARY OF TERMS. The following is a summary of the terms of this Lease. The terms used herein shall have the meanings as set forth in greater detail in the Sections, subsections, paragraphs and Schedules of this Lease that follow, and shall be governed by, and subject to, such provisions.

     2.  SCHEDULES AND DEFINITIONS.

          2.1. Schedules. The following schedules and exhibits are attached to this Lease; such schedules and exhibits, as well as all drawings and documents referenced thereon, shall be deemed to be a part of this Lease.

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          2.2. Definitions. For purposes of this Lease, the following terms shall have the respective meanings as set forth in the following Section, subsection and Schedule references:

     3.  LEASE OF PREMISES. Landlord hereby leases to Tenant, and Tenant hereby leases from Landlord, the Premises, together with the right to use, in common with others, the “Common Facilities,” as defined in Section 8.1 of this Lease, all for the Term as set forth in Section 4. The Premises has the agreed Rental Area as set forth in Section 1.10 and shall not be subject to measurement hereunder. The Premises are shown on the Plan attached hereto as SCHEDULE A.

     4.  TERM AND COMMENCEMENT OF TERM.

          4.1. Term. The Term of this Lease shall commence upon the date specified in Section 1.6, but if no date is specified, then upon the date (the “Commencement Date”) which is the earlier to occur of (i) the date on which Tenant occupies or uses the Premises to conduct business, or (ii) that date which is four (4) weeks after Landlord gives written notice to Tenant certifying that the Premises are Ready for Occupancy. Landlord anticipates that the Premises will be Ready for Occupancy on or before May 1, 2005. The four (4) weeks’ notice pursuant to subsection (ii) above, shall allow Tenant to utilize such four (4) weeks to install its furniture, data and telecommunications on a Rent-free basis, but subject to all other terms and conditions of this Lease respecting Tenant’s use and occupancy of the Premises. The Term shall be for the number of months set forth in Section 1.14, plus the fractional part of the month, if any, from the Commencement Date through the last day of the calendar month immediately prior to the first full calendar month of the Term. The Term shall end at midnight on the last day of the Term (the “Termination Date”), unless earlier terminated pursuant to any other provision of this Lease or pursuant to law. At Landlord’s request, Tenant shall promptly enter into one or more supplementary written agreements, in such form as Landlord shall reasonably prescribe, specifying the Commencement Date and the Termination Date. Notwithstanding the foregoing, if for any reason the Commencement Date of the Term of this Lease shall not have occurred by that date which is six (6) months after the date that Landlord has obtained the building permit for the installation of the Tenant Improvements (as hereinafter defined) (subject to extension for delays caused by Tenant) then, Tenant shall have the right for a period of thirty (30) days (but in no event after the Premises are Ready for Occupancy) after the end of the foregoing six (6) month period, to terminate this Lease upon written notice to Landlord, in which event this Lease shall be canceled, and neither party shall have any further liability arising hereunder, except that Landlord shall return any Advance Rent or Security Deposit paid by Tenant. Landlord shall use its best efforts (exclusive of the payment of monetary consideration) to obtain the

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building permit after the Final Plans and Specifications (as hereinafter defined) have been approved. Notwithstanding the foregoing, if for any reason the Commencement Date of the Term of this Lease shall not have occurred within eighteen (18) months from the date of this Lease for any reason, then, unless the parties shall otherwise agree, this Lease shall be canceled, and neither party shall have any further liability arising hereunder, except that Landlord shall return any Advance Rent or Security Deposit paid by Tenant. “Unavoidable Delays” shall mean delays caused by acts of God, strikes, civil commotion, riot, war, governmental regulations, adverse weather conditions or any other circumstances beyond the reasonable control of Landlord. The Commencement Date may be extended, at Landlord’s election, for the period of any delay attributable to Unavoidable Delays.

          4.2. Ready for Occupancy. For purposes of this Lease, the Premises shall be deemed conclusively to be ready for occupancy (“Ready for Occupancy”) upon the completion of the following conditions: (i) Landlord has substantially completed its work on the Tenant Improvements (subject to the completion of so-called “punch-list items”), so that they are ready for Tenant to occupy the same, or to commence the installation of Tenant’s Personal Property therein, and (ii) Landlord shall have received any governmental approvals which are necessary in order for Tenant to occupy the Premises, unless Tenant’s acts or omissions have caused such approvals to be denied, in which case Tenant shall be deemed to have waived this condition (ii).

     5.  CONSTRUCTION AND COMPLETION OF PREMISES.

          5.1. Landlord’s Obligations. Landlord shall, at its cost and expense (subject to the terms of the immediately succeeding sentence), construct Tenant’s leasehold improvements within the Premises for Tenant’s use and occupancy in accordance with plans and specifications mutually approved by Landlord and Tenant (the “Final Plans and Specifications”) attached as SCHEDULE B to this Lease (the “Tenant Improvements”). Notwithstanding the foregoing, those improvements itemized on SCHEDULE E to this Lease shall be completed by Landlord as part of the Tenant Improvements, but shall be at the sole cost and expense of Tenant (the “Tenant Upgrades”). Any improvements to the Premises in excess of the Tenant Improvements shall be at the sole cost and expense of Tenant. Landlord shall provide Tenant with a test-fit allowance in an amount equal to ten cents ($0.10) per square foot of Rental Area. The cost of the Tenant Upgrades and any improvements to the Premises in excess of the Tenant Improvements shall be payable by Tenant as follows: (i) 50% of the cost thereof upon execution of this Lease, and (ii) the balance on or before the Commencement Date.

          5.2. Intentionally Omitted .

          5.3. Acceptance of Premises. Under no circumstances shall Landlord be liable to Tenant for damages for any delay in commencing or completing construction of the Premises or for a total failure to complete or deliver the same. Except for those punch-list items scheduled by Landlord and Tenant prior to the Commencement Date of this Lease, Tenant’s occupancy of the Premises shall be deemed to constitute acceptance of same and acknowledgment by Tenant that Landlord has fully complied with its obligations hereunder to construct and deliver to Tenant the Premises in accordance with the Final Plans and Specifications. Landlord shall have thirty (30) days to correct all punchlist items and shall have the right to enter the Premises to complete or repair any such unfinished items. Such entry by Landlord, its agents, servants, employees or contractors for such purpose shall not constitute an actual or constructive eviction, in whole or in part, or entitle Tenant to any abatement or diminution of rent or relieve Tenant of any of its obligations under this Lease, or impose any liability upon Landlord or its agents, servants, employees or contractors.

     6.  RENT.

          6.1. Basic Rent. Tenant shall pay to Landlord during the Term of this Lease the Basic Rent, payable in advance in equal Monthly Installments of Basic Rent, without notice, demand, abatement, deduction or set-off, except as may be otherwise be expressly set forth in this Lease, on the first day of each and every calendar month from and after the Rent Commencement Date during the Term of this Lease; provided, however, that if the Term of this Lease shall commence on a day other than the first day of a month, the first payment shall include any prorated Basic Rent for the period from the Rent Commencement Date to the first day of the first full calendar month thereafter. Tenant shall pay to Landlord concurrently with the signing of this Lease the Advance Rent. Rent (as defined in Section 6.6) shall be paid to the Landlord or to the duly authorized agent of Landlord, at its principal offices during business hours.

          6.2. Basic Rent Adjustment. Intentionally omitted.

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          6.3. Additional Rent. Tenant shall pay to Landlord all other sums of money as shall become due from and payable by Tenant hereunder as additional rent (“Additional Rent”), including, but not limited to, the payment of “Tenant’s Proportionate Share of Increased Operating Costs” as defined in Section 7.2 hereof, and “Tenant’s Proportionate Share of Increased Taxes” as defined in Section 7.3 hereof, such Additional Rent to be paid in the manner set forth herein.

          6.4. Security Deposit. Tenant, contemporaneously with the execution of this Lease, has deposited with Landlord the Security Deposit, the receipt of which is hereby acknowledged by Landlord. Landlord shall have the right, but not the obligation, at any time to apply the Security Deposit to cure any breach by Tenant under this Lease after notice to Tenant, and in that event, Tenant shall pay Landlord any amount necessary to restore the Security Deposit to its original level within ten (10) days of any such application. To the extent permitted by law, Landlord shall be entitled to the full use of the Security Deposit and shall not be required either to keep the Security Deposit in a separate account or to pay interest on account thereof. The Security Deposit, or so much thereof as remains after application by Landlord as permitted by this Lease, shall be returned to Tenant within thirty (30) days following the later to occur of (a) the date of the expiration or earlier termination of this Lease, and (b) the date upon which Tenant has performed all of the obligations imposed upon Tenant pursuant to this Lease.

          6.5. Late Charge. All sums payable as Basic Rent or Additional Rent shall be paid by Tenant to Landlord’s Rental Payment Address, or at such other address as Landlord may from time to time designate by Notice given to Tenant care of Tenant’s Notice Address. If any check tendered by Tenant in payment of Rent is dishonored upon presentment for payment, then Landlord, in addition to all other rights and remedies contained in this Lease, may assess a dishonor charge of Fifty Dollars ($50.00); and Landlord shall thereafter have the right to insist that all of Tenant’s further payments be made by certified check. If Tenant fails to pay any Basic Rent or any Additional Rent within ten (10) days of the time it is due and payable (including deemed failure to pay due to dishonor of Tenant’s check upon presentation for payment), then Landlord, in addition to all other rights and remedies contained in this Lease, may assess a one-time per late payment late charge against Tenant in the amount of Five Hundred Dollars ($500.00). Additionally, if Tenant fails to pay any Basic Rent or any Additional Rent when due and payable, then such unpaid amounts shall bear interest from the due date thereof to the date of payment at a rate of twelve percent (12%) per annum (the “Default Rate”). This late charge is not a penalty; it has been agreed to by Landlord and Tenant as necessary to compensate Landlord for the Landlord’s additional costs incurred in connection with late payment of Rent. Tenant shall further be responsible for the payment of any reasonable legal expense and management fees incurred by Landlord in collecting any delinquent Rent due hereunder.

          6.6. Rent. All amounts payable by Tenant to or on behalf of Landlord under this Lease, whether or not expressly denominated as Basic Rent or Additional Rent, and including any and all advances, charges, costs or fees incurred by Landlord in collecting any sums due from Tenant hereunder, or otherwise in preserving the rights of Landlord hereunder or in enforcing the rights and obligations of Landlord and Tenant hereunder, (and specifically including legal expenses and management fees incurred by Landlord hereunder) shall constitute and shall be referred to as “Rent” for the purposes of this Lease as well as Section 502(b)(6) of the Bankruptcy Code, 11 U.S.C. Sec. 502(b)(6).

     7.  TAX AND OPERATING COST ESCALATION.

          7.1. Definitions. For purposes of this Lease, the following definitions shall apply:

               7.1.1. “Operating Year” shall mean each successive calendar year or part thereof during the Term of this Lease or any renewal thereof, or, at the option of Landlord, each successive fiscal year of Landlord or part thereof, during the Term of this Lease or any renewal thereof.

               7.1.2. “Property” shall mean the Building, the Land, the Common Facilities, and all fixtures and other improvements in or upon the Land, including, without limitation, the sidewalks, gardens, lawns, parking areas and loading areas, and also including such additional facilities in subsequent years as may be determined by Landlord to be reasonably necessary or desirable for the management, maintenance or operation of the Building.

               7.1.3. “Operating Costs” shall mean all expenses and costs of every kind and nature which Landlord shall pay or become obligated to pay because of or in connection with owning, operating, managing, painting, repair-

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ing, insuring and cleaning the Property, “grossed up” to reflect 95% of occupancy of the Building, including, but not limited to, the following:

                    a. cost of all supplies and materials used, and labor charges incurred, in the operation, maintenance, decoration, repairing and cleaning of the Property;

                    b. cost of all equipment purchased or rented which is utilized in the performance of Landlord’s obligations hereunder, and the cost of maintenance and operation of any such equipment, including janitorial service for all floor area leased to tenants;

                    c. cost of all maintenance and service agreements for the Property and the equipment therein, including, without limitation, alarm service, security service, window cleaning and elevator maintenance;

                    d. accounting costs, including the cost of audits by certified public accountants, legal and engineering fees and expenses incurred in connection with the operation and management of the Property;

                    e. wages, salaries and related expenses of all on-site agents or employees engaged in the operation, maintenance, security and management of the Property;

                    f. cost of all insurance coverage for the Property from time to time maintained by Landlord, including, but not limited to, the costs of premiums for insurance with respect to personal injury, death, property damage, business interruption, rental income and workmen’s compensation insurance covering personnel;

                    g. cost of repairs, replacements and general maintenance to the Property, structural or non-structural, including without limitation, the mechanical, electrical and heating, ventilating and air-conditioning equipment and/or systems (excluding repairs and general maintenance paid by proceeds of insurance or by tenants or other third parties, and alterations attributable solely to tenants and costs of replacements and repairs which are capital in nature under generally accepted accounting principles, consistently applied);

                    h. any and all Common Facilities maintenance, repair or redecoration (including repainting) and exterior and interior landscaping;

                    i. cost of removal of trash, rubbish, garbage and other refuse from the Property as well as removal of ice and snow from the sidewalks on or adjacent to the Property;

                    j. all charges for electricity (except as otherwise specifically paid for by individual tenants) and gas, water, sewerage service, heating, ventilation and air-conditioning and other utilities furnished to the Property;

                    k. amortization of capital improvements made to the Building after the year in which the Building is substantially completed, which improvements were undertaken with a reasonable expectation that they would result in a more efficient operation of the Building or are made to the Building by Landlord after the Commencement Date pursuant to any governmental law, regulation or action not applicable to the Building when its construction commenced; provided that the cost of each such capital improvement, together with any financing charges incurred in connection therewith, shall be amortized over the useful life thereof and only that portion attributable to each Operating Year shall be included herein for such Operating Year;

                    l. any management fee paid in connection with the operation and management of the Property, but not in excess of the lesser of (i) 4% of gross revenues from operations of the Property in any Operating Year, or (ii) a fair market management fee, provided, however notwithstanding the foregoing, in no event shall the management fee be less than 3% of gross revenues from operations of the Property in any Operating Year in which the existing Landlord as of the date of this Lease is the owner of the Building; and

                    m. every other cost and expense which would be considered as an expense of maintaining, operating, insuring, managing and/or repairing the Property; provided, however, that the term “Operating Costs” shall not include:

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                         i. Taxes;

                         ii. specific costs which are allocated or separately billed to and paid by specific tenants;

                         iii. payments of principal and interest on any Mortgages;

                         iv. leasing commissions or brokerage fees;

                         v. costs associated with preparing, improving or altering space for any leasing or re-leasing of any space within the Building;

                         vi. interest or penalties arising by reason of Landlord’s failure to timely pay any Operating Costs or Taxes;

                         vii. depreciation of the building or any equipment, machinery, fixtures or improvements therein;

                         viii. ground rents;

                         ix. capital improvements, except as otherwise provided in Section 7.1.3 above;

                         x. advertising for vacant space;

                         xi. executive salaries of Landlord;

                         xii. legal fees and expenses for leasing vacant space in the Building, enforcing Landlord’s rights under occupancy leases with tenants of the Property;

                         xiii. utilities and other similar expenses incurred directly by or on behalf of retail tenants in the Building

                         xiv. any costs, fines or penalties incurred due to the violation by Landlord of any governmental rule or authority;

                         xv. any other expense for which Landlord actually receives reimbursement from insurance, condemnation awards, other tenants or any other source;

                         xvi. costs of repairs, restoration, replacements or other work occasioned by fire, windstorm or other casualty and the amount of any non-commercially reasonable insurance deductible;

                         xvii. costs of repairs, restoration, replacements or other work occasioned by the exercise by governmental authorities of the right of eminent domain (whether such taking be total or partial);

                         xviii. costs incurred in connection with negotiations or disputes with tenants, other occupants, or prospective tenants, or costs and expenses incurred in connection with negotiations or disputes with employees, consultants, management agents, leasing agents, purchasers or mortgagees of the Building;

                         xix. allowances, concessions, permits, licenses, inspections, and other costs and expenses incurred in completing, fixturing, furnishing, renovating or otherwise improving, decorating or redecorating space for tenants (including Tenant), prospective tenants or other occupants or prospective occupants of the Building, or vacant leasable space in the Building, or constructing or finishing demising walls and public corridors with respect to any such space;

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                         xx. costs incurred in connection with the original construction of the Building;

                         xxi. Hazardous Materials remediation costs for which Landlord is responsible under this Lease;

                         xxii. costs of repairing, replacing or otherwise correcting defects (including latent defects) in or inadequacies of (but not the costs of ordinary and customary repair for normal wear and tear) the initial design or construction of the Building or the costs of repairing, replacing or correcting defects in the initial design or construction of any tenant improvements;

                         xxiii. costs incurred in connection with the sale, financing, refinancing, mortgaging, selling or change of ownership of the Building;

                         xxiv. costs incurred by Landlord which are associated with the operation of the business of the legal entity which constitutes Landlord as the same is separate and apart from the cost of the operation of the Property, including legal entity formation and legal entity accounting (including the incremental accounting fees relating to the operation of the Building to the extent incurred separately in reporting operating results to the Building’s owners or lenders);

                         xxv. general overhead and general administrative expenses and accounting, record-keeping and clerical support of Landlord or the management agent;

                         xxvi. the rent or rental-related expenses (such as expense reimbursements similar to the Additional Rent Tenant pays for Operating Expenses and Real Estate Taxes) for Landlord’s on-site or off-site leasing office or other employee office space or for any space in the Building set aside for storage facilities, or other facilities provided for the benefit of tenants;

                         xxvii. costs incurred to correct violations as of Lease Commencement Date by Landlord of any law, rule, order or regulation which was then in effect;

                         xxviii. services provided and costs incurred in connection with the operation of retail or other ancillary operations owned, operated or subsidized by Landlord;

                         xxix. costs for sculpture, paintings or other objects of art;

                         xxx. costs of overtime HVAC service whether provided to the Tenant or any other tenant of the Building;

                         xxxi. contributions to political or charitable organizations; or

                         xxxii. costs attributable to any revenue generating signs.

               7.1.4. “Taxes” shall mean real estate taxes, assessments (special or otherwise), levies, ad valorem charges, benefit charges, water and sewer rents, rates and charges, privilege permits and any other governmental liens, impositions or charges of a similar or dissimilar nature, and any payments in lieu of such charges, regardless of whether any such items shall be extraordinary or ordinary, general or special, foreseen or unforeseen, levied, assessed, or imposed on or with respect to all or any part of the Property or upon the rent due and payable hereunder, by the state, county or city in which the Property is located, or any other taxing authority; provided, however, that if at any time during the Term or any extension thereof the method of taxation prevailing at the commencement of the Term shall be altered or eliminated so as to cause the whole or any part of the above items which would otherwise be included in Taxes to be replaced by a levy, assessment or imposition, which is (A) a tax assessment, levy, imposition or charge based on the rents received from the Property whether or not wholly or partially a capital levy or otherwise, or (B) a tax, assessment, levy, imposition or charge measured by or based in whole or in part upon all or any portion of the Property and imposed on Landlord, or (C) a license fee measured by the rent

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payable by Tenant to Landlord, or (D) any other tax, levy, imposition, charge or license fee, however described or imposed, then such levy, assessment or imposition shall be included in Taxes; provided, however, in no event shall Tenant be required to pay any inheritance, estate, succession, income, profits or franchise taxes unless they are in lieu of or in substitution for any of the above items which would otherwise be included in Taxes;

               7.1.5. “Tax Year” shall mean the twelve (12) month period commencing July 1 of each year or such other twelve (12) month period (deemed, for purposes of this Section, to have three-hundred sixty-five (365) days) establishes a real estate tax year by the taxing authorities having local jurisdiction over the Property.

          7.2. Payment of Tenant’s Proportionate Share of Increased Operating Costs. Commencing with the Operating Year beginning January 1, 2006, if Operating Costs during any whole or partial Operating Year exceed the Base Operating Costs, Tenant shall pay to Landlord as Additional Rent, Tenant’s Proportionate Share of such excess (herein referred to as “Increased Operating Costs”) as follows:

               7.2.1. Prior to the commencement of any Operating Year in which Landlord estimates that Operating Costs shall exceed the Base Operating Cost, Landlord shall furnish Tenant with a written statement showing Landlord’s estimate of Operating Costs for the coming Operating Year (the “Estimated Operating Cost Statement”);

               7.2.2. The Estimated Operating Cost Statement shall also show Tenant’s monthly installment of the additional amount of Increased Operating Costs which installment shall be equal to one-twelfth (1/12th) of Tenant’s Proportionate Share of any estimated additional amount, which shall be due and payable monthly as Additional Rent beginning on the first day of each Operating Year;

               7.2.3. Within one hundred twenty (120) days after the end of each Operating Year, Landlord shall furnish Tenant with an annual adjustment statement (the “Operating Cost Adjustment Statement”) which shall show the actual Operating Costs incurred for the Operating Year just ending, the total payments for estimated Increased Operating Costs paid by Tenant for that Operating Year, and the amount by which Tenant’s total estimated payments exceeded or fell short of Tenant’s Proportionate Share of the actual Increased Operating Costs;

               7.2.4. Tenant shall pay Landlord the amount by which its total estimated payments fell short of Tenant’s Proportionate Share of the actual Increased Operating Costs within thirty (30) days after receipt of the Operating Cost Adjustment Statement or Tenant shall receive from Landlord, within thirty (30) days, a credit for the amount that its total estimated payments exceeded its Proportionate Share of the actual Increased Operating Costs, whichever is appropriate.

               7.2.5. If the tenancy expires or terminates on a date other than the last day of any Operating Year, the account of Tenant shall be proportionately adjusted within one hundred twenty (120) days after the close of the Operating Year in the same manner as if the tenancy had not expired or terminated based on a 365 day year. If such adjustment indicates an overpayment by Tenant of its Proportionate Share of Increased Operating Costs, then Landlord shall deliver a check for such excess within thirty (30) days of the date of Landlord’s Statement hereunder.

               7.2.6. If, during the course of any Operating Year, Landlord incurs an unforeseen increase in Operating Costs, Landlord shall have the right (not more than once in any Operating Year) to increase Tenant’s monthly installment of Operating Costs to compensate for this unforeseen increase. For the purposes of this Section 7.2, an “unforeseen increase” shall mean an increase of twenty-five percent (25%) or more in any of the components of Landlord’s Operating Costs estimate.

               7.2.7. Each Operating Costs Statement provided by Landlord shall be conclusive and binding upon Tenant unless within sixty (60) days after receipt thereof, Tenant notifies Landlord, in writing, that it disputes the correctness thereof, specifying those respects in which it claims the Operating Costs Statement to be incorrect. Unless resolved by the parties, such dispute shall be determined by a court of competent jurisdiction. Pending determination of the dispute, Tenant shall pay any amounts due from Tenant in accordance with the Operating Costs Statement, but such payment shall be without prejudice to Tenant’s claims. Upon at least ten (10) days written notice to Landlord, which shall be provided by Tenant prior to the end of the foregoing sixty (60) day period (the “Audit Notice”), Tenant or an independent certified public accountant of Tenant’s choosing (that is not being compensated by Tenant on a contingency fee basis) shall, for a period of sixty (60) days after delivery of the Audit Notice, have reasonable access during normal business hours to inspect the books

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and records of Landlord relating to Operating Expenses for the purpose of verifying the Operating Costs Statement, Tenant to bear all costs relating to such inspection, including, but not limited to, costs of photocopies. If (i) a court proceeding results in a determination, or (ii) Landlord and Tenant mutually agree that the Operating Costs Statement contained an aggregate discrepancy of five percent (5%) or more in Landlord’s favor, then Landlord shall promptly reimburse the reasonable out-of pocket costs paid by Tenant in connection with the inspection of the books and records of Landlord relating to Operating Expenses pursuant to this Section 7.2.7.

               7.2.8. For each Operating Year during the Term, for purposes of calculating Tenant’s Proportionate Share of the Increased Operating Costs during any whole or partial Operating Year (the “Current Operating Year”), total Operating Costs shall be deemed not to exceed the lesser of (A) the amount of all Operating Costs actually incurred by Landlord for such Operating Year or (B) the sum of (i) Landlord’s “Uncontrollable Costs” for such Operating Year plus (ii) Landlord’s “Controllable Costs” for the Operating Year immediately preceding the Current Operating Year, increased by five percent (5%). For purposes of this Section “Uncontrollable Costs” means Landlord’ Operating Cost component costs for snow and ice removal, insurance, Taxes and utilities for the Operating Year in question; and “Controllable Costs” means all of Landlord’s Operating Costs for the Operating Year in question minus Uncontrollable Costs.

          7.3. Payment of Tenant’s Proportionate Share of Increased Taxes. Commencing with the Operating Year beginning January 1, 2006 (the parties acknowledging that the Tax Year for Base Taxes shall end not sooner than June 30, 2006), if Taxes during any whole or partial Tax Year exceed the Base Taxes, then Tenant shall pay to Landlord as Additional Rent, Tenant’s Proportionate Share of such excess (herein referred to as “Increased Taxes”) as follows:

               7.3.1. Prior to the commencement of any Operating Year in which Landlord estimates that Taxes shall exceed the Base Taxes, Landlord shall furnish Tenant with a written statement showing Landlord’s estimate of Taxes for the coming Operating Year (the “Estimated Tax Statement”);

               7.3.2. The Estimated Tax Statement shall also show Tenant’s monthly installment of the additional amount of Increased Taxes which installment shall be equal to one-twelfth (1/12th) of Tenant’s Proportionate Share of any such estimated Increased Taxes, and, which shall be due and payable monthly as Additional Rent beginning on the first day of each Operating Year;

               7.3.3. Within one hundred twenty (120) days after the end of each Operating Year, Landlord shall furnish Tenant with an annual adjustment statement (the “Tax Adjustment Statement”) which shall show the actual Tax Costs incurred for the Operating Year just ended, the total payments for estimated Increased Taxes paid by Tenant for that Operating Year, and the amount by which Tenant’s total estimated payments for estimated Increased Taxes exceeded or fell short of Tenant’s Proportionate Share of the actual Increased Taxes;

               7.3.4. Tenant shall pay Landlord the amount by which its total payments for estimated Increased Taxes fell short of Tenant’s Proportionate Share of the actual Increased Taxes within thirty (30) days after receipt of the Tax Adjustment Statement or Tenant shall receive from Landlord, within thirty (30) days, a credit for the amount that Tenant’s total payments for estimated Increased Taxes exceeded its Proportionate Share of the actual Increased Taxes, whichever is appropriate.

               7.3.5. If the tenancy expires or terminates on a date other than the last day of any Operating Year, the account of Tenant shall be proportionately adjusted (based on a 365 day year) within one hundred twenty (120) days after the close of the Operating Year in the same manner as if the tenancy had not expired or terminated. If such adjustment indicates an overpayment by Tenant of its Proportionate Share of Increased Taxes, then Landlord shall deliver a check for such excess within thirty (30) days of the date of Landlord’s Tax Adjustment Statement hereunder.

               7.3.6. If, during the course of any Operating Year, Landlord determines that its previous Estimated Tax Statement was inaccurate, then Landlord shall have the right to re-estimate Tenant’s Proportionate Share of Increased Taxes by furnishing Tenant a Revised Estimated Tax Statement and Revised Monthly Installment of Tenant’s Proportionate Share of Increased Taxes.

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               7.3.7. Each Tax Statement provided by Landlord shall be conclusive and binding upon Tenant unless within sixty (60) days after receipt thereof, Tenant notifies Landlord, in writing, that it disputes the correctness thereof, specifying those respects in which Tenant claims the Tax Statement to be incorrect. Unless resolved by the parties, such dispute shall be determined by a court of competent jurisdiction. If the court proceedings result in a determination that the Tax Statement contained an aggregate discrepancy of five percent (5%) or more in Landlord’s favor, then Landlord shall bear all costs in connection with such litigation. If the court proceedings result in a determination that the Tax Statement contained an aggregate discrepancy of less than five percent (5%) in Landlord’s favor, Tenant shall bear all costs in connection with such litigation. Pending determination of the dispute, Tenant shall pay any amounts due from Tenant in accordance with the Estimated Tax Statement, but such payment shall be without prejudice to Tenant’s claims. Tenant, for a period of sixty (60) days after delivery of the Tax Statement in each Operating Year and upon at least ten (10) days written notice to Landlord, shall have reasonable access during normal business hours to inspect the books and records of Landlord relating to Taxes for the purpose of verifying the Tax Statement, Tenant to bear all costs relating to such inspection, including, but not limited to, costs of photocopies.

     If Landlord receives a tax credit or tax abatement from Howard County, Maryland and/or the State of Maryland as a result of the execution of this Lease (the “Credit”) then Landlord shall pass through to Tenant the benefit of such Credit by reducing Tenant’s Basic Rent obligations hereunder as and when the economic benefit of such Credit is realized by Landlord. If the amount of the Credit in any given month exceeds the monthly installment payment of Basic Rent due for such month then the balance of the Credit shall be applied against successive monthly installments of Basic Rent next coming due.

     8.  COMMON FACILITIES.

          8.1. Definition of Common Facilities. As used herein, “Common Facilities” shall mean those areas and facilities of the Property, as designated by Landlord from time to time, intended for the general common use and benefit of all tenants of the Building and their agents, representatives, licensees, employees and invitees, including, without limitation, all stairs, landings, roofs, utility and mechanical rooms and equipment, service closets, corridors, elevators, lobbies, lavatories and other public areas of the Building and any paved parking areas, parking deck, access roads, pedestrian walkways, plazas and landscaped areas located upon the Land.

          8.2. Use of Common Facilities. Tenant shall have the non-exclusive right to use the Common Facilities in common with Landlord, other tenants in the Building, and others entitled to the use of the Common Facilities pursuant to the applicable covenants and restrictions, subject to such reasonable rules and regulations governing the use of the Common Facilities as Landlord may from time to time prescribe and subject to such easements therein as Landlord may from time to time grant to others. Tenant shall not obstruct in any way any portion of the Common Facilities or in any way interfere with the rights of other persons entitled to use the Common Facilities and shall not, without the prior written consent of Landlord, use the Common Facilities in any manner, directly or indirectly, for the location or display of any merchandise or property belonging to Tenant or for the location of signs relating to Tenant’s operations in the Premises. The Common Facilities shall at all times be subject to the exclusive control and management of Landlord. Tenant shall also have access to and the right to park in not less than 5 standard parking spaces per 1,000 square feet of Premises, for use in common with other tenants of the Building, in designated common parking areas adjacent to the Building, and at no cost to Tenant during the Term or any renewal term, with overflow parking for use in common with others to be provided in the parking lot behind 7085 and 7095 Samuel Morse Drive, as shown on the attached SCHEDULE H (the “Overflow Parking”), so as to provide an overall parking ratio of 7 standard parking spaces per 1,000 square feet of Premises. Tenant shall take steps to insure that its usage of parking at the Center and in the Overflow Parking by its employees and visitors conforms to such ratio. Tenant shall be entitled to have its name inserted in the Building directory and Building standard suite entry signage, the costs of the same to be paid by Landlord. Tenant shall also have the right to have an exterior lighted “CoStar Group” sign above the third floor of the Building on the one façade of the Building facing Interstate Route 95. Tenant shall pay all costs and expenses in connection with the design, permitting, fabrication, installation, maintenance, repair and removal (including necessary repairs to the Building) of all such signs. Tenant’s rights with respect to any and all signs shall be subject to (a) Landlord’s prior approval, which approval shall not be unreasonably withheld, conditioned or delayed and (b) the pertinent requirements of applicable law or restrictive covenants. Landlord shall reasonably cooperate with Tenant, at no cost to Landlord, in Tenant’s efforts to obtain permits required for Tenant’s signage. Landlord has approved an exterior sign per the specifications attached hereto as SCHEDULE I.

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          8.3. Alterations to Common Facilities. Landlord shall have the right to change or alter the location, layout, nature or arrangement of the Common Facilities or any portion thereof, including, but not limited to, the arrangement and/or location of entrances, passageways, doors, corridors, stairs, lavatories, elevators and other public areas of the Building; provided, however, that no such change or alteration shall deprive Tenant of access to the Premises or reduce the Rental Area of the Premises, unless such reduction is required by Federal, state or local laws or regulations, in which event, a reduction in the Premises shall be permitted with a commensurate reduction in Rent. Landlord shall have the right to close temporarily all or any portion of the Common Facilities to such extent as may, in the reasonable opinion of Landlord, be necessary to prevent a dedication thereof to the public, provided that Tenant is not thereby denied access to the Premises, or for repairs, replacements or maintenance to the Common Facilities, provided such repairs, replacements or maintenance are performed expeditiously and in such a manner as not to deprive Tenant of access to the Premises, and further provided that any such alterations are consistent with the those applicable to a first class office building.

          8.4. Maintenance. Landlord covenants to keep, maintain, manage and operate the Common Facilities, or to cause the same to be done, in a manner consistent with the operation of a first class office building and to keep the sidewalks and driveways, if any, constituting a portion of the Common Facilities clean and reasonably clear of snow and ice. Landlord reserves the right of access to the Common Facilities through the Premises for the purposes of operation, decoration, cleaning, maintenance, safety, security, alterations and repairs.

          8.5. Alterations to Comply with Legal Requirements.

               8.5.1 If any Alterations (as hereinafter defined) are required to be made to the Premises, the Building or the Center due to Legal Requirements because the same were in actual violation of any Legal Requirements on the Commencement Date, or if, as a result of Landlord undertaking any Alterations elsewhere in the Center, Alterations are required to be made to the Premises, the Building or the Center due to Legal Requirements, then Landlord shall make such Alterations at its sole cost and expense (and such expenses shall not be included within Operating Costs or charged as Additional Rent to Tenant); and Landlord shall take all reasonable steps to minimize disruption to Tenant while making such Alterations. Landlord represents and warrants that the Building shall, as of the Commencement Date, be in compliance with the Americans with Disabilities Act.

               8.5.2 Subject to Landlord’s obligations set forth in the previous Subsection and in the following Subsection, if any Alterations are required to be made to the Premises, the Building or the Center due to a change in, or change in the interpretation of, or more stringent enforcement of, Legal Requirements occurring on or after the Commencement Date (and not in connection with Alterations elsewhere in the Center undertaken by Landlord), then Landlord shall make such Alterations as aforesaid, provided that the cost of such Alterations shall be amortized over their useful life and a ratable portion of such cost shall be included within the definition of Operating Costs in each Rental Year until such cost is fully amortized.

               8.5.3 If (i) any Alterations are required to be made to the Premises or to all or any part of the Center other than the Premises due to Legal Requirements and as a consequence of any Alterations made by Tenant within the Premises, or (ii) any Alterations are required to be made to all or any part of the Center, including the Premises, at any time during the Term pursuant to any Legal Requirements relating to accessibility by persons with disabilities or otherwise pursuant to the ADA (collectively, the “Accessibility Alterations”), because the Premises, as used by Tenant, is deemed to be a “place of public accommodation” under the ADA, then all such required Alterations shall be made by Tenant at its sole cost and expense unless Landlord otherwise agrees; and, if Landlord elects to make such Alterations, then such Alterations shall be at Tenant’s sole cost and expense, and payable by Tenant as Additional Rent.

               8.5.4 Within ten (10) days after receipt, Tenant shall advise Landlord in writing, and provide Landlord with a copy of (as applicable), any notices alleging violation of Legal Requirements relating to any portion of the Center or of the Premises; any claims made or threatened in writing regarding noncompliance with Legal Requirements and relating to any portion of the Center or of the Premises; or any governmental or regulatory actions or investigations instituted or threatened regarding noncompliance with the ADA and relating to any portion of the Center or the Premises.

               8.5.5 “Legal Requirements” shall mean (i) all laws, ordinances, notices, orders, rules, regulations and requirements of any and all Federal, state or municipal governments, and of the appropriate departments,

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commissions, boards and officers thereof, including but not limited to The Americans with Disabilities Act, 42 U.S.C. § 12101, et. seq. , and the ADA Disability Guidelines promulgated with respect thereto; (ii) all environmental laws; (iii) all zoning and other land use matters and utility availability regulations or directives; (iv) any direction of any public officer or officers, pursuant to law, which shall impose any duty upon Landlord or Tenant with respect to the use or occupation of the Premises; and (v) all notices, orders, rules and regulations of the National Board of Fire Underwriters, or any other body now or hereafter constituted and exercising similar functions, relating to all or any part of the Premises, regardless of when they became effective; (v) all covenants, conditions, restrictions, reciprocal easement agreements and the like which are recorded among the land records of the jurisdiction in which the Center is located and which are applicable to the Center generally.

     9.  SERVICES AND UTILITIES. So long as Tenant is not in default under this Lease, Landlord shall provide the following facilities and services to Tenant as part of Landlord’s Operating Costs (except as otherwise provided herein):

          9.1. Elevator. At least one elevator subject to call at all times, including Sundays and holidays, in elevator serviced buildings. The foregoing notwithstanding, if only one (1) elevator serves the Building, Landlord shall have the right to remove it from service for the performance of repairs, maintenance or testing or due to an emergency.

          9.2. Utilities. During Operating Hours, reasonable amounts of natural gas for gas-serviced buildings, electric current for lighting, small items of office equipment, subject to the provisions of Section 9.8 and central heating and air conditioning (“HVAC”) during the seasons of the year when these services are normally and usually furnished, and within the temperature ranges of three degrees fahrenheit plus or minus the dialed or regulated temperature on interior thermostats, and otherwise in such amounts normally or usually furnished in comparable office buildings in the locale of the Property. Landlord shall provide the aforesaid services at other times and on Sundays and holidays (“after-hours service”) at Tenant’s expense, provided Tenant gives Landlord notice by 1:00 p.m. on weekdays for after-hours service on the next weekday, by 1:00 p.m. the day before a holiday for service on a holiday, and by 1:00 p.m. on Friday for after-hours service on Saturday or service on Sunday. Such after-hours service shall be charged to Tenant at Landlord’s actual costs therefor, currently $40.00 per hour, as such costs may fluctuate from time to time. Tenant shall pay for such service, as Additional Rent, promptly upon receipt of an invoice with respect thereto.

          9.3. Cleaning. Cleaning in Landlord’s standard manner Monday through Friday exclusive of legal holidays. The existing cleaning specifications for the Premises are attached hereto as SCHEDULE G.

          9.4. Lighting. Replacement of light tubes or bulbs for building standard light fixtures. All light tube or bulb replacements for special non-standard lighting fixtures shall be furnished and installed by Landlord at Tenant’s expense.

          9.5. Lavatories. Rest room facilities and necessary lavatory supplies, including hot and cold running water at the points of supply, as provided for general use of all tenants in the Building.

          9.6. Common Facilities Maintenance. Routine maintenance, painting, and electric lighting service for all public areas of the Building in such manner as Landlord deems reasonable consistent with the operation of the Building as a first-class office building.

          9.7. Interruption of Service. Any failure by Landlord to furnish the foregoing services, resulting from circumstances beyond Landlord’s reasonable control or from interruption of such services due to repair or maintenance, shall not render Landlord liable in any respect for damages to either person or property, nor be construed as an eviction of Tenant, nor cause an abatement of rents hereunder, nor relieve Tenant from any of its obligations hereunder. If any public utility or governmental body shall require Landlord or Tenant to restrict the consumption of any utility or reduce any service for the Premises or the Building, Landlord and Tenant shall comply with such requirements, whether or not the utilities and services referred to in this Section are thereby reduced or otherwise affected, without any liability on the part of Landlord to Tenant or any other person or any reduction or adjustment in rents payable hereunder. Landlord and its agents shall be permitted reasonable access to the Premises after reasonable notice to Tenant for the purpose of installing and servicing systems within the Premises deemed necessary by Landlord to provide the services and utilities referred to in this Section to Tenant and other tenants in the Building. Notwithstanding anything to the contrary contained in this Section 9.7, in the event of the interruption of utility services to the Premises for a period of more than five (5) consecutive business days due to the negligence or willful misconduct of the Landlord, Tenant shall notify Landlord thereof and shall be entitled to an abatement

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of the Basic Rent beginning on the sixth (6th) business day of such interruption and continuing until such utility service has been restored.

          9.8. Tenant’s Consumption of Electricity. “Base Current” shall be defined as that amount of electrical current which is required for Tenant’s usage within the Premises based upon the Final Plans and Specifications. Landlord shall provide, at a minimum, the Base Current. Tenant covenants that, unless permitted pursuant to the terms of this Section, it shall not consume more electrical current than the Base Current. Tenant shall not install or use on the Premises any electrical equipment, appliance or machine requiring more electrical energy than the Base Current, unless the installation and use of such additional electrical equipment, appliance or machine has been approved by Landlord pursuant to terms and conditions set forth in a separate agreement, which approval may be conditioned upon the payment by Tenant, as Additional Rent, of the cost of the additional electrical energy and modifications to the Building electrical system required for the operation of such electrical equipment, appliance or machine.

     10.  REPAIRS BY LANDLORD. Landlord shall keep the Building and all machinery, equipment, fixtures and systems of every kind attached to, or used in connection with the operation of, the Building, including all electrical, heating, mechanical, sanitary, sprinkler, utility, power, plumbing, cleaning, refrigeration, ventilating, air-conditioning and elevator systems and equipment (excluding, however, lines, improvements, systems and machinery for water, gas, steam and electricity owned and maintained by any public utility company or governmental agency or body and any supplemental HVAC system approved by Landlord and installed by Tenant) in good order and repair consistent with the operation of the Building as a first-class office building. Landlord, at its cost and expense, shall make all repairs and replacements necessary to comply with its obligations set forth in the immediately preceding sentence, except for (a) repairs or alterations required to be made by Tenant pursuant to Section 11 hereof and (b) repairs caused or to the extent contributed to by the negligence or willful misconduct of Tenant, its agents, employees, invitees and guests, which repairs shall be made by Landlord at the cost of Tenant, and for which Tenant shall pay promptly upon receipt of an invoice setting forth the cost of such repairs, except as, and to the extent, otherwise provided in Section 14.5. There shall be no abatement in rents due and payable hereunder and no liability on the part of Landlord by reason of any inconvenience, annoyance or injury arising from Landlord’s making reasonable repairs, additions or improvements to the Building in accordance with its obligations hereunder. Notwithstanding the foregoing, Landlord shall make commercially reasonable efforts to avoid disruption of Tenant’s business. Landlord shall have no obligation hereunder to make repairs of Tenant Improvements, Tenant’s Alterations or Tenant’s Personal Property.

     11.  USE, CARE AND REPAIR OF PREMISES BY TENANT.

          11.1. Permitted Use. Tenant shall use and occupy the Premises solely for general office purposes in accordance with applicable zoning regulations and for no other purpose. Tenant shall not do, or permit anything to be done in or on the Premises, or bring or keep anything therein which will, in any way, obstruct, injure, annoy or interfere with the rights of Landlord or other tenants, or subject Landlord to any liability for injury to persons or damage to property, or interfere with the good order of the Building, or conflict with the laws, rules or regulations of any Federal, state or county authority. Tenant shall have access to the Common Facilities and the Premises twenty-four (24) hours per day, seven (7) days per week, three hundred sixty five (365) days per year. Tenant shall have the right, as an Alteration to the Premises, to install Tenant’s own security system for the Premises and shall provide Landlord with not less than five (5) access cards or other reasonable access, as applicable therefor.

          11.2. Care of Premises. Tenant shall, at its sole cost and expense, keep the Premises and the improvements and appurtenances therein in good order and condition consistent with the operation of a first-class office building and, at the expiration of the Term, or at the sooner termination of this Lease as herein provided, deliver up the same broom clean and in as good order and condition as at the beginning of the Term, ordinary wear and tear and damage by fire or other casualty excepted. Tenant, at its sole cost and expense, shall comply with all laws, rules, orders, ordinances, directions, regulations and requirements of federal, state, county and municipal authorities, now in force or which may hereafter be in force, which shall impose any duty upon Landlord (subject to the terms of Section 10) or Tenant with respect to the use, occupation or alteration of the Premises. Tenant, at its sole cost and expense, shall promptly replace scratched, damaged or broken doors and glass in and about the interior of the Premises and shall be responsible for the repair and maintenance of all improvements installed and placed within the Premises as Tenant Improvements. Tenant shall pay for all damage to the Property and any fixtures and appurtenances related thereto due to any waste, misuse or neglect of the Premises or due to any breach of this Lease by Tenant, its employees, agents, representatives or invitees, unless such damage is caused by Landlord,

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its agents, employees, servants or contractors. The covenants of this Section shall expressly survive the termination of this Lease.

          11.3. Compliance with Rules and Regulations. Tenant and its employees, agents and invitees shall abide by and observe the rules and regulations attached hereto as SCHEDULE C for the operation and maintenance of the Building or any new rules and regulations which may from time to time be issued by Landlord, provided that any new rules or regulations are in conformity with common practice or usage in comparable office buildings in locale of the Property, are not inconsistent with the provisions of this Lease, and provided further, that Tenant has received reasonable notice of such new rules and regulations and are not enforced against Tenant (as compared to enforcing any such rules and regulations against any other tenant in the Building) in a manner that intentionally discriminates against Tenant. Nothing in this Lease shall be interpreted to impose upon Landlord any duty or obligation to enforce any such rules and regulations against any other tenant in the Building, and Landlord shall not be liable to Tenant for any violation of these rules and regulations by any other tenant or its employees, agents or invitees.

          11.4. Hazardous Materials. (a) Landlord hereby makes the following warranties to Tenant, each of which is made only to the best of Landlord’s knowledge as of the date of this Lease: (i) Landlord has not placed or allowed to be placed on the Land any Hazardous Materials (other than in compliance with environmental laws) or otherwise violated any environmental laws with respect to the Premises or the construction and development of the Building which violation remains unremedied; (ii) Landlord has received no notice of, nor does Landlord have any knowledge of placement of Hazardous Materials on the Premises or the Land by third parties; (iii) Landlord has neither filed or been required to file any reports respecting Hazardous Materials with any governmental entity; and (iv) Landlord has received no notice from any governmental entity respecting Hazardous Materials on the Land.

          (b) The provisions of this subsection 11.4(b) only apply if (i) it is determined at any time by a court of competent jurisdiction that the representations of Landlord contained in subsection 11.4(a) are not correct and that Landlord had, to the best of its knowledge, knowledge of such incorrectness as of the date of this Lease; (ii) Landlord, its agents, employees or contractors (but not tenants of Landlord or their agents, employees or contractors) violate any environmental laws with respect to the Premises; or (iii) there are, as of the date hereof, Hazardous Materials on the Premises. If this subsection 11.4(b) applies because of an occurrence described in the immediately preceding sentence, then Landlord shall be responsible for all costs incurred in complying with all environmental laws which relate to the occurrence in question and Landlord shall indemnify, defend and hold Tenant harmless from and against any and all claims, judgments, damages, penalties, fines, costs, liabilities or losses (including, without limitation, sums paid in settlement of claims, and reasonable attorneys’ fees, consultant fees and expert fees) which arise during or after the Term from or in connection with the Hazardous Materials and the occurrence in question except for Tenant’s lost profits or damages or loss to Tenant’s business.

          (c) Tenant covenants and agrees that it will not use or allow the Premises to be used for the manufacture, storage, use, treatment, release or disposal of any “Hazardous Material”. The term “Hazardous Material” as used in this Lease means any substance or material in quantities which is, or becomes, controlled by any lawful governmental authority or is designated as hazardous or toxic by any governmental authority or is designated as a hazardous substance pursuant to Section 311 of the Federal Water Pollution Control Act (33 U.S.C. 11317), defined as a hazardous waste pursuant to Section 1004 of the Federal Resource Conservation and Recovery Act (42 U.S.C. 6901 et seq.) or as a hazardous substance pursuant to Section 101 of the Comprehensive Environmental Response, Compensation and Liability Act (42 U.S.C. 9601, et seq ., as amended) or Section 7-101, et seq . of the Environment Article of the Annotated Code of Maryland. Tenant covenants and agrees that at the Termination Date or earlier date of surrender of the Premises it shall return the same free and clear of any Hazardous Materials or Hazardous Material contamination other than that which existed prior to the date of this Lease, if any. The covenants of this Section shall expressly survive the termination of this Lease.

     12.  ALTERATIONS BY TENANT.

          12.1. Alterations. Tenant shall in no event make or permit to be made any alteration, modification, substitution or other change of any nature to the structural, mechanical, electrical, plumbing, HVAC and sprinkler systems within or serving the Premises. After completion of the Tenant Improvements within the Premises, Tenant shall not make or permit any other improvements, alterations, fixed decorations, substitutions or modifications, structural or otherwise, to the Premises or the Building (“Alterations”) without the prior written approval by Landlord of complete plans and specifications prepared and submitted by Tenant, which approval shall not be unreasonably withheld, conditioned or delayed. Landlord’s

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approval shall include the conditions under which acceptable Alterations may be made. Landlord’s approval of the plans, specifications and working drawings for Tenant’s Alterations shall create no responsibility or liability on the part of Landlord for their completeness, design sufficiency, or compliance with all laws, rules and regulations of governmental agencies or authorities. Alterations shall include, but not be limited to, the installation or modification of carpeting, walls, partitions, counters, doors, shelves, lighting fixtures, hardware, locks, ceiling, window and wall coverings; but shall not include the initial Tenant Improvements initially placed within the Premises pursuant to Section 5. All Alterations may be made by Tenant’s contractor (as reasonably approved by Landlord) at Tenant’s sole cost and only after Tenant has obtained any necessary permits from governmental authorities for the Alterations. If Tenant makes any Alterations without the prior consent of Landlord, then, in addition to Landlord’s other remedies, Landlord may correct or remove such Alterations and Tenant shall, on demand, pay the cost thereof (plus ten percent [10%] of such cost as a construction management fee) as Additional Rent. If any mechanic’s lien is filed against the Premises or the Building for work or materials furnished to Tenant (other than by Landlord) the lien shall be discharged by Tenant within twenty (20) days thereafter, solely at Tenant’s expense, by either paying off or bonding the lien. Should Tenant fail to discharge any lien within twenty (20) days of its filing, then, in addition to Landlord’s other remedies, Landlord shall have the right, but not the obligation, to discharge said lien at Tenant’s expense. Notwithstanding the terms of this Section 12.1 to the contrary, Tenant may install a generator and fuel supply (the “Generator”) in the location approved by Landlord near the Building and subject to Landlord’s prior approval of complete plans and specifications for the Generator, such approval to not be unreasonably withheld, conditioned or delayed. The Generator shall be deemed to be Tenant’s Personal Property, and Tenant shall cause the Generator (and all equipment associated therewith) to be removed at the expiration or earlier termination of this Lease. Tenant shall obtain and exhibit to Landlord at Landlord’s request copies of all requisite approvals and permits with respect to the Generator, including, to the extent required, building permits and any architectural approvals required under restrictive covenants applicable to the Build