Document:

Exhibit 10.12

 Exhibit 10.12 
 AGREEMENT OF SUBLEASE 
 AGREEMENT OF SUBLEASE (this “Sublease”) made this
     day of June, 1999 by and between ICF Kaiser International, Inc., a Delaware corporation, (referred to herein as “Sublessor”), and ICF Consulting Group, Inc., a Virginia corporation duly qualified to do
business in the Commonwealth of Virginia (“Sublessee”). 
 WITNESSETH 
 WHEREAS, ICF Kaiser Hunters Branch Leasing, Inc. (“ICF-HB”) is the tenant under certain Consolidated, Amended and Restated Deed of Lease
agreements by and between HMCE Associates Limited Partnership, R.L.L.P., as landlord, and ICF-HB, as tenant, dated as of November 12, 1997, for space in that building known as “Hunter’s Branch-Phase I” and located at 9300 Lee
Highway, Fairfax, Virginia (the “9300 Lease”) and for space in that building known as “Hunter’s Branch-Phase I, Building 2, located at 9302 Lee Highway (the “9302 Lease”), (together, the “Leases”); 

WHEREAS, ICF-HB sublet the entire “Leased Premises” (as that term is defined in each of the Leases) to Sublessor pursuant to those certain
Agreements of Sublease by and between ICF-HB, as Sublessor, and Sublessor, as sublessee, dated as March 24, 1998, and as of November 12, 1997 respectively, (the “9300 ICF-International Sublease” and the “9302 ICF
International Sublease”), (together, the “ICF-International Subleases”). 
 WHEREAS, HMCE Associates Limited Partnership,
R.L.L.P., assigned all of its rights, title and interest in and to the Leases to Hunters Branch Partners, L.L.C., a Virginia limited liability company (hereinafter referred to as “Lessor”), and Lessor assumed all of the obligations of HMCE
Associates Limited Partnership, R.L.L.P., as landlord under the Leases, pursuant to certain agreements entitled “Assignment and Assumption of Certain Tenancies and Written Contracts” dated as of March 24, 1998 for the 9300 Lease, and
as of November 12, 1997 for the 9302 Lease, each by and between HMCE Associates Limited Partnership, R.L.L.P., and Lessor; 
 WHEREAS,
Sublessee desires to occupy a portion of the space covered by the ICF-International Subleases (as defined herein), as hereinafter set forth. 
 NOW, THEREFORE, the parties hereto, intending to be legally bound, hereby agree as follows: 
 Section 1. Subleased
Premises 
 Sublessor hereby sublets to Sublessee, and Sublessee hereby hires and takes from the Sublessor the premises shown on
Exhibit A-1 attached hereto and made a part hereof, and consisting of approximately One Hundred and Fifty Nine Thousand One Hundred and Twenty One (159,121) total rentable square feet, located at 9300 Lee Highway, Fairfax, Virginia 22031
(“9300 Building”), as well as the premises consisting of the auditorium and “break-out room” shown on Exhibit A-2 attached hereto and made a part hereof, and consisting of approximately Six Thousand and One Hundred
(6,100) total rentable square feet, located at 9302 Lee Highway, Fairfax, Virginia 22031 (“9302 Building”) (collectively, the “Subleased Premises”). 

 Section 2. Term of Sublease 
 This Sublease and all of the parties’ respective rights, obligations and liabilities hereunder shall commence on the date of full execution hereof by
both Sublessor and Sublessee (the “Commencement Date”). The period of the sublease will commence on the Commencement Date and end on October 29, 2012 (the “Term”). 
 Section 3. Base Rent 
 Sublessee covenants and agrees to pay to Sublessor, in currency, which at the time of payment is legal tender for public and private debts in the United States of America. Commencing on the Commencement Date and continuing for a period of
one year, the fixed base rent (“Base Rent”) will be in the sum of Three Million Eight Hundred Sixty Eight Thousand and One Hundred Eighty Six dollars, ($3,868,186) per annum payable in equal monthly installments, subject to adjustment as
hereinafter provided. Commencing on the second year of this Sublease and continuing throughout the Term, the fixed base rent (“Base Rent”) during this period will be in the sum of Four Million, One Hundred Ninety Thousand and Five dollars
($4,190,005) per annum payable in equal monthly installments, subject to adjustment as hereinafter provided. Each monthly installment following the first shall be due and payable not later than the first (1st) day of each month during the Term. If the Commencement Date is not on the first of the month, the Base Rent shall be pro-rated for the initial
partial month of the Term (if necessary). 
 Section 4. Base Rental Adjustment 
 Beginning November 1, 2003 and each year thereafter during the Term, Base Rent shall be the amount equal to the Base Rent for the immediately
preceding sublease year, increased by the “Inflation Adjustment” (as hereinafter defined) for the sublease year in which the computation is made. The Inflation Adjustment for these purposes shall be as defined in the 9300 Lease, being the
lesser of 2.5% of the Base Rent for the immediately preceding sublease year or 225% of the percentage (if any) by which the CPI (as defined in the 9300 Lease) for the Comparison Month in the immediately preceding sublease year exceeds the CPI for
the Comparison Month in 1998. 
 Section 5. Additional Rent 
 (a) Notwithstanding the provisions of Sections 3 and 4 above, Sublessee agrees for each year during the Term, commencing on the first anniversary of the
Commencement Date, and continuing each year thereafter, to pay Sublessor, as additional rent under this Sublease, an amount equal to Sublessee’s “Percentage” (as hereinafter defined) of the amount by which “Operating
Expenses” and “Real Estate Taxes” (under and as defined in the 9300 ICF-International Sublease) exceed Operating Expenses and Real Estate Taxes under the 9300 ICF-International Sublease during the 1999 calendar year. Sublessee’s
Percentage for this purpose shall be deemed to be eighty percent (80%). 
  

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 (b) In addition, Sublessee agrees for each month during the Term, to pay, as additional rent under this
Sublease, all other operating expenses which are excluded from the aforesaid definition of Operating Expenses for the entire Subleased Premises, specifically including, but without limitation, the cost of electricity, cleaning, security, and
additional shuttle bus hours. Copies of all relevant statements and bills received by Sublessee or Sublessor will be provided pursuant to the applicable provisions of the ICF-International Sublease and pursuant hereto, together with a statement of
the amount of additional rent, if any, which Sublessee or Sublessor are required to pay under this Section. 
 (c) Sublessee’s
proportionate share of the additional rent payments described in Section 5(a) and 5(b) shall be paid on an estimated basis in accordance with the procedures described in Section 3(b) of the Leases and shall be reconciled in accordance with
Section 3(b) of the Leases; provided that Sublessee shall make all payment of additional rent in the same manner of payment of rent, on the first day of each month during the Term. Upon the request of Sublessee, Sublessor shall take all steps
possible to cause ICF-HB to cause an audit of the statement of Operating Expense Increases pursuant to Section 3(b) of the Leases; provided, however, that Sublessee shall pay all costs and expenses related to any such audit, and any such audit
shall be performed in accordance with the Leases. Sublessor shall deliver to Sublessee, within ten (10) business days after receipt thereof, Sublessee’s proportionate share of any refunds of any overpayments of additional rent for purposes
of payment of Operating Expenses or Real Estate Taxes received by Sublessor. Sublessee shall also pay to Sublessor, as additional rent, all reasonable and customary charges for any additional services provided to Sublessee hereunder in accordance
with the provisions hereof, including, without limitation, charges and fees for alterations; and after-hours heating and air-conditioning services. Sublessee’s obligation to pay additional rent and to receive refunds of additional rent
overpayments, if any, shall survive until reconciliation of such costs for the last year of the Term is complete. For purposes of this Sublease, all Base Rent and additional rent shall be referred to collectively as “Rental.” 

Section 6. The Leases and the ICF-International Subleases 
 (a) Sublessee acknowledges that it has reviewed and is familiar with all of the terms, covenants, and conditions of the Leases and the ICF-International
Subleases, complete copies of which Sublessor represents are attached hereto as Exhibit B and which are made a part hereof. Except as otherwise expressly provided in or otherwise inconsistent with the Sublease, or to the extent not applicable
to the Subleased Premises, all of the terms, covenants, conditions, stipulations, rights, obligations, remedies and agreements of the Leases and the ICF-International Subleases are incorporated herein and made a part hereof as if set forth herein at
length. The parties hereby specifically acknowledge and agree that, without limitation whatsoever to the foregoing: (i) the term “Basic Rent” in the Leases, and (ii) Section 3(i) of the 9300 Lease and Section 3(j) of
the 9302 Lease related to Lease Restructuring Fees are inconsistent with this Sublease. Sublessee assumes and agrees, except as otherwise provided herein, to perform, observe, and comply with all of the terms, covenants and conditions to be
performed, observed, and complied with by the tenant under the Leases and on the part of the Sublessor to be performed, observed and complied with under the ICF-International Subleases, as the same may or shall relate to the occupancy of the
Subleased Premises, and except as modified by this Sublease. Sublessee hereby makes all waivers and grants all rights, for the benefit of Sublessor, ICF-HB and Lessor, made or granted by Sublessor, as tenant under the ICF-International Subleases.

  

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 (b) This Sublease is expressly made subject to all of the terms, covenants, and conditions of the Leases
and the ICF-International Subleases, except as otherwise expressly provided herein. Subject to the Consent to Sublease and Recognition Agreement annexed hereto as Exhibit C, this Sublease shall terminate upon the expiration or termination of
either of the Leases, whereupon all covenants and agreements made by Sublessor herein shall cease without prejudice to the right of Sublessor to recover all Rental accrued to the latter of termination or recovery of the Subleased Premises.

 (c) The time limits set forth in the Leases and ICF-International Subleases for the giving of notices, making demands, performance of any
act, condition or covenant, or the exercise of any right, remedy or option, are changed for the purpose of this Sublease, by lengthening or shortening the same in each instance, as appropriate, so that notices may be given, demand made, or any act,
condition or covenant performed or any right, remedy or option hereunder exercised, by Sublessor or Sublessee, as the case may be, (and each party covenants that it will do so) within three (3) days prior to the expiration of the time limit,
taking into account the maximum grace period, if any, relating thereto contained in the Leases and ICF-International Subleases. 
 Section 7. Occupancy 
 (a) Sublessee shall use and occupy the Subleased Premises solely for the purposes
permitted under Section 6(a) of the Leases. 
 (b) Sublessee covenants that it will occupy the Subleased Premises in accordance with the
provisions hereof (including the provisions of the Leases and the ICF-International Subleases), and will not do or omit to do any act which results in a default under any of the terms hereof or of any of the Leases or the ICF-International
Subleases. Sublessee shall pay to Sublessor, as additional rent, any and all sums, which Sublessor is required to pay to the ICF-HB or Lessor as the result of Sublessee’s failure to comply with the provisions hereof, of the Leases, and/or the
ICF-International Subleases as they pertain to the Subleased Premises. Without limitation to the foregoing whatsoever, or to Sublessee’s obligations pursuant to Section 7(c) below, if Sublessee is a holdover tenant under this Sublease and
causes Sublessor to be deemed a holdover by the ICF-HB under either ICF-International Sublease, Sublessor, at its option, may remove Sublessee and all its possessions from the Subleased Premises without any liability whatsoever to the Sublessor.

 (c) In the event Sublessee continues to occupy the Subleased Premises after the termination of its right of possession pursuant to the
terms of this Sublease, then, in addition to other liabilities as set forth herein, Sublessee shall, throughout the entire holdover period, in addition to otherwise applicable additional rent, pay Base Rent equal to 150% of the Base Rent applicable
during the last year of the Term. No holding over by Sublessee or payments of money by Sublessee to Sublessor after expiration of the Term of this Sublease shall be construed to extend the Term of this Sublease or to prevent the recovery of
immediate possession of the 
  

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 Subleased Premises by summary proceedings or otherwise as permitted pursuant to applicable law, unless Sublessor has sent
written notice to Sublessee that Sublessor has elected to extend the Term of the Sublease. 
 (d) Notwithstanding anything to the contrary
contained in this Sublease, Sublessor shall not be required to perform any of the covenants and obligations of the Lessor under the Leases (a “Landlord Obligation”) including, but without limitation whatsoever, to provide any of the
services that Lessor has agreed to provide, whether or not specified in Section 5 of the Leases (or required by law), or furnish the electricity to the Subleased Premises that Lessor has agreed to furnish pursuant to the ICF-International
Subleases or the Leases (or required by law), or make any of the repairs or restorations that Lessor has agreed to make pursuant to the ICF-International Subleases or the Leases (or required by law), or to comply with any law or requirement of any
governmental authorities, or take any action that Lessor has agreed to provide, furnish, make, comply with, or take under the ICF International Subleases or the Leases, but Sublessor agrees to use all diligent efforts at Sublessee’s sole cost
and expense, obtain the same from the ICF-HB and/or to cause ICF-HB to obtain the same from Lessor, (provided, however, that Sublessor shall not be obligated to use such efforts or take any action which might give rise to a default under the
Sublease), and Sublessee shall rely upon and look solely to, ICF-HB or Lessor for the provision, furnishing, or making thereof or compliance therewith. If ICF-HB or Lessor shall default in the performance of any of its obligations under any of the
ICF-International Subleases or the Leases, as applicable, Sublessor shall, upon request and at the expense of Sublessee, institute and prosecute any action or proceeding which Sublessee in its reasonable judgment, deems meritorious, in order to have
ICF-HB make such repairs, furnish such services, or comply with any other obligations of ICF-HB under the ICF-International Subleases or as required by law. Sublessee shall indemnify and hold Sublessor harmless from and against any and all such
claims arising from or in connection with such request, action or proceeding, except to the extent of gross negligence or willful misconduct on the part of Sublessor, and its agents, employees, contractors, licensees, and invitees including
indemnity from and against any and all liability, fines, suits, damage, costs and expenses of any kind or nature, including without limitation, reasonable attorneys’ fees and disbursements, incurred in connection therewith. Sublessee shall not
make any claim against Sublessor for any damage which may arise, nor shall Sublessee’s obligations hereunder be diminished, by reason of (i) the failure of Lessor to keep, observe, or perform any of its obligations pursuant to any of the
Leases, as applicable, unless such failure is due to Sublessor’s gross negligence or willful misconduct, or (ii) the acts or omissions of Lessor, or its agents, contractors, servants, employees, invitees or licensees, except to the extent
of the gross negligence or willful misconduct of Sublessor. 
 (e) If any Event of Default described in Section 16 (Default Provisions)
of the Leases shall occur in respect of Sublessee or Sublessee’s property, or if Sublessee shall default in the payment of Base Rent or other Rental hereunder, or in the performance or observance of any of the terms, covenants, and conditions
of this Sublease or of the ICF-International Subleases or the Leases on the part of Sublessee to be performed or observed, which default continues uncured following written notice to Sublessee and the expiration of all applicable cure periods
specified in Section 16 (it being the parties’ intention that such cure periods shall apply in respect of breaches by and notices to Sublessee), Sublessor shall be entitled to the rights, remedies, and 
  

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 indemnifications herein provided and/or reserved by the Lessor and ICF-HB in the Leases and the ICF-International
Subleases, as applicable. In addition to all other said rights, remedies, and indemnifications, Sublessor shall have the right to suspend payments to Sublessee pursuant to Section 11(c), and to offset any sums due thereunder against
Sublessee’ s liability for damages to Sublessor. 
 Section 8. Leasehold Improvements and Allowances 
 (a) Sublessor subleases the Subleased Premises to Sublessee and Sublessee accepts the Subleased Premises in “as-is” condition. Sublessor has not
made and does not make any representations or warranties as to the physical condition of the Subleased Premises, the use to which the Subleased Premises may be put, or any other matter or thing affecting or relating to the Subleased Premises, except
as specifically set forth in this Sublease. Sublessor shall have no obligation whatsoever to alter, improve, decorate or otherwise prepare the Subleased Premises for Sublessee’s occupancy. Sublessor represents and warrants that to the best of
its actual knowledge, without inquiry or investigation, all alterations to the Subleased Premises which it has performed to date have been in compliance with applicable law and the Leases. 
 (b) Sublessee shall not make any alterations, installations, improvements, additions, or other physical changes in or about the Subleased Premises, or
any part thereof, structural or otherwise, or any change whatsoever in the use of the Subleased Premises, or any part thereof, without the prior written approvals and consents required in accordance with the Leases and the ICF-International
Subleases, and without the prior written consent of Sublessor, which consent shall not be unreasonably withheld. Sublessor’s sole obligation in respect of requested approvals and consents shall be to cause ICF-HB to request diligently on
Sublessee’s behalf that Lessor comply with the terms of the Leases. 
 Section 9. Security Deposit 
 (a) Upon execution of this Sublease, Sublessee shall provide Sublessor a security deposit in the sum of One Hundred Thousand Dollars ($100,000.00) in cash
or by letter of credit drawn on a bank as well as in form approved by Sublessor (the “Letter of Credit”) or other form acceptable to Sublessor as security for the prompt, full and faithful performance by Sublessee of each and every
provision of this Sublease and of all obligations of Sublessee hereunder (the “Security Deposit”). Said Security Deposit may not be commingled with other funds of Sublessor and all interest or income from said Security Deposit shall be due
Sublessee. At any time during the Term, Sublessee shall have the right to deliver to Sublessor the Letter of Credit in the amount of, and as replacement for, the original Security Deposit given upon execution of this Sublease, and upon such
replacement, the original Security Deposit shall be promptly returned to Sublessee. In the event of a default which continues beyond any applicable notice and cure period, Sublessor may use, apply, or retain all or any part of the Security Deposit
for payment of any: (i) Base Rent or other Rental; (ii) any sum expended by Sublessor on Sublessee’s behalf in accordance with the provisions of this Sublease; and/or (iii) any sum which Sublessor may expend or be required to
expend by reason of Sublessee’s default, including damages or deficiency in the reletting of the Subleased Premises. The use, application, or retention of the Security Deposit, or any portion thereof, by Sublessor shall not prevent Sub lessor
from exercising any other right or remedy provided by this Agreement of Sublease or by 
  

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 law; and, shall not operate as a limitation on any recovery to which Sublessor may otherwise be entitled. If any portion
of the Security Deposit is used, applied, or retained by Sublessor for a purpose set forth above, Sublessee agrees that within five (5) business days after a written demand therefor is made by Sublessor, Sublessee will deposit with the
Sublessor an amount sufficient to restore the Security Deposit to its original amount. 
 (b) Unless otherwise applied in accordance with the
provisions of this Sublease, the Security Deposit, or any balance thereof, shall be returned to Sublessee within thirty (30) days after the expiration of the Term. Upon return of the Security Deposit or balance thereof to the Sublessee, the
Sublessor shall be completely relieved of liability under this Section. 
 Section 10. Domain; Loss by Casualty

 Notwithstanding any contrary provision of this Sublease or the provisions of the ICF-International Subleases or the Leases herein
incorporated by reference, Sublessee shall not have the right to terminate this Sublease as to all or any part of the Subleased Premises, or be entitled to any abatement of Base Rent, additional rent or any other item of Rental, by reason of a
casualty or condemnation affecting the Subleased Premises unless Sublessor is entitled to terminate the applicable ICF-International Sublease or be entitled to a corresponding abatement with respect to its corresponding obligation under the
applicable ICF-International Sublease. If Sublessor is entitled to terminate the applicable ICF-International Sublease for all or any portion of the Subleased Premises by reason of casualty or condemnation, Sublessee may terminate this Sublease as
to any corresponding part of the Subleased Premises by written notice to Sublessor given at least five (5) business days prior to the date(s) Sublessor is required to give notice to ICF-HB of such termination under the terms of the applicable
ICF-International Sublease. In the event of any damage by fire or other casualty to the Subleased Premises rendering the Subleased Premises wholly or in part untenantable, Sublessee shall acquiesce in and be bound by any action taken by or agreement
with respect thereto entered into by Lessor pursuant to Section 13 of the Leases, and Sublessee shall be entitled to its proportionate share of (i) damages to the extent actually received and/or (ii) the rent abatement to the extent
conclusively determined by Sublessor for the Subleased Premises, as described therein. 
 Section 11. Assignment, Subletting, and
Subleased Premises in 9302 Building 
 (a) Except as specified in this Sublease, Sublessee shall not assign, sell, transfer (whether
by operation of law or otherwise), pledge, mortgage or otherwise encumber this Sublease or any portion of its interest in the Subleased Premises, nor sublet all or any portion of the Subleased Premises, or permit any other person or entity to use or
occupy all or any portion of the Subleased Premises, without the prior written consent of Sublessor and Lessor. It is further agreed that any sale, assignment or other disposition of a majority of the capital stock, a controlling interest in the
Company, and/or all or substantially all of the assets of the Sublessee to any person or entity shall constitute a transfer for purposes hereof, which shall require the prior written consent of Sublessor pursuant hereto. Provided that Sublessee
shall comply with the provisions of this Sublease, the ICF-International Subleases and the Leases with respect to subletting, Sublessor agrees that it shall not unreasonably withhold, condition or delay its consent to a subletting of all or any
portion of the Subleased Premises, provided that ICF-HB and 
  

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 Lessor shall consent to such subletting. Upon the written request of Sublessee, Sublessor, at Sublessee’s sole cost
and expense, shall request the consent of the ICF-HB and Lessor, and shall use commercially reasonable efforts to cooperate with Sublessee in obtaining any such consents. 
 (b) If this Sublease shall be assigned, or, if the Subleased Premises or arty part thereof be sublet or occupied by any person, firm, or corporation other than Sublessee in breach of Section (a) above, Sublessor
may, after default by Sublessee in its obligations hereunder, collect rent from the assignee, subtenant, or occupant and apply the net amount collected to the rent payments and additional rent payable hereunder; but, no such assignment, subletting,
occupancy, or collection shall be deemed a waiver of this covenant or the acceptance of the assignee, sublessee, or occupant as tenant, or a release of Sublessee from the future performance by it of the covenants on the part of it herein contained.
The consent by Sublessor to an assignment or a subletting shall not, in any way, be construed to relieve Sublessee from obtaining the express consent in writing of Sublessor to any further assignment or subletting. Any attempt to mortgage, or
encumber this Sublease, or to sublet, or to suffer or permit the Subleased Premises or any part thereof to be used by others, without the prior written consent of Sublessor, ICF-HB and Lessor will constitute a default under this Sublease. To do so
will subject Sublessee to all remedies and liabilities set forth herein. 
 (c) Notwithstanding anything to the contrary in this
Section 11 or elsewhere in this Sublease, Sublessee hereby acknowledges that Sublessor has granted or intends to grant to certain other subtenants in the 9302 Building listed in Exhibit E annexed hereto a non-exclusive license and right
to use the auditorium forming part of the Subleased Premises in that Building (“Auditorium”) on a first come, first serve basis. Sublessee hereby agrees to sublease the Subleased Premises in the 9302 Building subject to said licenses, and
to comply fully with the terms of said licenses and agreements. Sublessee further agrees that throughout the Term hereof, Sublessor, its sublessees and assigns, and the tenants and subtenants of the 9302 Building shall have the right, on a first
come, first serve basis, equal with Sublessee, and free of charge by Sublessee, except as hereinafter specified, to use the Subleased Premises located in the 9302 Building. Sublessee hereby irrevocably so grants to Sublessor and all other said
persons listed in Exhibit E annexed hereto a non-exclusive license to use said Subleased Premises. Sublessee shall have the obligation to schedule and coordinate the use of said Subleased Premises with all users and licensees, on a first
come, first serve basis, in consultation and coordination with Sublessor. Sublessee shall also collect, on behalf of Sublessor, as its agent, the payments for the use of the Auditorium made by the parties listed in Exhibit E, and remit such
payments to Sublessor promptly after collection. In consideration for all of the foregoing grants, rights, and obligations, Sublessor shall pay to Sublessee a sum equal to twenty percent (20%) of the direct, out of pocket costs to Sublessee of
subleasing and maintaining and operating the audiovisual and related equipment in the 9302 Building Subleased Premises on an annual basis. Sublessor shall pay such sum in equal monthly installments, within thirty (30) days of receipt of:
(1) an appropriate invoice therefor, evidencing in reasonable detail the total costs incurred by Sublessee and stating Sublessor’s percentage payment due, and (2) the payments for auditorium use collected by Sublessee for the benefit
of Sublessor as described herein. In the event of a default by Sublessor of its payment obligation pursuant to the preceding sentence, which continues uncured for more than five (5) days after Sublessee shall have given Sublessor a written
notice specifying such default, provided that this Sublease is in full force and effect, there is no default 
  

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 hereunder on the part of Sublessee, and Sublessee provides prior written notice to Sublessor, Sublessee shall have the
right to offset the sums due from Sublessor and hereunder against its obligations to pay Rental hereunder. From the date hereof, Sublessee shall have the exclusive right to grant to tenants and subtenants of the 9302 building, non-exclusive licenses
to use the Subleased Premises in the 9302 building, subject to, and accordance with, all rights and licenses (including those rights and licenses contained in any leases or subleases in connection with the 9302 building) of Sublessor and the other
parties listed on Exhibit E. 
 (d) Notwithstanding anything herein to the contrary, Sublessee shall have no rights (i) with
respect to Tenant’s Roof Use pursuant to Section 10(e) of the Leases, provided that Sublessee shall have a right to access and use the roof for emergency or regular maintenance and repair, subject to the consent of Sublessor (which consent
shall not be unreasonably withheld) and subject to the terms of the Leases or (ii) to extend the term of the Leases pursuant to Section 30 thereof. 
 Section 12. Quiet Enjoyment 
 Sublessor covenants and agrees with Sublessee that upon
Sublessee’s paying the Base Rent and additional rent as required hereunder, and observing and performing all of the terms, covenants, and conditions of this Sublease on Sublessee’s part to be observed and performed, Sublessee may peaceably
and quietly enjoy the Subleased Premises, subject, nevertheless, to the terms and conditions of this Sublease, the ICF-International Subleases, the Leases. 
 Section 13. “Sublessor” 
 The term “Sublessor” as used in this
Sublease means only the lessee under the ICF-International Subleases at the time in question, so that if the ICF-International Subleases shall be assigned, such assignor shall be thereupon released and discharged from all covenants, conditions, and
agreements of Sublessor hereunder, provided that such covenants, conditions, and agreements shall be binding upon each successor assignee until thereafter assigned. 
 Section 14. Insurance 
 Sublessee, at its sole expense, shall insure the Subleased
Premises throughout the Term hereof against all risks and in such amounts as set forth below and with carriers reasonably acceptable to Sublessor, ICF-HB and/or Lessor. Such policies shall afford protection to the limit of $5,000,000 with respect to
bodily injury or death to any one person, to the limit of $5,000,000 with respect to bodily injury or death to any number of persons in any one accident, and to the limit of $5,000,000 with respect to damage to the property of any one owner from one
occurrence. To the extent required by law, Sublessee shall also, at its sole expense, maintain in full force and effect throughout the Term hereof, worker’s compensation or similar insurance in form and amounts required by law. All such
insurance policies must name each of Sublessor, ICF-HB and Lessor as additional insureds and loss payees, and must provide that such insurance policies may not be canceled or altered without at least thirty (30) days prior written notice to
Sublessor. This Sublease is not effective unless and until Sublessee delivers copies of certificates of all such insurance to Sublessor. The waivers of subrogation contained in Section 12(c) of the Leases shall be expressly applicable to
Sublessee and Sublessor under this Sublease. Sublessor agrees to carry all insurance required of it by the ICF-HB Sublease. 
  

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 Section 15. Indemnity 
 (a) In addition to all other indemnities hereunder, Sublessee agrees to indemnify and hold harmless Sublessor and Lessor from and against any and all
claims, losses, actions, damages, liabilities, and expenses (including reasonable attorneys’ fees) that (i) arise from Sublessee’s possession, use, occupancy, management, repair, maintenance, or control of the Subleased Premises, or
any portion thereof, or (ii) arise from any willful or negligent act or omission of Sublessee or Sublessee’s agents, employees, subtenants, contractors, licensees, and/or invitees, or (iii) arise from injury or death to persons of
damage to property sustained on or about the Subleased Premises (“Indemnified Liabilities”). Sublessee shall, at its own cost and expense, defend any and all actions, suits, and proceedings which may be brought against Sublessor and/or
Lessor and which arise from Indemnified Liabilities. Sublessee shall pay, satisfy, and discharge any and all money judgments, which may be recovered against Sublessor and/or Lessor for an Indemnified Liability. Sublessee’s obligations hereunder
shall survive the expiration of this Sublease with respect to acts or events occurring or alleged to have occurred prior to the end of the Term, to the extent not caused by the gross negligence or willful misconduct of Sublessor. 
 (b) Sublessor hereby agrees to defend, indemnify and hold harmless Sublessee against any claim, proceeding, liability, cost or expense (including
reasonable attorneys’ fees) arising from a breach of the Leases by the “Tenant” thereunder or a breach of the ICF-International Subleases by the “Sublessee” thereunder, except to the extent that any such claim, proceeding,
liability, cost or expense arises directly or indirectly from any breach or default hereunder by Sublessee, or is an Indemnified Liability hereunder. 
 Section 16. Parking 
 At no additional expense to Sublessee, Sublessor will provide
Sublessee the right to the use of up to five hundred sixty (560) unreserved parking spaces in the structured parking facility located adjacent to the 9300 Building for the Term of the Sublease. 
 Section 17. Signage 
 Sublessor, at Sublessor’s expense, shall provide directory listings of Sublessee’s name in the building directory of the 9300 Building in a reasonable number as determined by Sublessor. Sublessee shall have the right to install
(i) 9300 Building standard suite entry signage on the Subleased Premises in the 9300 Building, and (ii) signage with Sublessee’s name on the exterior of the 9300 Building; however, signage must be approved by Sublessor and ICF-HB
(which approval shall not be unreasonably withheld), and by Lessor in accordance with the 9300 ICF-International Sublease and the 9300 Lease. Sublessor shall use commercially reasonable efforts, at Sublessee’s expense, to assist Sublessee in
placing signage in Sublessee’s name on the exterior of the 9300 Building, including assisting Sublessee in obtaining Lessor’s consent and complying with applicable zoning laws. Any such signs approved by Sublessor, ICF-HB and Lessor shall
be installed at Sublessee’s sole cost, expense, and risk. 
  

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 Section 18. Consent of Lessor Under Lease and Sublessor Under Sublease 
 Sublessee hereby acknowledges and agrees that this Sublease is subject to and conditioned upon Sublessor obtaining the written Consent to Sublease and
Recognition Agreement annexed hereto as Exhibit C (“Consent”) of ICF-HB and Lessor as provided in the Leases and ICF-International Subleases respectively. Promptly following the execution and delivery hereof, Sublessor shall submit
this Sublease and this Consent to ICF-HB and Lessor. Sublessee hereby agrees that it shall cooperate in good faith with Sublessor in the procurement of the Consent. In no event shall Sublessor or Sublessee be obligated to make any payment to ICF-HB
or Lessor in order to obtain the Consent or the consent to any provision hereof, other than as expressly set forth in this Sublease. In the event that (a) ICF-HB shall not have executed and delivered the Consent within five (5) business
days after the date of the full execution hereof and (b) Lessor shall not have executed and delivered the Consent within sixteen (16) days after the date of the full execution hereof, Sublessee shall have the right to cancel this Sublease
by giving five (5) business days prior written notice given to the other at any time thereafter prior to the execution and delivery of the Consent, and with the expiration of such notice period (except if such Consent is obtained prior thereto)
this Sublease shall be deemed canceled and of no further force or effect, and neither party shall have any liability or obligation to the other in respect thereof. 
 Section 19. Notices 
 Any notice or demand required or permitted to be given by the
provisions hereof must be in writing and will be conclusively deemed to have been given by a party hereto on the day it is delivered to such party at the address indicated below or, if sent by registered or certified U.S. mail, on the fifth business
day after the day on which mailed, or if sent by recognized commercial courier service, on the second day after the day delivered to the service, addressed to such party at such address: 
  

			
	If to Sublessor:	  	ICF Kaiser International, Inc.
		  	9300 Lee Highway
		  	Fairfax, VA 22031-1207
		  	ATTN: Facility Manager
		
	with a copy to:	  	Squire, Sanders & Dempsey L.L.P.
		  	1201 Pennsylvania Avenue, NW
		  	Suite 500
		  	Washington, DC 20004
		  	ATTN: Susan Bierman
		
	If to Sublessee:	  	ICF Consulting Group, Inc.
		  	9300 Lee Highway
		  	Fairfax, Virginia 22031
		  	ATTN: Kenneth Kolsky

  

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 The person to receive notices or the address for such notices may be changed from time to time by written
notice in accordance with this Section. 
 Section 20. Binding Effect 
 The covenants, conditions, and agreements contained herein shall be binding upon and inure to the benefit of Sublessor and Sublessee and their respective
heirs, executors, administrators, successors, and/or assigns, as permitted hereby. 
 Section 21. Applicable Law/Severability

 This Sublease is entered into in the Commonwealth of Virginia, and its validity and interpretation shall be construed in accordance
with the laws of that state (without giving effect to the doctrine of conflict of laws). Any provision of this Sublease prohibited by, or unlawful or unenforceable-under any applicable law shall be ineffective only to the extent invalid without
invalidating the remaining provisions of this Sublease. For purposes of Virginia law, this Sublease shall be deemed to be a deed of lease executed under seal. Neither this Sublease nor any memorandum thereof shall be recorded without the prior
written consent of Sublessor, ICF-HB and Lessor. 
 Section 22. Priority 
 In the event of conflict or ambiguity with the Leases or the ICF-International Subleases, the terms this Sublease shall control the rights and obligations
of the parties hereto. 
 Section 23. Brokerage 
 Sublessor and Sublessee represent and warrant each to the other that each has dealt with no broker, agent or other person in connection with this
transaction. Sublessee and Sublessor each agrees to indemnify and hold harmless the other from and against any claim by any other broker, agent or other person claiming a commission or other form of compensation by virtue of having dealt with
Sublessee or Sublessor, as applicable, with regard to this leasing transaction. The provisions of this Section shall survive the termination of this Sublease. 
 Section 24. Entire Agreement 
 Sublessor and Sublessee acknowledge that there are no
agreements or understandings, written or oral, between Sublessor and Sublessee with respect to the Subleased Premises, other than as set forth in this Sublease, including the Exhibits hereto, which Exhibits (including the ICF-International Subleases
and the Leases), are incorporated herein by reference, and in the Transition Services Agreement between the parties hereto of even date, a copy of which is attached hereto as Exhibit D and is also incorporated herein by this reference. This
Sublease and the Exhibits hereto may not be altered, modified, terminated or discharged except by a writing signed by the party against whom such alteration, modification or discharge is sought. Except as otherwise defined herein, all capitalized
terms used in this Sublease shall have the same meanings as set forth in the Leases. This Sublease is offered to Sublessee for signature with the 
  

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 express understanding and agreement that this Sublease shall not be binding upon Sublessor unless and until ICF-HB and
Lessor shall have executed and delivered a fully executed copy of the Consent to Sublessor and Sublessee. 
 Section 25.
Transmittal of Notices and Demands 
 Sublessor shall promptly transmit to Lessor and ICF-HB any material written notice or demand
received from Sublessee related to this Sublease or the Subleased Premises, and shall promptly transmit to Sublessee any material written notice or demand related to this Sublease, the Subleased Premises, or Sublessee’s occupancy of the
Subleased Premises received from Lessor or ICF-HB. Sublessee shall promptly transmit to Sublessor any notice or demand received from Lessor or ICF-HB or any other party relating to this Sublease, the Subleased Premises, or Sublessee’s occupancy
of the Subleased Premises (other than notices which are not material to the terms of this Sublease, received in the ordinary course of Sublessee’s business). 
  

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 IN WITNESS WHEREOF, Sublessor and Sublessee have caused this Sublease to be executed by their duly
authorized representatives all as of the day and year first above written. 
  

							
		 		 	SUBLESSOR:
			
	WITNESS:	 		 	ICF KAISER INTERNATIONAL, INC.
				
	 /s/ HEATHER M. BOALS
	 		 	By:	 	 /s/ TIMOTHY P. O’ CONNOR

		 		 	Title:	 	SVP
			
		 		 	SUBLESSEE:
			
	WITNESS	 		 	ICF CONSULTING GROUP, INC.
				
	 /s/ SANDRA D. LITTLE
	 		 	By:	 	 /s/ SUDHAKAR KESAVAN

		 		 	Title:	 	Chairman

  

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 AGREEMENT TO SUBLEASE 
 This Agreement of Sublease (“Sublease”) is made and entered into as of the 24th day of March 1998, effective for all purposes as of the
1st day of January, 1997, by and between ICF KAISTER HUNTERS BRANCH LEASING, INC., a Delaware corporation with
offices at 9300 Lee Highway, Fairfax, Virginia 22031 (“Sublessor”) and ICF KAISER INTERNATIONAL INC., a Delaware corporation with offices at 9300 Lee Highway, Fairfax, Virginia 22031 (“Sublessee”). 
 WITNESSETH: 
 WHEREAS, Sublessor
represents and warrants that it has leased approximately 199,959 square feet of rentable floor space on the first through penthouse floors of a commercial office building with a street address of 9300 Lee Highway, Fairfax, Virginia 22031 (the
“Leased Premises”), pursuant to a lease dated even date herewith, between Sublessor, as tenant, and HMCE Associates Limited Partnership, R.L.L.P., as landlord (“Landlord”), a copy of which lease (the “Lease”) has been
reviewed by Sublessee and is annexed hereto as Exhibit “A”. 
 WHEREAS, Sublessee desires to sublease the entire Leased Premises
from Sublessor upon terms hereinafter set forth: 
 NOW, THEREFORE, in consideration of the premises and other good and valuable
consideration, it is hereby mutually covenanted and agreed as follows: 
 1. Term. Sublessor hereby subleases the Leased Premises to
Sublessee and Sublessee hereby subleases the Leased Premises from the Sublessor upon and subject to the terms, covenants, rentals and conditions herein set forth, for a term (the “Term”) of approximately fifteen (15) years and ten
(10) months, commencing on January 1, 1997 (the “Commencement Date”) and expiring on October 30, 2012; provided, however, that if the Lease shall be terminated for any reason prior to October 30, 2012, then this
Sublease shall expire on the termination date of the Lease. 
 The period commencing with the Commencement Date and ending on the last day of
the twelfth calendar month thereafter shall constitute the first “Lease Year” as such term is used herein. Each successive full twelve (12) month period during the Term shall constitute a “Lease Year” and any portion of the
Term remaining after the last twelve (12) month period during said Term shall constitute the last “Lease Year” for the purposes of this Sublease. 
 2. Delivery and Acceptance of Leased Premises. Sublessee shall retain possession of the Leased Premises in its “as is” condition. It is understood and agreed that Sublessor has made no representations
or warranties with respect to the condition of the Leased Premises. 

 3. Rent. Commencing on the Commencement Date, Sublessee covenants and agrees to pay to Sublessor, at
Sublessor’s address (hereinabove set forth), as rent for the Leased Premises: 
 (a) Basic Annual Rent. A Basic Annual Rent of
Five Million One Hundred Ninety-eight Thousand Nine Hundred Thirty-four and No/100 Dollars ($5,198,934.00), payable in equal monthly installments of Four Hundred Thirty-three Thousand Two Hundred Forty-four and 50/100 Dollars ($433,244.50).
Sublessee shall pay the monthly installments of Basic Annual Rent in advance without prior demand, and without deduction or set-off of any kind, upon the first day of each and every calendar month throughout the term. 
 On November 12, 1997, the Basic Annual Rent shall be increased to Five Million Two Hundred Ninety-eight Thousand Nine Hundred Thirteen and 50/100
Dollars ($5,298,913.50), payable in equal monthly installments of Four Hundred Forty-one Thousand Five Hundred Seventy-six and 13/100 Dollars ($441,576.13). 
 On the first day of the sixth (6th) Lease Year, and on the first day of each Lease Year thereafter during the Term (including any Renewal Period), the Basic Annual Rent (then in effect) shall be increased by the
dollar of the increase, on such date, in the Basic Rent payable under the Lease. 
 (b) Additional Rent: Additional Rent, upon demand
therefor by Sublessor, consisting of: 
 (i) All operating Expense Increases (as defined in Section 1 of the Lease) payable under the
Lease, which Operating Expense increases shall be billed by Sublessor and payable by Sublessee in the same manner as set forth in Section 3(b) of the Lease; and 
 (ii) The actual cost to Sublessor of electricity supplied to the Leased Premises, which amounts shall be payable by Sublessee to Sublessor within ten (10) days after delivery to Sublessee of a bill therefor; and

 (iii) Any other payment (other than Basic Annual Rent) required to be paid by Sublessor to the Landlord under the terms of the Lease, or
required to be paid by Sublessee to Sublessor under the terms of this Sublease. 
 For default in payment of Additional Rent, Sublessor shall have the same
remedies as for a default in payment of Basic Annual Rent. 
 4. Use. Sublessee shall use and occupy the Leased Premises for general
office and storage use, and for no other purpose unless consented to in writing by Sublessor and Landlord. 
 5. Incorporation of
Lease: Except as herein otherwise expressly provided, all of the terms of the Lease are hereby incorporated into and made a part of this Sublease as if stated at length herein, and Sublessee accepts this Sublease subject to, and hereby, during
the Term of this Sublease, assumes all of the terms, covenants, conditions and agreements contained in the Lease to be performed by Sublessor thereunder. The parties hereto agree that subject to the provisions of this Sublease, wherever the words
“Landlord” and “Tenant” appear in the Lease, the words shall be deemed to refer to Sublessor and Sublessee respectively, so that, subject to the provisions of this Sublease, Sublessor shall have the rights and powers of the
Landlord under the 
  

 - 2 - 

 Lease, and Sublessee shall have and does hereby agree to bound by and accepts all the rights, powers, duties and
obligations of the Tenant under the Lease; provided, however, that notwithstanding the foregoing, Sublessor shall have no obligation to perform or furnish any of the work, services, repairs or maintenance undertaken to be made by Landlord under the
Lease, or any other term, covenant or condition required to be performed by Landlord under the Lease. Sublessee covenants and agrees that is shall do nothing which shall have the effect of creating a breach of any of the terms, covenants and
conditions of the Lease. Sublessee shall have the benefit of each and every covenant and agreement made by Landlord to Sublessor under the Lease. In the event that Landlord shall fail or refuse to comply with any of the respective provisions of the
Lease, Sublessor shall have no liability on account of any such failure or refusal, provided that the Sublessee shall have the right to exercise in the name of the Sublessor all the rights to enforce compliance on the part of Landlord as are
available to the Sublessor. Sublessor hereby agrees to cooperate with and execute, all at Sublessee’s expense, all instruments and supply information reasonably required by Sublessee in order to enforce such compliance. Sublessee hereby agrees
to indemnify and hold Sublessor harmless of and from any and all damages, liabilities, obligations, costs, claims, losses, demands, and expenses, including reasonable attorney’s fees, which may be incurred by Sublessor in or as a result of such
cooperation and execution. In amplification and not in limitation of the foregoing and without any allowance to Sublessee or other reduction or adjustment of rent, Sublessor shall not be responsible for furnishing electrical, elevator, heating, air
conditioning, cleaning, window washing, or other services, nor for any maintenance repairs in or to the Leased Premises or the building of which it is a part or to any of the facilities or equipment therein. 
 6. Transmittal of Notices and Demand: Sublessor shall promptly transmit to Landlord any notice or demand received from Sublessee and shall
promptly transmit to Sublessee any notice or demand received from Landlord. Sublessee shall promptly transmit to Sublessor any notice or demand received from Landlord or any other party relating to the Leased Premises (other than in the ordinary
course of Sublessee’s business). 
 7. Landlord’s Consent to Certain Acts: Sublessee agrees that in any case where the
provisions of the Lease or this Sublease require the consent or approval of Landlord or Sublessor prior to the taking of any action, it shall be a condition precedent to the taking of such action that the prior consent or approval of Landlord shall
have been obtained if Landlord’s consent must be obtained under the Lease in such cases. Sublessee agrees that Sublessor shall not have any duty or responsibility with respect to obtaining the consent or approval of Landlord when the same is
required under the terms of the Lease, other than the transmission by Sublessor to Landlord of Sublessee’s request for such consent or approval. 
 8. Sublessor’s Right to Cure Sublessee’s Default: Sublessee shall not do or suffer or permit anything to be done which would cause the Lease to be terminated or forfeited by virtue of any rights of
termination or forfeiture reserved or vested in Landlord or by law or in equity. If Sublessee shall default in the performance of any of its obligations under this Sublease or under the Lease, Sublessor, without being under any obligation to do so
and without thereby waiving such default, may remedy such default for the account and at the expense of Sublessee upon prior notice. If Sublessor makes any expenditures or incurs any obligation for the payment of money in connection therewith, such
sums paid or obligations incurred shall be deemed to be Additional Rent hereunder and shall be paid to Sublessor by Sublessee on demand. 
  

 - 3 - 

 9. Eminent Domain, Loss by Casualty: In the event of any taking by eminent domain or damage by
fire or other casualty to the Leased Premises thereby rendering the Leased Premises wholly or in part untenantable, Sublessee shall acquiesce in and be bound by any action take by or agreement entered into between Landlord and Sublessor with respect
thereto. 
 10. Notice and Demands: All notices or demands under this Sublease shall be in writing and shall be sent by registered or
certified mail, return receipt requested, or hand delivered, to Sublessor at its address set forth above, and to Sublessee at its address set forth above, or such other address as either of the parties may designate by written notice. All notices
hereunder shall be effective on the date of personal delivery or mailing, as the case may be. 
 11. Renewal of Term: Provided that
this Sublease shall be in full force and effect, Sublessee shall have the right, at Sublessee’s sole option, to extend this Sublease for one (1) consecutive additional period of five (5) years (such additional period being hereinafter
referred to as the “Renewal Period”, if exercised, and included in the definition of the Term). Such option to extend shall be exercised by Sublessee giving written notice of the exercise to Sublessor at least thirteen (13) months
prior to the expiration of the initial Term of this Sublease. The Renewal Period shall be for the same Basic Rent payable during the last Lease Year of the initial Term, escalated at the commencement of the Renewal Period and at the commencement of
each Lease Year thereafter by the Inflation Adjustment, and upon the same terms, covenants and conditions set forth in this Sublease with respect to the initial Term, and Sublessee’s obligations to pay Operating Expense Increases pursuant to
Section 3(b) shall continue without interruption during the Renewal Period. In the event Sublessee defaults beyond any applicable cure period under this Sublease after providing notice of exercise of its renewal option but prior to the
expiration of the initial Term, such exercise shall, at the Sublessor’s option exercised by written notice to Sublessee, be void ab initio. 
 12. Surrender of Leased Premises: Upon the expiration or other termination of the Term of this Sublease, Sublessee covenants to quit and surrender to Sublessor or Landlord, as the case may be, the Leased
Premises, broom clean, in good order and condition, ordinary wear and tear damage by fire or other casualty excepted, and at Sublessee’s expense to remove all property of Sublessee. Any property not so removed shall be deemed to have been
abandoned by Sublessee and may be retained or disposed of at Sublessee’s expense by Sublessor or Landlord, as either may desire. 
 13.
Quiet Enjoyment: So long as Sublessee shall observe and perform all of the covenants and agreements binding on it hereunder, (i) Sublessee shall at all times during the Term hereof peacefully and quietly have and enjoy possession of the
Leased Premises without hindrance by Sublessor, and (ii) Sublessor shall not default under the Lease, and (iii) Sublessor shall maintain the Lease in full force and effect throughout the Term hereof, unless a termination is caused by
factors beyond Sublessor’s control. 
  

 - 4 - 

 IN WITNESS WHEREOF, the parties hereto have duly executed this instrument the day and year first above
written. 
  

							
	ATTEST/WITNESS:	 		 	SUBLESSOR:
		 		 	ICF KAISER HUNTERS BRANCH LEASING, INC.
				
	 [ILLEGIBLE]
	 		 	By:	 	 /s/ TIMOTHY P.
O’CONNOR                        (SEAL)

			
	ATTEST/WITNESS:	 		 	SUBLESSEE:
		 		 	ICF KAISER INTERNATIONAL, INC.
				
	 /s/ ELAINE S. YANKEY
	 		 	By:	 	 /s/ REX C.
AKINS                                       
   (SEAL)

  

 - 5 - 

 EXHIBIT A 
 LEASE 

 Phase I Lease 
  

 DEED OF LEASE 
 between 
 HMCE ASSOCIATES LIMITED PARTNERSHIP, R.L.L.P. 
 (as Landlord) 
 and 

ICF KAISER HUNTERS BRANCH LEASING, INC. 
 (as Tenant) 
 Effective as of January 1, 1997 
  

 CONSOLIDATED, AMENDED AND RESTATED DEED OF LEASE 
 THIS CONSOLIDATED, AMENDED AND RESTATED DEED OF LEASE is made and entered into as of the 12th day of November, 1997, effective for all purposes as of the 1st day of January, 1997, by and between (i) HMCE ASSOCIATES LIMITED PARTNERSHIP, R.L.L.P., a
Virginia registered limited partnership, successor in interest to HMCE Associates Limited Partnership (hereinafter referred to as “Landlord”), and (ii) ICF KAISER HUNTERS BRANCH LEASING, INC., a Delaware corporation, successor
in interest to ICF International, Inc. (hereinafter referred to as “Tenant”), and referred to by singular pronouns of the neuter gender, regardless of the number and gender of the parties involved. 
 WHEREAS, the Landlord and Tenant are parties to a certain Lease Agreement dated January 30, 1987 (the “Lease”), pursuant to which Landlord
leased to Tenant certain office space containing approximately 196,749 square feet of net rentable area in the office building known as “Hunter’s Branch – Phase I” and located in Fairfax, Virginia (the “Building”); and

 WHEREAS, Landlord and Tenant entered into a First Amendment to Lease Agreement dated August 31, 1987 (the “First
Amendment”), wherein Landlord leased to Tenant certain additional space in the Building containing, in the aggregate, approximately 3,210 square feet of net rentable area; and 
 WHEREAS, Landlord and Tenant entered into a Second Amendment to Lease Agreement dated September 23, 1987 (the “Second Amendment”), for the
purpose of complying with the requirements of Landlord’s first Mortgagee; and 
 WHEREAS, Landlord and Tenant entered into a Third
Amendment to Lease Agreement dated February 12, 1990 (the “Third Amendment”), which modified certain provisions of the Lease relating to Basic Rent and Operating Expense increases; and 
 WHEREAS, Landlord and Tenant now desire to consolidate, amend and restate the Lease, the First Amendment, the Second Amendment and the Third Amendment in
this Consolidated, Amended and Restated Lease Agreement. 
 NOW, THEREFORE, in consideration of the mutual promises hereinafter set forth and
other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, Landlord hereby leases to Tenant, and Tenant hereby leases from Landlord, the Leased Premises, for the Term (as defined below), except that Landlord
reserves and Tenant shall have no right in and to (a) the use of the exterior faces of all perimeter walls of the Building, (b) except as otherwise provided in Section 10(d), the use of the roof of the Building, or (c) the use of
the air space above the Building. 
 1. Definitions. 
 (a) General Interpretive Principles. For purposes of this Lease, except as otherwise expressly provided or unless the context
otherwise requires, (i) the teams 

 defined in this Section have the meanings assigned to them is this Section and include the plural as well
as the singular, and the use of any gender herein shall be deemed to include the other genders; (ii) accounting terms not otherwise defined herein have the meanings assigned to them in accordance with generally accepted accounting principles;
(iii) references herein to “Sections,” “subsections,” “paragraphs” and other subdivisions without reference to a document are so designated. Sections, subsections, paragraphs and other subdivisions of this Lease;
(iv) a reference to a subsection without further reference to a Section is a reference to such subsection as contained in the same Section in which the reference appears, and this rule shall also apply to paragraphs and other subdivisions;
(v) the words “herein”, “hereof”, “hereunder” and other words of similar import refer to this Lease as a whole and not to any particular provision; and (vi) the word “including” means
“including, but not limited to.” 
 (b) Special Lease Definitions. As used in this Lease the following words
and phrases shall have the meanings indicated: 
 Basic Rent: For each Lease Year, an amount equal to the product
obtained by multiplying the Rentable Area of the Leased Premises by the Rent per Square Foot for such Lease Year. 
 Building: The office building known as the “ICF Kaiser Building,” located at 9300 Lee Highway, Fairfax, Virginia 22031, on the land described in Exhibit A to this Lease, including Tenant’s non-exclusive right in and to
the parking deck and Landlord’s leasehold estate in the underlying land. 
 Building Rentable Area: 201,929 square
feet. 
 Comparison Month: The calendar month of March. 
 CPI: The Consumer Price Index for All Urban Consumers (CPI-U) - All items (1982-84 = 100) for the Washington, DC - MD - VA
metropolitan area currently prepared by the Bureau of Labor Statistics of the United States Department of Labor and published bi-monthly. If, during the Term, the CPI ceases to be published, then Landlord and Tenant shall mutually agree upon a
substitute index, it being understood and agreed that such substitute index shall be similar index generally recognized as authoritative, and thee parties shall reconcile the base thereof with the base of the CPL. If the parties cannot agree upon a
substitute index, then the matter shall be submitted to arbitration under the roles of the American Arbitration Association. 
 First Rental Period: As defined in §4.2(b) of the Ground Lease. 
 Inflation Adjustment: For the
sixth Lease Year (i.e. commencing November 1, 2003) and each Lease Year thereafter during the Term (including any Renewal Period), the lesser of (i) 2.5% of the Rent per Square Foot for the immediately preceding Lease Year or
(ii) 225% of the percentage (if any) by 

 which (x) the CPI for the Comparison Month in the immediately preceding Lease Year exceeds
(y) the CPI for the Comparison Month in 1998. Exhibit C contains an illustration of the operation of the Inflation Adjustment. 
 Initial Term: The period commencing on the Lease Commencement Date and ending on October 31, 2012, but in any event the Initial Term shall end on any date when this Lease is sooner terminated pursuant to its terms. 

Land: The land described in Exhibit A. 
 Landlord’s Notice Address: 1355 Piccard Drive, Suite 470, Rockville, Maryland 20850. 
 Lease Commencement Date: January 1, 1997. 
 Leased Premises: The space containing 199,959 square feet of Rentable Area, consisting of the part of the Second Floor outlined on
the floor plans of the Building attached hereto as Exhibit B, the entire First Floor, the entire Third through Twelfth Floors inclusive, and the Penthouse. 
 Leasing Broker: The Carey Winston Company, which broker shall be paid by Tenant. 
 Office Park: The project consisting of the Building, the office building known as 9302 Lee Highway, Fairfax, Virginia 22031, and the common areas and facilities serving both such buildings. 
 Office Space: The portion of the Building consisting of the First through Twelfth Floors, inclusive. 
 Operating Expense Base: The quotient obtained by dividing (i) $1,162,899.00, by (ii) the Building Rentable Area.

 Operating Expense Commencement Date: January 1, 1998. 
 Operating Expense Increases: For the calendar year in which the Operating Expense Commencement Date occurs and each calendar year
thereafter during the Term, an amount equal to Tenant’s Proportionate Share of the excess of Landlord’s Operating Expenses for such calendar year over the product obtained by multiplying the Operating Expense Base by the Building Rentable
Area. 
 Renewal Period: The additional period of five years for which Tenant is permitted to extend the Initial Term
of this Lease pursuant to Section 30. 
 Rent Commencement Date: January 1, 1997. 

 Rent per Square Foot: $24.00 during the period from January 1, 1997 through
November 11, 1997 (i.e., total Basic Rent for such period shall be $4,141,616.55). $24.50 for the period from November 12, 1997 through December 31, 1997, and for each of the second, third, fourth and fifth Lease Years (i.e., Basic
Rent for such period shall be $4,898,995.50 per Lease Year). For the sixth Lease Year, the Rent per Square Foot shall be an amount equal to $24.00, increased by the Inflation Adjustment for the sixth Lease Year. For the seventh Lease Year, and for
each Lease Year thereafter during the Term, the Rent per Square Foot shall be an amount equal to the Rent per Square Foot for the immediately preceding Lease Year, increased by the Inflation Adjustment for the Lease Year for which the computation is
being made. The foregoing amounts are net of the cost of electricity for the Leased Premises, which shall be billed to and paid by Tenant. 
 Rentable Area: The net rentable area (in square feet) of all or any part of the Leased Premises from time to time. The net rentable area of the Leased Premises is agreed to be 199,959 square feet. 

Second Rental Period: As defined in §4.2(c) of the Ground Lease. 
 Security Deposit: $125,000. 
 Storage Space: The area, containing 4,855 square feet of Rentable Area, located in the Penthouse, which is shown on the floor plans attached as Exhibit B to this Lease. 
 Tenant’s Notice Address: 9300 Lee Highway, Fairfax, Virginia 22031-1207, Attn: Lease Administrator, with a copy to the same
address, Attn: General Counsel. 
 Tenant’s Proportionate Share: The percentage from time to time which the
Rentable Area of the Leased Premises is of the Building Rentable Area, which percentage is acknowledged and agreed to be ninety-nine percent (99%) as of the date of this Lease. 
 Term: The Initial Term and the Renewal Period, if any, as to which Tenant shall have effectively exercised its right to extend, but
in any event the Term shall end on any date when this Lease is sooner terminated pursuant to the terms hereof. 
 (c)
General Definitions. As used in this Lease the following words and phrases shall have the meanings indicated: 
 Additional Charges: All amounts payable by Tenant to Landlord under this Lease other than Basic Rent. All Additional Charges shall be deemed to be additional rent and all remedies applicable to the non-payment of Basic Rent shall be
applicable thereto. 

 Alterations: As defined in Section 9(a). 
 Business Days: All days except Saturdays, Sundays and the following legal holidays: New Years Day, Memorial Day, Fourth of July,
Labor Day, Thanksgiving Day and Christmas Day. 
 Default Interest Rate: A rate per annum equal to the lesser of
(a) the sum of (i) the base rate of interest from time to time established and publicly announced by NationsBank, N.A., Washington, D.C., in its sole discretion, as its then-applicable base rate of interest to be used in determining actual
interest rates to be charged to certain of its borrowers, said base rate to change from time to time as and when the change is announced as being effective, plus (ii) two percent (2%), or (b) ten percent (10%) per annum. 

Event of Default: Any of the events set forth in Section 16(a) as an event of default. 
 Floor: A floor of the Building located above the foundation slab or above an area below grade level which is designated as a
basement or cellar. The term “Floor” preceded by a number shall mean the indicated floor of the Building. 
 Ground Lease: The Lease Agreement dated May 29, 1986, between The First Union National Bank of Virginia, as Trustee, as successor by merger so First American Bank of Virginia, Trustee, as lessor, and Landlord, as lessee, as
amended by a First Amendment to Ground Lease, dated August 18, 1987, and as further amended by a Second Amendment to Ground Lease dated September 22, 1987, pursuant to which Landlord leases the land described in Exhibit A to this Lease.

 Landlord: The landlord named herein or any subsequent owner or lessee, from time to time, of the Landlord’s
interest in the Building. 
 Lease: This Deed of Lease, as amended from time to time, and all Exhibits attached hereto.

 Lease Year: The period of 12 months commencing on the Lease Commencement Date and ending on the last day of the
month which completes 12 full calendar months after the Lease Commencement Date, and each 12 month period thereafter commencing on the first day after the end of the immediately preceding Lease Year, except that the Lease Year shall end on the last
day of the Term. 

 Legal Requirements: All laws, statutes, ordinances, orders, rules, regulations and
requirements of all federal, state and municipal governments, and the appropriate agencies, officers, departments, boards and commissions thereof, and the board of fire underwriters and/or the fire insurance rating organization or similar
organization performing the same or similar functions, whether now or hereafter in force, applicable to the Building or any part thereof and/or the Leased Premises, and notices from Landlord’s Mortgagee, as to the manner of use or occupancy or
the maintenance, repair or condition of the Leased Premises and/or the Building, and the usual and customary requirements of the carriers of all fire insurance policies maintained by Landlord on the Building. 
 Mortgage: Any mortgage, deed of trust or other security instrument of record creating an interest in or affecting title to the
Building or the land on which it is constructed, or both, or any part thereof, including a leasehold mortgage or subleasebold mortgage, and any and all renewals, modifications, consolidations, or extensions of any such instrument; Mortgagee
shall mean the holder or beneficiary of any Mortgage. 
 Operating Expenses: The aggregate of all costs and expenses
reasonably and customarily paid or incurred on an accrual basis by Landlord in connection with the management, operation, servicing and maintenance of the Leased Premises, the Building, the Building parking facility and the land on which the
Building is constructed including, but not limited to, employees’ wages, salaries, welfare and pension benefits and other fringe benefits; payroll taxes; Real Estate Taxes; the Net Annual Rental payable by Landlord under (and as defined in) the
Ground Lease; electricity charges for the main lobby, service areas and other common areas of the Building and the operation of the Building elevators; telephone service; painting of public or other common areas of the Building; exterminating
service; detection and security services; trash removal; sewer and water charges; premiums for fire and casualty, liability, rent, workers’ compensation, sprinkler, water damage and other insurance; repairs and maintenance to the Building;
building, janitorial and cleaning supplies; uniforms and dry cleaning; snow removal; landscaping maintenance; window cleaning; service contracts for the maintenance of elevators, boilers, HVAC and other mechanical, plumbing and electrical equipment;
legal fees (other than legal fees relating to the negotiation of leases with present or prospective tenants of the Building or the enforcement of Landlord’s rights under leases with tenants for space in the Building); accounting fees;
advertising; management fees of four percent (4%) of gross Building rents (exclusive of Operating Expense payments), whether or not paid to any Person having an interest in or under common ownership with Landlord; one-half of all costs and
expenses of providing the shuttle bus services required by Section 31 (reduced by all amounts received by Landlord or its affiliates for after-hours shuttle bus service); dues and assessments to any property owners’ association in which
the Building is a member, window glass replacement, repair and cleaning; repair and maintenance of the grounds, including costs of landscaping, gardening and planting; service contracts with 

 independent contractors, including but not limited to security and energy management service contractors;
compensation (including employment taxes, fringe benefits, salaries, wages, medical, surgical and general welfare benefits [including health, accident and group life insurance]) for all personnel employed by Landlord or its property company who
perform duties in connection with the operation, management, maintenance and repair of the Building (in each case, allocated among all properties served by such employees on a reasonable basis, if such employees are utilized by more than one
property); including a proportionate share of the salary and benefits of the property manager assigned to the Building, based upon the number of properties served by such property manager, but in no event more than one-fourth (1/4) of such
salary and benefits; and all other expenses now or hereafter reasonably and customarily incurred in connection with the operation, maintenance, and management of first class office buildings in the Tysons Corner area of Northern Virginia. If
Landlord makes an expenditure for a capital improvement to the Building to reduce Operating Expenses or to comply with Legal Requirements now in effect at the time the Building was constructed, and if, under generally accepted accounting principles,
such expenditure is not a current expense, the cost thereof shall be amortized over a period equal to the useful life of such improvements, determined in accordance with generally accepted accounting principles, and the amortized cost allocated to
each calendar year during the Term shall be treated as an Operating Expense. Except as provided in the preceding sentence, capital expenditures, depreciation and amortization shall not be included in Operating Expenses. Refunds of Real Estate Taxes
(reduced by Landlord’s reasonable expenses in obtaining such refunds), amounts received by Landlord from tenants of the Building for after-hours heating and air conditioning service and other special services and (to the extent that Operating
Expenses include the cost of any repair or reconstruction work) the amount of any insurance recoveries, shall be credited against Operating Expenses in computing the amount thereof. Operating Expenses shall also be reduced as provided in
Section 3(b). Operating Expenses shall not include financing or mortgage costs; depreciation expense; advertising for vacant space or building promotion; leasing commissions; executive salaries or compensation to any employee of Landlord or its
property management company above the rank of the property manager assigned to the Building; more than one-fourth (1/4) of the salary and benefits of the property manager assigned to the Building; the cost of tenant improvements; legal fees for
leasing vacant space in the Building or enforcing Landlord’s rights under leases with tenants for space in the Building; or charges for electricity used directly by Tenant or by other tenants of the Building. Operating Expenses also shall not
include: costs of additional insurance premiums for the Building due to any tenant’s operations within such tenant’s demised premises, which are payable by such tenant under such tenant’s lease; the cost of repairs or replacements
incurred by reason of fire or other casualty; or any other costs or expenses for which Landlord actually receives reimbursement from any source (other than amounts paid by tenants of the Building with respect to Operating Expenses), including,
without limitation, insurance proceeds, condemnation awards or warranties. 

 Penthouse: The Floor immediately above the Twelfth Floor. 
 Person: A natural person, a partnership, a corporation, a limited liability company and any other form of business or legal
association or entity. 
 Real Estate Taxes: All taxes, assessments, vault rentals, water and sewer rents, if any, and
other charges, if any, general, special or other wise, including all assessments for schools, public betterments and general or local improvements, levied or assessed upon or with respect to the ownership of and/or all other taxable interests in the
Building and the land on which it is built imposed by any public or quasi-public authority having jurisdiction and personal property taxes levied or assessed on Landlord’s personal properly used in connection with the operation, maintenance and
repair of the Building. Real Estate Taxes shall not include any inheritance, estate, succession, transfer, recordation, gift, franchise, corporation, income or profit tax or capital levy. If at any time during the Term the methods of taxation shall
be altered so that in addition to or in lieu of or as a substitute for the whole or any part of any Real Estate Taxes levied, assessed or imposed there shall be levied, assessed or imposed (i) a tax, license fee, excise or other charge on the
rents received by Landlord, or (ii) any other type of tax or other imposition (except those excluded from Real Estate Taxes in the preceding sentence) in lieu of, or as a substitute for, or in addition to, the whole or any portion of any Real
Estate Taxes, then, the same shall be included as Real Estate Taxes. A tax bill or true copy thereof, together with any explanatory or detailed statement of the area or property covered thereby, submitted by Landlord to Tenant shall be conclusive
evidence of the amount of taxes assessed or levied, as well as of the items taxed. If any real property, tax or assessment levied against the Land, buildings or improvements covered thereby or the rents reserved therefrom, shall be evidenced by
improvement or other bonds, or in other form, which may be paid in annual installments, only the amount paid or payable in any Lease Year shall be included as Real Estate Taxes for that Lease Year. 
 Taking: A taking of property or any interest therein or right appurtenant or accruing thereto, by condemnation or eminent domain or
by action, proceedings, or agreement in lieu thereof, pursuant to governmental authority. 
 Tenant: The tenant named
herein and any permitted assignee under Section 15. 
 Tenant’s Special Installations: As defined in
Section 9(d). 
 Unavoidable Delays: Delays caused by strikes, acts of God, lockouts, labor difficulties, riots,
explosions, sabotage, accidents, inability to obtain labor or materials, governmental restrictions, enemy action, civil commotion, fire, unavoidable casualty or similar causes beyond the reasonable control of the Landlord or the Tenant, as the case
may be. No payment of any monetary 

 amounts required of, or the obtaining or delivery of any required insurance policies by, either Landlord
or Tenant shall be delayed or excused by acts of Unavoidable Delay. 
 2. Condition of Premises. 
 Tenant accepts the Leased Premises in their as-is, where-is condition as of the date of this Lease, subject to any and all deficiencies and defects
therein, and without any express or implied warranties of habitability, fitness, fitness for a particular purpose or otherwise. 
 3. Rent
and Additional Charges. 
 (a) Payment of Rent and Additional Charges. Tenant shall pay the Basic Rent for each
Lease Year in equal monthly installments in advance on the first (1st) day of each month during the Term. The Basic Rent and all Additional Charges shall be paid promptly when due, in lawful money of the United States, without notice or demand
and without deduction, diminution, abatement, counterclaim or setoff of any amount or for any reason whatsoever, except as otherwise expressly provided in subsections (b) and (g) and Sections 13 and 14, to Landlord by wire transfer to such
bank account as Landlord may from time to time designate. If Tenant makes any payment to Landlord by check (which, for any payment other than by wire transfer, shall require Landlord’s consent), such payment shall be by check of Tenant and
Landlord shall not be required to accept the check of any other person, and any check received by Landlord shall be deemed received subject to collection. If any check is mailed by Tenant, Tenant shall post such check in sufficient time prior to the
date when payment is due so that such check will be received by Landlord on or before the date when payment is due. Tenant shall assume the risk of lateness or failure of delivery of the mails, and no lateness or failure of the mails will excuse
Tenant from its obligation to have made the payment in question when required under this Lease. All bank service charges resulting from any bad checks shall be borne by Tenant. The rent reserved under this Lease shall be the total of all Basic Rent
and Additional Charges, increased and adjusted as elsewhere herein provided, payable during the entire Term and, accordingly, the methods of payment provided for herein, namely, annual and monthly rental payments, are for convenience only and are
made on account of the total rent reserved hereunder. 
 (b) Payment of Operating Expense Increases. Tenant shall pay
as additional rent Operating Expense Increases for each calendar year, commencing with the calendar year in which the Operating Expense Commencement Date occurs. Landlord shall make a reasonable estimate of Tenant’s Operating Expense interests
for each calendar year (based on the projected Real Estate Taxes payable for the real estate tax fiscal years included in such calendar year, the other Operating Expenses for the preceding calendar year and known increases in other Operating
Expenses for the current calendar year), and Tenant shall pay to Landlord 1/12th of the amount so estimated on the first day of each month in advance, beginning on January 1, 1998 and continuing thereafter throughout the Term. If
Landlord’s estimate of Tenant’s Operating Expense increases for any calendar year is received by Tenant after January l of the calendar year, Tenant shall pay to 

 Landlord in a lump sum, within 15 days after receipt of the estimate, the arrearages in the monthly
estimates for each month in the calendar year before receipt of the estimate and shall pay the remaining monthly installments on the first day of each month in advance during the balance of the calendar year. Within 150 days after the end of each
calendar year, Landlord shall submit to Tenant a statement prepared by an independent certified public accountant setting forth in reasonable detail the Operating Expenses for such calendar year and the amount of Tenant’s Operating Expense
Increases for such calendar year. If Tenant’s Operating Expense Increases so stated are more than the amount theretofore paid by Tenant for Operating Expense Increases based on Landlord’s estimate, Tenant shall pay to Landlord the
deficiency within 15 days after the submission of such statement. If Tenant’s Operating Expense Increases so stated are less than the amount theretofore paid by Tenant for Operating Expense Increases based on Landlord’s estimate, Landlord
shall refund to Tenant the excess within 15 days after submission of such statement or Landlord, at its option, shall credit the excess against the next monthly installment of Basic Rent thereafter payable by Tenant under this Lease. Tenant, at its
sole cost and expense, shall have the right, at reasonable times and upon reasonable notice given within 90 days after receipt of a statement for Tenant’s Operating Expense Increases for any calendar year, to audit the statements furnished to
Tenant for such calendar year. If either the Operating Expense Commencement Date shall not coincide with the beginning of a calendar year or the last day of the Term shall not coincide with the end of a calendar year, then the amount of Operating
Expense increases payable for the calendar year in which the Operating Expense Commencement Date or the last day of the Term occurs, as the case may be, shall be pro-rated on a daily basis between Landlord and Tenant based on the number of days in
such calendar year after the Operating Expense Commencement Date or before the last day of the Term. Tenant’s obligations under this subsection to pay Operating Expense increases and Landlord’s obligation to reimburse Tenant for an
overpayment of Operating Expenses shall survive the expiration of the Term. 
 (c) Interest. If Tenant fails to make
any payment of Basic Rent or Additional Charges by the earlier to occur of (i) 5 business days after the due dale thereof or (ii) 7 days after the due date thereof, interest shall, at Landlord’s option, accrue on the unpaid portion
thereof from the due date at the Default interest Rate, but in no event at a rate higher than the maximum rate allowed by law, and shall be payable on demand. 
 (d) Accord and Satisfaction. No payment by Tenant or receipt by Landlord of any lesser amount than the amount stipulated to be paid
hereunder shall be deemed other than on account of the earliest stipulated Basic Rent or Additional Charges; nor shall any endorsement or statement on any check or letter be deemed an accord and satisfaction, and Landlord may accept any check or
payment without prejudice to Landlord’s right to recover the balance due or to pursue any other remedy available to Landlord. 
 (e) Late Payment Charge. If Tenant fails to pay any Basic Rent or Additional Charges by the earlier to occur of: (i) 5 business days after the due date thereof or (ii) 7 days after the due date thereof, Tenant shall pay to
Landlord on demand a 

 late payment service charge (to cover Landlord’s administrative and overhead expenses of processing
late payments) equal to the greater of $100.00 or 5% of such unpaid sum for each and every calendar month or part thereof after the due date that such sum has not been paid to Landlord. Such payment shall be deemed liquidated damages and not a
penalty, but shall not excuse the untimely payment of rent. 
 (f) Reduction of Real Estate Taxes. Landlord shall give
Tenant a copy of any tax assessment notice with respect to the Building within 15 days after receipt thereof. Landlord will use reasonable efforts to obtain a reduction of Real Estate Taxes, provided Tenant makes a written request to Landlord so to
do and, in such request, agrees to pay its proportionate share of the costs thereof as hereinafter provided, and Landlord receives such request not less than 20 days prior to the last day on which Real Estate Tax reduction proceedings for the
particular real estate tax year in question may be commenced. The method and manner of conducting proceedings for such reduction, including the selection of counsel, shall be solely within the judgment and determination of Landlord, and Landlord may
cancel, discontinue or settle such proceedings if, in Landlord’s judgment, such cancellation, discontinuance or settlement is advisable. Landlord shall keep Tenant informed of the status of any such proceeding. If Landlord determines to cancel
or discontinue such proceeding, Tenant shall have the right, either alone or with other tenants of the Building, to continue such proceeding at its or their own expense. To the extent that the reasonable costs and expenses, including legal fees of
such proceedings instituted and conducted by Landlord, requested by Tenant and others, exceed the amount of any tax refund, Tenant shall pay that proportion of such excess cost and expense which the Rentable Area of the Leased Premises bears to the
total rentable area leased to all tenants making such request at the time it is made. 
 (g) Abatement of Basic Rent.
If, because of Landlord’s failure to provide any of the services referred to in Sections 5(h), all or substantially all of the Leased Premises becomes untenantable and Tenant is unable to and does not, in fact, use all or substantially all of
the Leased Premises for the uses permitted by Section 6(a) for a continuous period of 10 Business Days, then provided the cause of such cessation of services is not the result, in whole or in principal part, of Tenant’s negligence or
intentional misconduct, Tenant shall be entitled to an abatement of Basic Rent for the period of time in which Tenant is unable to use, and does not, in fact, use all or substantially all of the Leased Premises for the uses permitted by
Section 6(a). Any dispute between Landlord and Tenant as to Tenant’s entitlement to an abatement of Basic Rent shall be submitted to mediation pursuant to Section 28. 
 (h) Retroactive Rent Adjustment. Subject to the availability of Net Cash Flow, as defined in Section 2.2 of the Limited
Liability Company Agreement of Hunters Branch Partners, L.L.C., reduced only by the Retroactive Rent Adjustments described herein and in Tenant’s Lease for premises in 9302 Lee Highway, Vienna, Virginia (“Available Cash Flow”), Tenant
shall receive Retroactive Rent Adjustments in the following amounts for the following 12-month periods (“Adjustment Years”) during the Term: 

				
	 Adjustment Year
	  	Amount of Rent Adjustment
	 11/1/97 – 10/31/98
	  	$	269,455.00
	 11/1/98 – 10/31/99
	  	 	274,042.00
	 11/1/99 – 10/31/00
	  	 	287,035.00
	 11/1/00 – 10/31/01
	  	 	307,856.00
	 11/1/01 – 10/31/02
	  	 	319,547.00
	 11/1/02 – 10/31/03
	  	 	206,425.00
	 11/1/03 – 10/31/04
	  	 	216,051.00
	 11/1/04 – 10/31/05
	  	 	236,776.00
	 11/1/05 – 10/31/06
	  	 	240,617.00
	 11/1/06 – 10/31/07
	  	 	153,560.00
	 11/1/07 – 10/31/08
	  	 	262,733.00
	 11/1/08 – 10/31/09
	  	 	263,676.00
	 11/1/09 – 10/31/10
	  	 	298,457.00
	 11/1/10 – 10/31/11
	  	 	351,375.00
	 11/1/11 – 10/31/12
	  	 	379,037.00

 Subject to Available Cash Flow, the Retroactive Rent Adjustment shall be paid by Landlord to
Tenant in equal monthly installments in arrears. If the monthly installment of the Retroactive Rent Adjustment for any month is not fully paid because of the lack of Available Cash Flow, then the unpaid portion shall be paid in a later month of the
Term (if any) when there is sufficient Available Cash Flow to pay such unpaid portion. Landlord agrees that it will not pay, and Tenant agrees that it will not accept, a Retroactive Rent Adjustment for any month during any Adjustment Year unless the
Annual Priority Return (as defined in Section 2.2 of the Limited Liability Company Agreement of Hunters Branch Partners, L.L.C.) for such month (together with accrued interest, if any) has been paid by Hunters Branch Partners, L.L.C. to the
Person entitled to receive such payment. 
 (i) Lease Restructuring Fee. Upon execution of this Lease, Tenant has paid
Landlord a Lease Restructuring Fee in the amount of $660,767.80, receipt of which is hereby acknowledged by Landlord. 
 4. Common
Areas. 
 Throughout the Term, Tenant and its agents, employees and business invitees shall have the non-exclusive right, in common with
other tenants of the Building and the adjacent office building, to use the public lobbies, elevators, corridors, stairways, parking garage, sky walk, patios, sidewalks, roadways and other common areas in the Building and the Land, and the toilet
rooms in public areas of multi-tenant floors in the Building. Landlord shall have the right to rent parking spaces in the parking garage to persons other than tenants of the Building and the adjacent office building with Tenant’s prior written
approval, which approval shall not be unreasonably withheld, and which approval shall be deemed given provided that (i) no third party parking contract shall be for a period of more than one (1) month, (ii) access to the parking
garage shall be controlled by access or key cards, and (iii) reasonable security shall be provided 

 with respect to the parking garage area. Landlord shall have the right at any time, without the Tenant’s consent, to
change the arrangement or location of entrances, passageways, doors, doorways, corridors, stairs, toilet rooms or other public portions of the Building, provided any such change does not unreasonably obstruct Tenant’s access to the Leased
Premises. The balconies on the tenth, eleventh and twelfth floors of the Building shall be reserved for Tenant’s exclusive use. Notwithstanding anything to the contrary in this Lease, tenants of the other building in the Office Park (9302 Lee
Highway), their agents, employees and business invitees will not have any right to use the internal lobbies, elevators, corridors, stairways and toilet rooms in the Building. 
 5. Services and Utilities. 
 (a) Building Services. Throughout the Term, Landlord agrees that the Building will be managed and maintained in accordance with generally accepted industry practices and in a manner befitting a modern, first class rental office
building in Fairfax County, Virginia, and that, subject to Legal Requirements, it will furnish to Tenant the following services: 
 (1) Subject to the provisions of subsection (b), normal and usual electricity for lighting purposes and the operation of ordinary office equipment; 
 (2) Adequate supplies for toilet rooms located in public areas of the Building; 
 (3) Normal and usual cleaning and janitorial services after business hours on Business Days in accordance with the standards set forth in
Exhibit D attached hereto and made a part hereof, provided, however, that Landlord shall not provide cleaning and janitorial services to the double-secured areas of the Leased Premises; 
 (4) Hot and cold running water in the toilet rooms located in public areas of the Building and at valved outlets at the locations in the
Leased Premises shown on Tenant’s Space Layout; 
 (5) Subject to the provisions of subsections (c) and (e), heating
and air-conditioning to the Leased Premises when required for the comfortable occupancy of the Leased Premises, at reasonable temperatures, pressures and degrees of humidity, and in reasonable volumes and velocities, between the hours of 8:00 A.M.
and 7:00 P.M. on Business Days and between the hours of 9:00 AM. and 1:00 P.M. on Saturdays unless Saturday is a legal holiday; 
 (6) Automatically operated elevator facilities 24 hours a day, seven days a week throughout the Term; 
 (7) All
electric bulbs and fluorescent tubes in permanently installed light fixtures in the Leased Premises and in the public areas of the Building; 

 (8) Five (5) keys for the suite entry door to each portion of the Leased Premises
located on a separate Floor at no cost to Tenant, but all additional keys, including replacements for lost keys, shall be issued only upon the payment of a reasonable cost for each additional key; 
 (9) An electronic card security access system for the public areas of the Building and the garage and a reasonable number of access cards
for use by Tenant’s employees; and 
 (10) A fully-operational structured parking facility for use by tenants of the
Building with access limited to Persons authorized by Tenant or Landlord. 
 (b) Electricity. Landlord shall not be
liable in any way to Tenant for any failure or defect in the supply or character of electrical energy furnished to the Leased Premises by reason of any requirement, act or omission of the public utility serving the Building with electricity.
Tenant’s use of electrical energy in the Leased Premises shall not at any time exceed the capacity of any of the electrical conductors and equipment in or otherwise serving the Leased Premises as shown on Landlord’s Building Plans. Tenant
shall not install or operate in the Leased Premises any electrically operated equipment which uses electric current in excess of the capacity of the feeders and panel boards serving the Leased Premises as shown on Landlord’s Building Plans
without Landlord’s written consent, which consent may be conditioned upon Tenant’s agreement to pay the cost of any additional wiring which may be required for the operation of such equipment in order to insure that such capacity is not
exceeded and to avert a possible adverse effect upon the Building electrical service Tenant shall give notice to Landlord whenever Tenant shall connect to the Building electrical distribution system any electrically operated equipment other than
lamps, typewriters and similar small office machines. Any feeders or risers to supply Tenant’s electrical requirements in addition to those originally installed, and all other equipment proper and necessary in connection with such feeders or
risers, shall be installed by Landlord upon Tenant’s request, at the sole cost and expense of Tenant, provided that, in Landlord’s reasonable judgment, such additional feeders or risers are permissible under applicable laws and insurance
regulations and the installation of such feeders or risers will not cause permanent damage or injury to the Building or cause or create a dangerous condition or unreasonably interfere with other tenants of the Building. All Floors occupied entirely
by Tenant shall be separately metered or sub-metered for electricity and all other parts of the Leased Premises, may, at Landlord’s option, be separately metered or sub-metered for electricity. Tenant shall pay (or reimburse Landlord for) the
cost of purchasing and installing separate electric meters or sub-meters for each whole Floor and each part of a Floor included in the Leased Premises, and for any other part of the Leased Premises which Landlord elects to have metered or
sub-metered. Tenant shall pay directly to the public utility company all charges for electricity used by Tenant in all parts of the Leased Premises which are separately metered, or Tenant shall reimburse Landlord directly for its electrical usage in
all parts of the Leased Premises which are sub-metered. Landlord shall have the right from time to time to have a survey made by an independent electrical 

 engineer or electrical consulting firm to be selected and paid for by Landlord to determine the amount of
electricity consumed by Tenant in the parts of the Leased Premises which do not consist of an entire Floor. Tenant shall pay to Landlord, as monthly intervals upon receipt of an invoice therefor, the cost of electricity it consumes in the parts of
the Leased Premises which do not consist of an entire Floor as determined by such electrical engineer or consulting firm. 
 (c) Heating and Air-Conditioning. Landlord shall provide heat and air-conditioning at times in addition to those specified in paragraph (5) of subsection (a) at Tenant’s expense, provided Tenant gives Landlord notice
prior to 3:00 P.M. (in the case of after-hours service on weekdays) and prior to 3:00 P.M. on Fridays or the day preceding a holiday (in the case of after-hours service on Saturdays, Sundays or holidays). 
 (d) Maintenance of Pipes, Conduits, etc. Landlord reserves the right to erect, use, maintain and repair pipes, conduits, cables,
plumbing, vents and wires in, to and through the Leased Premises as and to the extent that Landlord may now or hereafter deem to be necessary or appropriate for the proper operation and maintenance of the Building, or other tenants’
installations in the Building, and the right at all times to transmit water, heat, air-conditioning and electric current through such pipes, conduits, cables, plumbing, vents and wires, provided that Landlord, in the exercise of such rights, shall
not unreasonably inconvenience Tenant or unreasonably interfere with Tenant’s use of the Leased Premises. 
 (e) HVAC
Specifications. Landlord agrees that the air-conditioning system in the portion of the Leased Premises consisting of Office Space will be capable of providing, and (unless otherwise ordered by federal, state or local governmental authorities)
the system shall provide, temperatures of nor more than 77°F dry bulb and a relative humidity not in excess of 50% with outside conditions of 95°F dry bulb and 78°F wet bulb, except as otherwise provided in this subsection. Landlord
agrees that the heating system in the portion of the Leased Premises consisting of Office Space will be capable of providing, and (unless otherwise ordered by federal, state or local governmental authorities) the system shall provide, temperatures
of not less than 70°F whenever the outdoor dry bulb temperature is lower than 65°F but no lower than 0°F, with indoor relative humidity at such level as not to permit the formation of condensation on the windows. Landlord shall not be
responsible if the normal operation of the Building air-conditioning system shall fail to provide conditioned air at reasonable temperatures, pressures or degrees of humidity or in reasonable volumes or velocities in any portions of the Leased
Premises consisting of Office Spice which (i) shall have a connected electrical load in excess of three watts per square foot of Rentable Area of the Leased Premises for all purposes (including lighting and power) or which shall have a human
occupancy factor in excess of one person for each 100 square feet of Rentable Area of the portion of the Leased Premises consisting of Office Space (the average electrical load and human occupancy factors for which the Building air-conditioning
system is designed), or (ii) because of rearrangement of partitioning or other Alterations made by or on behalf of Tenant or any Person claiming, through or under Tenant (excepting work performed by Landlord for Tenant prior to Tenant’s
initial occupancy of the Leased Premises). 

 (f) Access to HVAC Facilities. Landlord shall have unrestricted access to any and
all air-conditioning facilities in the Leased Premises for the purposes of repairs, maintenance, alterations and improvements, but in exercising its rights under this subsection Landlord shall use its best efforts to minimize interference with
Tenant’s business in the Leased Premises. Notwithstanding anything to the contrary herein or in Section 5(d), except in the event of an emergency, Landlord may obtain access to the double-secured areas of the Leased Premises only with the
permission and assistance of Tenant’s Director of Facilities or his designee. Tenant shall provide Landlord with keys to the double-secured areas of the Leased Premises. Tenant’s Director of Facilities, or his designee, shall be available
to provide access to the double-secured areas of the Leased Premises on a non-emergency basis promptly after Landlord’s request for permission to enter the same, and in any event no later than 24 hours after such request. 
 (g) Reduction of Air-Conditioning Use. Tenant agrees to use reasonable efforts to keep or cause to be kept closed all window
draperies or venetian blinds in the Leased Premises as and when necessary because of the sun’s position whenever the air-conditioning system is in operation, and Tenant agrees at all times to cooperate fully with Landlord and to abide by all
the reasonable regulations and requirements which Landlord may prescribe for the proper functioning and protection of the Building air-conditioning system. 
 (h) Cessation of HVAC and Mechanical Services. Landlord reserves the right to stop the service of heating, air-conditioning, ventilating, elevator, plumbing, electricity or other mechanical systems or
facilities in the Building, if necessary by reason of accident or emergency, or for repairs, alterations, replacements, additions or improvements which, in the reasonable judgment of Landlord, are desirable or necessary, until said repairs,
alterations, replacements, additions or improvements shall have been completed. The exercise of such right by Landlord shall not constitute an actual or constructive eviction, in whole or in part, or relieve Tenant from any of its obligations under
this Lease, or impose any liability upon Landlord or its agents by reason of inconvenience or annoyance to Tenant, or injury to, or interruption of Tenant’s business, or otherwise, or entitle Tenant to any abatement or diminution of rent except
as provided in Section 3(i). Except in cases of emergency repairs, Landlord will give Tenant reasonable advance notice of any contemplated stoppage of any such systems or facilities pursuant to the foregoing. In all cases, Landlord will use due
diligence to complete any such repairs, alterations, replacements, additions or improvements promptly. Landlord shall also perform any such work in a manner designed to minimize interference with Tenant’s normal business operations. 

6. Use of Leased Premises. 
 (a) Permitted Uses. Tenant shall use and occupy the portion of the Leased Premises consisting of Office Space solely for general office purposes, and shall use and 

 occupy the portion of the Leased Premises consisting of Storage Space solely for storage, all in
accordance with the applicable zoning regulations and consistent with the character and dignity of the Building, and shall not use, permit or suffer the use of the Leased Premises for any other purpose whatsoever without the prior written consent of
the Landlord, Tenant shall not use, or permit the Leased Premises to be used, for the sale of food, beverages or tobacco products, except that Tenant may operate on the Leased Premises vending machines for the sale of food, beverages and tobacco
products to the employees. Tenant shall not permit or suffer the Leased Premises to be occupied by anyone other than Tenant except as provided by Section 15. Tenant shall at all times have access to the Leased Premises 24 hours a day, seven
days a week, subject, however, in all respects to all the terms, covenants and conditions contained in this Lease. However, Landlord may regulate and restrict access to Building at times other than normal business hours on Business Days for security
purposes so long as Tenant’s employees and agents have reasonable access to the Leased Premises without unreasonable inconvenience. 
 (b) Restrictions on Use. Throughout the Term, Tenant covenants and agrees: (i) to pay 10 days before delinquency any and all taxes, assessments and public charges levied, assessed or imposed upon
Tenant’s business conducted in the Leased Premises, upon the leasehold estate created by this Lease or upon Tenant’s fixtures, furnishings or equipment in the Leased Premises; (ii) not to use or permit or suffer the use of any portion
of the Leased Premises for any unlawful purpose; (iii) not to use the plumbing facilities for any purpose other than that for which they were constructed, or dispose of any foreign substances therein; (iv) not to place a load on any floor
exceeding the floor load per square foot which such floor was designed to carry in accordance with Landlord’s Building Plans, and not to install, operate or maintain in the Leased Premises any heavy item of equipment except in such manner as to
achieve a proper distribution of weight; (v) not to strip, overload, damage or deface the Leased Premises, or the hallways, stairways, elevators, parking facilities or other public areas of the Building, or the fixtures therein or used
therewith, (vi) not to move any furniture or equipment into or out of the Leased Premises except at such times as Landlord may from time to time reasonably designate; (vii) not to use any floor adhesive in the installation of any
carpeting, (viii) not to install any other equipment of any kind or nature which will or may necessitate any changes, replacements or additions to, or in the use of, the water system, heating system, plumbing system, air-conditioning system or
electrical system of the Leased Premises or the Building, without first obtaining the written consent of Landlord; and (ix) at all times to comply with all Legal Requirements. 
 (c) Compliance with Legal Requirements. Tenant will not use or occupy the Leased Premises in violation of any Legal Requirements.
If any governmental authority, after the commencement of the Term, shall contend or declare that the Leased Premises are being used for a purpose which is in violation of any Legal Requirements, then Tenant shall, upon five days’ notice from
Landlord, immediately discontinue such use of the Leased Premises. If thereafter the governmental authority asserting such violation threatens, commences or continues criminal or civil proceedings against Landlord for Tenant’s failure to
discontinue such use, in addition to any and all rights, privileges and 

 remedies given to Landlord under this Lease for default therein, Landlord shall have the right to
terminate this Lease forthwith. Tenant shall indemnify and hold Landlord harmless from and against any and all liability for any such violation or violations. 
 (d) Compliance with Insurance Requirements. Tenant shall not do any act, matter, thing or failure to act in respect of the Leased
Premises and/or the Building that will invalidate or be in conflict with fire insurance policies covering the Building or any part thereof, and shall not do, or permit anything to be done, in or upon the Leased Premises and/or the Building, or bring
or keep anything therein, which shall increase the rate of fire insurance on the Building or on any property located therein. If, by reason of the failure of Tenant to comply with the provisions of this subsection, the fire insurance rate shall at
any time be higher than it otherwise would be, then Tenant shall reimburse Landlord and any other tenant of the Building, on demand, for that part of all premiums for any insurance coverage that shall have been charged because of such violation by
Tenant and which Landlord or such other tenant, or both, shall have paid on account of an increase in the rate or rates in its own policies of insurance. Tenant shall not be responsible for any increase in fire insurance rates generally applicable
to office space in Fairfax County, Virginia, and not resulting from the particular manner in which Tenant uses the Leased Premises. 
 (e) No Flammable Substances. Tenant shall not bring or permit to be brought or kept in or on the Leased Premises any flammable combustible or explosive fluid, material, chemical or substance except standard cleaning fluid, standard
equipment and materials (including magnetic tape) customarily used in conjunction with business machines and equipment of the type used from time to time by Tenant in reasonable quantities. 
 7. Care of Leased Premises. 
 (a) By Tenant. Tenant shall act with care in its use and occupancy of the Leased Premises and the fixtures therein and, at Tenant’s sole cost and expense, shall make all repairs and replacements to the Leased Premises,
structural or otherwise, necessitated or caused by the acts, omissions or negligence of Tenant or any Person claiming through or under Tenant or by the use or occupancy or manner of use or occupancy of the Leased Premises by Tenant or any such
Person; however the foregoing provisions of this subsection shall be subject to the provisions of Section 13. Without affecting Tenant’s obligations set forth in the preceding sentence, Tenant, at Tenant’s sole cost and expense, shall
also (i) make all repairs and replacements, as and when necessary, to Tenant’s Special Installations and to any Alterations made or performed by or on behalf of Tenant or any Person claiming through or under Tenant, (ii) perform all
maintenance and make all repairs and replacements, as and when necessary, to any air-conditioning equipment, private elevators, escalators, conveyors or mechanical systems (other than the standard equipment and systems serving the Building) which
may be installed in the Leased Premises, or elsewhere in the Building and serving the Leased Premises, by Landlord, Tenant or others, (iii) perform all maintenance and make all repairs and replacements, as and when necessary, to the antennas
and satellite dishes 

 installed by Tenant on the roof of the Building and make all repairs to the roof caused by such
installation, and (iv) perform regular cleaning and janitorial services in the double-secured areas of the Leased Premises. However, except as otherwise provided in this Lease, Tenant shall not have any right to install air-conditioning
equipment, elevators, escalators, conveyors or mechanical systems. In addition to the foregoing, all damage or injury to the Leased Premises and to its fixtures, appurtenances and equipment or to the Building or to its fixtures, appurtenances and
equipment caused by Tenant moving property in or out of the Building or by installation or removal of furniture, fixtures or other property by Tenant shall be repaired, restored or replaced promptly by Tenant, at its sole cost and expense, to the
reasonable satisfaction of Landlord. All such aforesaid repairs, restoration and replacements shall be in quality and class equal to the original work or installation but in no event need exceed Building standards. 
 (b) By Landlord. Except as otherwise provided in subsection (a), Landlord shall perform the following maintenance and repairs as
and when necessary (the costs of which shall be Operating Expenses hereunder, to the extent included in the definition of Operating Expenses in Section 1(c)): (i) structural repairs to the Leased Premises and Building;
(ii) maintenance and repairs required in order to provide the elevator, plumbing, electrical, heating and air-conditioning services to be furnished by Landlord pursuant to this Lease; (iii) maintenance of and repairs to exterior portions
of the Building, including the windows, balconies and roof thereof; (iv) maintenance of and repairs to the toilet room in the Building, and to the public lobbies, elevators, corridors, stairways, parking garage, sky walk, patios, sidewalks,
roadways and other common areas in the Building and the Land; and (v) other repairs to the Leased Premises and the Building necessary for Tenant’s use and enjoyment of the Leased Premises. Landlord’s obligations to make repairs to the
Leased Premises under the preceding sentence shall not accrue until after notice to Landlord of the necessity for any specific repair. 
 8.
Rules and Regulations. 
 Tenant and its agents and employees shall comply with and observe all reasonable rules and regulations
concerning the use, management, operation, safety and good order of the Leased Premises and the Building which may from time to time be promulgated by Landlord, provided that such rules and regulations are not inconsistent with the provisions of
this Lease and do not materially interfere with Tenant’s use of the Leased Premises. Initial rules and regulations, which shall be effective until amended by Landlord, are attached to this Lease as Exhibit E hereto and made a part hereof.
Tenant shall be deemed to have received notice of any amendment to the rules and regulations when a copy of such amendment has been delivered to Tenant at the Leased Premises or has been mailed to Tenant in the manner prescribed for the giving of
notices. If Tenant disputes the reasonableness of any additional rule or regulation hereafter made or adopted by Landlord, the parties agree to submit the question of the reasonableness of such rule or regulation for decision to the governing board
for the time being of the Building Owners and Managers Association of Washington, D.C., or to such impartial person or persons as it or the parties hereto may designate, whose determination shall be final and conclusive upon the parties hereto.
Tenant may not dispute the reasonableness of any additional rule or regulation unless Tenant’s intention to do so shall be asserted by notice given 

 to Landlord within 15 days after notice is given to Tenant of the adoption of any such additional rule or regulation.
Landlord shall nor be responsible to Tenant for any violation of the rules and regulations, or the covenants or agreements contained in any other lease, by any other tenant of the Building, or such tenant’s agents or employees, and Landlord may
waive in writing, or otherwise, any or all of the rules or regulations in respect of any one or more tenants. 
 9. Tenant’s
Alterations and Installments. 
 (a) Restrictions on Alterations. Tenant shall not make or perform or permit the
making or performance of, any alterations, installations, improvements, additions or other physical changes in or about the Leased Premises (referred to collectively as “Alterations”) without Landlord’s prior consent. Landlord
agrees not unreasonably to withhold or delay its consent to any nonstructural Alterations proposed to be made by Tenant to adapt the Leased Premises for Tenant’s business purposes or the business purposes of any other permitted occupant of the
Leased Premises, except that Landlord shall have no obligation to consent to any Alteration which will reduce the value or utility of the Building or affect the outside appearance of the Building or the color or style of any venetian blinds supplied
by Landlord (except that Tenant may remove any such venetian blinds provided Tenant promptly replaces such venetian blinds with venetian blinds of a similar type and color). Notwithstanding the foregoing provisions of this subsection or
Landlord’s consent to any Alterations, all Alterations, whether made prior to or during the Term, shall be made and performed in conformity with and subject to the following provisions: (i) all Alterations shall be made and performed at
Tenant’s sole cost and expense and at such time and in such manner as Landlord may reasonably from time to time designate; (ii) Alterations shall be made only by contractors or mechanics approved by Landlord, such approval not to be
unreasonably withheld or delayed; (iii) no Alteration shall materially affect any part of the Building other than the Leased Premises or adversely affect any service required to be furnished by Landlord to Tenant or to any other tenant or
occupant of the Building; (iv) all business machines and mechanical equipment shall be placed and maintained by Tenant in settings sufficient in Landlord’s reasonable judgment to absorb and prevent vibration, noise and annoyance to other
tenants or occupants of the Building; (v) Tenant shall submit to Landlord reasonably detailed plans and specifications for each proposed alteration and shall not commence any such Alteration without first obtaining Landlord’s approval of
such plans and specifications, which approval will not be unreasonably withheld or delayed; (vi) all Alterations in or to the electrical facilities in or serving the Leased Premises shall be subject to the provisions of Section 5 relating
to exceeding electrical capacity; (vii) notwithstanding Landlord’s approval of plans and specifications for any Alteration, all Alterations shall be made and performed in full compliance with all Legal Requirements and in accordance with
the Rules and Regulations; (viii) all materials and equipment to be incorporated in the Leased Premises as a result of all Alterations shall be of good quality; and (ix) Tenant shall require any contractor performing Alterations to carry
and maintain at all times during the performance of the work, at no expense to Landlord, (i) a policy of comprehensive public liability insurance, including contractors’ liability coverage, contractual liability coverage, completed
operations coverage contractor’s protective liability coverage and a broad form property damage endorsement, naming Landlord and (at Landlord’s request) any Mortgagee of the Building 

 and any management agent as additional named insureds), with such policy to afford protection to the
limit of not less than $2,000,000 with respect to bodily injury or death to any number of persons in any one accident and to the limit of not less than $1,000,000 to damage to the party of any one owner from one occurrence, and
(ii) workers’ compensation or similar insurance in the form and amounts required by the laws of the State of Virginia. In the event that estimated cost of an Alteration (which shall include the aggregate cost of a series of Alterations
which are reasonably aggregated into a single project) is in excess of $100,000.00, or in the event of an Alteration to a structural member of, or mechanical system in, the Leased Premises, Landlord shall have the right to place other and further
restrictions and conditions thereon prior to Tenant being authorized to commence such Alteration. Such additional conditions may include, by way of illustration and not of limitation, the requirement that the contractor be bonded or bondable. In the
event of any dispute between the parties as to whether or not Landlord has acted reasonably in any case with respect to which Landlord is required, pursuant to the provisions of this subsection (a), to do so, Tenant’s sole remedy shall be to
submit such dispute to mediation pursuant to Section 28. If the determination in any such mediation shall be adverse to Landlord, Landlord nevertheless shall not be liable to Tenant for breach of Landlord’s covenant to act reasonably, and
Tenant’s sole remedy in such event shall be to proceed with the proposed Alterations. However, if the parties are unable to settle such matter by mediation, and such matter is submitted to Litigation, Landlord’s liability and Tenant’s
remedies shall not be so limited. 
 (b) Tenant’s Right to Cure. If Tenant shall be in default under this Section
by reason of the making of any Alteration not hereby authorized or by reason of failure to give any notice or to obtain any approval required herein, Tenant may cure such default within the applicable grace period provided in this Lease for curing
such default by removing such Alteration and restoring the Leased Premises to their former condition, as provided in Section 7. 
 (c) Fixtures Become Landlord’s Property. Except to the extent specifically provided in subsection (e), all appurtenances, fixtures, improvements, additions and other property attached to or installed in the Leased Premises,
whether by Landlord or Tenant or others, and whether at Landlord’s expense, or Tenant’s expense, or the joint expense of Landlord and Tenant, which are of a permanent nature or which cannot be removed without structural damage to the
Building, shall be and remain the property of Landlord. Any replacements of any property of Landlord, whether made at Tenant’s expense or otherwise, shall be and remain the property of Landlord. 
 (d) Tenant’s Special Installations. All furniture, furnishings and trade fixtures, excepting lighting fixtures and equipment,
but including, without limitation, murals, carpets, rugs, business machines and equipment, vaults, vault doors end door frames, and vault equipment, if any, safe deposit equipment, counterscreens, grillwork, cages, partitions which are moveable,
railings, raised floors, escalators, conveyors, stairs, elevators, paneling, equipment relating to food preparation, food storage and serving, dishwashing and cleaning devices and air-conditioning equipment, and any other 

 moveable property installed by, or at the expense of Tenant, including any such property paid for with
any allowance provided by Landlord to Tenant, shall remain the property of Tenant and are referred to herein as “Tenant’s Special Installations”. Tenant may at its expense remove any part of said property at any time during the
Term, and shall at its expense remove all of said property at the expiration or other termination of the Term unless Landlord shall otherwise consent in writing. Upon removal of any or all of said property Tenant shall then repair all damage caused
by such removal. Any of Tenant’s Special installations which are not removed from the Leased Premises at the expiration of the Term shall be deemed to have been abandoned by Tenant and may be disposed of by Landlord without liability to Tenant.

 (e) Mechanics’ Liens. Notice is hereby given that Landlord shall not be liable for any labor or materials
furnished or to be furnished to Tenant upon credit, and that no mechanic’s, materialman’s or other lien for any such labor or materials shall attach to or affect the reversion or other estate or interest of Landlord in and to the Leased
Premises or the Building. Whenever and as often as any mechanic’s lien or materialman’s lien shall have been filed against the Leased Premises or the Building based upon any act or interest of Tenant or of anyone claiming through Tenant or
of any lien or security interest with respect thereto shall have been filed after any materials, machinery or fixtures used in the construction, repair or operation thereof of annexed thereto by Tenant or its successors in interest, Tenant shall
forthwith take such action by bonding, deposit or payment as will remove or satisfy the lien or other security interest and in default thereof after the expiration of 20 days after notice to Tenant, Landlord, in addition to any other remedy under
this Lease, may pay the amount secured by such lien or security interest or discharge the same by deposit and the amount so paid or deposited shall be collectible as additional rent. The provisions of this subsection shall not be applicable to liens
filed with respect to work done for Tenant’s account by Landlord. 
 10. Name of Building; Tenant’s Signs. 
 (a) Name. Provided that no Event of Default (as defined in Section 16) or Event of Bankruptcy (as defined in Section 17)
has occurred and is continuing, throughout the Term, the Building shall be designated as the “ICF Kaiser Building”, and Landlord shall use that name in all advertising prepared by, or at the direction of, Landlord in connection with the
leasing of space in the Building to the pubic. Notwithstanding the foregoing, if Tenant shall change its corporate name, then Tenant shall have the right, by written notice to Landlord, to require Landlord to re-designate the Building with a name
incorporating all or part of Tenant’s new name, provided the same is not in violation of any rule, regulation or statute having jurisdiction over the Building or Landlord. In such event, Tenant shall bear all costs of changing the signage on
the Building, and Tenant shall, within fifteen (15) days after receipt of an invoice therefor, reimburse Landlord for Landlord’s reasonable costs incurred in connection with the Building name change, including costs incurred to change
Landlord’s advertising and costs of any required notices to any governmental agencies. Landlord expressly reserves the right to have the Building designated by a street number or numbers and to affix to the Building at locations designated by
Landlord, signs indicating any such number or numbers and the name of the Building (if any) as selected from time to time by Tenant in accordance with the provisions of this subsection. 

 (b) Restrictions on Exterior Signs. Except as otherwise provided in subsection
(d), Landlord has not granted to Tenant any rights in or to the roof or the outer side of the outside walls of the Building, control of which is hereby reserved by Landlord. Tenant shall not display or erect any lettering, signs, advertisements,
awnings or other projections on the exterior of the Leased Premises or in the interior of the Leased Premises if visible from a public way, except for customary hallway door lettering. 
 (c) Directory Tablets. Landlord, at its expense, shall maintain the existing directory tablets (i) in the main lobby of the
other building in the Office Park, (ii) in the skywalk between the Building and the other building in the Office Park (located at 9302 Lee Highway), and (iii) on the walkway between the Building and the other building in the Office Park,
upon each of which Landlord, at Tenant’s expense, will affix Tenant’s name and a reasonable number of names of its officers, partners or employees. The size, color and style of such directories and names affixed thereto shall be selected
by Landlord. 
 (d) Tenant’s Permitted Signs. Subject to Section 10(a) above, Landlord shall permit Tenant
throughout the Term to install and maintain, subject to Legal Requirements, two suitable signs on the exterior of the Building. The location, size, color and style of Tenant’s exterior signs shall be subject to Landlord’s approval, such
approval not to be unreasonably withheld or delayed. Landlord hereby approves Tenant’s signs which are currently on the Building, and agrees that, if the name of the Building is changed pursuant to Section 10(a), Tenant, at its expense,
may replace such signs with similar signs displaying the new name. 
 (e) Access to Roof. Throughout the Term, Landlord
shall permit Tenant to install and maintain, subject to Legal Requirements and the provisions of this Section 10(e), not more than three (3) satellite or antenna dishes on the roof of the Building (“Tenant’s Roof Use”).

 (i) Landlord shall make available to Tenant access to and locations mutually acceptable to Landlord and Tenant on the roof
for the construction, installation, maintenance, repair, operation and use of such satellite or antenna dishes. Tenant shall screen such installations in a manner mutually acceptable to Landlord and Tenant. Tenant shall have the right to remove such
satellite or antenna dishes and any related equipment from the Building at the expiration or other termination of the Term of this Lease, provided that Tenant repairs any damage occasioned by such removal. Tenant shall pay all costs associated with
the installation, maintenance, repair, use, insurance and removal of such satellite or antenna dishes and any related equipment. 
 (ii) Tenant shall give Landlord’s Building manager reasonable telephonic notice before any entry onto the roof of the Building by Tenant’s 

 agents, employees or contractors, and shall permit Landlord’s Building manager to accompany
Tenant’s agents, employees or contractors on any such entry onto the roof. Except as otherwise hereinafter set forth in this Section 10(e), Landlord shall not be liable for any claims, losses, actions, damages, liabilities or expenses
arising from any satellite or antenna dishes or related equipment installed by Tenant on the roof of the Building, or the installation, maintenance, repair, use or removal of such dishes and relaxed equipment, unless caused by the negligence or
willful misconduct of Landlord, its agents, employees or contractors. 
 (iii) If Landlord permits any other party to install
satellite or antenna dishes on the roof of the Building, and such equipment interferes with the operation of Tenant’s equipment, then Landlord, at its expense, shall take whatever measures may be necessary to eliminate such interference.

 (iv) If the rate of any insurance carried by Landlord is increased as a result of Tenant’s Roof Use, then Tenant will
pay to Landlord within ten (10) days before the date Landlord is obligated to pay a premium on the insurance (or within ten (10) days after Landlord delivers to Tenant a certified statement from Landlord’s insurance carrier stating
that the rate increase was caused by Tenant’s Roof Use, whichever date is later), a sum equal to the difference between the original premium and the increased premium resulting from Tenant’s Roof Use. 
 (v) Landlord has not made any representations or promises pertaining to the suitability of the Building’s roof for Tenant’s Root
Use. Tenant, solely for the purpose of this Section 10(e) and its right to rooftop access hereunder, accepts the rooftop in its “as is” condition. 
 (vi) Tenant will obtain prior to installation, any and all governmental licenses, approvals necessary for the installation, maintenance
and use of any equipment installed pursuant to this Section 10(e), Tenant’s Roof Use shall not in any way conflict with any applicable Legal Requirements. Tenant shall indemnify and hold Landlord harmless from and against any and all loss,
cost (including reasonable attorney’s fees incurred in defending Landlord), damage or liability arising out of any violation by Tenant’s Roof Use of any applicable Legal Requirements. 
 (vii) Tenant’s Roof Use shall be exercised: (1) in such manner as will not create any hazardous condition or interfere with or
impair the operation of the heating, ventilation, air conditioning, plumbing, electrical, fire protection, life, safety, public utilities or other systems or facilities in the Building; (2) in compliance with all applicable Legal Requirements;
(3) in such a manner as will not unreasonably interfere with Landlord’s operation or maintenance of the Building; (4) at Tenant’s cost, including the cost of repairing any damage to the Building and any personal injury and/or
property damage caused by the installation, inspection, adjustment, maintenance, removal or replacement of any of Tenant’s equipment on the roof and (5) in a manner which will not void or 

 invalidate any roof warranty then in effect with respect to the roof of the Building. Tenant’s Roof
Use shall be used solely in the ordinary course of Tenant’s business operations (and not for resale by Tenant), and any use of the roof outside of the ordinary course of Tenant’s business operations (such as, but not limited to, subleasing
portions of the roof for profit to third parties, in order for such third parties to establish communications transmission facilities) shall be subject to Landlord’s consent, which consent shall not be unreasonably withheld, but may be
conditioned, inter alia, upon the payment by Tenant to Landlord of any net revenues paid to Tenant in respect thereof. 
 11. Liability
Insurance. 
 (a) Required Coverage. Tenant, at Tenant’s sole cost and expense, shall obtain and maintain in
effect at all times during the Term, a policy of comprehensive general public liability insurance with broad form property damage endorsement, naming Landlord and (at Landlord’s request) any Mortgages of the Building and any management agent as
additional insured(s), protecting Landlord, Tenant and any such Mortgagee and management agent against any liability for bodily injury, death or property damage occurring upon, in or about any part of the Building, including the roof, or the Land,
the Leased Premises or any appurtenances thereto, with such policies to afford protection to the limit of $5,000,000 with respect to bodily injury or death to any one person, to the limit of $5,000,000 with respect to bodily injury or death to any
number of persons in any one accident, and to the limit of $5,000,000 with respect to damage to the property of any one owner from one occurrence. Such comprehensive liability insurance may be effected by a policy or policies of blanket insurance
which cover other property in addition to the Leased Premises, provided that the protection afforded thereunder shall be not less than that which would have been afforded under a separate policy or policies relating only to the Leased Premises and
provided further that in all other respects any such policy shall comply with the other provisions of this Section. 
 (b)
Policy Requirements. The insurance policy required to be obtained by Tenant under this Section: (i) shall be issued by insurance companies rated A- or better in the most current issue of Best’s Insurance Reports, licensed to do
business in the state in which the Building is located and domiciled in the United States; and (ii) shall be written as primary policy coverage and not contributing with or in excess of any coverage which Landlord may carry. Neither the
issuance of any insurance policy required under this Lease, nor the minimum limits specified herein with respect to Tenant’s insurance coverage, shall be deemed to limit or restrict in any way Tenant’s liability arising under or out of
this Lease. With respect to each insurance policy required to be obtained by Tenant under this Section, on or before the Lease Commencement Date, and at least 30 days before the expiration of the expiring policy or certificate previously furnished,
Tenant shall deliver to Landlord a certificate of insurance therefor, together with evidence of payment of all applicable premiums. Each insurance policy required to be carried hereunder by or on behalf of Tenant shall provide (and any certificate
evidencing the existence of each such insurance policy shall certify) that such insurance policy shall not be canceled unless Landlord shall have received 20 days’ prior written notice of cancellation. 

 (c) Indemnification of Landlord. Except for the willful or negligent acts or
omissions of Landlord or its agents or employees, Tenant hereby agrees to indemnify and hold harmless Landlord from and against any and all claims, losses, actions, damages, liabilities and expenses (including attorneys’ fees) that
(i) arise from or are in connection with Tenant’s possession, use, occupancy, management, repair, maintenance or control of the Leased Premises, or any portion thereof, or (ii) arise from or are in connection with any willful or
negligent act or omission of Tenant or Tenant’s agents, employees or subtenants, or (iii) result from any default, breach, violation or nonperformance of this Lease or any provision therein by Tenant, or (iv) arise from injury or
death to persons or damage to property sustained on or about the Leased Premises, or (v) arise from Tenant’s installation, maintenance, repair, use or removal of any rooftop satellite or antenna dishes or related equipment. Tenant shall,
at its own cost and expense, defend any and all actions, suits and proceedings which may be brought against Landlord with respect to the foregoing or in which Landlord may be impleaded. Tenant shall pay, satisfy and discharge any and all money
judgments which may be recovered against Landlord in connection with the foregoing. 
 (d) Indemnification of Tenant.
Except for the willful or negligent acts or omissions of Tenant or its agents or employees, Landlord hereby agrees to indemnify and hold harmless Tenant from and against any and all claims, losses, actions, damages, liabilities and expenses
(including attorneys’ fees) that (i) arise from or are in connection with Landlord’s possession, use, occupancy, management, repair, maintenance or control of the common areas of the Building located on any Floor not wholly occupied
by Tenant, or (ii) arise from or are in connection with any willful or negligent act or omission of Landlord or Landlord’s agents or employees, or (iii) result from any default, breach, violation or nonperformance of this Lease or any
provision therein by Landlord, or (iv) arise from injury or death to persons or damage to property sustained on or about the common areas of the Building located on any Floor not wholly occupied by Tenant. Landlord shall, at its own cost and
expense, defend any and all actions, suits and proceedings which may be brought against Tenant with respect to the foregoing or in which Tenant may be impleaded. Landlord shall pay, satisfy and discharge any and all money judgments which may be
recovered against Tenant in connection with the foregoing. 
 12. Fire Insurance. 
 (a) Required Coverage. Landlord shall, throughout the Term, at its expense, keep the Building, but not Tenant’s Special
Installations, Alterations or Tenant’s furniture, furnishings, trade fixtures or property removable by Tenant under the provisions of this Lease (including any rooftop satellite or antenna dishes and related equipment), insured against all loss
or damage by fire with extended coverage in such amount as any first Mortgagee of the Building may from time to time require. Tenant shall, throughout the Term, at its expense, keep Tenant’s Special Installations and 

 Alterations and Tenant’s personal property, including any rooftop satellite or antenna dishes and
related equipment, insured against all loss or damage by fire with extended coverage in an amount sufficient to prevent Tenant from becoming a co-insurer. Tenant’s policies of insurance shall contain, if available from the insurer, an
appropriate clause or endorsement under which the insurer agrees that such policy shall not be canceled without at least 30 days notice to Landlord. 
 (b) Notice of Insurance Coverage. Landlord and Tenant will (i) if requested, advise the other as to the provisions of fire and extended coverage insurance policies obtained pursuant to this Section, and
(ii) notify the other promptly of any change in the terms of any such policy which would affect such provisions. 
 (c)
Mutual Waiver of Subrogation. 
 (i) Notwithstanding anything to the contrary in this Lease, whether the loss or damage
is due to the negligence of Landlord or Landlord’s agents or employees, or any other cause, Tenant hereby releases Landlord and Landlord’s agents and employees from responsibility for and waives its entire claim of recovery for
(i) any and all loss or damage to the personal property of Tenant located in the Building (excluding any personal property required to be insured by Landlord pursuant to the provisions hereof), arising out of any of the perils which are covered
by Tenant’s property insurance policy, with extended coverage endorsements which Tenant is required to obtain under the applicable provisions of this Lease, whether or not actually obtained. 
 (ii) Notwithstanding anything to the contrary in this Lease, whether the loss or damage is due to the negligence of Tenant or
Tenant’s agents or employees, or any other cause, Landlord hereby releases Tenant and Tenant’s agents and employees from responsibility for and waives its entire claim of recovery for any and all loss or damage to the Building or any
personal property of Landlord located about the Building and the Building generally and all property attached thereto (excluding any such property required to be insured by Tenant hereunder), arising out of any of the perils which are covered by
Landlord’s property insurance policy which Landlord is required to obtain under the applicable provisions of this Lease, whether or not actually obtained. 
 (iii) Landlord and Tenant shall each cause its respective property insurance carrier(s) to consent to such waiver of all rights of
subrogation against the other, and to issue an endorsement to all policies of property insurance obtained by such party confirming that the foregoing release and waiver will not invalidate such policies. 

 13. Damage by Fire or Other Casualty. 
 In the event of loss of, or damage to, the Leased Premises or the Building by fire or other casualty, the rights and obligations of the parties hereto
shall be as follows: 
 (a) Repair of Damage. If the Leased Premises or any part thereof shall be damaged by fire or
other casualty, Tenant shall give prompt notice thereof to Landlord, and Landlord, upon receiving such notice, shall proceed promptly and with reasonable diligence, subject to Unavoidable Delays, to repair, or cause not to be repaired, such damage
in a manner designed to minimize interference with Tenant’s occupancy (but with no obligation to employ labor at overtime or other premium pay rates). If the Leased Premises or any part thereof shall be rendered untenantable by reason of such
damage, whether to the Leased Premises or the Building. the Basic Rent and Additional Charges shall proportionately abate, with respect thereto for the period from the date of such damage to the date when such damage shall have been repaired for the
portion of the Leased Premises rendered untenantable. However, if, prior to the date when all of such damage shall have been repaired, any part of the Leased Premises is damaged shall be rendered tenantable and shall be used or occupied by Tenant or
any Person or Persons claiming through or under Tenant, then the amount by which the Basic Rant and Additional Charges shall abate shall be equitably apportioned for the period from the date of any such use. 
 (b) Termination of Lease by Landlord or Tenant. If as a result of fire or other casualty more than one-half (1/2) of the
Building Rentable Area is rendered untenantable, Landlord within 60 days from the date of such fire or casualty may terminate this Lease by notice to Tenant, specifying a date, not less than 20 nor more than 40 days after the giving of such notice,
on which the Term shall expire as fully and completely as if such date were the date herein originally fixed for the expiration of the Term. If the Lease Premises are damaged as a result of fire or other casualty and if the damage to the Leased
Premises (but not including Tenant’s Special Installations or Alterations) is so extensive that such damage cannot be substantially repaired within 240 days from the date of the fire or other casualty (except for Unavoidable Delays), either
Landlord or Tenant within 30 days from the date of such fire or other casualty may terminate this Lease by notice to the other, specifying a date, not less than 20 nor more than 40 days after the giving of such notice on which the Term shall expire
as fully and completely as if such date were the date originally fixed for the expiration of the Term. If either Landlord or Tenant terminate this Lease, the Basic Rent and Additional Charges shall be apportioned as of the date of such fire or other
casualty. If neither Landlord nor Tenant so elects to terminate this Lease, then Landlord shall proceed to repair the damage to the Building and the damage to the Leased Premises (but not Tenant’s Special Installations or Alterations), if any
shall have occurred, and the Basic Rent and Additional Charges shall meanwhile be apportioned and abated all as provided in subsection (a). However, if such damage is not repaired and the Leased Premises and the Building restored to reasonably the
same condition as they were prior to such damage within 240 days front the date of such damage (such 240 day period to be extended by the period of any Unavoidable Delays), Tenant, within 30 days from the expiration of such 240-day period (as the
same may be extended), may terminate this Lease by notice to Landlord, specifying a date not more than 60 days after the giving of such notice on which the Term shall expire as fully and completely as if such date were the date herein originally
fixed for the expiration of the Term. 

 (c) Termination of Lease by Landlord. If the Leased Premises shall be rendered
untenantable to the extent of eighty percent (80%) or more by fire or other casualty during the last six months of the Term, Landlord or Tenant may terminate this Lease upon notice to the other party given within 90 days alter such fire or
other casualty specifying a date, not less than 20 days nor more than 40 days after the giving of such notice, on which the Term shall expire as fully and completely as if such date were the date originally fixed for the expiration of the Term. If
either Landlord or Tenant terminates this Lease pursuant to this subsection, the Basic Rent and Additional Charges shall be apportioned as of the date of such fire or casualty. 
 (d) Limitation on Landlord’s Repair Obligation. Landlord shall not be required no repair or replace any of Tenant’s
Special Installations or Alterations or any other personal property of Tenant and no damages, compensation or claim shall be payable by Landlord for inconvenience, loss of business or annoyance arising from any repair or restoration of any portion
of the Leased Premises or of the Building, but the foregoing shall not be deemed to relieve Landlord of liability for its breach of any covenant of this Lease. 
 (e) Inapplicability of Other Laws. The provisions of this Section shall be considered an express agreement governing any instance
of damage or destruction of the Building or the Leased Premises by fire or other casualty, and any law now or hereafter in force providing for such a contingency in the absence of express agreement shall have no application. 
 (f) Landlord Released from Liability. Notwithstanding any other provision of this Lease, Landlord shall not be liable or
responsible for, and Tenant hereby releases Landlord end its partners, officers, directors, agents and employees from, any and all liability or responsibility to Tenant or any Person claiming by, through or under Tenant, by way of subrogation or
otherwise, for any injury, loss or damage to Tenant’s property caused by any of the perils insured against by the fire insurance policy with extended coverage endorsement which is customarily issued in Fairfax County, Virginia, and Tenant shall
require its insurer(s) to include in all of Tenant’s insurance policies which could give rise to a right of subrogation against Landlord a clause or endorsement whereby the insurer(s) shall waive any right of subrogation against Landlord.

 (g) Tenant Released from Liability. Notwithstanding any other provision of this Lease, Tenant shall not be liable or
responsible for, and Landlord hereby releases Tenant and its partners, officers, directors, agents and employees from, any and all liability or responsibility to Landlord or any Person claiming by, through or under Landlord by way of subrogation or
otherwise; for any injury, loss or damage to Landlord’s property caused by any of the perils insured against by the fire insurance policy with extended coverage endorsement which is customarily issued in Fairfax County, Virginia, and Landlord
shall require its insurer(s) to include in all of Landlord’s insurance policies which could give rise to a right of subrogation against Tenant a clause or endorsement whereby the insurer(s) shall waive any rights of subrogation against Tenant.

 (h) Insurance Proceeds. The proceeds payable under all fire and other hazard
insurance policies maintained by Landlord on the Building shall belong to and be the property of Landlord, and Tenant shall not have any interest in such proceeds. Tenant agrees to look to its own fire and hazard insurance policies in the event of
damage to Tenant’s Special Installations or Alterations or its personal property. 
 14. Condemnation. 
 (a) Effect of Taking. In the event of a Taking of the whole of the Leased Premises, this Lease shall terminate as of the date of
such Taking. If only a part of the Leased Premises shall be so taken then, except as otherwise provided in this subsection, this Lease shall continue in force and effect but, from and after the date of the Taking, the Basic Rent and Additional
Charges shall be reduced on the basis of the square footage of the portion of the Leased Premises so taken. If a part of the Building shall be taken, and if either (i) the part of the Building so taken contains more than twenty-five percent
(25%) of the Rentable Area of the Leased Premises, immediately prior no such Taking, or (ii) in Landlord’s reasonable opinion, it shall be impracticable to continue to operate the Building, then Landlord, at Landlord’s option,
may give to Tenant within 60 days after Building, then Landlord, at Landlord’s option, may give to Tenant within 60 days after the date upon which Landlord shall have received notice of the Taking, a 30 days’ notice of termination of this
Lease. If a part of the Building shall be taken, and if either (i) the part of the Building taken contains more than thirty-five percent (35%) of the Rentable Area of the Leased Premises immediately prior to such Taking, or (ii) by
reason of such Taking, all or substantially all of the Leased Premises becomes untenantable and Tenant is unable and does not, in fact use all or substantially all of the Leased Premises for the uses permitted by Section 6(a), then Tenant, at
Tenant’s option, may give to Landlord within 60 days after the date upon which Tenant shall have received notice of such Taking, a 30 days’ notice of termination of this Lease. If a 30 days’ notice of termination is given by Landlord
or Tenant, this Lease shall terminate upon the expiration of the 30-day period. If this Lease is terminated pursuant to the foregoing provisions of this subsection, then, to the extent permitted by applicable law and such Taking, Tenant shall have
access to the Leased Premises in order to remove Tenant’s Special Installations and any other personal property then owned by Tenant and which Tenant is entitled to remove pursuant to this Lease during the period of 30 days from the date Tenant
is permitted access therefor. If a Taking occurs which does not result in the termination of this Lease, Landlord shall repair, alter and restore the remaining portions of the Leased Premises to their former condition to the extent that the same may
be feasible. 
 (b) Award. Landlord shall have the exclusive right to receive any and all awards made for damages to
the Leased Premises and the Building accruing by reason of a Taking or by reason of anything lawfully done I pursuance of public or other authority. Tenant hereby releases and assigns to Landlord all of Tenant’s rights to such awards, and
covenants to deliver such further assignments and assurances thereof as Landlord may 

 from time to time request, hereby irrevocably designating and appointing Landlord as its attorney-in-fact
to execute and deliver in Tenant’s name and behalf all such further assignments thereof. However, Tenant shall have the right to make its own claim against the condemning authority for a separate award for the value of any of Tenant’s
Special Installations and Alterations, for moving and relocation expenses and for such business damages and/or consequential damages as may be allowed by law which do not constitute part of the compensation for the Building and do not diminish the
amount of the award to which Landlord would otherwise be entitled. 
 15. Assignment and Subletting. 
 (a) Subletting to ICF Kaiser International, Inc. It is understood and agreed that Tenant will sublet the entire Leased Premises to
its affiliate, ICF Kaiser International, Inc., for a basic rent in excess of the Basic Rent payable hereunder. Upon the written request of Landlord or any Mortgagee following an event of default under any loan secured by a Mortgage, Tenant shall pay
to Landlord one hundred percent (100%) of the amount of such excess, monthly as received by Tenant from ICF Kaiser International, Inc. 
 (b) Assignment and Subletting Prohibited. Tenant shall not mortgage, pledge, encumber, sell, assign or transfer this Lease, in whole or in part, by operation of law or otherwise, or sublease all or any part of
the Leased Premises, without Landlord’s written consent, which consent may be withheld for any reason whatsoever except as provided in subsection (a) and subsection (d). In connection with any request by Tenant for such consent to assign
or sublet, Tenant shall submit to Landlord, in writing, a statement containing the name of the proposed assignee or subtenant, such information as to its financial responsibility and standing as Landlord may reasonably require, and all of the terms
and provisions upon which the proposed assignment or subletting is to be made, and, unless the proposed sublet area shall constitute the entire Leased Premises, such statement shall be accompanied by a floor plan delineating the proposed sublet
area. Any attempted transfer, assignment, subletting, mortgaging or encumbering of this Lease in violation of the provisions of this Section shall be void and confer no rights upon any third person. No permitted assignment or subletting shall
relieve Tenant of any of its obligations under this Lease. 
 (c) Merger and Consolidation. Notwithstanding the
provisions of subsection (b), Tenant shall have the privilege, without the consent of Landlord, to assign its interest in this Lease to any corporation which is a successor to Tenant, either by merger or consolidation, or to any corporation which
controls, is controlled by, or is under common control with, the Tenant. However, no such assignment shall be valid unless, within 10 days after the consummation thereof, Tenant shall deliver to Landlord (i) a duplicate original instrument of
assignment in form reasonably satisfactory to Landlord, duly executed by Tenant, and (ii) an instrument in form and substance reasonably satisfactory to Landlord, duly executed by the assignee, in which such assignee shall agree to observe and
perform, and to be personally bound by, all of the terms, covenants and conditions of this Lease on Tenant’s part to be observed and performed, whether or not accruing prior to or after the date of such assignment and whether or not relating to
matters arising prior to such assignment. 

 (d) Permitted Subletting. Unless an Event of Default has occurred and is
continuing, Landlord shall not unreasonably withhold or delay Landlord’s consent to sublettings by Tenant of a part or parts of the Leased Premises, but Landlord shall not be obligated to consent to a subletting for a use prohibited by
Section 6(a). Each such subletting shall be for undivided occupancy by the subtenant of that part of the Floor affected thereby for the use permitted under this Lease. Landlord may, however, withhold such consent if; in Landlord’s
reasonable judgment, the proposed subtenant is not engaged in a business consistent with the character and dignity of the Building, or will impose any additional material burden upon Landlord in the operation of the Building (to an extent greater
than the burden to which Landlord would have been put if Tenant continued to use, or used, such part of the Leased Premises for its own purpose). In the event of any dispute between Landlord and Tenant as to the reasonableness of Landlord’s
refusal to consent to any subletting such dispute shall be submitted to mediation pursuant to Section 28. Except as otherwise set forth in subsection (a) if any portion of the Leased Premises is sublet at any time, and if the rent received
by Tenant on account of such subletting exceeds the Basic Rent,              allocated to the space subject to the sublease in the proportion of the area of such space to the
Rentable Area of the Leased Premises; plus actual out-of-pocket expenses incurred by Tenant in connection with Tenant’s subleasing of such space, including advertising, advertising, attorneys’ fees, brokerage commissions and the
unamortized cost of preparing such space for occupancy by the subtenant, then, except as otherwise provided in the next sentence, Tenant shall pay to Landlord fifty percent (50%) of such excess, monthly as received by Tenant from the subtenant.
Except as otherwise set forth in subsection (a), Landlord shall not share in any profit derived by Tenant from the permitted subletting of allot any part of the space located on the Floor designated by Tenant as its “Sublet Floor” in a
notice given to Landlord before Tenant enters into its first permitted sublease pursuant to this subsection. Notwithstanding anything to the contrary in this Section 15(d), Tenant shall have the right to sublet space in the Leased Premises to
Tenant’s affiliates (hereinafter defined), subcontractors or consultants without notice to or the consent of Landlord, and, except as set forth in Section 15(a), without paying any portion of the profits of such subletting to Landlord. As
used herein, a “Tenant’s affiliate” shall mean a corporation or other entity which controls, is controlled by or is under common control with Tenant, or which is a joint venture partner of Tenant. 
 (e) Collection of Rent from Assignee. If Tenant’s interest in this Lease is assigned, whether or not in violation of the
provisions of this Section, Landlord may collect rent from the assignee; if the Leased Premises or any part thereof are sublet to, or occupied by, or used by, any Person other than Tenant, whether or nor in violation of this Section, Landlord, after
default by Tenant under this Lease, may collect rent from the subtenant, user or occupant. In either case, Landlord shall apply the amount collected to the rents reserved in this Lease, but neither any such assignment, subletting, occupancy or use,
whether with or without Landlord’s prior consent, nor any such collection or application, shall be deemed a waiver of any neon, covenant or condition of this Lease or 

 the acceptance by Landlord of such assignee, subtenant, occupant or user as tenant. The consent by
Landlord to any assignment or subletting shall not relieve Tenant from its obligation to obtain the express prior consent of Landlord to any further assignment or subletting. The listing of any name other than that of Tenant on any door of the
Leased Premises or on any directory in the Building, or otherwise, shall not operate to vest in the Person so named any right or interest in this Lease or in the Leased Premises or be deemed to constitute, or serve as a substitute for, any prior
consent of Landlord required under this Section, and it is understood that any such listing shall constitute a privilege extended by Landlord which shall be revocable at Landlord’s will by notice to Tenant. Neither an assignment of
Tenant’s interest in this Lease nor a subletting, occupancy or use of the Leased Premises or any part thereof by any Person other than Tenant, nor the collection of rent by Landlord from any Person other than Tenant as provided in this
subsection, nor the application of any such rent as provided in this subsection shall, in any circumstances, relieve Tenant from its obligation fully to observe and perform the terms, covenants and conditions of this Lease on Tenant’s part to
be observed and performed. 
 16. Default Provisions. 
 (a) Events of Default. Each of the following events shall be deemed to be, and is referred to in this Lease as, an “Event of
Default”: 
 (1) A default by Tenant in making any payment of Basic Rent or Additional Charges on the date such payment
is due and payable which continues for more than five days after Landlord shall have given Tenant a written notice specifying such default. 
 (2) If, within any period of 12 consecutive months, Landlord has given two written notices to Tenant pursuant to paragraph (1), a further default by Tenant, within the 12-month period after the giving of the second
such notice, in making any payment of Basic Rent or Additional Charges on the date such payment is due which continues for more than 10 days after such payment is due; or 
 (3) The neglect or failure of Tenant to perform or observe any of the terms, covenants or conditions contained in this Lease on
Tenant’s part to be performed or observed (other than those referred to in paragraph (1) above) which is not remedied by Tenant (i) within 20 days after Landlord shall have given to Tenant written notice specifying such neglect or
failure, or (ii) in the case of any such neglect or failure which cannot with due diligence and in good faith be cured within 20 days, within such additional period, if any, as may be reasonably required to cure such default with due diligence
and in good faith provided that Tenant commences the curing of the same within the 20-day period (it being intended that, in connection with any such default which is not susceptible of being cured with due diligence and in good faith within 20
days, the time within which the Tenant is required no cure such default shall be extended (or such additional period as may be necessary for the curing thereof with due diligence and in good faith); or 

 (4) The assignment, transfer, mortgaging or encumbering of this Lease or the subletting
of the Leased Premises in a manner not permitted by Section 15; or 
 (5) The taking of this Lease or the Leased
Premises, or any part thereof, upon execution or by other process of law directed against Tenant, or upon or subject to any attachment at the instance of any creditor of or claimant against Tenant, which execution or attachment shall not be
discharged or disposed of within 30 days after the levy thereof. 
 (b) Landlord’s Rights Upon Event of Default.
Upon the occurrence of an Event of Default, Landlord shall have the right, at its election, then or at any time thereafter while such Event of Default shall continue, either: 
 (1) To give Tenant written notice that this Lease will terminate on a date to be specified in such notice, which date shall not be less
than three days after such notice if such notice is sent by registered or certified mail, but which date may be the date of such notice or any date thereafter if such notice is delivered in person, and on the date specified in such notice
Tenant’s right to possession of the Leased Premises shall cease and this Lease shall thereupon be terminated, but Tenant shall remain liable as provided in subsection (c); or 
 (2) Without demand or notice, to reenter or take possession of the Leased Premises, or any part thereof, and repossess the same as of
Landlord’s former estate and expel Tenant and those claiming through or under Tenant and remove the effects of both or either, either by summary proceedings, or by action at law or in equity, without being deemed guilty of any manner of
trespass and without prejudice to any remedies for arrears of rent or preceding breach of covenant. 
 If Landlord elects to re-enter under
paragraph (2), Landlord may terminate this Lease, or, from time to time, without terminating this Lease, may relet the Leased Premises, or any part thereof, as agent for Tenant for such term or terms and it such rental or rentals and upon such other
terms and conditions as Landlord may deem advisable, with the right to make alterations and repairs to the Leased Premises. No such re-entry or taking of possession of the Leased Premises by Landlord shall be construed as an election on
Landlord’s part to terminate this Lease unless a written notice of such intention is given to Tenant under paragraph (1) or unless the termination thereof be decreed by a court of competent jurisdiction. Tenant waives any right to the
service of any notice of Landlord’s intention to reenter provided for by any present or future law. 
 (c)
Tenant’s Liability for Damages. If Landlord terminates this Lease pursuant to subsection (b), Tenant shall remain liable (in addition to accrued liabilities) to 

 the extent legally permissible for (i) the sum of (A) all Basic Rent and Additional Charges
provided (or in this Lease until the date this Lease would have expired had such termination not occurred, and (B) any and all reasonable expenses incurred by Landlord in reentering the Leased Premises, repossessing the same, making good any
default of Tenant, painting, altering or dividing the Leased Premises, combining the same with any adjacent space for any new tenants, putting the same in proper repair, reletting the same (including any and all reasonable attorney’s fees and
disbursements and reasonable brokerage fees incurred in so doing), and any and all expenses which Landlord may incur during the occupancy of any new tenant (other than expenses of a type that are Landlord’s responsibility under the terms of
this Lease); less (ii) the proceeds of any reletting. Tenant agrees to pay to Landlord the difference between items (i) and (ii) above with respect to each month during the Term, at the end of such month. Any suit brought by Landlord
to enforce collection of such difference for any one month shall not prejudice Landlord’s right to enforce the collection of any difference for any subsequent month. In addition to the foregoing, Tenant shall pay to Landlord, whether or not the
Lease is terminated, such sums as the court which has jurisdiction thereover may adjudge reasonable as attorney’s fees with respect to any successful law suit or action instituted by Landlord to enforce the provisions of this Lease. Landlord
shall have the right, at its sole option, to relet the whole or any part of this Leased Premises for the whole of the unexpired Term, or longer, or from time to time for shorter periods, for any rental then obtainable, giving such concessions of
rent and making such special repairs, alterations, decorations and paintings for any new tenant as Landlord, in its sole and absolute discretion, may deem advisable. Tenant’s liability as aforesaid shall survive the institution of summary
proceedings and the issuance of any warrant thereunder. Landlord shall be under no obligation to relet the Leased Premises, but agrees to use its best efforts to do so. 
 (d) Liquidated Damages. If Landlord terminates this Lease pursuant to subsection (b), Landlord shall have the right, at any time,
at its option, to require Tenant to pay to Landlord, on demand, as liquidated and agreed final damages in lieu of Tenant’s liability under subsection (c), an amount equal to the difference discounted to the date of such demand at an annual rate
of interest equal to the then-current yield on actively traded U.S. Treasury bonds with 10-year maturities, as published in the Federal Reserve Statistical Release for the week prior to the date of such termination, between (i) the Basic Rent
and Additional Charges, computed on the basis of the then current annual rate of Basic Rent and Additional Charges, which would have been payable from the date of such demand to the date when this Lease would have expired, if it had not been
terminated, and (ii) the then fair rental value of the Leased Premises for the same period. Upon exercise of this option by Landlord and payment of such liquidated and agreed final damages, Tenant shall be released from all further liability
under this Lease with respect to the period after the date of such demand. If, after the Event of Default giving rise to the termination of this Lease, but before presentation of proof of such liquidated damages, the Leased Premises, or any part
thereof, shall be relet by Landlord for a term of one year or more, the amount of rent reserved upon such reletting shall be deemed to be the fair rental value for the part of the Leased Premises so relet during the term of such reletting.

 (e) Rights and Remedies Cumulative. The rights and remedies herein conferred are
cumulative and not exclusive of any other rights or remedies, and shall be in addition to every other right, power and remedy that Landlord may have, whether specifically granted herein, or presently or hereafter existing at law, in equity, or by
statute. 
 17. Bankruptcy 
 (a) Events of Bankruptcy. The following shall be Events of Bankruptcy under this Lease: (i) Tenant’s becoming insolvent, as that term is defined in Title 11 of the United States Code (the
“Bankruptcy Code”) or under the insolvency laws of any state, district, commonwealth or territory of the United States (the “Insolvency Laws”); (ii) the appointment of a receiver or custodian for any or all of Tenant’s
property or assets, or the institution of a foreclosure action upon any of Tenant’s real or personal property; (iii) the filing of a voluntary petition under the provisions of the Bankruptcy Code or insolvency Laws; (iv) the filing of
an involuntary petition against Tenant as the subject debtor under the Bankruptcy Code or insolvency Laws, which either (A) is not dismissed within sixty (60) days of filing, or (B) results in the issuance of an order for relief
against the debtor or (iv) Tenants making or consenting to an assignment for the benefit of creditors or a common law composition of creditors. 
 (b) Landlord’s Rights Upon Event of Bankruptcy. Upon the occurrence of an Event of Bankruptcy, Landlord shall have all rights and remedies available no Landlord pursuant no Section 16; provided,
however, that while a case in which Tenant is the subject debtor under the Bankruptcy Code is pending, Landlord shall not exercise its rights and remedies pursuant to Section 16 so long as (1) the Bankruptcy Code prohibits the exercise of
such rights and remedies, and (2) Tenant or its Trustee in Bankruptcy (hereinafter referred to as “Trustee”) (i) cures all defaults under this Lease, (ii) compensates Landlord for monetary damages incurred as a result of
such defaults, (iii) provides adequate assurance of future performance on the pert of Tenant as debtor in possession or on the part of the assignee tenant, and (iv) complies with all other requirements of the Bankruptcy Code. 

18. Either Party May Perform the Other’s Obligations. 
 If Tenant shall fail to keep or perform any of its obligations as provided in this Lease in respect to (a) maintenance of insurance, (b) repairs and maintenance of the Leased Premises, (c) compliance
with Legal Requirements, or (d) the making of any other payment or performance of any other obligation, then Landlord may (but shall not be obligated to do so) upon the continuance of such failure on Tenant’s part for 10 days after written
notice to Tenant (or after such additional period, if any, as Tenant may reasonably require to cure such failure if of a nature which cannot be cured within said 10 day period), or without notice in the case of an emergency, and without waiving or
releasing Tenant from any obligation, and as an additional but not exclusive remedy, make any such payment or perform any such obligation and all sums so paid by Landlord and all necessary incidental costs and expenses, including attorney’s
fees, incurred by Landlord in making such payment or performing such obligation, 

 together with interest thereon from the date of payment at the Default Interest Rate, shall be deemed additional rent and
shall be paid to Landlord on demand, or at Landlord’s option may be added to any installment of Basic Rent thereafter filling due, and if not so paid by Tenant, Landlord shall have the same rights and remedies as in the case of a default by
Tenant in the payment of Basic Rent. If Landlord shall fail to keep or perform any of its obligations as provided in this Lease in respect to (a) maintenance of insurance, (b) repairs and maintenance of the Leased Premises, the Building or
the common areas, or (c) the making of any other payment or performance of any other obligation, then Tenant may (but shall not be obligated to do so) upon the continuance of such failure on Landlord’s part for 10 days after written notice
to Landlord (or after such additional period, if any, as Landlord may reasonably require to cure such failure if of a nature which cannot be cured within said 10 day period), or without notice in the case of an emergency, and without waiving or
releasing Landlord from any obligation, and us an additional but not exclusive remedy, make any such payment or perform any such obligation and all sums so paid by Tenant and all necessary incidental costs and expenses, including-attorney’s
fees, incurred by Tenant in making such payment or performing such obligation, together with interest thereon from the date of payment at the Default Interest Rate, shall be paid by Landlord to Tenant on demand. 
 19. Security Deposit. 
 (a) Use and Application. Tenant has deposited with Landlord the Security Deposit, as security for the prompt, full and faithful performance by Tenant of each and every provision of this Lease and of all obligations of Tenant
hereunder. Landlord has invested the Security Deposit and shall keep the same invested, in (i) prime commercial paper, banker’s acceptances or certificates of deposit in United States commercial banks (having net assets in excess of
$100,000,000) in each case having a maturity of not more than 30 days, or (ii) obligations of the United Stares Government having a maturity of not more than 90 days, or (iii) one or more mutual finds which invest their assets primarily in
investment of the type described in clauses (i) and (ii), or (iv) one or more interest-bearing accounts in financial institutions the deposits in which are insured by an agency of the United States. If an Event of Default occurs, Landlord
may use, apply or retain the whole or any part of the Security Deposit for the payment of (i) any Basic Rent or Additional Charges which Tenant may nor have paid or which may become due after the occurrence of such Event of Default,
(ii) any sum expended by Landlord on Tenant’s behalf in accordance with the provisions of this Lease, or (iii) any sum which Landlord may expend or be required to expend by reason of Tenant’s default, including damages or
deficiency in the reletting of the Leased Premises as provided in Section 16. The use, application or retention of the Security Deposit, or any portion thereof, by Landlord shall not prevent Landlord from exercising any other right or remedy
provided by this Lease or by law and shall not operate as a limitation on any recovery to which Landlord may otherwise be entitled. If any portion of the Security Deposit is used, applied or retained by Landlord for the purpose set forth above,
Tenant agrees, within 10 days after a written demand therefor is made by Landlord, to deposit cash with the Landlord in an amount sufficient to restore the Security Deposit to its original amount. 

 (b) Return of Security Deposit. Provided that Tenant is not then in default, the
Security Deposit, or any balance thereof, and all accrued interest or gains thereon, shall be returned to Tenant within thirty (30) days after the expiration of the Term. In the absence of evidence satisfactory to Landlord of any permitted
assignment of the right to receive the Security Deposit, or the remaining balance thereof, Landlord may return the same to the original Tenant, regardless of one or more assignments of Tenant’s interest in this Lease or the Security Deposit. In
such event, upon the return of the Security Deposit (or balance thereof) to the original Tenant, Landlord shall be completely relieved of liability under this Section. 
 (c) Return of Accrued Interest on Security Deposit. Within thirty (30) days after the execution of this Lease by both parties
hereto, Landlord will return all accrued interest on the Security Deposit to Tenant. 
 (d) Transfer of Security
Deposit. In the event of a transfer of Landlord’s interest in the Leased Premises, Landlord shall have the right to transfer the Security Deposit to the transferee thereof. In such event, upon the delivery by Landlord to Tenant of such
transferee’s written acknowledgment of its receipt of the Security Deposit, Landlord shall be deemed to have been released by Tenant from all liability or obligation for the return of the Security Deposit, and Tenant agrees to look solely to
such transferee for the return of the Security Deposit and the transferee shall be bound by all provisions o this Lease relating to the return of the Security Deposit. 
 (e) Restrictions on Encumbering. The Security Deposit shall not be mortgaged, assigned or encumbered in any manner whatsoever by
Tenant without the prior written consent of Landlord. 
 (f) Letter of Credit. At any time during the Term, Tenant
shall have the right to deliver to Landlord a letter of credit in the amount of the Security Deposit, to be held by Landlord as security for the performance by Tenant of all of the obligations to be performed by it under this Lease. In such event,
Landlord shall refund the cash Security Deposit and all accrued interest thereon to Tenant within fifteen (15) days after receipt of such letter of credit. The letter of credit (and each replacement or renewal thereof) shall (i) be
irrevocable, (ii) be issued by NationsBank, N.A. or another national bank having an office in Washington, D.C. or Fairfax County, Virginia, which has net assets of $50,000,000 or more, (iii) be for a term of not less than 12 months after
the date of issuance, and (iv) authorize Landlord to draw thereon by a sight draft delivered to the issuing bank accompanied by an affidavit of a general partner, or executive officer, of Landlord that an Event of Default has occurred and is
continuing or that Tenant has failed to deliver a replacement letter of credit within the time required by this subsection. Tenant shall, on or before the 30th day before the expiration date of the letter of credit then being held by Landlord under
this subsection, deliver to Landlord an extension or renewal of the letter of credit for a period of not less than 12 months. Tenant shall extend or renew the letter of credit, or any extension or renewal thereof, for successive periods of at least
12 months each throughout the Term. Upon the occurrence of an Event of Default or the Tenant’s failure to deliver a replacement letter of credit within the time 

 required by this subsection, Landlord shall be authorized to draw on the letter of credit then being held
by it. Landlord shall receive, hold and apply the proceeds of the letter of credit in the same manner and on the same terms as the Security Deposit. All references in this Lease to the “Security Deposit” shall be deemed to include the
proceeds of the letter of credit. 
 20. Subordination. 
 (a) Mortgages. This Lease and Tenant’s interest hereunder shall have priority over, and be senior to, the lien of any Mortgage
made by Landlord after the date of this Lease. However, if at any rime or from time to time during the Term, a Mortgagee or prospective Mortgagee requests that this Lease be subject and subordinate to its Mortgage, this Lease and Tenant’s
interest hereunder shall be subject and subordinate to the lien of such Mortgage and to all renewals, modifications, replacements consolidations and extensions thereof and to any and all advances made thereunder and the interest thereon. Tenant
agrees that, within 10 days after receipt of a written request therefor from Landlord, it will, from time to time, execute and deliver any instrument or other document required by any such Mortgagee to subordinate this Lease and its interest in the
Leased Premises to the lien of such Mortgage. If, at any time or from time to time during the Term, a Mortgagee of a Mortgage made prior to the date of this Lease shall request that this lease have priority over the lien of such Mortgage, and if
Landlord consents thereto, this Lease shall have priority over the lien of such Mortgage and all renewals, modifications, replacements, consolidations and extensions thereof and all advances made thereunder and the interest thereon, and Tenant
shall, within 10 days after receipt of a written request therefor from Landlord, execute, acknowledge and deliver any and all documents and instruments confirming the priority of this Lease. In any event, however, if this Lease shall have priority
over the lien of a Mortgage, this Lease shall not become subject or subordinate to the lien of any subordinate Mortgage, and Tenant shall not execute any subordination documents or instruments for any subordinate Mortgagee, without the written
consent of the prior Mortgagee. 
 (b) Ground Leases. This Lease and Tenant’s interest hereunder shall be subject
and subordinate to each and every ground or underlying lease hereafter made of the Building or the land on which it is constructed, or both, and to all renewals, modifications, replacements and extensions thereof. Tenant agrees that, within 10 days
after receipt of written request therefor from Landlord, it will, from time to time, execute, acknowledge and deliver any instrument or other document required by any such lessor to subordinate this Lease and its interest in the Leased Premises to
such ground or underlying lease. 
 (c) First Mortgagee’s Right of Cure. If (i) the Building, or any part
thereof, or the land on which the Building is constructed, or the Landlord’s leasehold estate in the Building, is at any time subject to a first Mortgage, and (ii) this Lease, or the Basic Rent and Additional Charges payable under this
Lease is assigned to the first Mortgagee; and (iii) the Tenant is given written notice of such assignment, including the name and address of the assignee, then, in that event, Tenant shall not terminate this Lease or make 

 any abatement in the Basic Rent payable hereunder for any default on the part of the Landlord without
first giving written notice, in the manner provided, elsewhere in this Lease for the giving of notices, to such first Mortgagee, specifying the default in reasonable detail, and affording such first Mortgagee a reasonable opportunity to make
performance, as its election, for and on behalf of the Landlord. 
 (d) Non-Disturbance Agreement. Notwithstanding the
provisions of subsections (a) and (b), neither this Lease nor any right, title or interest of Tenant in the Leased Premises shall be subordinate to the lien of any ground or underlying lease or any Mortgage made or placed after the date of this
Lease, and Tenant shall not be required to subordinate this Lease or Tenant’s interest in the Leased Premises to any such ground or underlying lease or any such Mortgage, unless such lease or Mortgage contains an express provision (or the
lessor or the Mortgagee or other party secured by the Mortgage agrees in writing) to the effect that so long as this Lease has not been terminated by reason of the occurrence of an Event of Default, the lessor or the Mortgagee (or other party
secured by the Mortgage) will be bound by all of the terms and provisions of this Lease (except as otherwise set forth in such agreement), a default by the Landlord under such lease or by the mortgagor under such Mortgage shall not have any effect
upon Tenant’s right to occupy the Leased Premises in accordance with all of the terms and conditions of this Lease, and the term, estate and options of Tenant under this Lease shall not be terminated or otherwise effected by a termination of
such ground or underlying lease or a foreclosure and sale or other action instituted under or in connection with such Mortgage. Contemporaneously with the execution of this Lease, Landlord shall deliver to Tenant a non-disturbance agreement, in form
reasonably satisfactory to Tenant, from the Mortgagee under any existing Mortgage, to the effect that so long as this Lease has not been terminated by reason of the occurrence of an Event of Default, the Mortgagee (or other party secured by the
Mortgage) will be bound by all of the terms and provisions of this Lease, a default by the mortgagor under such Mortgage shall not have any effect upon Tenant’s right to occupy the Leased Premises in accordance with all of the terms and
conditions of this Lease, and the term, estate and options of Tenant under this Lease shall not be terminated or otherwise affected by a foreclosure and sale or other action instituted under or in connection with such Mortgage. Contemporaneously
with the execution of this Agreement, Landlord shall deliver to Tenant a non-disturbance agreement, its form reasonably satisfactory to Tenant, from the lessor under the Ground Lease, to the effect that so long as this Lease has not been terminated
by reason of the occurrence of an Event of Default, the lessor will be bound by all of the terms and provisions of this Lease, a default by the Landlord under such Ground Lease shall not have any effect upon Tenant’s right to occupy the Leased
Premises in accordance with all of the terms and conditions of this Lease, and the term, estate and options of Tenant under this Lease shall not be terminated or otherwise affected by a termination of such Ground Lease. 
 21. Attornment. 
 In the event of
(a) a transfer of Landlord’s interest in the Leased Premises, (b) the termination of any ground or underlying lease of the Building or the land on which it is 

 constructed, or both, or (c) the purchase of the Building or Landlord’s interest therein in a foreclosure sale
or by deed in lieu of foreclosure under any Mortgage or pursuant to a power of sale contained in any Mortgage, then in any of such events Tenant shall, at Landlord’s request, attorn to and recognize the transferee or purchaser of
Landlord’s interest or the lessor under the terminated ground or underlying lease, as the case may be, as Landlord under this Lease for the balance then remaining of the Term, and thereafter this Lease shall continued as a direct lease between
such person, as “Landlord” and Tenant, as “Tenant,” except that such lessor, transferee or purchase shall not be liable for any act or omission of Landlord prior to such lease termination or prior to such
person’s succession to title, nor be subject to any offset, defense or counterclaim accruing prior to such lease termination or prior to such person’s succession to title, nor be bound by any payment of Basic Rent or Additional Charges
prior to such lease termination or prior to such person’s succession to title for more than one month in advance. Tenant shall, upon request by Landlord or the transferee or purchaser of Landlord’s interest or the lessor under the
terminated ground or underling lease, as the case may be, execute and delivery an instrument or instruments confirming the foregoing provisions of this Section. Tenant hereby waives the provisions of any present or future law or regulation which
gives or purports to give Tenant any right to terminate or otherwise adversely affect this Lease, or the obligations of Tenant hereunder, upon or as a result of the termination of any such ground or underlying lease or the completion of any such
foreclosure and sale. 
 22. Quiet Enjoyment. 
 Landlord covenants that Tenant, upon paying the Basic Rent and the Additional Charges provided for in this Lease, and upon performing and observing all of the terms, covenants, conditions and provisions of this Lease
on Tenant’s part to be kept, observed and performed, shall quietly hold, occupy and enjoy the Leased Premises during the Term without hindrance, ejection or molestation by Landlord or any party lawfully claiming through or under Landlord.

 23. Landlord’s Right of Access to Leased Premises. 
 (a) Right of Entry. Landlord and its agents shall have the following rights in and about the Leased Premises; (i) to enter the
Leased Premises at all reasonable times to examine the Leased Premises or for any of the purposes set forth in this Section or for the purpose of performing any obligation of Landlord under this Lease or exercising any right or remedy reserved to
Landlord in this Lease, and if Tenant, its officers, partners, agents or employees shall not be personally present or shall not open and permit an entry into the Leased Premises at any time when such entry shall be necessary or permissible, to use a
master key or forcibly to enter the Leased Premises; (ii) to erect, install, use and maintain pipes, ducts and conduits in and through the Leased Premises which, when completed, will not substantially interfere with the use or appearance or
materially reduce the space afforded to Tenant in the Leased Premises; (iii) to exhibit the Leased Premises to others at reasonable times and for reasonable purposes, (iv) to make such repairs, alterations or improvements, or to perform
maintenance of all heating, air-conditioning, elevator, plumbing, electrical and other mechanical facilities installed by Landlord, as may be required from time to time by this Lease to be made or performed by Landlord; (v) to take all
materials into and upon the Leased Premises that may be required in 

 connection with any such repairs, alterations, improvements or maintenance; and (vi) to alter,
renovate and decorate the Leased Premises at any time during the Term if Tenant shall have removed all or substantially all of Tenant’s property from the Leased Premises. Landlord agrees to give prior notice before it exercises its rights under
this subsection, except that Landlord may enter the Leased Premises without notice in the case of an emergency. In making such an entry, Landlord agrees to use reasonable efforts to avoid interfering with the regular amid usual conduct of the
Tenant’s business. Notwithstanding anything to the contrary herein, Landlord may obtain access to the double-secured areas of the Leased Premises only with the permission and assistance of Tenant’s Director of Facilities, except in the
event of an emergency posing a threat of immediate injury to persons or property. 
 (b) Rights in Adjacent Areas.
Except as otherwise provided in Section 10, all parts (except surfaces facing the interior of the Leased Premises) of all walls, windows and doors bounding the Leased Premises (including exterior Building walls, corridor walls, doors and
entrances), all balconies, terraces and roofs adjacent to the Leased Premises, all space in or adjacent to the Leased Premises used for shafts, stacks, stairways, chutes, pipes, conduits, ducts, fan rooms, heating, air-conditioning, plumbing,
electrical and other mechanical facilities installed by Landlord, service closets and other Building facilities, and the use thereof, as well as access thereto through the Leased Premises for the purposes of operation, maintenance, alteration and
repair, are hereby reserved to Landlord. Nothing contained in this Section shall impose any obligation upon Landlord with respect to the operation, maintenance, alteration or repair of the Leased Premises or the Building. 
 (c) Effect of Landlord’s Entry. The exercise by Landlord or its agents of any right reserved to Landlord in this Section 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 from any of its obligations under this Lease, or impose any liability upon Landlord, or its agents,
or upon any lessor under any ground or underlying lease, by reason of inconvenience or annoyance to Tenant, or injury to or interruption of Tenant’s business, or otherwise. Landlord agrees to exercise its rights under this Section in a manner
designed to minimize interference with Tenant’s normal business operations, without any obligation, however, to employ labor at overtime or other premium pay rates. 
 24. Limitation on Landlord’s Liability. 
 (a) Accidents, etc. Except for
damages resulting from the willful or negligent act or omission of Landlord, its agents, employees or contractors, Landlord shall not be liable to Tenant, its employees, agents, business invitees, licensees, customers, guests or trespassers, for any
damage or loss to the property of Tenant or others located on the Leased Premises, or in the Building or the land on which it is built, or for any accident or injury to Persons in the Leased Premises or the Building, resulting from the necessity of
repairing any portion of the Building; the use or operation (by Tenant or any other Person or Persons whatsoever) of any elevators, or heating, cooling, electrical or plumbing equipment or apparatus; the termination of this Lease by reason of the
destruction of the 

 Building or the Leased Premises; any fire, robbery, theft, and/or any other casualty; any leaking in any
part or portion of the Leased Premises or the Building; any water, wind, rain, or snow that may leak into, or flow from any part of the Leased Premises or the Building; any acts or omissions of any occupant of any space adjacent to or adjoining all
or any part of the Leased Premises, any water, gas, steam, fire, explosion, electricity or falling plaster, the bursting, stoppage or leakage of any pipes, sewer pipes, drains, conduits, appliances or plumbing works; or any other cause whatsoever.

 (b) Unavoidable Delays. Neither Landlord nor Tenant shall be required to perform any of its obligations under any
provision of this Lease, or be liable for loss or damage for failure to do so, nor shall the other party be released from any of its obligations under this Lease because of such party’s failure to perform, where such failure arises from or
through Unavoidable Delays or Legal Requirements. If Landlord or Tenant is so delayed or prevented from performing any of its obligations during the Term, the period of such delay or such prevention shall be deemed added to the time herein provided
for the performance of any such obligation. Lack of funds shall not be deemed an Unavoidable Delay for purposes of this Section 24(b), and nothing in this Section 24(b) shall excuse Tenant’s failure to promptly pay any Basic Rent or
Additional Charges due under this Lease, or Landlord’s or Tenant’s failure to maintain policies or deliver certificates of insurance required hereunder. 
 (c) Building Services. If Landlord shall fail to supply, or be delayed in applying, any service expressly or impliedly to be
supplied under this Lease, or shall be unable to make, or be delayed in making, any repairs, alterations, additions, improvements or decorations, or shall be unable to supply, or be delayed in supplying, any equipment or fixtures, and if such
failure, delay or inability shall result from Unavoidable Delays, such failure, delay or inability shall not constitute an actual or constructive eviction, in whole or in part, or relieve Tenant from any of its obligations under this Lease, or
impose any liability upon Landlord or its agents by reason of inconvenience to Tenant, or injury to, or interruption of, Tenant’s business, or otherwise, or entitle Tenant to any abatement or diminution of rent except as provided in
Section 3(i). 
 (d) Liability Limited to Landlord’s Estate. Notwithstanding any provision to the contrary,
Tenant shall look solely to the estate and property of Landlord in and to the Building (or the proceeds received by Landlord on a sale of such estate and property but not the proceeds of any financing or refinancing thereof) in the event of any
claim against Landlord arising out of or in connection with this Lease, the relationship of Landlord and Tenant or Tenant’s use of the Leased Premises, and Tenant agrees that the liability of Landlord arising out of or in connection with this
Lease, the relationship of Landlord and Tenant or Tenant’s use of the Leased Premises, shall be limited to such estate and property of Landlord (or sale, insurance or condemnation proceeds in connection therewith). No other properties or assets
of Landlord shall be subject to levy, execution or other enforcement procedures for the satisfaction of any judgment (or other judicial process) or for the satisfaction of any other remedy of Tenant arising out of or in connection with this Lease,
the relationship of Landlord and Tenant or Tenant’s use of 

 the Leased Premises, and if Tenant shall acquire a lien on or interest in any other properties or assets
by judgment or otherwise, Tenant shall promptly release such lien on or interest in such other properties and assets by executing, acknowledging and delivering to Landlord an instrument to that effect prepared by Landlord’s attorneys.

 25. Estoppel Certificates. 
 Tenant and Landlord each agrees, from time to time, within 15 days after written request therefor by the other parry, to execute, acknowledge and deliver to the other party a statement in writing certifying to the other party, any
Mortgagee, assignee of a Mortgagee, or any purchaser, of the Building or the land on which it is constructed, or both, or any other Person designated by the other party, as of the date of such statement, (i) that Tenant is in possession of the
Leased Premises; (ii) that this Lease is unmodified and in full force and effect (or, if there have been modifications, that this Lease is in full force and effect as modified and setting forth such modifications); (iii) whether or not
there are then existing any set-offs or defenses known to such party against the enforcement of any right or remedy of the other party, or any duty or obligation of such party, hereunder (and, if so, specifying the same in detail); (iv) the
dates, if any, to which any Basic Rent or Additional Charges have been paid in advance; (v) that such party has no knowledge of any uncured defaults on the part of the other party under this Lease (or, if such party has knowledge of any such
uncured defaults, specifying the same in detail); (vi) that such party has no knowledge of any event having occurred that authorizes the termination of this Lease by such party (or, if such party has such knowledge, specifying the same in
detail); (vii) the amount of any Security Deposit held by Landlord; and (viii) any additional facts reasonably requested by any such Mortgagee, assignee of a Mortgagee, purchaser or other Person. 
 26. Surrender of Leased Premises. 
 (a) Possession. Tenant shall, on or before the last day of the Term, except as otherwise expressly provided elsewhere in this Lease, remove all of its property and peaceably and quietly leave, surrender and
yield up to the Landlord the Leased Premises, free of subtenancies, broom clean and in good order and condition except for reasonable wear and tear, damage by fire or other casualty, or conditions requiring repair by Landlord hereunder at
Landlord’s expense. 
 (b) Inspection of Leased Premises. At the time Tenant surrenders the Leased Premises at the
end of the Term, or within twenty (20) days thereafter, Landlord and Tenant, or their respective agents shall inspect the Leased Premises and shall prepare and sign an inspection form to describe the condition of the Leased Premises at the time
[ILLEGIBLE] 
 If Tenant shall hold over possession of the Leased Premises after the end of the Term, Tenant shall be deemed to be occupying
the Leased Premises as a Tenant from month-to-month, at one hundred fifty percent (150%) of the Basic Rent, adjusted to a monthly basis, and subject to all the other conditions, provisions and obligations of this Lease insofar as the same are
applicable, or as the same shall be adjusted, to a month-to-month tenancy. 

 28. Mediation. 
 In any case in which it is provided by the terms of this Lease that any matter shall be determined by mediation, then such mediation shall be in accordance with the Commercial Mediation Rules then in effect of the
American Arbitration Association (“AAA”). The mediation proceeding shall be conducted in Washington, D.C., by one mediator selected by the AAA. The cost of the mediation, including filing fees with the AAA and the cost of the mediator,
shall be borne equally by the parties. In the mediation sessions, the parties shall endeavor in good faith to resolve the claim or controversy at issue. Any party or the mediator shall have the right to terminate the mediation at any time after the
first mediation session. Neither party may make any disclosure of the existence or results of the mediation without the prior written consent of the other party. The mediator may not make any disclosure of the existence or results of the mediation
without the prior written consent of both parties. No discussions in the mediation shall be admissible in any litigation between the parties, and the mediator shall not be subject to subpoena to testify to any communication between the mediator and
either party. If the parties are unable to settle the matter by mediation, then either party may submit such matter to litigation. 
 29.
Parking. 
 Throughout the Term, Tenant shall be entitled to the use of 675 parking spaces in the structured parking facility for the
Office Park (the “Parking Spaces”), without additional charge therefor. The Parking Spaces shall be available to Tenant and/or its employees on an unreserved basis, in common with the other tenants of the Office Park. 
 30. Renewal of Term. 
 Provided that
this Lease shall be in full force and effect and that Tenant shall not then be in default, Tenant shall have the right, at Tenant’s sole option, to extend the Lease for one (1) consecutive additional period of five (5) years (such
additional period being hereinafter referred to as the “Renewal Period”, if exercised, and included in the definition of the Term). Such option to extend shall be exercised by Tenant giving written notice of the exercise to Landlord at
least twenty-four (24) months prior to the expiration of the Initial Term of this Lease. The Renewal Period shall be for the same Basic Rent payable during the last Lease Year of the Initial Term, escalated at the commencement of the Renewal
Period and at the commencement of each Lease Year thereafter by the inflation Adjustment, and upon the same terms, covenants and conditions set forth in this Lease with respect to the Initial Term, and Tenant’s obligations to pay Operating
Expense Increases pursuant to Section 3(b) shall continue without interruption during the Renewal Period. In the event Tenant defaults beyond any applicable cure period under this Lease after providing notice of exercise of its renewal option
but prior to the expiration of the Initial Term, such exercise shall, at Landlord’s option exercised by written notice to Tenant, be ab initio. 

 31. Shuttle Service. 
 Landlord shall provide for Tenant’s employees, other tenants of the Building and other adjacent buildings owned by Landlord or affiliates, and the employees of such other tenants a private shuttle bus service
between the Building and the Vienna Metro Station. Subject to Unavoidable Delays, the shuttle bus service shall be provided throughout the Term and continuously during the hours between 7:00 a.m. and 8:00 p.m. on Business Days. Landlord shall use
shuttle buses which have reasonably adequate seating capacity taking into account average passenger usage from time to time. Landlord shall provide private shuttle bus service for Tenant’s employees at times in addition to those specified in
this Section, at Tenant’s expense, as mutually agreed upon by Landlord and Tenant. Landlord shall charge Tenant for after-hours service at an hourly rate from time to time established by Landlord, in its sole discretion, but in no event will
the rate per hour charged to Tenant be more than an amount per hour which represents Landlord’s reasonable estimate of its actual cost of providing such after-hours service, including labor, cost of fuel, and wear and tear on equipment, plus an
allowance of 10% thereof to cover general overhead. In the event the same after-hours service is also requested by other tenants of the Building (or any other building owned by Landlord or its affiliates) in addition to Tenant, the charge therefor
to each tenant requesting such after-hours service shall be a pro-rated amount based upon the net rentable area of the leased premises of all tenants requesting such after-hours service. Payment for such charges shall be due and payable to Landlord
within 15 days after Tenant’s receipt of an invoice therefor. Any dispute between Landlord and Tenant with respect to the adequacy of Landlord’s shuttle bus service shall be submitted to mediation pursuant to Section 28. 

32. Leasing Commission. 
 Landlord
and Tenant each represent and warrant to the other that neither of them has employed any broker, other than The Carey Winston Company, in carrying on the negotiations relative to this Lease. Tenant shall pay any commission due The Carey Winston
Company in connection with this Lease. Landlord and Tenant shall each indemnify and hold harmless the other from and against any claim or claims for brokerage or other commission arising from or out of any breach of the foregoing representation and
warranty. 
 33. Telephone Switch. 
 Tenant intends, at its expense, to install a telephone switch in the Office Space to provide telephone service to the Leased Premises. Subject to agreement by Landlord and Tenant on marketing arrangements and other
matters, Tenant shall have the right to use its telephone switch to provide telephone service to other tenants of the Building and any adjacent office building located in the Office Park. Tenant hereby agrees to indemnify and hold harmless Landlord
from and against any and all claims, cases, actions, damages, liabilities and expenses (including attorneys’ fees) that arise from or are in connection with Tenant’s provision of telephone services to other tenants. 

 34. General Provisions. 
 (a) Binding Effect. The covenants, conditions, agreements, terms and provisions herein contained shall be binding upon, and shall
inure to the benefit of, the parties hereto and, subject to the provisions of Section 15, each of their respective personal representatives, successors and assigns. 
 (b) Governing Law. It is the intention of the parties hereto that this Lease (and the terms and provisions hereof) shall be
construed and enforced in accordance with the laws of the State of Virginia. 
 (c) Waivers. No failure by Landlord to
insist upon the strict performance of any term, covenant, agreement, provision, condition or limitation of this Lease or to exercise any right or remedy consequent upon a breach thereof, and no acceptance by the Landlord of full or partial rent
during the continuance of any such breach, shall constitute a waiver of any such breach or of any such term, covenant, agreement, provision, condition or limitation. No term, covenant, agreement, provision, condition or limitation of this Lease to
be kept, observed or performed by Landlord or by Tenant, and no breach thereof, shall be waived, altered or modified except by a written instrument executed by Landlord or by Tenant, as the case may be. No waiver of any breach shall affect or alter
this Lease, but each and every term, covenant, agreement, provision, condition and limitation of this Lease shall continue in full force and effect with respect to any other then existing or subsequent breach thereof. 
 (d) Notices. No notice, request, consent, approval, waiver or other communication which may be or is required or permitted to be
given under this Lease shall be effective unless the same is in writing and is delivered in person or sent by registered or certified mail, return receipt requested, first-class postage prepaid, (1) if to Landlord, at Landlord’s Notice
Address, or (2) if to Tenant, at Tenant’s Notice Address, or as any other address that may be given by one party to the other by notice pursuant to this subsection. Such notices, if sent by registered or certified mail, shall be deemed to
have been given at the time of mailing. 
 (e) Entire Agreement. It is understood and agreed by and between the parties
hereto that this Lease contains the final and entire agreement between said parties, and that they shall not be bound by any terms, statements, conditions or representations, oral or written, express or implied, not herein contained. It is
understood and agreed, however, that the terms hereof shall be modified, if so required, for the purposes of complying with or fulfilling the requirements of any Mortgagee secured by a first Mortgage that may now be or hereafter become a lien on the
Building, provided, however, that such modification shall not be in substantial derogation or diminution of any of the rights of the parties hereunder, nor increase any of the obligation or liabilities of the parties hereunder. 
 (f) Jury Trial. Landlord and Tenant each hereby waives all right to trial by jury in any claim, action, proceeding or counterclaim
by either Landlord or Tenant against the other on any matters arising out of or in any way connected with this Lease, the relationship of Landlord and Tenant and/or Tenant’s use or occupancy of the Leased Premises. 

 (g) Venue. Tenant hereby waives any objection to the venue of any action filed by
Landlord against Tenant in any state or federal court in the jurisdiction in which the Building is located, and Tenant further waives any right, claim or power, under the doctrine of forum non conveniens or otherwise, to transfer any such
action filed by Landlord to any other court. 
 (h) Corporate Authority. Concurrently with the signing of this Lease,
Tenant shall furnish to Landlord certified copies of the resolutions of its Board of Directors (or of the executive committee of its Board of Directors) authorizing Tenant to enter into this Lease; and Tenant shall also furnish to Landlord evidence
(reasonably satisfactory to Landlord and its counsel) that Tenant is a duly organized corporation in good standing under the laws of the jurisdiction of its incorporation, is qualified to do business in good standing in the State of Virginia, has
the power and authority to enter into this Lease, and that all corporate action requisite to authorize Tenant to enter into this Lease has been duly taken. 
 (i) Time of the Essence. Time is of the essence in the performance of Landlord’s and Tenant’s obligations under this Lease. 
 (j) Gender. Wherever appropriate herein, the singular includes the plural and the plural includes the singular. 
 (k) Invalidity. If any provision of this Lease shall be invalid, illegal or unenforceable, the validity, legality and
enforceability of the remaining provisions shall not be affected thereby. 
 (l) Captions. The captions in this Lease
are for convenience only and shall not affect the interpretation of the provisions hereof. 
 (m) No Partnership. This
Lease is not intended to create a partnership or joint venture between Landlord and Tenant in the conduct of their respective businesses. 
 (n) Counterparts. This Lease has been executed in several counterparts, but all counterparts shall constitute one and the same instrument. 
 (o) Deed of Lease. To the extent required under applicable law to make this Lease legally effective, this Lease shall constitute a
deed of lease. 
 35. Approval of Building Food Service Tenants. 
 Throughout the Lease Term, Landlord shall not lease any space in the Building to a food service tenant, or approve the transfer of any lease of space in
the Building to a food service tenant, without Tenant’s prior written approval of such food service tenant, which approval shall not be unreasonably withheld, conditioned or delayed. 

 36. Termination of Prior Lease. 
 This Lease entirely supersedes the Lease Agreement dated January 30, 1987, as amended by the First Amendment, the Second Amendment and the Third
Amendment, and the Lease Agreement dated January 30, 1987, as amended, is hereby terminated. 
 IN WITNESS WHEREOF, Landlord and Tenant
have caused this Lease to be signed by their duly authorized partners or officers as of the day and year first above written. 
  

			
	Landlord
	
	HMCE ASSOCIATES LIMITED
	    PARTNERSHIP, R.L.L.P.
		
	By	 	 /s/ [ILLEGIBLE]

	
	Tenant
	
	 ICF KAISER HUNTERS BRANCH LEASING,
     INC.

		
	By	 	 /s/ TIMOTHY P. O’CONNORExhibit 10.13

 Exhibit 10.13 
 ASSIGNMENT AGREEMENT 
 This Assignment Agreement dated as of October 7, 2005 (“Assignment
Agreement”) among B2TECS (“Assignor”), Hunters Branch Leasing, LLC (“Landlord”) and ICF Consulting Group, Inc. (“Assignee”). 
 WHEREAS, the Assignor and Landlord are parties to the Deed of Lease dated May 2003 concerning the fifth floor of the building located at 9302 Lee Highway (together with all attachments thereto, the
“Lease”), pursuant to which Landlord agreed to provide to the Assignor a leasehold interest in the Premises; 
 WHEREAS,
(i) the Assignor intends to assign all of its rights and obligations under the Lease to the Assignee, (ii) Landlord is willing to agree to the assignment by the Assignor and the assumption by the Assignee of such rights and obligations,
and (iii) the Assignee is willing to agree to such assignment and to assume such rights and obligations; 
 NOW, THEREFORE, in
consideration of the foregoing premises and the covenants and agreements contained herein and for other good and valuable consideration the receipt and sufficiency of which are hereby acknowledged, the parties hereby agree as follows: 
 Section 1. Definitions. Except as otherwise defined in this Assignment, terms defined in the Lease are used herein as defined therein.

 Section 2. Assignment. As of the date hereof, (i) the Assignor hereby agrees to transfer and assign to the Assignee all
of the Assignor’s rights and obligations under the Lease, effective on December 15, 2005 (“Effective Date”) (ii) the Assignee hereby accepts such assignment and assumes all such rights and obligations on the Effective Date,
and (iii) except as otherwise provided in the Assignment Agreement, after the Effective Date, the Assignor shall have no further obligations under the Lease. 
 Section 3. Consent. Landlord hereby consents to (i) the assignment by the Assignor to the Assignee of all of the Assignor’s rights and obligations under the Lease, and (ii) the acceptance by
the Assignee of all such rights and obligations. 
 Section 4. On-Going Obligations. The Assignor would be liable to the Landlord
for all Base Rent, Additional Rent, Operating Costs, Real Estate Taxes, and any other fees which are due under the Lease based on the Assignor’s occupancy prior to the Effective Date. 
 Section 5. Surrender of Possession. On the Effective Date, the Assignor agrees to surrender the Premises to the Assignee pursuant to the
terms of the Lease, with the terms of the Lease being modified so that the Assignee shall be substituted for the Landlord. 
 Section 6.
Security Deposit. The Assignee shall return to the Assignor the amount of the Security Deposit being held by the Landlord within fifteen (15) days of the Assignee taking possession of the Premises. The Assignee shall reduce from this
payment any expenses 

 reasonably incurred to restore the Premises to an appropriate condition for business use. After the Assignee’s
payment to the Assignor pursuant to this Section 6, both the Landlord and the Assignor shall then consider the Assignor’s Security Deposit to be the property of the Assignee. 
 Section 7. Miscellaneous. 
 (a)
Headings. Captions and headings in this Assignment are for ease of reference only and do not constitute part of this Assignment of Agreement. 
 (b) Counterparts. This Assignment Agreement may be executed in any number of counterparts, all of which when taken together shall constitute one and the same instrument and any of the parties hereto may execute
this Assignment Agreement by signing any such counterpart. 
 (c) Successors and Assigns. This Assignment Agreement shall inure to the
benefit of, be binding upon, and be enforceable by and against the parties hereto and their respective successors and permitted assigns. 
 (d) Governing Law. This Assignment shall be governed by, and construed in accordance with, the laws of the Commonwealth of Virginia (without regard to its conflict of law provisions). 

 IN WITNESS WHEREOF, the parties hereto have caused this Assignment to be duly executed as of the day and
year first written above. 
  

			
	B2TECS
		
	 By:
	 	 /s/ Sunil Bala

	 Name:
	 	 Sunil Bala

	 Title:
	 	 Chairman

	
	ICF Consulting Group, Inc.
		
	 By:
	 	 /s/ Kenneth Kolsky

	 Name:
	 	 Kenneth Kolsky

	 Title:
	 	 Director of Administration &
 Contracts

	
	Acknowledged and Agreed:
	
	 Hunters Branch Leasing, LLC

		
	 By:
	 	 /s/ Richard Perlmutter

	 Name:
	 	 Richard Perlmutter

	 Title:
	 	 Manager

 DEED OF LEASE 
 BY AND BETWEEN 
 HUNTERS BRANCH LEASING, LLC 
 (“LANDLORD”) 
 AND

 B2TECS, a Virginia Corporation 
 (“TENANT”) 

 TABLE OF CONTENTS 
  

					
	 1.
	 	TERMS.	  	1
			
	 2.
	 	PAYMENT OF BASE RENT & ADDITIONAL RENT	  	4
			
	 3.
	 	SECURITY DEPOSIT	  	4
			
	 4.
	 	USES; TENANT COVENANTS	  	5
			
	 5.
	 	ENVIRONMENTAL PROVISIONS; RECYCLING	  	5
			
	 6.
	 	LATE CHARGES; INTEREST	  	9
			
	 7.
	 	REPAIRS AND MAINTENANCE	  	10
			
	 8.
	 	UTILITIES AND SERVICES	  	11
			
	 9.
	 	OPERATING COSTS	  	12
			
	 10.
	 	REAL ESTATE TAXES	  	16
			
	 11.
	 	ADDITIONAL PROVISIONS; OPERATING COSTS AND REAL ESTATE TAXES	  	18
			
	 12.
	 	TENANT’S INSURANCE	  	19
			
	 13.
	 	LANDLORD’S INSURANCE	  	20
			
	 14.
	 	DAMAGE OR DESTRUCTION	  	20
			
	 15.
	 	MACHINERY AND EQUIPMENT; ALTERATIONS AND ADDITIONS; REMOVAL OF FIXTURES	  	23
			
	 16.
	 	ACCEPTANCE OF PREMISES	  	24
			
	 17.
	 	TENANT IMPROVEMENTS	  	24
			
	 18.
	 	ACCESS	  	24
			
	 19.
	 	MUTUAL WAIVER OF SUBROGATION	  	25
			
	 20.
	 	INDEMNIFICATION	  	26
			
	 21.
	 	ASSIGNMENT AND SUBLETTING	  	26

					
	 22.
	 	ADVERTISING	  	28
			
	 23.
	 	LIENS	  	28
			
	 24.
	 	DEFAULT	  	28
			
	 25.
	 	SUBORDINATION	  	32
			
	 26.
	 	SURRENDER OF POSSESSION	  	33
			
	 27.
	 	NON-WAIVER	  	33
			
	 28.
	 	HOLDOVER	  	33
			
	 29.
	 	CONDEMNATION	  	33
			
	 30
	 	NOTICES	  	34
			
	 31.
	 	MORTGAGEE PROTECTION	  	35
			
	 32.
	 	COSTS AND ATTORNEYS’ FEES	  	35
			
	 33.
	 	BROKERS	  	35
			
	 34.
	 	LANDLORD’S LIABILITY	  	35
			
	 35.
	 	ESTOPPEL CERTIFICATES	  	36
			
	 36.
	 	FINANCIAL REPRESENTATIONS AND INFORMATION	  	36
			
	 37.
	 	TRANSFER OF LANDLORD’S INTEREST	  	37
			
	 38.
	 	RIGHT TO PERFORM	  	37
			
	 39.
	 	COMMON AREAS	  	37
			
	 40.
	 	SALES AND AUCTIONS	  	37
			
	 41.
	 	ACCESS TO ROOF	  	38
			
	 42.
	 	ACCESS	  	38
			
	 43.
	 	AUTHORITY OF LANDLORD AND TENANT	  	38

					
	 44.
	 	NO ACCORD OR SATISFACTION	  	38
			
	 45.
	 	LEGAL REQUIREMENTS	  	38
			
	 46.
	 	PARKING	  	39
			
	 47.
	 	GENERAL PROVISIONS	  	39
			
	 48.
	 	RULES AND REGULATIONS	  	41
			
	 49.
	 	ARBITRATION	  	41
			
	 50.
	 	WAIVER OF JURY TRIAL	  	42

  

			
	EXHIBIT A	 	Location and Dimensions of Premises
		
	EXHIBIT B	 	 Description of Land

		
	EXHIBIT C	 	 Intentionally Deleted

		
	EXHIBIT D	 	 Rules and Regulations

		
	EXHIBIT E	 	 Declaration of Lease Commencement

		
	EXHIBIT F	 	 Form of Estoppel Certificate

 DEED OF LEASE 
 THIS DEED OF LEASE (“Lease”) is made as of the      day of May, 2003, by and between HUNTERS BRANCH LEASING, LLC, a Delaware limited liability company
(“Landlord”) and B2TECS, a Virginia corporation (“Tenant”), and is joined in by HUNTERS BRANCH PARTNERS, L.L.C., a Virginia limited liability company (“Prime Landlord”), for the purposes set forth in the
Joinder appended hereto. 
 R E C I T A L S: 
 Landlord is the tenant under a certain lease agreement dated November 12, 1997 (the “Prime Lease”) by and between Landlord (as successor to ICF Kaiser Hunters Branch Leasing, Inc.), as tenant, and Prime
Landlord (as successor in interest to HMCE Associates Limited Partnership, R.L.L.P.), as landlord, pursuant to which Prime Lease Landlord leased from Prime Landlord various space in the Building (as defined below), including, but not limited to, the
Premises (also as defined below). Prime Landlord is joining in the execution hereof for those purpose as are set forth in the Joinder hereto. 
 Landlord, for and in consideration of the rents and all other charges and payments hereunder and of the covenants, agreements, terms, provisions and conditions to be kept and performed hereunder by Tenant grants and conveys to Tenant, and
Tenant hereby hires and takes from Landlord, a leasehold interest in the premises described below (“Premises”), subject to all matters hereinafter set forth and upon and subject to the covenants, agreements, terms, provisions and
conditions of this Lease for the term hereinafter stated. 
 NOW THEREFORE Landlord and Tenant hereby agree to the following: 
 1. TERMS. 
 1.1 Premises. The premises demised by this
Lease will consist of approximately 15,875 rentable square feet of space (the “Premises”) measured in accordance with the (January) 1995 Greater Washington, D.C. Commercial Association of Realtors (“GWCAR”) Standard Method of
Measurement, and located on the fifth (5th) floor in that building at the Hunters Branch Office Park, Fairfax
County, Virginia and known as 9302 Lee Highway, Fairfax, Virginia (the “Building”), together with the right to the use of not more than three and six-tenths (3.6) unreserved parking permits for each one thousand (1,000) square
feet of space within the Premises, located or in the adjacent surface parking and parking structure, and the non-exclusive use of various Common Areas (as defined in Section 39 hereof), as more particularly set forth herein. The land upon which
the Building is situated, which is generally depicted on the diagram attached hereto as Exhibit B (the “Site Plan”) and incorporated herein by reference, shall be referred to hereinafter as the “Land”. The Land and the
Building are collectively referred to herein as the “Project”. The location and dimensions of the Premises are shown on the conceptual floor plans attached hereto as Exhibit A and incorporated herein by reference. No easement for
light or air is incorporated in or intended to be conveyed with the Premises. 

 1.2 Tenant’s Share. “Tenant’s Share” shall mean a fraction, the numerator of
which is the total rentable square footage of the Premises as determined in accordance with Section 1.1 hereof, and the denominator of which is the total rentable square footage of the Building. No adjustment shall be made for space within the
Building occupied by any building engineer(s) or similar on-site property management or operational personnel, provided any such space will be located within a core area location to be determined within the reasonable judgment of Landlord. The
number comprising such denominator shall be changed if and to the extent of any addition of space to the Building or the deletion of space from the Building or in the amount of space leased by tenants (retail or otherwise) who pay by separate meter
for their electrical and/or janitorial, cleaning, or other utilities or services so that Tenant actually pays its fair, accurate and proportionate share of Operating Costs (as defined in Section 9) and Real Estate Taxes (as defined in
Section 10). The numerator shall be adjusted from time to time to reflect additions to or reductions in the total rentable square footage of space beyond the initial Premises that is leased to Tenant pursuant to this Lease and any addenda as a
result of the exercise of any options in this Lease or otherwise. 
 1.3 Lease Term. The term of this Lease (the “Term” or
“Lease Term”) shall commence on the Commencement Date and shall expire on October 31, 2012 (the “Lease Expiration Date”). 
 1.4 Commencement Date. 
 1.4.1 The “Commencement Date” shall be June 1, 2003, provided only that the existing
tenant located within the Premises has terminated its lease and vacated the Premises. In the event such tenant has not vacated the Premises as of the Commencement Date, the Commencement Date shall be the first day of the first full calendar month
after the date that such existing tenant has vacated the Premises; provided that if the Commencement Date does not occur within one hundred eighty (180) days after the date hereof, this Lease shall be null and void ab initio. 

1.5 Base Rent. The base rent payable by Tenant hereunder (“Base Rent”) is set forth in this Section 1.5.1, below. The Base Rent
is in addition to (and not to be reduced by) any payment of Additional Rent (as hereinafter defined) hereunder. Commencing as of the Commencement Date, and thereafter throughout the Term, Base Rent shall be payable monthly, in equal monthly
installments, in advance, on the first day of each calendar month of the Term, without prior notice, demand, deduction or offset of any kind. 
 1.5.1 Subject to the provisions of Section 1.5.2 below, the annual Base Rent for the Premises (monthly installments of which may be referred to herein as “Monthly Base Rent”) for the initial Lease Year of the Term shall be
Twenty Three Dollars and 50/100 ($23.50) per square foot of the Premises. The annual Base Rent for the Premises for the second Lease Year of the Term shall be Twenty Four Dollars ($24.00) per square foot of the Premises. Thereafter, as of the first
day of the third Lease Year and on the first day of each and every Lease Year thereafter during the Lease Term, the Base Rent shall be increased to an amount equal to one hundred three percent (103%) of the Base Rent for the immediately
preceding Lease Year. 
  

 - 2 - 

 1.6 Additional Rent. Tenant’s Share (as hereinafter defined) of increases in Real Estate
Taxes (as defined in Section 10), Operating Costs (as defined in Section 9) and any other sum owed or reimbursable by Tenant to Landlord under this Lease (excluding Base Rent) shall be considered additional rent hereunder (collectively
“Additional Rent”), and, except for items of Additional Rent for which demand is required pursuant to the express terms of this Lease, shall be payable without demand, set-off or deduction. Commencing on the first day of the second Lease
Year, estimates of those items of Additional Rent described in Section 9 and Section 10 of this Lease shall be payable monthly, in advance, on the first day of each calendar month of the Term, together with Tenant’s monthly payment of
Base Rent, without demand, set-off or deduction. 
 1.7 Notice and Payment Addresses. Any notices under this Lease shall be governed
by the terms of Section 30, below. The notice addresses of the parties are as follows: 
  

			
	If to Landlord:	 	c/o Argo Investment Company
		 	9600 Blackwell Road
		 	Suite 300
		 	Rockville, Maryland 20850
		 	Attention: Mr. Richard L. Perlmutter
		
	And a copy to:	 	J. Richard Saas, Esq.
		 	Tenenbaum & Saas, P.C.
		 	4330 East West Highway
		 	Suite 1150
		 	Bethesda, Maryland 20814
		
	If to Tenant:	 	At the Premises
		 	Attention: Dr. Sunil K. Bala

 Either party may, by ten (10) days’ prior written notice to the other, designate a new address to which
all notices hereunder shall be directed. 
 1.8 Rent Payment Address. Tenant shall send payments of Base Rent and Additional Rent
hereunder to Landlord at the following address, or to such other address of which Landlord may advise Tenant in writing: 
 c/o FB Argo
Management LC 
 9600 Blackwell Road 
 Suite 300 
 Rockville, Maryland 20850 
 1.9 Lease Year. The first “Lease Year” shall commence on the Commencement Date and terminate on the last day of the twelfth full calendar month after the Commencement Date. Each subsequent Lease Year
shall commence on the date immediately following the last day of the preceding Lease Year and shall continue for a period of twelve (12) full calendar months, except that the last Lease Year of the Lease Term shall terminate on the date this
Lease expires or is otherwise terminated. 
  

 - 3 - 

 1.10 Deed of Lease. To the extent required under applicable law to make this Lease legally
effective, this Lease shall constitute a deed of lease. 
 2. PAYMENT OF BASE RENT & ADDITIONAL RENT. 
 Tenant shall pay Landlord the Base Rent and Additional Rent due under this Lease without prior notice, demand, deduction or offset, except as otherwise
specifically and expressly set forth herein, in lawful money of the United States. Base Rent and Additional Rent shall be paid at the address noted in Section 1.8, or to such other party or at such other place as Landlord may hereafter from
time to time designate in writing. Base Rent and Additional Rent under this Lease for any partial month at the beginning or end of the Lease Term shall be prorated. Except for monthly installments of estimated Additional Rent as set forth in
Sections 9 and 10 of this Lease, or as otherwise provided in this Lease, all payments of Additional Rent shall be paid no later than thirty (30) business days after the date Landlord notifies Tenant in writing of the amount thereof in the event
of any dispute concerning the computation of the amount of any Additional Rent due, Tenant shall pay the amount specified by Landlord pending the resolution of the dispute, and, subject to Section 9.4 hereof, such payment shall be without
prejudice to Tenant’s right to continue to challenge the disputed computation. In the event Tenant prevails in any dispute concerning the amount of any Additional Rent due hereunder, Landlord shall promptly refund to Tenant the amount of such
overpayment, together with interest thereon at the Prime Rate (as hereinafter defined) from the date such payment was made. 
 3. SECURITY AND ADVANCE
DEPOSITS. 
 3.1 Security Deposit. 
 (a) Simultaneously with the execution of this Lease by Tenant, Tenant shall provide Landlord with a cash security deposit in an amount equal to $38,168.00 (the “Security Deposit”). 
 (b) The Security Deposit shall constitute security for payment of Base Rent and Additional Rent and for any and all other obligations of Tenant under
this Lease. If Tenant defaults, beyond any applicable cure period, with respect to any covenant or condition of this Lease, including but not limited to the payment of Base Rent, Additional Rent or any other payment due under this Lease, and the
obligation of Tenant to maintain the Premises and deliver possession thereof back to Landlord at the expiration or earlier termination of the Lease Term in the condition required herein, then Landlord may (without any waiver of Tenant’s default
being deemed to have occurred) apply all or any part of the Security Deposit to the payment of any sum in default beyond any applicable cure period, or any other sum which Landlord may be required or deem necessary to spend or incur by reason of
Tenant’s default, or to satisfy in part or in whole any damages suffered by Landlord as a result of Tenant’s default which continues to exist beyond any applicable cure period. In the event of such application, Tenant shall promptly
deposit with Landlord, in cash, the amount necessary to restore the Security Deposit to the full amount set forth above. The parties expressly acknowledge and agree that the Security Deposit 
  

 - 4 - 

 is not an advance payment of Base Rent or Additional Rent, nor a measure of Landlord’s damages in the event of any
default by Tenant. If Tenant shall have fully complied with all of the covenants and conditions of this Lease, but not otherwise, the amount of the Security Deposit then held by Landlord shall be repaid to Tenant within thirty (30) days after
the expiration or sooner termination of this Lease. In the event of a sale or transfer of Landlord’s estate or interest in the Building, Landlord shall transfer the Security Deposit to the purchaser or transferee, and upon such transfer,
provided such transferee acknowledges receipt of the Security Deposit, Landlord shall be considered released by Tenant from all liability for the return of the Security Deposit. 
 3.2 [Intentionally Deleted] 
 3 3 No
Separate Account. Landlord shall not be obligated to hold the Security Deposit in a separate account from other Building or Project funds. 
 4. USES;
TENANT COVENANTS. 
 4.1 Permitted Uses. The Premises are to be used for general office and administration purposes and such other
uses incidental to general office use and consistent with the operation of a first class office building as may be permitted by applicable law, provided such uses shall not include any retail, industrial or manufacturing use. 
 4.2 Other General Use Covenants. Tenant shall not commit or allow to be committed any waste upon the Premises, or any public or private nuisance.
Tenant, at its expense, shall comply with all laws relating to its use and occupancy of the Premises and shall observe the Rules and Regulations attached hereto as Exhibit D. No act shall be done in or about the Premises that is unlawful, or
which will increase the existing rate of insurance on the Building. In the event of a breach of the covenant set forth in the immediately preceding sentence regarding insurance rates, Landlord shall provide Tenant ten (10) days prior written
notice thereof and Tenant shall cease the activity giving rise to such increase and, to the extent any increased insurance premiums were in fact paid by Landlord as a result of such activity, Tenant shall pay to Landlord any and all such increases
in insurance premiums resulting from such breach, provided that so long as Tenant continues to pay such increases in premiums, and provided that the activity giving rise to such increased premiums is an activity permitted under
Section 4.1, above, the continuation of such activity by Tenant shall not be prohibited or constitute a breach of this Lease. Landlord represents and warrants that, to the best of its knowledge, Tenant’s permitted use of the Premises as
provided in Section 4.1 above will not, as of the Commencement Date, increase Landlord’s insurance costs. 
 5. ENVIRONMENTAL PROVISIONS;
RECYCLING. 
 5.1 General. Tenant agrees to comply (and to cause its agents, employees, contractors and, while within the Premises,
invitees to comply) with any and all applicable Environmental Laws (as defined below) in connection with (1) Tenant’s use and occupancy of the Premises, (2) any use and occupancy of the Premises arising in connection with any
assignment of this Lease, or sublease or license of the Premises or any part thereof, and (3) any 
  

 - 5 - 

 other fact or circumstance the existence of which legally imposes on Tenant the obligation to so comply therewith. Tenant
shall provide all information within Tenant’s control requested by Landlord and/or governmental authorities in connection with Environmental Laws or Hazardous Materials (defined below) relating to the matters contemplated in the preceding
sentence. 
 5.2 Tenant’s Warranties and Covenants 
 During the Term and any Renewal Term (as hereafter defined) of the Lease, Tenant warrants, represents and covenants to and with Landlord as follows: 
 5 2 1 Tenant will not introduce, or permit or suffer the introduction, within the Premises or the Project of (A) asbestos in any form, (B) urea
formaldehyde foam insulation, (C) transformers or other equipment which contain dielectric fluid containing polychlorinated biphenyls, or (D) except as permitted below, any flammable explosives, radioactive materials or other substance
constituting “hazardous materials” or “hazardous wastes” pursuant to the Comprehensive Environmental Response, Compensation and Liability Act of 1980, as amended (42 U.S.C. Sections 9601 et seq.), the Hazardous Materials
Transportation Act, as amended (49 U.S.C. Sections 1801 et seq.), the Resource Conservation and Recovery Act, as amended (42 U.S.C. Sections 9601 et seq.) and the regulations adopted and promulgated pursuant thereto, the Federal Water
Pollution Control Act (33 U.S.C. Section 1251 et seq.), the Clean Air Act (42 U.S.C. Section 7401 et seq.), and in the regulations adopted and publications promulgated pursuant thereto, or successor legislation thereto, or any other
Federal, state or local environmental law, ordinance, rule, regulation and/or other statute of a governmental or quasi-governmental authority relating to pollution or protection of the environment (collectively, “Environmental Laws”). The
substances described in (A), (B), (C) or (D) above are hereinafter collectively referred to herein as “Hazardous Materials”. 
 5.2.2 Except as expressly permitted hereby, the Premises will never be used by Tenant for any activities involving, directly or indirectly, the use, generation, treatment, transportation, storage or disposal of any Hazardous Materials, or
to refine, produce, store, handle, transfer, process or transport Hazardous Materials. 
 5.2.3 Tenant (A) shall comply with the
Environmental Laws and all other applicable laws, rules arid regulations or orders pertaining to health, the environment or Hazardous Materials, in so far as such laws pertain to Tenant’s use and occupancy of the Premises or the need for such
compliance arises due to the acts or omissions of Tenant, its agents, employees, contractors, invitees (while within the Premises), subtenants or assignees, (B) shall not, except as specifically permitted hereby, store, utilize, generate,
treat, transport or dispose of (or permit or acquiesce in the storage, utilization, generation, transportation, treatment or disposal of) any Hazardous Materials on or from the Premises, (C) shall cause its agents, employees, licensees,
contractors, invitees (while within the Premises), subtenants and assignees to comply with the representations, warranties and covenants herein contained and be responsible for any non-compliance by any such party(ies), (D) agrees that no
portion of the Premises will be used by Tenant or any assignee or subtenant of Tenant as a landfill or a dump, and (B) will not install any underground tanks of any type. 
  

 - 6 - 

 5.2.4 In the event of any future storage, presence, utilization, generation, transportation, treatment or
disposal of Hazardous Materials in, on or about the Premises, or in the event of any Hazardous Materials Release (as hereinafter defined) which in either case is attributable, in whole or in part, to the presence of Hazardous Materials existing in,
on or about on the Project subsequent to the Commencement Date and is caused, directly by Tenant or Tenant’s agents, employees, contractors, licensees, invitees (while within the Premises), sub-tenants or assignees, or is otherwise
Tenant’s responsibility under the terms of this Lease, Tenant shall, at the direction of Landlord or any federal, state, or local authority or other governmental authority, remove or cause the removal of any such Hazardous Materials and rectify
any such Hazardous Materials Release, and otherwise comply or cause compliance with the laws, rules, regulations or orders of such authority, all at the expense of Tenant, including without limitation, the undertaking and completion of all
investigations, studies, sampling and testing and all remedial, removal and other actions necessary to clean up and remove all Hazardous Materials, on, from or affecting the Premises. If, under such circumstances, Tenant shall fail to proceed with
such removal or otherwise comply with such laws, rules, regulations or orders within the cure period permitted under the applicable regulation or order, the same shall constitute a Default under this Lease (without any notice to Tenant required),
and Landlord may, but shall not be obligated to, take such action as may be reasonably necessary under the circumstance to eliminate such Hazardous Materials from the Premises or otherwise comply with the applicable law, rule, regulation or order,
acting either in its own name or in the name of Tenant pursuant to this Section, and the cost thereof shall be borne by Tenant and thereupon become due and payable as Additional Rent hereunder, provided, however, that Landlord shall not exercise its
self-help rights hereunder, nor exercise any right otherwise provided herein to terminate this Lease or Tenant’s right of possession due to Tenant’s failure or inability to correct such problem within a time certain as long as Tenant is at
all times using its best efforts to correct the problem (provided however, that if Landlord determines, in its reasonable discretion, that there exists a substantial risk of governmental enforcement action against Landlord, or governmental or third
party civil liability to Landlord, if Landlord fails to take independent action immediately to remediate an environmental problem which is otherwise Tenant’s responsibility under this Section 5, then Landlord shall, notwithstanding
Tenant’s continuing best efforts to correct the problem, be entitled to take such independent action, and to recover the reasonable and actual costs associated therewith from Tenant) Tenant shall give to Landlord and its authorized agents and
employees access to the Premises for such purposes and hereby specifically grants to Landlord a license to remove the Hazardous Materials and otherwise comply with such applicable laws, rules, regulations or orders, acting either in its own name or
in the name of the Tenant pursuant to this Section. 
 5.2.5 Landlord represents, warrants and covenants that to the best of its current
actual knowledge, as of the date of execution hereof, the Premises, Building and Land do not contain asbestos or any other Hazardous Materials in violation of any Environmental Laws, nor will the use of any such materials knowingly be permitted by
Landlord. In the event Landlord is advised, or it shall come to Landlord’s attention, that Hazardous Materials exist in the Premises in violation of any Environmental Laws that were not introduced therein by Tenant or Tenant’s agents,
employees, contractors, licensees, subtenants, assignees or invitees, Landlord shall take all commercially reasonable steps necessary to promptly remove or remediate (or cause to be removed or remediated) at Landlord’s expense (and not as an
Operating Cost), all such Hazardous Materials, and in doing so, Landlord shall use its reasonable efforts not to interfere with the conduct of Tenant’s business. 
  

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 5.2.6 Each of Tenant and Landlord hereby indemnifies and holds the other and their respective
shareholders, constituents, subsidiaries, affiliates, officers, directors, partners, employees, agents and trustees harmless from, against, for and in respect of, any and all damages, losses, settlement payments, obligations, liabilities, claims,
actions or causes of actions, encumbrances, fines, penalties, and costs and expenses suffered, sustained, incurred or required to be paid by any such indemnified party (including, without limitation, reasonable fees and disbursements or attorneys,
engineers, laboratories, contractors and consultants) because of, or arising out of or relating to a violation of any of the indemnifying party’s representations, warranties and covenants under this Section, including any Environmental
Liabilities (as hereinbelow defined) arising therefrom. For purposes of this indemnification clause, “Environmental Liabilities” shall include all costs and liabilities with respect to the presence, removal, utilization, generation,
storage, transportation, disposal or treatment of any Hazardous Materials or any release, spill, leak, pumping, pouring, emitting, emptying, discharge, injection, escaping, leaching, dumping or disposing into the environment (air, land or water) of
any Hazardous Materials (each a “Hazardous Materials Release”), including without limitation, cleanups, remedial and response actions, remedial investigations and feasibility studies, permits and licenses required by, or undertaken in
order to comply with the requirements of, any federal, state or local law, regulation, or agency or court, any damages for injury to person, property or natural resources, claims of governmental agencies or third parties for cleanup costs and costs
of removal, discharge, and satisfaction of all liens, encumbrances and restrictions on the Premises relating to the foregoing. The foregoing notwithstanding, the foregoing indemnifications shall not encompass indirect losses or consequential damages
or damages related to loss of business or business interruption which may arise on account of the presence of any Hazardous Materials on or about the Project. The foregoing indemnification and the responsibilities of Tenant and Landlord under this
Section shall survive the termination or expiration of this Lease. 
 5.2.7 Tenant shall promptly notify Landlord in writing of the
occurrence of any Hazardous Materials Release or any pending or threatened regulatory actions, or any claims made by any governmental authority or third party, relating to any Hazardous Materials or Hazardous Materials Release on or from the
Premises, and shall promptly furnish Landlord with copies of any correspondence or legal pleadings or documents in connection therewith. Landlord shall have the right, but shall not be obligated, to notify any governmental authority of any state of
facts which may come to its attention with respect to any Hazardous Materials or Hazardous Materials Release on or from the Premises following consultation with Tenant. 
 5.2.8 Tenant agrees that Landlord shall have the right (but not the obligation) to conduct, or to have conducted by its agents or contractors, such periodic environmental inspections of the Project as Landlord shall
reasonably deem necessary or advisable from time to time. Landlord agrees that it shall limit such inspection to not more than once in each twelve (12) month period (except in the event of the sale, financing or refinancing of the Project, or
in the event Landlord has reasonable evidence that there are any violations of any Environmental Laws, in any of which events Landlord shall be entitled to conduct such inspection(s) even if another inspection has occurred during the current twelve
(12)-month period). Landlord shall provide 
  

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 Tenant with no less than seventy-two (72) hours prior notice of any such inspection within the interior of the
Premises, except in case of an emergency, in which case only such notice as may be practicable under the circumstance shall be required. The cost of any such inspection shall be borne by Tenant in the event such inspection determines that Tenant has
breached the covenants set forth in Section 5.2.3 above. 
 5.3 Permitted Materials. Notwithstanding the foregoing, Tenant and
its assignees, subtenants and licensees shall be permitted to store reasonable amounts of Hazardous Materials that are typically used in an ordinary general office use environment such as ordinary cleaners, printer and duplication supplies and
similar materials (the “Permitted Materials”) provided such Permitted Materials are properly used, stored and disposed of in a manner and location meeting all Environmental Laws. Any such use, storage and disposal shall be subject to all
of the terms of this Section (except for the terms prohibiting same), and Tenant shall be responsible for obtaining any required permits and paying any fees and providing any testing required by any governmental agency with respect to the Permitted
Materials. If Landlord in its reasonable opinion determines that said Permitted Materials are being improperly stored, used or disposed of, then Tenant shall immediately take such corrective action as requested by Landlord. Should Tenant fail to
take such corrective action within twenty-four (24) hours, Landlord shall have the right to perform such work on Tenant’s behalf and at Tenant’s sole expense, and Tenant shall promptly reimburse Landlord for any and all costs
associated with said work. 
 5.4 Recycling Regulations. Landlord shall, as an Operating Cost hereunder, provide receptacles and
containers as necessary for Tenant to comply with all orders, requirements and conditions now or hereafter imposed by any ordinances, laws, orders and/or regulations (hereinafter collectively called “regulations”) of any governmental body
having jurisdiction over the Premises or the Building regarding the collection, sorting, separation and recycling of waste products, garbage, refuse and trash (hereinafter collectively called “waste products”). 
 6. LATE CHARGES; INTEREST. 
 6.1 Tenant hereby
acknowledges that late payment to Landlord of Base Rent or Additional Rent will cause Landlord to incur administrative costs and loss of investment income not contemplated by this Lease, the exact amount of which will be extremely difficult to
ascertain. If any Base Rent or Additional Rent due from Tenant is not received by Landlord or Landlord’s designated agent within five (5) days after the date due, then Tenant shall pay to Landlord a late charge equal to five percent
(5%) of such overdue amount. The parties hereby agree that such late charges represent a fair and reasonable estimate of the administrative cost that Landlord will incur by reason of Tenant’s late payment. Landlord’s acceptance of
such late charges shall not constitute a waiver of Tenant’s Default with respect to such overdue amount or otherwise estop Landlord from exercising any of the other rights and remedies granted hereunder. 
 6.2 In addition to the administrative late charge provided for under Section 6.1, above, if any Base Rent or Additional Rent or any other sum due
hereunder from Tenant to Landlord is not paid as and when due under this Lease, and such amount remains unpaid five (5) days after such due date, then the unpaid amount shall bear interest from the date originally due until the date paid at an
annual rate of interest equal to the “prime rate” of interest as published in the 
  

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 Wall Street Journal (or, if not published, as established by the then largest national banking association in the United
States of America) from time to time (the “Prime Rate”) plus three percent (3%) (the “Default Rate”). 
 7. REPAIRS AND
MAINTENANCE. 
 7.1 Landlord’s Obligations. Landlord shall maintain, repair, replace and keep in good operating condition,
comparable to similar properties in the Fairfax, Virginia area, the Common Areas (as defined in Section 39 below) (including, without limitation, the lobbies, elevators, stairs, grounds, loading areas and corridors), the roofs, foundations,
load-bearing elements, conduits and structural walls and other structural elements of the Building, the underground utility and sewer pipes of the Building, all base building mechanical, electrical, plumbing, HVAC system and the sprinkler system and
other fire and life-safety systems, and the adjacent parking structure and connector, the cost of which shall be included within Operating Costs except to the extent set forth in Section 9.6, hereof, provided that, to the extent the need for
any such repairs or replacements arise as a the result of the gross negligence or willful misconduct of Tenant (or Tenant’s agents, employees, contractors, invitees (while within the Premises), assignees or sub-tenants) and the same is not
covered under the policies of casualty insurance which are required to be carried by the parties pursuant to this Lease (in which case the proceeds of such insurance will be utilized to satisfy the cost thereof), the cost of such repairs or
replacements shall be reimbursable by Tenant to Landlord as Additional Rent under this Lease, and such reimbursement shall be due not later than thirty (30) days after Landlord’s written demand therefore. Landlord, at its cost and expense
(or at the expense of Landlord’s contractor, but in any event not as an Operating Cost), upon prior notice from Tenant shall promptly repair or replace all materials, workmanship, fixtures or equipment incorporated by Landlord in the Premises
that shall prove to be defective during any applicable warranty period. In performing any warranty work pursuant to this Section 7.1, Landlord and its contractors and subcontractors shall use reasonable efforts to minimize disruption to Tenant.
Subject to reimbursement as an Operating Cost pursuant to Section 9 hereof (if applicable), Landlord shall comply or cause compliance with all notices it receives of violation of Legal Requirements (as hereinafter defined) that are applicable
to the operation of the common and public areas in the Building and to the machinery and equipment provided by Landlord or used by its agents or contractors in the design, construction, or operation of the Building, including those portions of the
base Building systems that are contained in or serve the Premises. “Legal Requirements” are all present and future laws, ordinances (including zoning ordinances and land use requirements), regulations, and orders of the Commonwealth
of Virginia, Fairfax County, the United States of America and any other public or quasi-public authority having jurisdiction over the Project, including, but not limited to the Americans with Disabilities Act and regulations promulgated from time to
time thereunder to the extent the same are applicable to Landlord and/or any portion of the Project. 
 7.2 Repair Standards. All
repairs and maintenance required of Landlord pursuant to this Section or elsewhere in this Lease shall be performed in accordance with standards applicable to comparable office buildings in Fairfax, Virginia, and performed in a timely and diligent
fashion. Landlord agrees to diligently attend to any routine repairs or maintenance needs brought to its attention by Tenant as soon as reasonably practicable and in a manner calculated to minimize to the extent possible disruption of Tenant’s
business activities. 
  

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 7.3 Tenant’s Obligations. Subject to Landlord’s obligations as set forth in
Section 7.1 above and its right of access pursuant to Section 18, and except for janitorial and cleaning services (to the extent provided for under Section 8.1, below), Tenant shall be exclusively responsible for all repairs and
maintenance to the interior non-structural portions of the Premises. Tenant shall promptly report in writing to Landlord any defective condition in the Premises known to Tenant which Landlord is required to repair, and failure to so report such
defects shall excuse any delay by Landlord in commencing and completing such repair to the extent the same would otherwise be Landlord’s responsibility under this Lease, provided that (i) Landlord shall not be so excused if Landlord had
actual knowledge of the need for such repair independent of Tenant’s notification, and (ii) once Landlord is notified or has actual knowledge of the need for such repair, Landlord’s repair obligation under Section 7.1, above,
shall be fully effective as to such item (and, to the extent any delay in reporting such defects results in the otherwise avoidable need to perform a capital repair or replacement which under Section 9.5 is excluded from Operating Costs, in
lieu of an ordinary repair which under Section 9.5 would be included within Operating Costs, Tenant shall be responsible for the reasonable and actual cost of such capital repair or replacement unless Tenant can demonstrate that a capital
repair or replacement to such item would in any event have been necessary within twelve (12) months thereafter, even if the defective condition had been reported to Landlord or known by Landlord in a timely fashion). Landlord’s obligation
to make repairs shall be Limited to the express obligations stated herein. 
 8. UTILITIES AND SERVICES. 
 8.1 Services. Landlord shall furnish Tenant with the following services and facilities consistent with the level of services provided in comparable
office buildings in the Fairfax, Virginia area; (i) at least one elevator in the Building subject to call at all times, including Sundays and holidays; (ii) zoned heating, ventilation and air conditioning at all times during business
hours, within the temperature and humidity ranges usually furnished in comparable office buildings in the Fairfax, Virginia area, (iii) balancing of the HVAC system when necessary in an effort to provide reasonably uniform air temperatures
throughout the zones within the Premises, (iv) hot and cold running water sufficient for needs attributable to a general office use, (v) public lavatory facilities and supplies and janitorial and char services, including trash removal and
recycling, Monday through Friday, excepting holidays, in accordance with the cleaning specifications promulgated by Landlord from time to time, (v) replacement of light bulbs (in fixed lighting fixtures only) and lighting fixtures throughout
the Premises, and (vi) access to the Project 24 hours a day, 365 days a year, including holidays, and the cost of which shall be deemed an Operating Cost hereunder unless otherwise provided above. For purposes hereof, “holidays” shall
be; New Year’s Day, Memorial Day, July 4th, Labor Day, Thanksgiving, and Christmas, and business hours shall be 7:00 a.m. to 6:00 p.m. Monday through Friday, excluding holidays, and 9.00 a.m. to 1.00 p.m. on Saturdays, excluding holidays.
Landlord agrees to provide an access-control system in the Building comparable to the system in first-class office buildings in the Fairfax, Virginia area, which shall permit Tenant to have, and shall provide Tenant with, access LO the Premises and
the parking areas of the garage on a 24-hour, seven-days-a-week basis Landlord shall, at its cost, provide an initial set of security access cards to the Building and garage, which initial set shall contain 3 6 access cards for each one thousand

  

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 (1,000) square feet of rentable area in the Premises and shall be supplemented by additional access cards in the same
ratio in the event of any expansion of the Premises. If Tenant requests replacement access cards from Landlord, such replacement cards shall be provided by Landlord, and Tenant shall reimburse Landlord Eight and 50/100 Dollars ($8 50) for each such
replacement card. 
 8.2 Additional Services. If Tenant requires cleaning services, light bulb or fixture replacement or other
services on weekends or holidays, Landlord shall make reasonable efforts to provide such additional service after reasonable prior written request therefor from Tenant, and Tenant shall reimburse Landlord for such additional service within thirty
(30) days of request therefore, at the actual direct out-of-pocket cost to Landlord. Additionally, if Tenant desires HVAC services at any time beyond normal business hours, Landlord shall provide such additional services provided that Tenant
shall pay 100% of the cost thereof as Additional Rent hereunder; such cost to include the actual cost of the service plus Landlord’s reasonable estimate of the additional repair and maintenance as well as the diminution of the useful life of
such Building system, as a result of any excessive use. 
 8.3 Additional Provisions. Except as specifically and expressly set forth
hereinbelow, in no event shall Landlord be liable to Tenant for (a) any damage to the Premises, or (b) any loss, damage or injury to any property therein or thereon, or (c) any claims for the interruption of or loss to Tenant’s
business or for any damages or consequential losses occasioned by bursting, rupture, leakage or overflow of any plumbing or other pipes or other similar cause in, above, upon or about the Premises or the Building, unless such loss, damage or injury
is the result of the gross negligence or willful misconduct of Landlord, and is not covered by the insurance required to be carried by Tenant hereunder. If any public utility or governmental body shall require Landlord or Tenant to restrict the
consumption of any utility or reduce any service to the Premises or the Building, Landlord and Tenant shall comply with such requirements, without any abatement or reduction of the Base Rent, Additional Rent or other sums payable by Tenant
hereunder. 
 9. OPERATING COSTS. 
 9.1
Defined. Commencing as of the first day of the second Lease Year and thereafter during each calendar year or portion thereof during the Term, Tenant shall pay as Additional Rent to Landlord, without diminution, set-off or deduction,
Tenant’s Share of Increases in “Operating Costs” (as defined below) for each calendar year. 
 9.2 Estimated Payments.
Commencing as of the first day of the second Lease Year Tenant shall make monthly installment payments toward Tenant’s Share of Increases in Operating Costs on an estimated basis, based on Landlord’s reasonable estimate of Operating Costs
for such calendar year Tenant shall pay Landlord, as Additional Rent, commencing on the first day of the second Lease Year and on the first day of each month thereafter throughout the Term (and any extension thereof), one-twelfth (1/12th) of
Landlord’s estimate of Tenant’s Share of Increases in Operating Costs for the then-current calendar year. If at any time or times during such calendar year it appears to Landlord that Tenant’s Share of Increases in Operating Costs for
such calendar year will vary from Landlord’s estimate by more than five percent (5%) on an annualized basis, Landlord may, by written notice to Tenant, revise its estimate for such calendar year and Tenant’s estimated payments
hereunder for such calendar year shall thereupon be based on such revised estimate. 
  

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 9.3 Annual Reconciliation. Within one hundred twenty (120) days after the end of each
calendar year, Landlord shall provide to Tenant a detailed, itemized statement (the “Expense Statement”), calculated in accordance with Section 9.1, above, setting forth the total actual Operating Costs for such calendar year and
Tenant’s Share of Increases in Operating Costs. The Expense Statement shall be certified by Landlord as being true and correct in all material respects. Landlord shall respond to any inquiries and requests for invoices or other information with
respect to Operating Costs within ten (10) days of any written request therefore by Tenant. Within thirty (30) days after the delivery of such Expense Statement, to the extent of any overpayment in the amount of estimated payments paid by
Tenant, Landlord shall pay to Tenant such overpayment within thirty (30) days of the delivery of the Expense Statement to Tenant To the extent of any underpayment in the amount of estimated payments paid by Tenant, Tenant shall pay to Landlord
the amount of any shortfall in the amount of estimated payments made to Landlord pursuant to Section 9.2 on account of Tenant’s Share of Increases in Operating Costs for such calendar year, and the actual amount shown as Tenant’s
Share of Increases in Operating Costs for such calendar year, but such payment shall not prejudice Tenant’s right to object to the same pursuant to the provisions of Section 9.4, below. In the event the Expense Statement reflects an
overpayment of Tenant’s Share of Increases in Operating Costs for such year, such overpayment shall be credited against the next due Base Rent hereunder. 
 9.4 Operating Costs. The term “Operating Costs” shall mean all third-party, reasonable and customary expenses incurred by Landlord in connection with the operation, management, maintenance and repair
of the Building, Common Areas and the Land in accordance with the standards applicable to comparable first class office properties in the Fairfax, Virginia, subject to the qualifications set forth below. All Operating Costs shall be determined
according to generally accepted accounting principles which shall be consistently applied. Operating Costs include, but are not limited to, the following items: (a) the cost of the personal property used in conjunction with the Building and the
Project; (b) except as set forth in Section 9.6 with respect to capital repairs and replacements costs to repair and maintain the Building and the Common Areas; (c) all expenses paid or incurred by Landlord for water, gas, electric,
sewer and oil services for the Building; (d) the costs and expenses incurred in connection with the provision of the services set forth in Section 8, above; (e) subject to Section 9.6(1) below with respect to matters of a capital
nature, building supplies and materials used in connection with repairs to the Project, (f) cleaning and janitorial services in or about the Premises, the Building (including without limitation Common Areas) and the land, (g) window glass
replacement, repair and cleaning, (h) repair and maintenance of the grounds, including costs of landscaping, gardening and planting, including service or management contracts with independent contractors, including but not limited to security
and energy management services and costs, (i) operational costs to achieve compliance with any governmental laws, rules, orders or regulations (“Laws”) promulgated after the Commencement Date and excluding capital expenses associated
therewith except to the extent specifically set forth below, and excluding capital expenses associated therewith except to the extent specifically set forth below, (j) utility taxes; (k) compensation (including employment taxes, fringe
benefits, salaries, wages, medical, surgical, and general welfare benefits (including health, accident and group life insurance), pension payments, payroll 
  

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 taxes for all personnel employed by Landlord or its management company who perform duties in connection with the
operation, management, maintenance and repair of the Building (allocated among all properties served by such employees as determined by Landlord in its reasonable discretion, if such employees are utilized by more than one property) plus the salary
and benefits of the property manager assigned to the Project; (1) any (i) capital expenditures incurred to reduce Operating Costs, to the extent of such reduction (and with any amount remaining unrecovered by virtue of such limitation to
carry forward to subsequent calendar years, to the extent of any such continuing reduction achieved in each such subsequent calendar year, until recovered in full), (ii) capital expenditures incurred to comply with any Law which is enacted or
becomes effective after the Commencement Date, and (iii) capital expenditures made for the replacement of items (the repair of which would be included within Operating Costs) in lieu of repairs thereto, provided (A) replacement of the item
in lieu of repair is either less costly on an annual basis than repair of the item in question, or is necessary given the non-functioning condition of the item in question, as determined by Landlord in good faith, (B) this provision shall not
apply to general renovations, as opposed to needed repairs, of the Building or any elements therein, and (C) any expenditure shall be recoverable only over the useful life of the item in question (as determined in accordance with GAAP) by
amortizing such expenditure over such useful life at an annual interest rate equal to the Prime Rate at the time of such expenditure, and only the sum of all amortization payments payable during the year in question shall be included in Operating
Costs in each year during such recovery period; (m) cast of premiums for casualty and liability insurance policies required to be maintained by Landlord hereunder and any other insurance carried by Landlord with respect to the Project that are
consistent with the limitations set forth in Section 13.1 below; (n) license, permit and inspection fees; (o) management fees based upon a percentage of gross rental receipts, Operating Costs, Real Estate Taxes and utility costs;
(p) consulting fees in connection with the provision of common area maintenance services, (q) personal property taxes; (r) trash removal, including all costs incurred in connection with waste product recycling, (s) snow and ice
removal or prevention; (t) maintenance, repair and striping of all parking areas used by tenants of the Building, and any other cost or assessment payable in connection with the maintaining of such parking areas, (u) uniforms and dry
cleaning for personnel below the grade of Building Manager; (v) telephone, cellular phone, paging, telegraph, postage, stationery supplies and other materials and expenses required for the routine operation of the Building; (w) association
assessments for maintenance of offsite improvements serving or benefiting the Building or the Land, (x) ground rent and/or ground lease payments required to be paid by Owner for the Land on which the Building is located; and (y) other
association assessments for common area services provided to owners in the Hunters Branch complex. 
 9.5 Exclusions. Except as
otherwise provided in this Lease, Operating Costs shall not include any of the following: (1) capital expenditures, except those specifically set forth above; (2) costs of any special services rendered to individual tenants (including
Tenant); (3) painting, redecorating or other work which Landlord performs for specific tenants; (4) Real Estate Taxes (as defined in Section 10), (5) depreciation or amortization of costs required to be capitalized in accordance
with generally accepted accounting practices (except as set forth in Section 9.4, above), (6) interest and amortization of funds borrowed by Landlord, (7) leasing commissions, and advertising, legal, space planning and construction
expenses incurred in procuring tenants for the Building; (8) salaries, wages, or other compensation paid to officers or executives of 
  

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 Landlord or its property management company in their capacities as officers and executives; (9) any other expenses
for which Landlord actually receives direct reimbursement from insurance, condemnation awards, warranties, other tenants or any other source but excluding general payments of Operating Costs pursuant to this Section 9 by Tenant and other
tenants of the Building, (10) all costs incurred in the initial construction of the Project; (11) costs directly resulting from the willful misconduct of Landlord, its employees, agents, contractors or employees, (12) legal fees and
other expenses incurred by Landlord except in administering, contracting for services which are a part of, and disputing Operating Costs; (13) costs or fees relating to the defense of Landlord’s title or interest in the Land;
(14) costs incurred due to violation by Landlord of violation of any Laws or in existence as of the Commencement Date the terms and conditions of this Lease; (15) renovation of the Project made necessary by casualty or the exercise of
eminent domain, (16) costs arising from the presence of Hazardous Materials in, about or below the Project, (17) costs incurred for any items to the extent of Landlord’s recovery under a manufacturer’s, materialmen’s,
vendor’s or contractor’s warranty (except to the extent of costs incurred in such recovery); (18) income, excess profits, franchise taxes or other such taxes imposed on or measured by the net income of Landlord from the operation of
the Building (other than business professional occupational license tax); (19) reserves for repairs, maintenance and replacements; (20) Landlord’s general overhead expenses; (21) costs incurred to achieve compliance with any
governmental laws, ordinances, rules, regulations or orders, except to the extent recoverable under Section 9.4(i) and 9.4(l), above; (22) any penalties or interest expenses incurred because of Landlord’s failure timely to pay any
Operating Costs (unless the same is the result of Tenant’s failure to timely make any payment in respect thereof required hereunder); (23) accounting fees other than those attributable to reviewing and preparing operating statements for
the Building; (24) rental or similar payments made in connection with the leasing of any equipment deemed to be capital in nature except to the extent the acquisition of such item would have been recoverable under Section 9.4(1), above,
(25) principal or interest payments on and any other charges (including, but not limited to, late charges, default interest or other penalties) paid by Landlord in connection with any mortgages, deeds of trust or other financing or refinancing
encumbrances; (26) deductions for depreciation for the Building, except to the extent expressly included in Section 9.4(1) above; (27) the costs of special services, tenant improvements and concessions, repairs, maintenance items or
utilities separately chargeable to, or specifically provided for, individual tenants of the Building, including, without limitation, the cost of preparing any space in the Building for occupancy by any tenant and/or for altering, renovating,
repainting, decorating, planning and designing spaces (other than Common Areas) for any tenant in the Building in connection with the renewal of its lease and/or costs of preparing or renovating any vacant space for lease in the Building (including
permit, license and inspection fees); (28) attorney’s fees and disbursements, accounting fees, recording costs, mortgage recording taxes, title insurance premiums, title closer’s gratuity and other similar costs, incurred in
connection with any mortgage financing or refinancing or execution, modification or extension of any ground lease; loan prepayment penalties, premiums, fees or charges; (29) fees, costs and expenses incurred by Landlord in connection with or
relating to claims against or disputes with tenants of the Building or the negotiation of leases with tenants or prospective tenants, including, without limitation, legal fees and disbursements, (30) costs incurred by Landlord in curing,
repairing or replacing any structural portion of the Building made necessary as a result of defects in design, workmanship or materials; (31) costs and expenses incurred by Landlord for services which are duplicative of or are normally included
in any management fees 
  

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 paid by Landlord; (32) that portion of any Annual Operating Cost that is paid to any entity affiliated with Landlord
that is in excess of the amount that would otherwise be paid to an entity that is not affiliated with Landlord for the provision of the same service; (33) rental for personal property leased to Landlord except for rent for personal property
leased to Landlord the purchase price for which, if purchased, would be included (in whole or part) in Operating Costs in the year of purchase; (34) attorney’s fees and disbursements, brokerage commissions, transfer taxes, recording costs
and taxes, title insurance premiums, title closer’s fees and gratuities and other similar costs incurred in connection with the sale or transfer of an interest in Landlord (including any restructuring, recapitalization or similar events or
activities) or the Building; (35) all costs and expenses attributable to any testing, investigation, management, maintenance, remediation, or removal of Hazardous Materials (other than any testing or monitoring customarily conducted by owners
of similar office buildings in the ordinary course of operating and managing a building) or the resolution of Y2000 issues; (36) the costs of all sculptures, paintings, and other works of art, and any costs and expenses related to the display
or maintenance thereof; and (37) costs of increases in insurance premiums to the extent such increase is solely attributable to the use, occupancy or act of another tenant. 
 9.6 Further Adjustment. Operating Costs for each calendar year shall be adjusted to include all costs, expenses and disbursements that Landlord
reasonably determines would have been incurred if Landlord had provided all utilities and services within the definition of Operating Costs to tenants and occupants in the Building had the Building been ninety five percent (95%) occupied
throughout such year. 
 9.7 Multi-Project Operating Costs. The Building is a part of a larger project or development and as such,
Landlord shall have the right (but not the obligation) to allocate to the Building an appropriate portion of those Operating Costs which are incurred with respect to the project as a whole. By way of example, landscaping costs for a multi-building
project shall be allocated on an appropriate basis between all tenantable buildings in the project. 
 9.8 Increases in Operating
Costs. For purposes hereof, “Increases in Operating Costs” shall be deemed to mean the increase (if any) in Operating Costs incurred in operating the Building for the Lease Year in question compared to the Operating Costs for the
Building incurred in calendar year 2004 (the “Base Year”). 
 10. REAL ESTATE TAXES 
 10.1 Defined. Commencing as of the first day of the second Lease Year and thereafter during each calendar year or portion thereof during the Term,
Tenant shall pay as Additional Rent to Landlord, without diminution, set-off or deduction, Tenant’s Share of Increases in “Real Estate Taxes” (as defined in Section 10.3, below) paid in such calendar year. 
 10.2 Estimated Payment. Commencing on the first day of the second Lease Year, Tenant shall make monthly installment payments toward Tenant’s
Share of Increases in Real Estate Taxes on an estimated basis, based on Landlord’s reasonable estimate of Real Estate Taxes for such calendar year. Tenant shall pay Landlord, as Additional Rent, commencing on the first day of the second Lease
Year and on the first day of each month thereafter throughout 
  

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 the Term (and any extension thereof), one-twelfth (1/12th) of Landlord’s estimate of Tenant’s Share of
Increases in Real Estate Taxes for the then-current calendar year. If at any time or times during such calendar year it appears to Landlord that Tenant’s Share of Increases in Real Estate Taxes for such calendar year will vary from
Landlord’s estimate by more than five percent (5%) on an annualized basis, Landlord may, by written notice to Tenant, revise its estimate for such calendar year and Tenant’s estimated payments hereunder for such calendar year shall
thereupon be based on such revised estimate. 
 10.3 Real Estate Taxes. For purposes of this Lease, “Real Estate Taxes”
shall mean all taxes and assessments, general or special, ordinary or extraordinary, foreseen or unforeseen, assessed, levied or imposed upon the Building or the Land, or assessed, levied or imposed upon the fixtures, machinery, equipment or systems
in, upon or used in connection with the operation of the Building or the Land under the current or any future taxation or assessment system or modification of, supplement to, or substitute for such system Real Estate Taxes shall include all
reasonable expenses (including, but not limited to, attorneys’ fees, disbursements and actual costs) incurred by Landlord in obtaining or attempting to obtain a reduction of such taxes, rates or assessments, including any legal fees and costs
incurred in connection with contesting or appealing the amounts or the imposition of any Real Estate Taxes. In the event Real Estate Taxes (including special assessments) may be paid in installments, they may be paid in installments or in lump sum,
at Landlord’s election (and in such event Real Estate Taxes shall include such installments and interest paid on the unpaid balance of the assessment, or the entirety thereof, as applicable). The foregoing notwithstanding, Real Estate Taxes
shall not include: (i) any franchise, corporation, income, excess profits taxes or, grantor’s and recordation net profits tax which may be assessed against Landlord or the Project or both, (ii) transfer, grantor’s and recordation
taxes assessed against Landlord or the Project or both, (iii) penalties or interest on any late payments of Landlord, (iv) personal property taxes of Tenant, (v) any rental or other charges or fee imposed upon Landlord in connection
with the lease or use of any vault space, (vi) estate taxes, inheritance taxes, succession taxes, (vii) gift taxes, (viii) unincorporated business tax, or (ix) taxes on personal property of Landlord not used in connection with
the operation, repair or maintenance of the Project Real Estate Taxes also shall exclude any interest or penalties arising by reason of the late payment of same, provided Tenant has timely made all payments of Tenant’s Share of Increases in
Real Estate Taxes as required hereunder. 
 10.4 Annual Reconciliation. Within one hundred twenty (120) days after the end of
each calendar year, Landlord shall provide to Tenant Landlord’s calculation of Tenant’s Share thereof (the “Tax Statement”). Within thirty (30) days after the delivery of the Tax Statement, Tenant shall pay to Landlord the
amount of any shortfall in the amount of estimated payments made to Landlord pursuant to Section 10.2 on account of Tenant’s Share of Increases in Real Estate Taxes for such calendar year, and the actual amount shown as Tenant’s Share
of Increases in Real Estate Taxes for such calendar year. In the event the Tax Statement reflects an overpayment of Tenant’s Share of Increases in Operating Costs for such year, such overpayment shall be credited against the next due Base Rent
hereunder. 
 10.5 Increases in Real Estate Taxes. For purposes hereof, “Increases in Real estate Taxes” shall be deemed to
mean the increase (if any) in Real Estate Taxes incurred for the Building for the Lease Year in question compared to the Real Estate Taxes for the Building incurred in the Base Year. 
  

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 11. ADDITIONAL PROVISIONS; OPERATING COSTS AND REAL ESTATE TAXES. 
 11.1 Partial Year; End of Term. To the extent that a more accurate method of allocating same cannot be implemented by Landlord, Tenant’s Share
of Operating Costs and Real Estate Taxes for any partial calendar year shall be determined by multiplying the amount of Tenant’s Share thereof for the full calendar year by a fraction, the numerator of which is the number of days during such
partial year falling within the Term and the denominator of which is 365. If this Lease terminates on a day other than the last day of a calendar year, the amount of any adjustment to Tenant’s Share of Real Estate Taxes with respect to the year
in which such termination occurs shall be prorated on the basis which the number of days from January 1 of such year to and including such termination date bears to 365, and any amount payable by Landlord to Tenant or Tenant to Landlord with
respect to such adjustment shall be payable within thirty (30) days after delivery by Landlord to Tenant of the applicable Expense Statement and Tax Statement with respect to such year. 
 11.2 Other Taxes. In addition to Tenant’s Share of Operating Costs and Real Estate Taxes, Tenant shall pay, prior to delinquency, all
personal property taxes payable with respect to all property of Tenant located in the Premises or the Building, and shall provide promptly, upon request of Landlord, written proof of such payment. 
 11.3 Covenant Regarding Timely Payment of Operating Costs and Real Estate Taxes. Landlord covenants to pay all Operating Costs and Real Estate
Taxes before the same become delinquent, subject to Tenant’s obligation to make the payments contemplated by Article 9 and Article 10, above, in a timely fashion. 
 11.4 Contesting Real Estate Taxes. Landlord will have the right to employ a tax consulting firm to attempt to assure a fair tax burden on the Project, provided Landlord will use reasonable efforts to minimize
the cost of such service. The reasonable cost of such service shall be included in the Real Estate Taxes hereunder in the year same were incurred or paid, at Landlord’s-election. Additionally, during any such period, Landlord shall have the
right, in its reasonable judgment, to contest any tax assessment, valuation or levy against the Project, and to retain legal counsel and expert witnesses to assist in such contest and otherwise to incur expenses in such contest, and any reasonable
fees, expenses and costs incurred by Landlord in contesting any assessments, levies or tax rate applicable to the Project, whether or not such contest is successful, shall be included in Real Estate Taxes as set forth above. 
 11.5 Arbitration. Disputes regarding Operating Costs, Real Estate Taxes, and any audit thereof, shall be subject to arbitration in accordance with
the provisions of Section 49 hereof. 
  

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 12. TENANT’S INSURANCE. 
 12.1 Coverage Requirements. Tenant shall during the Term of this Lease, procure at its expense and keep in force the following insurance:

 Commercial general liability insurance naming the Landlord and Landlord’s managing agent as additional insureds
against any and all claims for bodily injury and property damage occurring in or about the Premises or any appurtenances thereto covering the operation of the Tenant and any subtenants, licensees and concessionaires of the Tenant. Such insurance
shall be written on an “Occurrence Form” and shall include, without limitation, blanket contractual liability recognizing provisions of this Lease, broad form property damage, coverage for independent contractors, personal injury liability
and coverage for hired auto and non-ownership auto liability. Such insurance shall be primary and not contributing to any insurance available to Landlord and Landlord’s insurance shall be in excess thereto. Such insurance shall have a limit of
not less than One Million Dollars ($1,000,000.00) per occurrence with a Two Million Dollars ($2,000,000 00) general aggregate with an excess (umbrella) liability insurance in the amount of Two Million Dollars ($2,000,000.00) per occurrence and Two
Million Dollars ($2,000,000.00) annually in the aggregate; provided, however that no such limits shall be deemed limitation of the liability of Tenant hereunder. If Tenant has other locations that it owns or leases, the policy shall include an
aggregate limit per location endorsement. Such liability insurance shall be primary and not contributing to any insurance available to Landlord and Landlord’s insurance shall be in excess thereto. In no event shall the limits of such insurance
be considered as limiting the liability of Tenant under this Lease; 
 Personal property insurance insuring all equipment,
trade fixtures, inventory, fixtures and personal property located within the Premises (excluding leasehold improvements, which shall be insured by and remain the property of Landlord). Such insurance shall be written on a replacement cost basis in
an amount equal to one hundred percent (100%) of the full replacement value of the aggregate of the foregoing, 
 Workers’ compensation and occupational disease insurance, employee benefit insurance and any other insurance in the statutory amounts required by the laws of the State where the operations are to be performed with broad-form all-states
endorsement Employer’s liability insurance with a limit of Five Hundred Thousand Dollars ($500,000.00) for each accident. 
 Business income insurance in an amount equal to at least to twelve (12) months Rent. 
 12.2 Rating; Certificates;
Cancellation. The policies required to be maintained by Tenant shall be with companies rated A-III or better in the most current issue of Best’s Insurance Reports. Insurers shall be licensed to do business in the Commonwealth of Virginia
and domiciled in the USA. Any deductible amounts under any insurance policies required hereunder shall be commercially reasonable Certificates of insurance and certified copies of the policies shall be delivered to Landlord prior to the Commencement
Date and annually thereafter at least 
  

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 thirty (30) days prior to the expiration date of the old policy. Tenant shall have the right to provide insurance
coverage which it is obligated to carry pursuant to the terms hereof in a blanket policy, provided such blanket policy expressly affords coverage to the Premises and to Landlord as required by this Lease. Each policy of insurance shall provide
notification to Landlord and any mortgagee(s) of Landlord at least thirty (30) days prior to any cancellation or modification to reduce the insurance coverage. 
 12.3 Other. In the event Tenant does not purchase the insurance required by this Lease or keep the same in full force and effect, and the same is not corrected within one (1) business day following written
notice thereof from Landlord to Tenant, then Landlord may, but shall not be obligated to, purchase the necessary insurance and pay the premium therefore. Tenant shall repay to Landlord, as Additional Rent, any and all reasonable expenses (including
attorneys’ fees) and damages which Landlord may sustain by reason of the failure of Tenant to obtain and maintain insurance. 
 13. LANDLORD’S
INSURANCE. 
 13.1 Coverage. At all times during the Lease Term, Landlord will maintain, the cost of which shall be reimbursable as
an Operating Cost hereunder, (a) fire and extended coverage insurance covering the Project, in an amount equal to one hundred percent (100%) of the replacement value thereof, (b) primary and non-contributory public liability and
property damage insurance in such amounts as Landlord deems reasonable from time to time, and (c) rent loss insurance for all Rent hereunder for a period of twelve (12) mouths. Landlord shall also have the right to obtain such other types
and amounts of insurance coverage on the Building (including loss of rental insurance) and Landlord’s liability in connection with the Building as are customary or advisable for a comparable office project in the Fairfax, Virginia area, as
determined by Landlord in Landlord’s reasonable judgment. Any dispute regarding the appropriateness of such additional insurance coverage shall be subject to arbitration pursuant to Section 49 of this Lease. 
 13.2 Rating; Certificates; Cancellation. The policies required to be maintained by Landlord shall be with companies rated A-X or better in the
most current issue of Best’s Insurance Reports Insurers shall be licensed to do business in the Commonwealth of Virginia and domiciled in the USA. Any deductible amounts under any insurance policies required hereunder shall be commercially
reasonable, in Landlord’s reasonable judgment. Landlord shall have the right to provide insurance coverage which it is obligated to carry pursuant to the terms hereof in a blanket policy, provided such blanket policy expressly affords coverage
to the Project and to Tenant as required by this Lease. 
 14. DAMAGE OR DESTRUCTION. 
 14.1 Damage Repair. 
 14.1.1 If the
Premises shall be destroyed or rendered untenantable, either wholly or in part, by fire or other casualty, then Landlord shall, within thirty (30) days after the date of such casualty, provide Tenant with Landlord’s good faith written
estimate (the “Estimate”) of how long it will take to repair or restore the Premises. 
  

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 14.1.2 If neither party elects to terminate this Lease in accordance with the terms hereof following any
casualty, then Landlord shall commence promptly and diligently prosecute to completion the restoration of the Premises to their previous condition, subject to Force Majeure as defined herein and delays caused by Tenant; and pending substantial
completion of such restoration, the Base Rent and Additional Rent shall be abated in the same proportion as the untenantable portion of the Premises bears to the whole thereof, and this Lease shall continue in full force and effect. 
 14.1.3 If Landlord estimates within the Estimate that it will require in excess of one hundred eighty (180) days after the date Tenant’s right
of termination hereunder expires to fully repair or restore the Premises in accordance herewith, then, within thirty (30) days after Landlord delivers Tenant the Estimate, Tenant and Landlord shall each have the right to terminate this Lease by
written notice to the other, which termination shall be effective as of the date of such notice of termination, and all liabilities and obligations of Landlord and Tenant thereafter accruing shall terminate and be of no legal force and effect except
as otherwise specifically set forth herein. Notwithstanding the foregoing, Tenant shall not have the right to terminate this Lease if the fire or other casualty was the result of Tenant’s gross negligence or willful misconduct. 
 14.1.4 If neither party elects to terminate the Lease and Landlord fails or declines to exercise any other termination right pursuant to this
Section 14, Landlord will use all reasonable efforts to commence and complete its restoration of the affected portions of the Premises promptly, and in the event Landlord is unable to complete such restoration within one hundred eighty
(180) days after the date Tenant’s right of termination hereunder expires (or such longer period as was referenced in the Estimate, if applicable), as such period may be extended due to Force Majeure (not to exceed ninety (90) days)
or due to any delays caused by Tenant (and not limited as to the number of days) then within thirty (30) days after the expiration of such period (but in all events prior to the date Landlord completes its restoration of the Premises), Tenant
shall again have the right to terminate this Lease upon thirty (30) days prior written notice to Landlord, provided, however, that if Landlord substantially completes such restoration prior to the end of the thirty (30) day notice period,
Tenant’s notice of termination shall be deemed rescinded and ineffective for all purposes, and this Lease shall continue in full force and effect. The provisions of this Section are in lieu of any statutory termination provisions allowable in
the event of casualty damage. 
 14.1.5 If at any time in the course of its restoration of damaged portions of the Premises, Landlord
believes in good faith that its original Estimate is no longer accurate for reasons other than Force Majeure (in which event the provisions of Section 14.1 4 shall control), Landlord shall have the right to deliver a revised Estimate to Tenant
of the additional time period which Landlord believes will be required to fully repair or restore the Premises in accordance herewith, and, unless Tenant terminates this Lease by written notice to Landlord within ten (10) business days after
its receipt of such revised Estimate from Landlord, Tenant shall be deemed to have agreed that, for all purposes of this Section 14.1, the one hundred eighty (180) day time 
  

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 limit otherwise imposed upon completion of Landlord’s restoration of the damaged portions of the Premises shall be
extended by the number of additional days needed to complete estimated by Landlord within such revised Estimate. If Tenant elects to terminate this Lease as to the damaged Building after receiving such a revised Estimate from Landlord, as aforesaid,
such termination shall be effective as of the date of such notice of termination, and all liabilities and obligations of Landlord and Tenant thereafter accruing hereunder with respect to such Building shall terminate and be of no legal force and
effect except as otherwise specifically set forth herein. 
 14.2 Reconstruction. If all or any portion of the Premises is damaged by
fire or other casualty and this Lease is not terminated in accordance with the provisions hereof; then all insurance proceeds under the policy referred to in Section 13.1 hereof that are recovered by Landlord on account of any such damage by
fire or casualty shall be made available for the payment of the cost of repair, replacing and rebuilding. 
 14.3 Business
Interruption. Other than rental abatement as and to the extent provided in Section 14.1, no damages, compensation or claim shall be payable by Landlord for inconvenience or loss of business arising from interruption of business, repair or
restoration of the Building or Premises. 
 14.4 Repairs. Landlord’s repair obligations, should it elect to repair, shall be
limited to the base Building, Common Areas and all interior improvements to and property within the Premises which are covered or required to be covered hereunder by Landlord’s insurance. Landlord shall use reasonable efforts to commence such
repairs and restorations within a reasonable period after Landlord elects to restore the Premises, and to complete such repairs within the time frames referenced in Section 14.1, above. Tenant acknowledges that any such repairs or restorations
shall be subject to applicable laws and governmental requirements, any disbursement requirements imposed by Landlord’s mortgagee (if any), and to delay in the process of adjusting any insurance claim associated therewith, and delays resulting
from any of the foregoing shall constitute a “Force Majeure” hereunder, shall not in any event constitute a breach of this Lease by Landlord, and shall extend the time for completing such restoration as long as Landlord uses reasonable
efforts to commence and complete such repairs and restorations in a timely fashion. 
 14.5 End of Term Casualty. Anything herein to
the contrary notwithstanding, if more than thirty (30%) of the Premises is destroyed or damaged during the last eighteen (18) months of the Lease Term, then either Landlord or Tenant shall have the right to terminate this Lease (in whole
if the damage extends to all of the Premises or otherwise as to the affected portion of the Premises within the Building) upon thirty (30) days prior written notice to the other, which termination shall be effective on the thirtieth
(30th) day after the other party’s receipt of such notice. Such notice must be delivered within thirty (30) days after such casualty, or shall be deemed waived; provided, however, that Tenant may revoke such termination notice, and
require Landlord to restore the Premises, by exercising any renewal option provided herein, if any. 
  

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 15. MACHINERY AND EQUIPMENT ALTERATIONS AND ADDITIONS; REMOVAL OF FIXTURES. 
 15.1 Tenant shall not place a load upon the floor of the Premises which exceeds the maximum live load per square foot which Landlord (or Landlord’s
architect or engineer) reasonably determines is appropriate for the Building without Landlord’s prior written consent. Tenant will not install or operate in the Premises any electrical or other equipment requiring any changes, replacements or
additions to any base building system, without Landlord’s prior written consent, which shall not be unreasonably withheld, conditioned or delayed (and if such consent is granted Tenant shall be responsible for the costs of such changes,
replacements or additions). 
 15.2 Tenant shall not make or allow to be made any alterations, additions or improvements to or on the
Premises which affect any structural or building system components of the Premises or which, under applicable codes, rules and/or regulations require any building electrical, plumbing or other permit, without Landlord’s prior written consent,
which consent shall not be unreasonably withheld, conditioned or delayed. Tenant shall have the right to make any other alterations, repairs, additions or improvements in or to the Premises without Landlord’s prior written consent provided
Tenant provides Landlord with prior written notice thereof; provided, however that no exterior modification shall be made in any event without Landlord’s prior written consent in all cases. Any such alterations, additions or improvements,
including, but not limited to, wall covering, paneling and built-in cabinet work, shall be made at Tenant’s sole expense (and, with respect to structural alterations, according to plans and specifications approved in writing by Landlord, which
approval shall not be unreasonably withheld, conditioned or delayed), in compliance with all applicable laws, by a licensed contractor, and in a good and workmanlike manner conforming in quality and design with the Premises existing as of the
Commencement Date, and shall at once become a part of the realty and shall be surrendered with the Premises (except as provided in Section 15.3, below). Tenant shall have the right to use its own vendors to perform alterations to the Premises,
subject to Landlord’s reasonable prior approval in cases where the underlying alteration requires Landlord’s consent hereunder. 
 15.3 Upon the expiration or sooner termination of the Lease Term, Tenant shall, at Tenant’s sole expense, with due diligence, remove any alterations, additions, or improvements made by Tenant which are designated by Landlord to be
removed at the time its consent to the installation thereof is granted, and repair any damage to the Premises caused by such removal; provided, however, that Landlord may only require that Tenant remove any improvements if in Landlord’s
reasonable professional judgment such improvements (i) are not customarily found in comparable office buildings in the Fairfax, Virginia area, or (ii) would make it difficult for Landlord to re-lease the Premises without removing or
altering such improvements. Tenant shall remove any of its movable property, trade fixtures and roof devices. Tenant shall pay Landlord any damages for injury to the Premises or Building resulting from such removal. All items of Tenant’s
personal property that are not removed from the Premises or the Building by Tenant at the termination of this Lease shall be deemed abandoned and become the exclusive property of Landlord, without further notice to or demand upon Tenant. If the
Premises are not surrendered as and when aforesaid, Tenant shall indemnify Landlord against all claims, losses, costs, expenses (including reasonable attorneys’ fees) and liabilities resulting from the delay by Tenant 
  

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 in so surrendering the same, including without limitation any claims made by any succeeding occupant founded on such
delay. Tenant’s obligations under these Sections 15.2 and 15.3 shall survive the expiration or termination of this Lease. 
 16. ACCEPTANCE OF
PREMISES. 
 Landlord shall tender, and Tenant shall accept possession of; the Premises in it’s as-is condition. 
 17. TENANT IMPROVEMENTS. 
 Landlord shall not be
required to provide or construct any improvements or other alterations to the premises. Tenant shall be entitled to make such improvements to the Premises as it shall deem advisable, subject in all events to the reasonable prior approval of Landlord
and compliance with the terms of Section 15 hereof. Any such improvements shall be undertaken in a first class lien free manner, at the sole cost and expense of Tenant. Provided that Tenant is not in default hereunder, Landlord shall provide an
allowance in the amount of $317,505.00 (the “Allowance”) to Tenant to fund a portion of the cost of the improvements to be undertaken by Tenant in the Premises. The Allowance shall be funded as follows: $106,615.00 on the Commencement
Date, $6,615.00 on the first day of each month for the following eleven (11) months, $75,000.00 on the first day of the second Lease Year, and $63,125.00 on the first day of the second calendar month of the third Lease Year. The foregoing
notwithstanding, in the event Tenant has in place contracted gross revenue of not less than $8,000,000.00 for the Base Year, and provides reasonable evidence to Landlord to such effect, the final payment of the Allowance as is set forth above shall
be paid simultaneously with the $75,000.00 payment from the Allowance to be paid on the first day of the second Lease Year. 
 18. ACCESS. 

18.1 Subject to the restrictions set forth below, Tenant shall permit Landlord and its agents to enter the Premises at all reasonable times (provided
such access does not interfere with Tenant’s permitted use of the Premises) to inspect the same; to show the Premises to prospective tenants, or interested parties such as prospective lenders and purchasers; to exercise its rights under
Section 48; to clean, repair, alter or improve the Premises or the Building; to discharge Tenant’s obligations when Tenant has failed to do so within a reasonable time after written notice from Landlord, to post notices of
non-responsibility and similar notices and “For Sale” signs and during the last twelve (12) months of the Lease Term, to place “For Lease” signs upon or adjacent to the Building or the Premises. Tenant shall permit Landlord
and its agents to enter the Premises at any time in the event of an emergency. When reasonably necessary, Landlord may temporarily close entrances, doors, corridors, elevators or other facilities without liability to Tenant by reason of such
closure. In exercising the foregoing rights, Landlord shall use reasonable efforts to minimize any disruption to Tenant’s business. Landlord shall coordinate any entry into the Premises with Tenant’s facilities supervisor at least 24 hours
in advance (except in cases of emergency involving fire or other casualty, or other risk of injury or death to persons), and Landlord acknowledges that Tenant may require Landlord and its agents to be accompanied by a representative of Tenant for
security purposes upon Landlord’s entry to 
  

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 certain limited portions of the Premises (other than in cases of emergency involving fire or other casualty, or other
risk of injury or death to persons) for legitimate, documented security purposes. Tenant shall supply Landlord with telephone numbers for Tenant’s facilities supervisor so that Landlord will be able to comply with established security
procedures to the extent feasible under the circumstances in the event Landlord requires immediate access to the Premises to cure any emergency situation. In the event Tenant, though no act or omission of its own, is deprived of access to the
Premises as a result of Landlord’s closure of all access to the Building or Premises for a period exceeding five (5) consecutive business days, and as a result thereof Tenant is unable to and does not in fact occupy or conduct business
from any portion of the Premises, then from and after such fifth (5th) business day and until the restoration of access to the Building and/or Premises, as applicable, Tenant shall be entitled to abate its Rent obligations hereunder.

 18.2 Landlord shall be excused from such of its obligations under this Lease as are directly and materially impacted by the inability of
Landlord to access the Premises or any applicable part thereof due to Tenant’s security restrictions, if and to the extent the performance of such obligations was in fact hindered, frustrated, or rendered impossible or impracticable due to the
effect of such restrictions on access. 
 19. MUTUAL WAIVER OF SUBROGATION. 
 19.1 Tenant. Notwithstanding anything to the contrary in this Lease, whether the loss or damage is due to the negligence of Landlord or
Landlord’s agents or employees, or any other cause, Tenant hereby releases Landlord and Landlord’s agents and employees from responsibility for and waives its entire claim of recovery for (i) any and all loss or damage to the personal
property of Tenant located in the Project, arising out of any of the perils which are covered by Tenant’s property insurance policy, with extended coverage endorsements which Tenant is required to obtain under the applicable provisions of this
Lease, whether or not actually obtained, or (ii) loss resulting from business interruption at the Premises, arising out of any of the perils which may be covered by any business interruption insurance policy which may be carried by Tenant.

 19.2 Landlord. Notwithstanding anything to the contrary in this Lease, whether the loss or damage is due to the negligence of
Tenant or Tenant’s agents or employees, or any other cause, Landlord hereby releases Tenant and Tenant’s agents and employees from responsibility for and waives its entire claim of recovery for any and all loss or damage to the Building or
any personal property of Landlord located about the Project and the Building generally and all property attached thereto (excluding any such property required to be insured by Tenant hereunder), arising out of any of the perils which are covered by
Landlord’s property insurance policy which Landlord is required to obtain under the applicable provisions of this Lease, whether or not actually obtained. 
 19.3 Carriers. Landlord and Tenant shall each cause its respective insurance carrier(s) to consent to such waiver of all rights of subrogation against the other, and to issue an endorsement to all policies of
insurance obtained by such party confirming that the foregoing release and waiver will not invalidate such policies. 
  

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 20. INDEMNIFICATION. 
 20.1 Subject to the provisions of Section 19 hereof and other provisions of this Lease, Tenant shall indemnify and hold harmless Landlord, its agents, employees, officers, directors, partners and shareholders
from and against any and all third party claims, liabilities, judgments, demands, causes of action, claims, losses, damages, costs and expenses, including reasonable attorneys’ fees and costs, arising out of such third party claims, to the
extent arising out of (i) the use and occupancy of the Premises by Tenant, its officers, contractors, licensees, agents, servants, employees, guests, invitees, visitors, assignees or subtenants, (ii) the gross negligence or willful
misconduct of Tenant, its officers, contractors, licensees, agents, servants, employees, guests, invitees, visitors, assignees or subtenants, in or about the Project; and/or (iii) any breach or Default by Tenant under this Lease; provided that
this indemnity shall not apply to any loss, damage, liability or expense resulting from injuries to third parties caused by the gross negligence or willful misconduct of Landlord, or its officers, contractors, licensees, agents, employees or
invitees (while within the Premises) Tenant shall not be responsible or liable for any claims for the interruption of or loss to Landlord’s business, nor any other consequential or indirect damages on account of or in connection with the
indemnifications set forth above. 
 20.2 The indemnifications set forth in this Section 20 shall survive termination of this Lease.

 21. ASSIGNMENT AND SUBLETTING. 
 21.1
Consent Required. Except as specifically set forth herein to the contrary, Tenant shall not assign, encumber, mortgage, pledge, license, hypothecate or otherwise transfer the Premises or this Lease, or sublease all or any part of the
Premises, or permit the use or occupancy of the Premises by any party other than Tenant, without the prior written consent of Landlord, which consent shall not be unreasonably withheld, conditioned or delayed. Upon any permitted assignment or
sublease (other than as set forth in subsection 21.4 hereof, in which event this sentence does not apply), Landlord and Tenant shall share equally in any rent, additional rent or other payments made by the assignee or subtenant which are in excess
of the Base Rent, Tenant’s Share of Increases in Operating Costs, Tenant’s Share of Increases in Real Estate Taxes, and other additional rent payable by Tenant hereunder (calculated after Tenant has recovered in full from such
consideration its “Transaction Expenses” (as hereafter defined)). The term “Transaction Expenses” shall mean all reasonable and actual out-of-pocket expenses incurred by Tenant in procuring such assignment or sublease, including
broker fees and legal fees (if any) paid by Tenant, any improvements which Tenant makes to the applicable portion of the Premises at Tenant’s expense in connection with such assignment or sublease, and any buy-out of the assignee’s or
sublessee’s existing lease paid for by Tenant as a part of such transaction. 
 21.2 Procedure. Tenant must request
Landlord’s consent to such assignment or sublease in writing at least fifteen (15) business days prior to the commencement date of the proposed sublease or assignment, which written request must include (a) the name and address of the
proposed assignee or subtenant, (b) the nature and character of the business of the proposed assignee or subtenant, (c) financial information (including financial statements) of the proposed assignee or subtenant, and (d) a copy of
the proposed sublet or assignment agreement. Tenant 
  

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 shall also provide any additional information Landlord reasonably requests regarding such proposed assignment or
subletting. Within ten (10) days after Landlord receives Tenant’s request (with all required information included), Landlord shall, by written notice to Tenant, elect either: (i) to grant its consent to such proposed assignment or
subletting, or (ii) to deny its consent to such proposed assignment or subletting, setting forth with specificity the reason for such denial. If Landlord does not exercise either of the above options within fifteen (15) business days after
Landlord receives Tenant’s request, then Tenant may assign or sublease the Premises upon the terms stated in Tenant’s request. 
 21.3 Conditions. Any subleases and/or assignments hereunder are also subject to all of the following terms and conditions: 
 21.3.1 No consent to any assignment or sublease shall constitute a further waiver of the provisions of this Section, and all subsequent assignments or subleases may be made only with the prior written consent of Landlord. In no event shall
any consent by Landlord be construed to permit reassignment or resubletting by a permitted assignee or sublessee, nor shall any assignment or sublease effectuate a release of Tenant from its obligations hereunder. 
 21.3.2 Tenant shall remain liable for all Lease obligations, all of which shall be unaffected by any such sublease or assignment, and which Lease
obligations shall remain in full force and effect for all purposes. An assignee of Tenant, at the option of Landlord, shall become directly liable to Landlord for all obligations of Tenant hereunder, but no sublease or assignment by Tenant shall
relieve Tenant of any liability hereunder. 
 21.3.3 Any assignment or sublease without Landlord’s prior written consent shall be void,
and shall, at the option of the Landlord, constitute a Default under this Lease. 
 21.3.4 The term of any such assignment or sublease shall
not extend beyond the Lease Term. In no event will any assignee or subtenant (other than pursuant to a transfer of the Lease within the scope of Section 21.4, below) have the right to renew or extend the term of this Lease pursuant to
Section 51, below. 
 21.3.5 Without limitation, it shall not be unreasonable for Landlord to deny its consent to any proposed
assignment or sublease if the proposed assignee or subtenant fails to satisfy any one or more of the following criteria: (1) if the proposed assignee or sublessee has a net worth less than that of Tenant’s at the time Tenant and Landlord
execute this Lease and Landlord determines in its reasonable judgment that the proposed assignee or subtenant may be unable to meet its financial and other obligations under this Lease after such assignment or sublease; (2) if the proposed
assignee or subtenant proposes to use the Premises for a purpose which is not a general office use or administrative use; (3) if the proposed assignee or subtenant has a history of landlord/tenant or debtor/creditor problems (such as, but not
limited to, defaults, evictions, or other disputes) with Landlord, other landlords or other creditors, or (4) Landlord determines, in its reasonable judgment, that the proposed assignment/sublease documentation is not acceptable. 
  

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 22. ADVERTISING. 
 Except with respect to building directory signage provided in Landlord’s standard directory format, Tenant shall not display any sign, graphics, notice, picture, or poster, or any advertising matter whatsoever,
anywhere in or about the Premises or the Building at places visible from anywhere outside or at the entrance to the Premises without first obtaining Landlord’s written consent thereto, which Landlord may grant or withhold .in its sole
discretion Tenant shall be responsible to maintain any permitted signs and remove the same at Lease termination. If Tenant shall fail to do so, Landlord may do so at Tenant’s cost Tenant shall be responsible to Landlord for any damage caused by
the installation, use, maintenance or removal of any such signs. 
 23. LIENS. 
 Tenant shall keep the Premises and the Building free from any liens arising out of any work performed, materials ordered or obligations incurred by or on
behalf of Tenant, and Tenant hereby agrees to indemnify and hold Landlord, its agents, employees independent contractors, officers, directors, partners, and shareholders harmless from any liability, cost or expense (including attorneys’ fees
and defense costs) for or arising from such liens. Tenant shall cause any such lien imposed to be released of record by payment or posting of the proper bond acceptable to Landlord within twenty (20) days after written request by Landlord.
Tenant shall give Landlord written notice of Tenant’s intention to perform work on the Premises which might result in any claim of lien at least ten (10) days prior to the commencement of such work to enable Landlord to post and record a
Notice of Nonresponsibility or other notice deemed proper before commencement of any such work. If Tenant fails to remove any lien within the prescribed twenty (20) day period, then Landlord may do so at Tenant’s expense and Tenant’s
reimbursement to Landlord for such amount, including reasonable attorneys’ fees and costs, shall be deemed Additional Rent hereunder. 
 24.
DEFAULT. 
 24.1 Tenant’s Default. A “Default” under this Lease by Tenant shall exist if any of the following
occurs (taking into account the expiration of the notice and cure periods provided for below): 
 24.1.1 If Tenant fails to pay Base Rent,
Additional Rent or any other sum required to be paid hereunder within five (5) days after written notice from Landlord that such payment was due, but was not paid as of the due date (provided, however, if Landlord has delivered two
(2) such notices to Tenant within the prior twelve (12) month period, any subsequent failure to pay Base Rent, Additional Rent or any other sum required to be paid to Landlord hereunder on or before the due date for such payment occurring
shall constitute a Default by Tenant without requirement of such five (5) day notice and opportunity to cure, but in the event a full year elapses between such failures then Tenant shall again have the right to such cure period), or 

 

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 24.1.2 If Tenant fails to perform any term, covenant or condition of this Lease except those requiring
the payment of money to Landlord as set forth in Section 24.11 above, and Tenant fails to cure such breach within thirty (30) days after written notice from Landlord where such breach could reasonably be cured within such thirty
(30) day period, provided, however, that where such failure could not reasonably be cured within the thirty (30) day period, that Tenant shall not be in Default if it commences such performance promptly after its receipt of Landlord’s
written notice and diligently thereafter prosecutes the same to completion, provided that no such grace period to be permitted in the event of any one or more of the following: (i) the Default relates to the maintenance of insurance
obligations, (ii) the Default relates to the assignment and subletting provisions, (iii) the Default relates to a violation of Section 5.2 of this Lease, (iv) the Default is of a nature as set forth in Section 24.1.3, in
which event the periods set forth therein shall control, or Section 24.1.4, in which event there shall be no applicable cure period, or (v) there exists a reasonable possibility of danger to the health or safety of the Landlord, the
Tenant, Tenant’s invitees, or any other occupants of, or visitors to, the Building, or 
 24.1.3 lf Tenant shall (i) make an
assignment for the benefit of creditors, (ii) acquiesce in a petition in any court in any bankruptcy, reorganization, composition, extension or insolvency proceedings, (iii) seek, consent to or acquiesce in the appointment of any trustee,
receiver or liquidator of Tenant and of all or substantially all of Tenant’s property, (iv) file a petition seeking an order for relief under the Bankruptcy Code, as now or hereafter amended or supplemented, or by filing any petition under
any other present or future federal, state or other statute or law for the same or similar relief, or (v) fail to win the dismissal, discontinuation or vacating of any involuntary bankruptcy proceeding within sixty (60) days after such
proceeding is initiated, or 
 24.1.4 If Tenant shall have abandoned the Premises or any material (i.e., in excess of 70%) portion thereof.

 24.2 Remedies. Upon a Default, Landlord shall have the following remedies, in addition to all other rights and remedies provided by
law or available in equity or otherwise provided in this Lease, any one or more of which Landlord may resort to cumulatively, consecutively, or in the alternative. 
 24.2.1 Landlord may continue this Lease in full force and effect, and this Lease shall continue in full force and effect as Long as Landlord does not terminate this Lease, and Landlord shall have the right to collect
Base Rent, Additional Rent and other charges when due. 
 24.2.2 Landlord may terminate this Lease, or may terminate Tenant’s right to
possession of the Premises, at any time by giving written notice to that effect, in which event Landlord covenants to use commercially reasonable efforts to relet the Premises or any part thereof and mitigate its damages, as more fully set forth
herein. Upon the giving of a notice of the termination of this Lease, this Lease (and all of Tenant’s rights hereunder) shall immediately terminate, provided that, without limitation, Tenant’s obligation to pay Base Rent, Additional Rent,
and any damages otherwise payable under this Section 24, shall survive such termination and shall not be extinguished thereby. Upon the giving of a notice of the termination of Tenant’s right of possession, all of Tenant’s rights in
and to possession of the Premises shall terminate but 
  

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 this Lease shall continue subject to the effect of this Section 24. Upon either such termination, Tenant shall
surrender and vacate the Premises in the condition required by Section 26, and Landlord may re-enter and take possession of the Premises and all the remaining improvements or property and eject Tenant or any of the Tenant’s subtenants,
assignees or other person or persons claiming any right under or through Tenant or eject some and not others or eject none. This Lease may also be terminated by a judgment specifically providing for termination. Any termination under this Section
shall not release Tenant from the payment of any sum then due Landlord or from any claim for damages or Base Rent, Additional Rent or other sum previously accrued or thereafter accruing against Tenant, all of which shall expressly survive such
termination. Reletting may be for a period shorter or longer than the remaining Lease Term. No act by Landlord other than giving written notice to Tenant shall terminate this Lease Acts of maintenance, efforts to relet the Premises or the
appointment of a receiver on Landlord’s initiative to protect Landlord’s interest under this Lease shall not constitute a constructive or other termination of Tenant’s right to possession or of this Lease, either of which may be
effected solely by an express written notice from Landlord to Tenant. On termination, Landlord shall have the right to remove all Tenant’s personal property and store same at Tenant’s cost, and to recover from Tenant as damages:

 (A) The worth at the time of award of unpaid Base Rent, Additional Rent and other sums due and payable which had been earned at the time
of termination; plus 
 (B) The worth at the time of award of the amount by which the unpaid Base Rent, Additional Rent and other sums due
and payable which would have been payable after termination for the balance of the Lease Term exceeds the fair rental value of the Premises for the balance of the Term; plus 
 (C) Any other amount necessary to compensate Landlord for all of the reasonable, actual out-of-pocket costs incurred on account of Tenant’s failure
to perform Tenant’s obligations under this Lease, including, without limitation, any costs or expenses reasonably incurred by Landlord; (i) in retaking possession of the Premises; (ii) in maintaining, repairing, preserving, restoring,
replacing, cleaning, altering or rehabilitating the Premises or a portion thereof including such acts for reletting to a new tenant or tenants; (iii) for the unamortized portion of the leasing commissions; or (iv) for any other costs
necessary or appropriate to relet the Premises. To the extent any of such costs are incurred in connection with a lease transaction having a term in excess of the remaining Term hereof, all of the foregoing costs incurred in connection therewith
shall be amortized on a straight-line basis over the term of such new lease, assuming equal monthly installments of principal and interest, at an interest rate of twelve percent (12%), and Tenant’s liability shall be limited to the amortized
portion of the same (i.e., the monthly payments as so determined) falling within the Term hereof. 
 (D) The “worth at the time of
award” of the amounts referred to in Section 24.2.2.1 is computed by allowing interest at the Default Rate through the date of payment. The “worth at the time of award” of the amounts referred to in Section 24.2.2.2 shall be
computed by discounting the same to present value using the Discount Rate. In lieu of the amounts recoverable by Landlord pursuant to Section 24.2.2.2, above, but in addition to the amounts specified in Section 24.2.2.1 and 24.2.2.3 (or
any other portion of this Section 24), 
  

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 Landlord may, at its sole election, recover “Indemnity Payments,” as defined hereinbelow, from Tenant For
purposes of this Lease “Indemnity Payments” means an amount equal to the Base Rent, Additional Rent and other payments provided for in this Lease which would have become due and owing hereunder from time to time during the unexpired Lease
Term after the effective date of the termination, but for such termination, less the Base Rent, Additional Rent and other payments, if any, actually collected by Landlord and allocable to the Premises. If Landlord elects to pursue Indemnity Payments
as set forth above, Tenant shall, on demand, make Indemnity Payments monthly, and Landlord may sue for all Indemnity Payments at any time after they accrue, either monthly, or at less frequent intervals Tenant further agrees that Landlord may bring
suit for Indemnity Payments and/or any other damages recoverable herein at or after the end of the Lease Term as originally contemplated under this Lease, and Tenant agrees that, in such event, Landlord’s cause of action to recover the
Indemnity Payments shall be deemed to have accrued on the last day of the Lease Term as originally contemplated. In seeking any new tenant for the Premises, Landlord shall be entitled to grant any concessions it deems reasonably necessary. In no
event shall Tenant be entitled to any excess of any rental obtained by reletting over and above the rental herein reserved. To the fullest extent permitted by law, Tenant waives redemption or relief from forfeiture under any other present or future
law, in the event Tenant is evicted or Landlord takes possession of the Premises by reason of any Default of Tenant hereunder. 
 24.2.3
Landlord may, with or without terminating this Lease, re-enter the Premises pursuant to judicial process (except in the event of Tenant’s abandonment of the Premises in which event no judicial process shall be required) and remove all persons
and property from the Premises; such property may be removed and stored in a public warehouse or elsewhere at the cost of and for the account of Tenant. No re-entry or taking possession of the Premises by Landlord pursuant to this Section shall be
construed as an election to terminate this Lease unless a written notice of such intention is given to Tenant. 
 24.2.4 Tenant, on its own
behalf and on behalf of all persons claiming through or under Tenant, including all creditors, does hereby specifically waive and surrender any and all rights and privileges, so far as is permitted by law, which Tenant and all such persons might
otherwise have under any present or future law (1) except as may be otherwise specifically required herein, to the service of any notice to quit or of Landlord’s intention to re-enter or to institute legal proceedings, which notice may
otherwise be required to be given, (2) to redeem the Premises, (3) to re-enter or repossess the Premises, (4) to restore the operation of this Lease, with respect to any dispossession of Tenant by judgment or warrant of any court or
judge, or any re-entry by Landlord, or any expiration or termination of this Lease, whether such dispossession, re-entry, expiration or termination shall be by operation of law or pursuant to the provisions of this Lease, (5) to the benefit of
any law which exempts property from liability for debt or for distress for rent or (6) to a trial by jury in any claim, action proceeding or counter-claim arising out of or in any way connected with this Lease. 
 24.2.5 In the event of termination of this Lease or repossession of the Premises after a Default, Landlord agrees to use commercially reasonable efforts
to mitigate its damages and relet the Premises after any termination of this Lease or Tenant’s right to possession of the Premises hereunder, provided that (i) (if applicable) Landlord shall not be obligated to show 
  

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 preference for reletting the Premises over any other vacant space in the Project, (ii) Landlord shall have the right
(but not the obligation) to divide the Premises, or to consolidate portions of the Premises with other spaces, in order to facilitate such reletting, as Landlord deems appropriate, (iii) Landlord shall not have any obligation to use efforts
other than commercially reasonable efforts under the circumstances to collect rental after any such reletting, and (iv) Landlord may relet the whole or any portion of the Premises for any period, to any tenant, and for any use and purpose, upon
such terms as it deems appropriate, and may grant any rental or other lease concessions as it deems advisable, including free rent. In any dispute regarding whether Landlord has met its obligation to use commercially reasonable efforts to mitigate
its damages hereunder, Tenant shall have the burden of proving, by clear and convincing evidence, that Landlord has failed to do so. In no event shall Tenant be entitled to any excess of any rental obtained under this Section 24.2.5 by
reletting over and above the Base Rent and Additional Rent herein reserved. 
 24.2.6 Notwithstanding anything herein to the contrary, except
as specifically set forth in Section 24.2.3, in no event shall Landlord be entitled to take possession of the Premises except pursuant to legal proceedings. 
 25. SUBORDINATION. 
 This Lease shall at all times be and remain subject and subordinate to the lien of any mortgage, deed of
trust, ground lease or underlying lease now or hereafter in force against the Premises, and to all advances made or hereafter to be made upon the security thereof Tenant shall execute and return to Landlord any customary documentation requested by
Landlord in order to confirm the foregoing subordination within ten (10) days after Landlord’s written request. In the event any proceedings are brought for foreclosure, or in the event of the exercise of the power of sale under any
mortgage or deed of trust made by the Landlord covering the Premises, Tenant shall attorn to the purchaser at any such foreclosure, or to the grantee of a deed in lieu of foreclosure, and recognize such purchaser or grantee as the Landlord under
this Lease. Tenant agrees that no mortgagee or successor to such mortgagee shall be (i) bound by any payment of Base Rent or Additional Rent for more than one (1) month in advance, (ii) bound by any amendment or modification of this
Lease made without the consent of Landlord’s mortgagee or such successor in interest, (iii) liable for damages for any breach, act or omission of any prior landlord, or (iv) subject to any claim of offset or defenses that Tenant may
have against any prior landlord; provided that such mortgagee or successor shall not be relieved of the obligation to comply with all of the Landlord’s obligations under the Lease accruing from and after the date such mortgagee or successor
takes title to the Project, irrespective of whether the original noncompliance with any such obligation arose prior to and is continuing as of such date, or arose on or after such date (provided however that if such obligation arose prior to the
date such mortgagee or successor took title to the Project, such mortgagee or successor shall not be deemed in default until after the provision of any notice of default required by this Lease to such mortgagee or successor, and its failure to cure
same within the cure period provided for herein). 
  

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 26. SURRENDER OF POSSESSION. 
 Upon expiration of the Lease Term, Tenant shall promptly and peacefully surrender the Premises to Landlord in as good condition as when received by Tenant from Landlord or as thereafter improved, reasonable use and
wear and tear and damage by fire, casualty and condemnation excepted. If the Premises are not surrendered in accordance with the terms of this Lease, Tenant shall indemnify Landlord and its agents, employees, independent contractors, officers,
directors, partners, and shareholders against any loss or liability including reasonable attorneys’ fees and costs, and including liability to succeeding tenants, resulting from delay by Tenant in so surrendering the Premises. This
indemnification shall survive termination of this Lease. 
 27. NON-WAIVER. 
 Waiver by Landlord o any breach of any term, covenant or condition herein contained shall not be deemed to be a waiver of such term, covenant, or
condition(s), or any subsequent breach of the same or any other term, covenant or condition of this Lease, other than the failure of Tenant to pay the particular rental so accepted, regardless of Landlord’s knowledge of such preceding breach at
the time of acceptance of such Base Rent. 
 28. HOLDOVER. 
 If Tenant shall, without the written consent of Landlord, hold over after the expiration of the Lease Term, Tenant shall be deemed a tenant at sufferance, which tenancy may be terminated as provided by applicable
state law. During any holdover tenancy (whether or not consented to by Landlord), unless Landlord has otherwise agreed in writing, Tenant agrees to pay to Landlord, a per diem occupancy charge equal to one hundred fifty percent (150%) of the
per diem Base Rent and Additional Rent as was in effect under this Lease for the last month of the Lease Term. Such payments shall be made within five (5) business days after Landlord’s demand, and in no event less often than once per
month (in advance). In the case of a holdover which has been consented to by Landlord, unless otherwise agreed to in writing by Landlord and Tenant, Tenant shall give to Landlord thirty (30) days prior written notice of any intention to quit
the Premises, and Tenant shall be entitled to thirty (30) days prior written notice to quit the Premises, except in the event of non-payment of Base Rent or Additional Rent in advance or the breach of any other covenant or the existence of a
Default. Upon expiration of the Lease Term as provided herein, Tenant shall not be entitled to any notice to quit, the usual notice to quit being hereby expressly waived under such circumstances, and Tenant shall surrender the Premises on the last
day of the Lease Term as provided in Section 26, above. 
 29. CONDEMNATION. 
 29.1 Definitions. The terms “eminent domain”, “condemnation”, and “taken”, and the like in this Section 29
include takings for public or quasi-public use, and sales under threat of condemnation and private purchases in place of condemnation by any authority authorized to exercise the power of eminent domain. 
  

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 29.2 Taking. If the whole of the Premises is taken, either permanently or temporarily, by eminent
domain or condemnation, this Lease shall automatically terminate as of the date title vests in the condemning authority, and Tenant shall pay all Base Rent, Additional Rent, and other payments up to that date. If twenty percent (20%) or more of
the Premises is permanently taken, or if access to the by Tenant is, by virtue of a taking, permanently denied, by eminent domain or condemnation, then Landlord or Tenant shall have the right (to be exercised by written notice to the other within
sixty (60) days after receipt of notice of said taking) to terminate this Lease from the date when possession is taken thereunder pursuant to such proceeding or purchase. If neither party elects to terminate this Lease, as aforesaid, then
Landlord shall within a reasonable time after title vests in the condemning authority, repair and restore, at Landlord’s expense, the portion not taken so as to render same into an architectural whole to the fullest extent reasonably possible,
and, if any portion of the Premises is taken, thereafter the Base Rent and Additional Rent shall be reduced (on a per square foot basis) in proportion to the portion of the Premises taken. If there is a temporary taking involving the Premises or
Building, if a taking of other portions of the Building or Common Areas does not deny Tenant access to the Building and Premises, or if less than twenty percent (20%) of the Premises is permanently taken by eminent domain or condemnation, then
this Lease shall not terminate, and Landlord shall repair and restore, at its own expense, the portion not taken so as to render same into an architectural whole to the fullest extent reasonably possible, and, if any portion of the Premises was
taken, thereafter the Base Rent and Additional Rent shall be reduced (on a per square foot basis) in proportion to the portion of the Premises taken. 
 29.3 Award. Except as set forth below, Landlord reserves all rights to damages to the Premises or arising out of the loss of any leasehold interest in the Premises created hereby, arising in connection with any
partial or entire taking by eminent domain or condemnation. Tenant hereby assigns to Landlord any right Tenant may have to such damages or award, and Tenant shall make no claim against Landlord or the condemning authority for damages for termination
of Tenant’s leasehold interest or for interference with Tenant’s business as a result of such taking. The foregoing notwithstanding, Tenant shall have the right to claim and recover from the condemning authority compensation for any loss
which Tenant may incur for Tenant’s moving expenses, business interruption or taking of Tenant’s personal property, trade fixtures and other improvements within the Premises (but specifically excluding any leasehold interest in the
Building or Premises and any such fixtures or improvements funded by the Allowance) under the then applicable law provided that Tenant shall not make any claim that will detract from or diminish any award for which Landlord may make a claim.

 30. NOTICES. 
 All notices and demands
which may be required or permitted to be given to either party hereunder shall be in writing, and shall be delivered personally or sent by United States certified mail, postage prepaid, return receipt requested, or by Federal Express or other
reputable overnight carrier, to the addresses set out in Section 1.7, and to such other person or place as each party may from time to time designate in a notice to the other Notice shall be deemed given upon the earlier of actual receipt or
refusal of delivery. 
  

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 31. MORTGAGEE PROTECTION. 
 Tenant agrees to give any mortgagee(s) and/or trust deed holder(s), by registered mail, a copy of any notice of default served upon the Landlord, provided that prior to such notice Tenant has been notified in writing
(by way of notice of assignment of rents and leases, or otherwise) of the addresses of such mortgagee(s) and/or trust deed holder(s). Tenant further agrees that if Landlord shall have failed to cure such default within the time provided for in this
Lease, then the mortgagee(s) and/or trust deed holder(s) shall have an additional thirty (30) days within which to cure such default or if such default cannot be cured within that time, then such additional time as may be necessary if within
such thirty (30) days any mortgagee and/or trust deed holder(s) has commenced and is diligently pursuing the remedies necessary to cure such default, during which time Tenant shall not have the right to pursue any claim against Landlord, such
mortgagee and/or such trust deed holder(s), including but not limited to any claim of actual or constructive eviction. 
 32. COSTS AND ATTORNEYS’
FEES. 
 In any litigation between the parties arising out of this Lease, and in connection with any consultations with counsel and other
actions taken or notices delivered, in relation to a default by any party to this Lease, the non-prevailing party shall pay to the prevailing party all reasonable expenses and court costs including attorneys’ fees incurred by the prevailing
party, in preparation for and (if applicable) at trial, and on appeal. Such attorney’s fees and costs shall be payable upon demand. 
 33.
BROKERS. 
 Tenant represents and warrants to Landlord that neither it nor its officers or agents nor anyone acting on its behalf has
dealt with any real estate broker other than Transwestern Commercial Services, LLC in the negotiating or making of this Lease, both of which shall be paid a fee by Landlord pursuant to separate written agreement upon the consummation of this Lease.
Tenant and Landlord each agree to indemnify the other, and its respective agents, employees, partners, directors, shareholders and independent contractors harmless from all liabilities, costs, demands, judgments, settlements, claims and losses,
including reasonable attorney’s fees and costs, incurred in conjunction with any such claim or claims of any other broker or brokers claiming to have interested Tenant in the Building or Premises or claiming to have procured or claim to have
represented such party lathe Lease. Landlord and Tenant each represents that it has not dealt with any brokers other than the parties listed above in negotiating and entering into this Lease, and shall indemnify, defend and bold the other harmless
from any breach of the foregoing representation and warranty. 
 34. LANDLORD’S LIABILITY. 
 Anything in this Lease to the contrary notwithstanding, covenants, undertakings and agreements herein made on the part of the Landlord are made and
intended not for the purpose of binding Landlord personally or the assets of Landlord but are made and intended to bind only the Landlord’s interest in the Premises and Building, as the same may, from time to time, be 
  

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 encumbered, and no personal liability shall at any time be asserted or enforceable against Landlord or its stockholders,
officers or partners or their respective heirs, legal representatives, successors and assigns on account of the Lease or on account of any covenant, undertaking or agreement of Landlord in this Lease. In addition, in no event shall Landlord be in
default of this Lease unless Tenant notifies Landlord in writing of the precise nature of the alleged breach by Landlord, and Landlord fails to cure such breach within fifteen (15) days after the date of Landlord’s receipt of such notice
(provided that if the alleged breach is of such a nature that it cannot reasonably be cured within such fifteen (15) day period, then Landlord shall not be in default if Landlord commences a cure within such fifteen (15) day period and
diligently thereafter prosecutes such cure to completion). In no event shall Tenant have any right to terminate this Lease by virtue of any uncured default by Landlord. 
 35. ESTOPPEL CERTIFICATES. 
 Tenant shall, from time to time, within ten (10) business days of
Landlord’s written request, execute, acknowledge and deliver to Landlord or its designee a written statement stating: the date the Lease was executed and the date it expires, the date the Tenant entered occupancy of the Premises, the amount of
Base Rent, Additional Rent and other charges due hereunder and the date to which such amounts have been paid, that this Lease is in full force and effect and has not been assigned, modified, supplemented or amended in any way (or specifying the date
and terms of any agreement so affecting this Lease); that this Lease represents the entire agreement between the parties as to this leasing; that all conditions under this Lease to be performed by the Landlord have been satisfied (or specifying any
such conditions that have not been satisfied); that all required contributions by Landlord to Tenant on account of Tenant’s improvements have been received (or specifying any such contributions that have not been received); that to
Tenant’s knowledge, following reasonable investigation and inquiry, there are no existing defenses or offsets which the Tenant has against the enforcement of this Lease by the Landlord; that no Base Rent or Additional Rent has been paid more
than one (1) month in advance; that no security has been deposited with Landlord (or, if so, the amount thereof) other than the Security Deposit, or any other customary factual matters evidencing the status of the Lease, as may be reasonably
required either by a lender making a loan to Landlord to be secured by a deed or trust or mortgage against the Building, or a purchaser of the Building, which written statement shall, to the extent the certifications required to be made therein are
true and correct as of such time, be in substantially the same form as Exhibit F attached hereto and made a part hereof by this reference. It is intended that any such statement delivered pursuant to this paragraph may be relied upon by a
prospective purchaser of Landlord’s interest or a mortgagee of Landlord’s interest or assignee of any mortgage upon Landlord’s interest in the Building. If Tenant fails to respond within ten (10) business days after receipt by
Tenant of a written request by Landlord as herein provided, Tenant shall be deemed to have given such certificate as above provided without modification and shall be deemed to have admitted the accuracy of any information supplied by Landlord to a
prospective purchaser or mortgagee consistent with the terms of the estoppel so requested. 
 36. FINANCIAL REPRESENTATIONS AND INFORMATION.

 Tenant shall from time to time deliver to Landlord updated financial information, certified by Tenant’s chief financial officer as
true, correct and complete as of the close of the 
  

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 Tenant’s most recent fiscal year for which financial statements have been completed, within ten (10) business
days after Landlord’s written request (which shall be limited to one (1) request per calendar year during the Lease Term). 
 37. TRANSFER OF
LANDLORD’S INTEREST. 
 In the event of any transfer(s) of Landlord’s interest in the Premises or the Building to a bona-fide
third-party purchaser, other than a transfer for security purposes only, the transferor shall be automatically relieved of any and all obligations and liabilities on the part of Landlord accruing from and after the date of such transfer, and Tenant
agrees to attorn to the transferee. 
 38. RIGHT TO PERFORM. 
 If Tenant shall fail to pay any sum of money, other than Base Rent and Additional Rent, required to be paid by it hereunder or shall fail to perform any other act on its part to be performed hereunder, and (except in
the event of emergency in which case no grace or cure period shall be applicable or required) such failure shall continue for ten (10) days (or such longer cure period as may be provided for herein) after written notice thereof, Landlord may,
but shall not be obligated so to do, and without waiving or releasing Tenant from any obligations of Tenant, make any such payment or perform any such other act on Tenant’s part to be made or performed as provided in this Lease. Landlord shall
have (in addition to any other right or remedy of Landlord) the same rights and remedies in the event of the nonpayment of sums due under this section as in the case of Default by Tenant in the payment of Base Rent. All sums paid by Landlord and all
penalties, interest and costs in connection therewith, shall be due and payable by Tenant upon written demand within ten (10) business days after such payment by Landlord, together with interest thereon at the Default Rate from such date to the
date of payment. 
 39. COMMON AREAS. 
 For purposes hereof, the term “Common Areas” shall mean (i) all portions of the Land other than portions upon which the Building is situated, including landscaped areas and the like, as the same may be modified from time to
time by Landlord; (ii) all loading docks, corridors, lobbies, elevator cabs, stairs and other portions of the Building that would customarily be made available to tenants of the Building, as the same may be modified from time to time by
Landlord; (iii) any parking deck, parking structure, or surface parking facility, and any connector from the Building thereto; and (iv) any areas which are common areas for, on, or utilized in general by tenants, owners and/or occupants of
the Hunters Branch complex, including both current and any future phases thereof. 
 40. SALES AND AUCTIONS. 
 Tenant may not display or sell merchandise outside the exterior walls and doorways of the Premises and may not use such areas for storage. Tenant shall
not conduct or permit to be conducted any sale by auction in, upon or from the Premises whether said auction be voluntary, involuntary, pursuant to any assignment for the payment of creditors or pursuant to any bankruptcy or other insolvency
proceedings. 
  

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 41. ACCESS TO ROOF. 
 Tenant shall have no access to, or the right to use, the roof of the Building for any purpose, without Landlord’s prior written consent, given or withheld in Landlord’s sole and absolute discretion.

 42. ACCESS. 
 Tenant shall have access
to the Premises twenty four (24) hours per day, seven (7) days per week. 
 43. AUTHORITY OF LANDLORD AND TENANT. 
 Each of Landlord and Tenant shall furnish the other with appropriate partnership and/or corporate resolutions, as applicable, confirming that the
individual executing this Lease on behalf of each has been duly authorized to execute and deliver this Lease on behalf of such party and that this Lease is binding upon such party. 
 44. NO ACCORD OR SATISFACTION. 
 No payment by Tenant or receipt by Landlord of a lesser amount than
the Base Rent, Additional Rent and other sums due hereunder shall be deemed to be other than on account of the earliest Base Rent or other sums due, nor shall any endorsement or statement on any check or accompanying any check or payment be deemed
an accord and satisfaction; and Landlord may accept such check or payment without prejudice to Landlord’s right to recover the balance of such Base Rent, Additional Rent or other sum and to pursue any other remedy provided in this Lease.

 45. LEGAL REQUIREMENTS. 
 Tenant shall,
as part of Tenant’s Work, cause the Premises to comply as of the Commencement Date with all laws, orders, ordinances and regulations of Federal and local authorities and with directions of public rules, recommendations, requirements and
regulations of the Board of Fire Underwriters, Landlord’s insurance companies and any other organization establishing insurance rates in the geographical area where the Project is located and all applicable building codes, to the extent the
same are applicable to the Premises or the Building, respecting all matters pertaining to the use and occupancy of the Premises by Tenant, including, without limitation, the accessibility requirements of the Americans with Disabilities Act
(“ADA”), all zoning and other land use laws, and all Environmental Laws. 
  

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 46. PARKING. 
 Tenant shall have the right (together with Landlord and its agents, employees and contractors, and together with the rights of other tenants in the Building and the Project) to use, from the parking areas available to the Project in the
parking structure and surface parking on the Project and Common Areas an amount of parking as set forth in Section 1.1 hereof. Such parking right shall be non-exclusive, and on an unreserved basis, and Tenant agrees not to overburden the
Building’s parking facilities. 
 47. GENERAL PROVISIONS. 
 47.1 Acceptance. This Lease shall only become effective and binding upon full execution hereof by Landlord and Tenant and delivery of a signed copy by Landlord to Tenant. 
 47.2 Joint Obligation. If there be more than one Tenant, the obligations hereunder imposed shall be joint and several. 
 47.3 Marginal Headings, Etc. The marginal headings, Table of Contents, lease summary sheet and titles to the sections of this Lease are not a part
of the Lease and shall have no effect upon the construction or interpretation of any part hereof. 
 47.4 Choice of Law. This Lease
shall be governed by and construed in accordance with the laws of the Commonwealth of Virginia (without regard to the choice of law and/or conflict of law principles applicable in such State). 
 47.5 Successors and Assigns. The covenants and conditions herein contained, subject to the provisions as to assignment, inure to and bind the
heirs, successors, executors, administrators and assigns of the parties hereto. 
 47.6 Recordation. Except to the extent otherwise
required by law, neither Landlord nor Tenant shall record this Lease or a memorandum hereof. 
 47.7 Quiet Possession. Upon
Tenant’s paying the Base Rent and Additional Rent reserved hereunder and observing and performing all of the covenants, conditions and provisions on Tenant’s part to be observed and performed hereunder, Tenant shall have quiet possession
and enjoyment of the Premises for the Lease Term hereof free from any disturbance or molestation by Landlord, or anyone claiming by, through or under Landlord, but in all events subject to all the provisions of this Lease. 
 47.8 Inability to Perform; Force Majeure. This Lease and the obligations of the Tenant hereunder shall not be affected or impaired because either
Landlord or Tenant is unable to fulfill any of its obligations hereunder or is delayed in doing so, to the extent such inability or delay is caused by reason of war, civil unrest, strike, labor troubles, unusually inclement weather, governmental
delays, inability to procure services or materials despite reasonable efforts, third party delays, acts of God, or any other cause(s) beyond the reasonable control of the Landlord (which causes are referred to collectively herein as “Force
Majeure”). Any time specified 
  

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 obligation of Landlord in this Lease shall be extended one day for each day of delay suffered by Landlord as a result of
the occurrence of any Force Majeure. The foregoing notwithstanding in no event will an event of Force Majeure extend the time within which Tenant or Landlord must perform any of its monetary obligations under this Lease. 
 47.9 Partial Invalidity. Any provision of this Lease which shall prove to be invalid, void, or illegal shall in no way affect, impair or
invalidate any other provision hereof and such other provision(s) shall remain in full force and effect. 
 47.10 Cumulative Remedies.
No remedy or election hereunder shall be deemed exclusive but shall, whenever possible, be cumulative with all other remedies at law or in equity. 
 47.11 Entire Agreement. This Lease contains the entire agreement of the parties hereto and no representations, inducements, promises or agreements, oral or otherwise, between the parties, not embodied herein, shall be of any force or
effect. 
 47.12 Survival. All indemnities set forth in this Lease shall survive the expiration or earlier termination of this Lease.

 47.13 Consents. If any provision of this Lease subjects any action, inaction, activity or other right or obligation of any party to
the prior consent or approval of the other, such consent shall not be unreasonably withheld, conditioned or delayed unless otherwise specifically provided herein. 
 47.14 Saving Clause. In the event (but solely to the extent) the limitations on Landlord’s liability set forth in Section 8.3 of this Lease would be held to be unenforceable or void in the absence of
a modification holding the Landlord liable to Tenant or to another person for injury, loss, damage or liability arising from Landlord’s omission, fault, negligence or other misconduct on or about the Premises, or other areas of the Building
appurtenant thereto or used in connection therewith and not under Tenant’s exclusive control, then such provision shall be deemed modified as and to the extent (but solely to the extent) necessary to render such provision enforceable under
applicable law. The foregoing shall not affect the application of Section 34 of this Lease to limit the assets available for execution of any claim against Landlord. 
 47.15 Rule Against Perpetuities. In order to ensure the compliance of this Lease with any rule against perpetuities that may be in force in the state in which the Premises are located, and without limiting or
otherwise affecting either Land lord’s or Tenant’s obligations under this Lease, as stated in the other sections hereof, or modifying any other termination rights which may be set forth herein, Landlord and Tenant agree that, irrespective
of the reasons therefor (other than a Default by Tenant), in the event Tenant fails to take possession of the Premises and commence paying Base Rent and Additional Rent hereunder within ten (10) years after the date of execution of this Lease,
then this Lease, and the obligations of the parties hereunder, shall be deemed to be null and void and of no further force and effect. Without affecting the specific timing requirements otherwise applicable thereto under this Lease, any and all
options granted to Tenant under this Lease (including, without limitation, expansion, renewal, right of first refusal, right of first offer, and like options) must be exercised by Tenant, if at all, during the term of this Lease. 
  

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 48. RULES AND REGULATIONS. 
 Tenant agrees to comply with the Rules and Regulations attached hereto as Exhibit D. Notwithstanding the foregoing, Landlord shall use reasonable efforts to enforce all such rules and regulations, including any
exceptions thereto, uniformly and in a manner which does not unreasonably discriminate against Tenant, or increase Tenant’s monetary obligations under this Lease, although it is understood that Landlord may grant exceptions to such rules and
regulations in circumstances in which it reasonably determines such exceptions are warranted. In the event of any conflict between the rules and regulations attached to the Lease (or provided separately to Tenant as reasonably modified from time to
time) and the terms of the main body of the Lease, the terms of the main body of the Lease shall govern and control. 
 49. ARBITRATION. 

49.1 If arbitration is specifically agreed upon hereunder as a dispute resolution procedure, the arbitration shall be conducted as provided in this
Section. All proceedings shall be conducted according to the Commercial Arbitration Rules of the American Arbitration Association, except as hereinafter provided. No action at law or in equity in connection with any such dispute shall be brought
until arbitration hereunder shall have been waived, either expressly or pursuant to this Section. The judgment upon the award rendered in any arbitration hereunder shall be final and binding on both parties hereto and may be entered in any court
having jurisdiction thereof. During any arbitration proceeding pursuant to this Section, the parties shall continue to perform and discharge all of their respective obligations under this Lease, except as otherwise provided in this Lease.

 49.2 All disputes that are required to be arbitrated in accordance with this Lease shall be raised by notice to the other party, which
notice shall state with particularity the nature of the dispute and the demand for relief, making specific reference by article number and title of the provisions of this Lease alleged to have given rise to the dispute. The notice shall also refer
to this Section and shall state whether or not the party giving the notice demands arbitration under this Section. 
 49.3 Within thirty
(30) days of any demand for arbitration, each of Tenant and Landlord shall appoint one (l) arbitrator, and within ten (10) days of their appointment, the two (2) arbitrators thus selected shall jointly select a third
(3rd) arbitrator. All arbitrators shall have at least tea (10) years’ experience in commercial real estate matters and, in particular, the subject matter of the dispute, to act as arbitrator hereunder. If either party fails to select
an arbitrator within the initial thirty (30) day period, or if the two (2) arbitrators are unable to agree upon a third (3rd) arbitrator, then, upon the request of either party, the remaining arbitrator(s) shall be appointed by The
American Arbitration Association. The arbitration proceedings shall take place in a mutually acceptable location in the Washington, D C. area. 
  

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 49.4 The right of Landlord and Tenant to submit a dispute to arbitration is limited to issues
specifically agreed in this Lease to be submitted to arbitration, and specifically does not apply to any remedial action undertaken by Landlord pursuant to the provisions of Section 24 hereof. When resolving any dispute, the arbitrator shall
apply the pertinent provisions of this Lease without departure therefrom in any respect. The arbitrator shall not have the power to change any of the provisions of this Lease, but this Section shall not prevent in any appropriate case the
interpretation, construction and determination by the arbitrator of the applicable provisions of this Lease to the extent necessary in applying the same to the matters to be determined by arbitration. 
 50. WAIVER OF JURY TRIAL. 
 Landlord and
Tenant hereby waive trial by jury in any action, proceeding or counterclaim brought by either of them against the other on all matters arising out of this Lease, or the use and occupancy of the Premises. If Landlord commences any summary proceeding
for non-payment of Base Rent or Additional Rent, Tenant will not interpose (and waives the right to interpose) any non-mandatory counterclaim in any such proceeding. 
  

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 IN WITNESS WHEREOF, Landlord and Tenant have executed this Deed of Lease, or have caused this Deed of
Lease to be executed on their respective behalves by their duly authorized officers, as of the day and year first above written. 
  

							
	LANDLORD:
	
	HUNTERS BRANCH LEASING, LLC
		
	 By:
	 	 Nutley Partners, LLC, its Managing Member

			
		 	 By:
	 	 FP-Argo Hunters Branch, LC, its manager

				
		 		 	 By:
	 	 Argo Investment Company, LC, its manager

				
		 		 	 By:
	 	 /s/ RICHARD L. PERLMUTTER

		 		 		 	 Richard L. Perlmutter

		 		 		 	 Manager

	
	TENANT:
	
	 B2TECS
 a Virginia corporation

		
	 By:
	 	 /s/ SUNIL K. BALA

		 	Dr. Sunil K. Bala
		 	President

  

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 JOINDER 
 The undersigned Hunters Branch Partners, L.L.C. joins in the execution hereof to (i) evidence its consent to the terms, conditions and existence hereof, and (ii) to agree with Tenant that, in the event of
the termination of the Prime Lease for any reason, this Lease shall automatically become a direct lease between Tenant and Hunters Branch Partners, L.L.C., and each hereby irrevocably and unconditionally agree that in such event, each of Hunters
Branch Partners, L.L.C. and Tenant shall execute a declaration evidencing the continuation hereof as a direct lease between Tenant and Hunters Branch Partners, L.L.C. 
  

							
	HUNTERS BRANCH PARTNERS, L.L.C.
		
	By:	 	IFA Nutley Partners, LLC, its Managing Member
			
		 	By:	 	Hunters Branch Manager, Inc.
				
		 		 	By:	 	 /s/ RICHARD L. PERLMUTTER

		 		 		 	Richard L. Perlmutter
		 		 		 	Manager

 JOINDER OF GUARANTOR 
 The undersigned Sunil K. Bala (“Guarantor) joins in the execution hereof for the purpose of guaranteeing the timely, complete, continuous,
and strict performance and observance by the Tenant of any and all of the terms, covenants, agreements, and conditions contained in the foregoing Lease, both monetary arid non-monetary, and any existing or future documents, instruments, agreements,
and writings of every kind, nature, type, and variety which evidence, reflect, embody, or secure the Lease, and all amendments, modifications, and restatements thereof, as though such Guarantor was a signatory thereto. 
  

			
	 /s/ SUNIL K. BALA
	 	(SEAL)
	 Name: Dr. Sunil K. Bala
	 	
	 SS # (Intentionally Deleted)
	 	

  

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