<PAGE>
          Confidential Material omitted and filed separately with the
        Securities and Exchange Commission. Asterisks denote omissions.

                                                                    Exhibit 10.6

                                              HARVARD/ARSENAL/ATHENAHEALTH LEASE

                                   ----------

             HARVARD REAL ESTATE SERVICES, HOLYOKE CENTER, SUITE 800
                       CAMBRIDGE, MASSACHUSETTS 02138-3826

                                   ----------

                                      LEASE

                                     BETWEEN

                    PRESIDENT AND FELLOWS OF HARVARD COLLEGE

                                   AS LANDLORD

                                       AND

                               ATHENAHEALTH, INC.

                                    AS TENANT

                          DATED AS OF NOVEMBER 8, 2004

                                   ----------

                          OFFICE OF THE GENERAL COUNSEL
                               HARVARD UNIVERSITY

                                   ----------

<PAGE>

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                            Page
                                                                            ----
<S>                                                                         <C>
ARTICLE 1. - PARTIES, PREMISES, AND DEFINITIONS.........................       1
   Section 1.1.    Parties, Premises....................................       1
   Section 1.2.    Definitions..........................................       1
   Section 1.3.    Exhibits.............................................       6

ARTICLE 2. - LEASING CLAUSES............................................       6
   Section 2.1.    Grant of Lease.......................................       6
   Section 2.2.    Encumbrances, Common Facilities, Exceptions, and
                   Reservations.........................................       6
   Section 2.3.    Use: Hours of Access.................................       6
   Section 2.4.    Lease Term: Possession...............................       7
   Section 2.5.    Payment of Rent......................................       7
   Section 2.6.    Application of Payments: Check Endorsements..........       7
   Section 2.7.    Parking Spaces/Bicvcles.............................        7
           2.7.1.  Additional Parking...................................       8
   Section 2.8.    Transportation Services of the Complex...............       8
   Section 2.9.    Second Floor Building 311 Premises...................       9
           2.9.1.  Delayed Delivery Date................................       9
   Section 2.10.   Ancillary Uses of the Premises.......................      10
   Section 2.11.   Entry Premises and Terrace Premises..................      10

ARTICLE 3. - RENT.......................................................      10
   Section 3.1.    Basic Rent...........................................      10
           3.1.1.  Lease Year Defined...................................      10
           3.1.2.  Late Payments, Additional Rent.......................      10
           3.1.3.  Other Additional Rent................................      11
   Section 3.2.    Expense Allocation...................................      11
           3.2.1.  Expense Allocation Proration.........................      12
           3.2.2.  Complex Operating Costs Defined......................      12
           3.2.3.  Building Operating Costs Defined.....................      13
           3.2.4.  Exclusions from Operating Costs......................      14
           3.2.5.  Method of Payment....................................      15
           3.2.6.  Record Keeping.......................................      16
           3.2.7.  Inspection and Audit Rights..........................      16

ARTICLE 4. - REIMBURSEMENT FOR REAL ESTATE TAXES........................      17
   Section 4.1.    Tenant to Reimburse Landlord for Real Estate Taxes...      17
   Section 4.2.    Payment of the Tax Reimbursement.....................      18
   Section 4.3.    Abatement............................................      18
   Section 4.4.    Landlord's Right to Recover..........................      19

ARTICLE 5. - COVENANTS..................................................      19
   Section 5.1.    Tenant's Covenants...................................      19
           5.1.1.  Rent and other Payments; Independent Covenant........      19
</TABLE>


                                        i

<PAGE>

<TABLE>
<S>                                                                         <C>
           5.1.2.  Care of Premises.....................................      19
           5.1.3.  Glass................................................      20
           5.1.4.  Yielding Up of Premises on Termination or
                   Expiration, Security Interests.......................      20
           5.1.5.  Overloading, Nuisance, Flammables, Increase in
                   Insurance Premiums...................................      20
           5.1.6.  No Obstruction; Rules and Regulations................      21
           5.1.7.  Compliance with Laws:  Safety; Health................      21
           5.1.8.  No Assignment or Subletting..........................      21
           5.1.9.  Landlord's Consent Required for Tenant's
                   Alterations..........................................      25
           5.1.10. Licenses and Permits.................................      26
           5.1.11. Indemnification......................................      26
           5.1.12. Enforcement Costs....................................      27
           5.1.13. No Interference......................................      27
           5.1.14. Delivery of Financial Statements.....................      27
           5.1.15. No Violation.........................................      28
           5.1.16. Use..................................................      28
           5.1.17. Keys.................................................      28
           5.1.18. Security Alarm.......................................      28
           5.1.19. No Parking...........................................      28
           5.1.20. Insurance............................................      28
           5.1.21. Subordination........................................      30
           5.1.22. Harvard Name.........................................      30
           5.1.23. Tenant's Managers....................................      31
           5.1.24. Tenant's Expense, Personal Property Taxes............      31
           5.1.25. Hazardous Materials..................................      31
           5.1.26. Existing Environmental Conditions....................      32
           5.1.27. Tenant's Business Name...............................      32
   Section 5.2.    Landlord's Covenants.................................      32
           5.2.1.  Quiet Eniovment......................................      32
           5.2.2.  Landlord's Default...................................      32
           5.2.3.  Landlord's Insurance.................................      33
   Section 5.3.    Notice to Mortgagee and Ground Lessor................      33
   Section 5.4.    HIPAA................................................      33

ARTICLE 6. - TENANT'S DEFAULT...........................................      33
   Section 6.1.    Event of Default.....................................      33
           6.1.1.  Written Notice of Termination........................      35
           6.1.2.  Bankruptcy...........................................      35
   Section 6.2.    Tenant's Obligations After Termination...............      35
           6.2.1.  Evidence of Value....................................      36
   Section 6.3.    Other Matters Relating to Termination................      36
           6.3.1.  Landlord's Right to Relet............................      36
           6.3.2.  Landlord's Other Remedies............................      37
           6.3.3.  Right to Equitable Relief............................      37
           6.3.4.  Landlord's Right To Cure Tenant's Default............      37
</TABLE>


                                       ii

<PAGE>

<TABLE>
<S>                                                                         <C>
ARTICLE 7. - LETTER OF CREDIT...........................................      37
   Section 7.1.    Definitions..........................................      37
   Section 7.2.    Requirements of Letter of Credit, Amount, Form.......      37
   Section 7.3.    Decrease in Amount of Letter of Credit...............      38
           7.3.1.  Reduction Deliveries.................................      38
           7.3.2.  Amendment to Letter of Credit........................      39
   Section 7.4.    Landlord's Rights Upon an Event of Default...........      39

ARTICLE 8. - GENERAL MATTERS............................................      39
   Section 8.1.    Condition of Premises................................      39
   Section 8.2.    Casualty and Eminent Domain..........................      40
           8.2.1.  Casualty, Partial Taking.............................      40
           8.2.2.  Total Takin//Partial Taking..........................      40
           8.2.3.  Restoration..........................................      41
           8.2.4.  Landlord's Right to Damages..........................      41
   Section 8.3.    Access to Premises; Landlord's Right to Repair
                   and Alter............................................      41
           8.3.1.  Viewing, Inspecting, Repairing.......................      41
           8.3.2.  Landlord Alterations, Pest Extermination.............      42
           8.3.3.  Right to Remove Certain Items and Improvements.......      42
           8.3.4.  Right to Affix "For Rent" Sign.......................      42
           8.3.5.  Right to Modify Complex..............................      42
   Section 8.4.    Amendment, Severability..............................      43
   Section 8.5.    Cumulative Effect....................................      43
   Section 8.6.    Estoppel Certificates................................      43
   Section 8.7.    Brokers..............................................      43
   Section 8.8.    When Lease is Binding on Landlord....................      44
   Section 8.9.    Transfer of Complex..................................      44
   Section 8.10.   Holding Over.........................................      44
   Section 8.11.   Captions; Rules of Construction......................      44
   Section 8.12.   Notices..............................................      45
   Section 8.13.   No Waiver, No Exhaustion of Rights...................      46
   Section 8.14.   Representative Capacity..............................      47
   Section 8.15.   No Invalidity........................................      47
   Section 8.16.   No Recording.........................................      47
   Section 8.17.   Time to Commence Actions; No Jury Trial..............      47
   Section 8.18.   Landlord's Right to Erect Obstructions...............      47
   Section 8.19.   Effect of Unavoidable Delays.........................      47
   Section 8.20.   No Representations or Inducements....................      48
   Section 8.21.   Formalities of Execution.............................      48
   Section 8.22.   Community Outreach Agreement.........................      48
   Section 8.23.   Patriot Act..........................................      48

ARTICLE 9. - ADDITIONAL PROVISIONS......................................      49
   Section 9.1.    Services to the Premises.............................      49
   Section 9.2.    Electricity..........................................      49
           9.2.1.  Replacement Lamps/Bulbs..............................      49
           9.2.2.  Selection of Power Providers/Interruption of
                   Utility Service......................................      49
</TABLE>


                                       iii

<PAGE>

<TABLE>
<S>                                                                         <C>
           9.2.3.  Alterations to Electrical Equipment..................      50
           9.2.4.  Additional Electricity Requirements..................      50
   Section 9.3.    Water................................................      51
   Section 9.4.    Elevators, Heat, Air Conditioning, Cleaning..........      51
           9.4.1.  Elevators............................................      51
           9.4.2.  Heating, Venting and Air Conditioning: for the
                   Building 97 Premises.................................      51
           9.4.3.  Heating, Venting and Air Conditioning for the
                   Building 311 Premises................................      51
           9.4.4.  Cleaning.............................................      51
           9.4.5.  Common Area Maintenance/Repairs......................      51
   Section 9.5.    Energy Conservation..................................      52
   Section 9.6.    Premises Population..................................      52
   Section 9.7.    Security.............................................      52
   Section 9.8.    Loading Docks........................................      52
   Section 9.9.    Telecommunication Service Provider...................      53
   Section 9.10.   Signage..............................................      53
   Section 9.11.   Rooftop Equipment and Communication Devices..........      53

ARTICLE 10. - OPTION TO EXTEND LEASE TERM...............................      53
   Section 10.1.   Tenant's Option to Extend............................      53
   Section 10.2.   Determination of Rent for the Extension Term.........      54
   Section 10.3.   Costs and Expenses...................................      55
   Section 10.4.   Continuation of Terms and Conditions.................      55
   Section 10.5.   Definition...........................................      55
</TABLE>


                                       iv

<PAGE>

                                    EXHIBITS

ExhibitA   Rules and Regulations
B          Form of Transmittal Letter
C          Form of Letter of Credit
C-1        Approved Form of Letter of Credit
D          Floor Plan of Premises
D-1        Floor Plan of Building 97 Premises
D-2        Floor Plan of Building 311 Premises
E          Site Plan
F          Work Letter
G          List of Environmental Restrictions
H          Cleaning Specifications
I          Base Building Specifications
I-1        Building 97 Base Building Specifications
1-2        Building 311 Base Building Specifications
J          Existing Lease Obligations
K          Lease Rider Lease Rider
L          Shuttle Bus Schedule
L-1        4th Shuttle Bus Schedule


                                        v

<PAGE>

                 ARTICLE 1. - PARTIES, PREMISES, AND DEFINITIONS

     Section 1.1. Parties, Premises. The parties to this Lease ("Landlord" and
"Tenant") and the premises ("Premises") covered hereby are as follows:

     LANDLORD: President and Fellows of Harvard College, a Massachusetts
educational and charitable corporation.

     TENANT: athenahealth, Inc.

     TENANT'S MAILING ADDRESS: One Moody Street, Waltham, Massachusetts 02453.

     TENANT'S BUSINESS NAME: athenahealth.

     DATE OF THIS LEASE: November 8, 2004.

     PREMISES: The space shown on the plan attached hereto as Exhibits D-1 and
D-2 and containing approximately 133,616 rentable square feet of space comprised
of (i) all of Building 97 as shown on the plans attached hereto as Exhibit D-1,
containing approximately 21,000 rentable square feet of space, and including the
Terrace Premises (the "Building 97 Premises"), (ii) portions of the second and
third floors of Building 311 as shown on the plans attached hereto as Exhibit
D-2, containing approximately 112,616 rentable square feet of space (the
"Building 311 Premises").

     ADDRESS OF PREMISES: Building 97 is located at 300 North Beacon Street, the
Arsenal on the Charles, Watertown, MA 02472 and Building 311 is located at 311
Arsenal Street, the Arsenal on the Charles, Watertown, MA 02472.

     Section 1.2. Definitions. As used herein, the following terms have the
following meanings.

     ADDITIONAL RENT: The additional rent payable by Tenant under Section 3.2
and Article 4 of this Lease, any Construction Rent payable by Tenant under the
Work Letter, and Existing Lease Additional Rent payments under Exhibit J.

     ART/THEATRE CENTER: The space designated to be used as an art/theatre
center and located in a portion of Building 312 in the Complex.

     ART/THEATRE CENTER COSTS: All costs incurred by Landlord in operating up to
10,000 square feet of the Art/Theatre Center, including, but not limited to
utilities, and normal, regularly-occurring maintenance and repairs to the public
areas, exterior glass, and Structural Components of Building 312 to the extent
required to be paid by Landlord under the lease for the Art/Theatre Center, but
excluding any expenses of any artists or arts related activities or functions
within the Art/Theatre Center.

     AUTHORIZATIONS: All franchises, licenses, permits, approvals, variances,
certificates, special permits, and other consents issued by Governmental
Authorities pursuant to Legal

<PAGE>
          Confidential Material omitted and filed separately with the
        Securities and Exchange Commission. Asterisks denote omissions.

Requirements that are or may be required for, or applicable to, the use and
occupancy of the Premises and the conduct or continuation of the Permitted Use
therein.

     BASIC RENT:

<TABLE>
<CAPTION>
         Period            Annual Basic Rent   Monthly Basic Rent
         ------            -----------------   ------------------
<S>                        <C>                 <C>
Lease Year 1 (commencing
   on the Rent
   Commencement Date)        $ *                  $ *
Lease Year 2                 $ *                  $ *
Lease Year 3                 $ *                  $ *
Lease Year 4                 $ *                  $ *
Lease Year 5                 $ *                  $ *
Lease Year 6                 $ *                  $ *
Lease Year 7                 $ *                  $ *
Lease Year 8                 $ *                  $ *
Lease Year 9                 $ *                  $ *
Lease Year 10                $ *                  $ *
</TABLE>

See Section 3.1.

     Brokers: Beal and Company, Inc. (Broker for Landlord) and Grubb & Ellis
Company (Broker for Tenant). See Section 8.7.

     BUILDING OPERATING COSTS: See Section 3.2.3.

     BUILDING SYSTEMS: All mechanical, HVAC, plumbing, and electrical systems
within and serving the Buildings exclusively.

     BUILDING 97. "Building 97" shall mean the building known as Building 97, as
shown on the Site Plan. Building 97 contains approximately 21,000 rentable
square feet of space.

     BUILDING 311. "Building 311" shall mean the building known as Building 311,
as shown on the Site Plan. Building 311 contains approximately 366,112 rentable
square feet of space.

     BUILDINGS: The term "Buildings" shall mean, collectively, the buildings
known as Building 97 and Building 311.

     BUSINESS HOURS: Mondays through Fridays, excepting legal holidays, from
7:00 a.m. to 7:00 p.m. and on Saturdays, excepting legal holidays, from 8:00
a.m. to 3:00 p.m.

     BUSINESS DAYS: All days except Saturdays, Sundays, days observed as
holidays by the federal government, including, New Year's Day, Martin Luther
King Day, President's Day, Patriots Day, Memorial Day, Independence Day, Labor
Day, Columbus Day, Thanksgiving Day, Christmas Day (or the day of observance of
such holiday where the holiday falls on a Saturday or Sunday).


                                       2

<PAGE>

     COMMON FACILITIES: Public or common lobbies, hallways, stairways,
shaftways, street entrances, elevators (if any), mechanical and electrical
rooms, mechanical systems and equipment serving more than one tenant, and if the
portion of the Premises on any floor includes less than the entire floor, the
common toilets, corridors, and lobby of such floor; and the access roads,
driveways, parking areas, the Parking Garage, loading areas, pedestrian
sidewalks, landscaped areas, trash enclosures, recreation areas, and other areas
or facilities that are located within the Complex and designated by Landlord
from time to time for the non-exclusive use of tenants and other occupants of
the Complex, and the services provided to tenants from time to time as an
amenity of the Complex. Lobbies, hallways, and toilets, if any, solely serving
the Tenant and located wholly within the Premises are part of the Premises, and
are not Common Facilities, except to the extent deemed necessary by Landlord so
that Landlord can operate and manage the Buildings in accordance with Legal
Requirements and Insurance Requirements.

     COMPLEX: The real property and improvements thereon known as "The Arsenal
on the Charles," located on Arsenal Street and North Beacon Street, Watertown,
Massachusetts, being shown on the Site Plan.

     COMPLEX OPERATING COSTS: See Section 3.2.2.

     CONSTRUCTION WORK: See Section 5.1.9.

     DEDUCTIBLE COSTS: See Section 5.1.8.5.

     EVENT OF DEFAULT: See Article 6.

     ENVIRONMENTAL RESTRICTIONS: See Section 5.1.25.

     ENTRY PREMISES: A portion of the Building 311 Premises consisting of the
lobby area on the second floor of Building 311, and labeled "Entry Premises" on
Exhibit D-2.

     EXISTING LEASE OBLIGATIONS: See Exhibit J.

     EXISTING TENANT: See Section 2.9.

     EXTENSION TERM: A portion of the Lease Term constituting two successive
terms of five years (each an "Extension Term"). The first Extension Term shall
commence on the day after the Lease Expiration Date, if this Lease is validly
extended. (See Article 10).

     FISCAL YEAR: Landlord's annual accounting period ending on June 30 each
year, or such other fiscal year as Landlord may from time to time adopt.

     GOVERNMENTAL AUTHORITY: The United States of America, The Commonwealth of
Massachusetts, the municipality in which the Premises are located, the county in
which said municipality is located, and any political subdivision of any of them
and any agency, department, commission, court, board, bureau, or instrumentality
of any of them.

     HAZARDOUS MATERIAL(S): See Section 5.1.25.


                                       3

<PAGE>

     HIPAA: See Section 5.1.4.

     INITIAL LEASE TERM: The period commencing on the Lease Commencement Date
and ending on the Lease Expiration Date, unless sooner terminated as provided in
this Lease.

     INSURANCE REQUIREMENTS: All terms and provisions of any policy of insurance
maintained by Landlord or Tenant and applicable to all or any part of the
Premises, the Buildings, or the Complex and all requirements of the issuer of
any such policy and all orders, rules, regulations, and other requirements of
the National Board of Fire Underwriters (and any other body exercising similar
functions) applicable to or affecting any condition, operation, use, or
occupancy of the Premises, the Buildings, the Complex, the sidewalks adjoining
the Complex, or any part or parts of either.

     INVOLUNTARY RATE: An annual rate equal to the lesser of (i) Prime Rate plus
10% (i.e. plus 1,000 basis points); or (ii) 18% (which is a daily rate of
..0493150685%), but if such interest rate should ever exceed that permitted by
law, the highest interest rate permitted by law shall be applicable.

     LANDLORD'S APPROVAL LETTER. See Exhibit F.

     LATE PAYMENTS: See Section 3.1.2.

     LEASE COMMENCEMENT DATE: The date of execution and delivery of the Lease by
Landlord, and delivery to, and acceptance by Landlord of the Letter of Credit
pursuant to the terms of Exhibit B provided that with respect to the Second
Floor Building 311 Premises and the Entry Premises, the Lease Commencement Date
shall be the Second Floor Lease Commencement Date (as defined in Section 2.9).

     LEASE EXPIRATION DATE: The date that is ten years after the Rent
Commencement Date, or such earlier date upon which the Lease Term may expire or
be terminated pursuant to any of the conditions or other provisions of this
Lease or pursuant to law.

     LEASE RIDER: The Lease Rider attached to this Lease as Exhibit K. The terms
of the Lease Rider are incorporated herein by reference as if set forth in this
Lease.

     LEASE TERM: The Initial Lease Term. If this Lease provides for a right to
extend the term of this Lease, and if Tenant validly so extends this Lease, then
during the applicable Extension Term, references to "Lease Term" shall be deemed
to refer to the applicable Extension Term.

     LEASE YEAR: See Section 3.1.1.

     LEGAL REQUIREMENTS: All statutes, codes, acts, and ordinances including
zoning by-laws and ordinances, building, health, and, safety codes, historic
preservation laws, and environmental protection laws (and all rules and
regulations thereunder), all executive orders and other administrative orders,
the terms and conditions of all Authorizations, and all judgments, decrees,
injunctions, and other judicial orders of or by any Governmental Authority that
may at any time


                                       4

<PAGE>
          Confidential Materials omitted and filed separately with the
        Securities and Exchange Commission. Asterisks denote omissions.


be applicable to parts or appurtenances of the Premises, the Buildings, the
Common Facilities or the Complex, or the sidewalks adjoining the Complex, or to
any condition or use thereof.

     LETTER OF CREDIT: See Article 7. The Letter of Credit is in the original
face amount of $ *.

     MINIMUM LIABILITY INSURANCE COVERAGE: $5,000,000. See Section 5.1.20.

     OCCUPANCY DATE: The date on which Tenant initially occupies all or any part
of the Premises for the conduct of the Permitted Use.

     OTHER ADDITIONAL RENT: See Section 3.1.3.

     PARKING GARAGE: The parking garage included in the Common Facilities of the
Complex and shown on the Site Plan.

     PERMITTED USE: The Premises shall be used for general office use, and for
any other uses as Landlord may approve in its reasonable discretion, and for the
ancillary uses set forth in Section 2.10, subject in all cases to the provisions
of the Lease, and no other uses. The Entry Premises and the Terrace Premises
shall be used for the uses specified in Section 2.11, and for no other uses.

     PRIME RATE: The "Prime Rate" as calculated and published by The Wall Street
Journal, or if discontinued, such other standard as shall then be recognized by
the banking community as having replaced the "prime rate."

     RENT: The total of Basic Rent, Additional Rent, and other additional rent.

     RENT COMMENCEMENT DATE: July 1, 2005, except that if Tenant occupies all or
any portion of the Premises for the conduct of the Permitted Use prior to April
1, 2005, Tenant shall pay Rent on all such occupied portions of the Premises
beginning on the date that is ninety days after such occupancy date. Landlord
will send Tenant a written notice setting forth the Rent Commencement Date.

     RENT PAYMENT DAY: See Section 2.5.

     RENTABLE SQUARE FEET OF THE COMPLEX: The rentable square feet of all the
buildings in the Complex, excluding the Parking Garage, the Art/Theatre Center
and the management office, currently estimated to be 743,176.

     ROOFTOP EQUIPMENT: See Exhibit K.

     RULES AND REGULATIONS: See Section 5.1.6.

     SECOND FLOOR BUILDING 311 PREMISES: A portion of the Building 311 Premises
comprised of space on the second floor of Building 311 and labeled "Second Floor
Building 311 Premises" on Exhibit D-2 and containing approximately 25,235
rentable square feet.


                                       5

<PAGE>

     SECOND FLOOR LEASE COMMENCEMENT DATE: See Section 2.9.

     SITE PLAN: The site plan of the Complex attached hereto as Exhibit E.

     STRUCTURAL COMPONENTS: All foundations, columns, structural walls (i.e.,
loadbearing walls), floors, perimeter walls of the Buildings (except for the
inner surfaces thereof in the Premises), roof, exterior windows and glass, glass
in any demising walls in the Building 311 Premises, and other structural
components of the Buildings.

     TENANT: The term "tenant" means persons other than Tenant, who occupy space
in the Complex other than the Premises, whether under a lease or otherwise.

     TENANT'S SHARE OF PARKING SPACES: 347 unreserved parking spaces located in
the parking areas of the Complex, to be used in accordance with Section 2.7.

     TENANT'S WORK: See the Work Letter.

     TERRACE PREMISES: the outdoor space immediately east of, and adjacent to
Building 97, and labeled "Terrace Premises" on Exhibit D-1.

     WORK LETTER: See Exhibit F.

     YEAR: References in this Lease to "year" or "Year" mean a 365-day (366-day
in case of a leap year) period of time.

     Section 1.3. Exhibits. The Exhibits to this Lease are part of this Lease,
are incorporated herein by reference, and are to be treated as part of this
Lease for all purposes. Undertakings contained in such Exhibits are agreements
on the part of Landlord and Tenant, as the case may be, to perform the
obligations stated therein.

                          ARTICLE 2. - LEASING CLAUSES

     Section 2.1. Grant of Lease. Landlord hereby leases unto Tenant, and Tenant
hereby takes and hires from Landlord, the Premises on the terms, covenants,
provisions, and conditions set forth in this Lease.

     Section 2.2. Encumbrances, Common Facilities, Exceptions, and Reservations.
The Premises are hereby leased subject to existing easements and party wall
agreements and to recorded easements, restrictions, rights, and encumbrances. As
part of this Lease, Tenant shall have the right to the non-exclusive use of the
Common Facilities in common with Landlord and others from time to time thereto
entitled. Tenant's rights to possession and use of the Premises and the Common
Facilities are subject to the provisions of this Lease, applicable Insurance
Requirements, the Rules and Regulations, and applicable Legal Requirements.

     Section 2.3. Use: Hours of Access. The Premises may be used (whether by the
named Tenant, by any subsequent holder of the tenant interest hereunder, or by
others) only for the Permitted Use, and no others. Tenant covenants to use the
Premises only for the Permitted Use.


                                       6

<PAGE>

Subject to the provisions of Section 2.2, Tenant will have access to the
Premises on a 24 hour per day, 7 day per week basis.

     Section 2.4. Lease Term: Possession. The Premises are hereby leased by
Landlord to Tenant for the Lease Term. Except for the Second Floor Building 311
Premises, and the Entry Premises, which shall be delivered in accordance with
Section 2.9 below, Landlord shall deliver possession of the remaining Premises
to Tenant as of the Lease Commencement Date.

     Section 2.5. Payment of Rent. Tenant hereby agrees to pay Landlord the Rent
as defined in this Lease. All Rent payments are due to Landlord on the first day
of each calendar month (the "RENT PAYMENT DAY") unless otherwise specifically
provided. In all cases, Rent shall be paid either by recent check drawn on a
bank payable to "Harvard University" and shall be mailed or delivered c/o Beal &
Company, Inc., 177 Milk Street, Boston, Massachusetts 02109, Attention: Accounts
Receivable, or such other address as Landlord may from time to time by notice
direct or by wire transfer of immediate available federal funds to a bank
account designated by Landlord or Landlord's managing agent.

     Section 2.6. Application of Payments: Check Endorsements. Regardless of how
the payment is characterized by Tenant (or the person making payment on behalf
of Tenant) at the time of payment or otherwise, any payment made by or on behalf
of Tenant to Landlord may be applied by Landlord, in Landlord's sole election,
to Rent or any other amount due from Tenant to Landlord. No acceptance by
Landlord of a sum less than the Rent or any other amount then due shall be
deemed to be other than on account of the next due installment of such Rent or
other amount, and Landlord shall be permitted to apply such lesser amount to
Rent or any other amount then due, regardless of how Tenant characterizes the
payment. Landlord, by notice to Tenant, may require Tenant to pay Rent and any
other amounts due from Tenant to Landlord by an "electronic funds transfer"
system arranged by and among Tenant, Tenant's bank, and Landlord. No endorsement
or statement by Tenant on any check or in any letter or writing accompanying any
check or payment (regardless of how payment is made) shall be deemed an accord
and satisfaction, whether under common law or M.G.L. c. 106 Section 3-311 or
other law or statute, and Landlord may accept such check or payment to
Landlord's exclusive benefit without prejudice to Landlord's right to recover
the balance of such installment or to pursue any other remedy under this Lease
or otherwise. IN NO EVENT SHALL TENANT ASSERT ACCORD AND SATISFACTION UNDER
M.G.L. C. 106 SECTION 3-311, UNLESS THE CHECK AND ANY ACCOMPANYING DOCUMENTS ARE
DELIVERED TO THE OFFICE OF THE GENERAL COUNSEL, HARVARD UNIVERSITY, HOLYOKE
CENTER, SUITE 980, CAMBRIDGE, MASSACHUSETTS 02138-3834, ATTENTION: ROBERT E.
MCGAW, JNIVERSITY ATTORNEY.

     Section 2.7. Parking Spaces/Bicycles. Tenant shall have the right (subject
to the Rules and Regulations) to use Tenant's Share of Parking Spaces without
additional charge (except pursuant to Section 3.2), which shall be on a
non-exclusive, unreserved basis, except that seventeen of Tenant's parking
spaces will be located immediately adjacent to Building 97, in an area to be
designated by Landlord, and will be marked with signage as "Reserved Parking."
Landlord reserves the right to (i) designate areas where Tenant should park; and
(ii) implement a parking management plan for the Complex which may include the
designation of certain areas or


                                       7

<PAGE>

spaces for Tenant's Share of unreserved Parking Spaces or the issuance of access
cards/parking passes for each parking space.

          2.7.1. Additional Parking. If at any time Tenant determines that
Tenant's Share of Parking Spaces is materially inadequate for Tenant's use of
the Premises, and such material inadequacy is resulting in an inability for
Tenant's employees to find available parking in the Complex, Tenant may send a
notice to Landlord ("Tenant's Parking Notice") requesting that Landlord
determine if alternative parking management procedures can be implemented to
address Tenant's shortage of parking. Landlord agrees that after receipt of
Tenant's Parking Notice, and provided that no Event of Default shall have
occurred and be continuing under this Lease or that Tenant is not otherwise in
default in the performance of any of the terms, covenants or conditions
contained in this Lease, Landlord will endeavor to implement alternative
measures in order to address the shortage described in Tenant's Parking Notice,
which measures may include: (i) designating a specific area of the Parking
Garage for Tenant's Share of Parking Spaces; (ii) allowing Tenant to tandem park
on a designated level in the Parking Garage; or (iii) initiating a valet parking
program. All Landlord's reasonable costs and expenses incurred in connection
with implementing and maintaining any alternative parking management procedures
under this Section 2.7.1 shall be payable by Tenant as other additional rent.
Landlord shall not be required to (i) implement any measure that violates Legal
Requirements; or (ii) implement any measure that would result in a violation of
the permits and approvals for the Complex.

     Section 2.8. Transportation Services of the Complex. Tenant shall, subject
to seating availability, also have the right to use the limited transportation
services provided by Landlord from the Complex to Harvard Square in Cambridge,
Massachusetts. Two shuttle buses shall operate, continuously between the Complex
and Harvard Square during Business Days between the hours of 7:00 a.m. and 8:00
p.m., and a third shuttle bus shall operate between the Complex to Harvard
Square during Business Days between the hours of 7:00 a.m. and 9:00 a.m. The
shuttle buses shall operate substantially in accordance with the schedule
attached hereto as Exhibit L subject to weather and traffic conditions. In
addition, Tenant shall have the right, exercisable by delivery of notice to
Landlord at any time prior to July 1, 2005, to request that Landlord add a
fourth shuttle bus. Within 60 days of receipt of Tenant's notice, Landlord will
cause to be added a fourth shuttle bus to operate between 7:00 a.m. and 9:00
a.m. substantially in accordance with the schedule attached hereto as Exhibit
L-1, subject to weather and traffic conditions. The costs and expense of
operating the fourth shuttle bus for the initial 60 day period shall be paid by
Tenant to Landlord as other additional rent. At the end of the 60 day period,
Landlord shall assess demand for the fourth shuttle bus, and if Landlord
determines that all four shuttle buses are operating at 70% or more occupancy,
then Landlord shall continue operating the fourth shuttle bus, and the costs and
expense of operating such bus shall be included in Complex Operating Costs. If
Landlord at any time after the initial 60 day period determines that all four
shuttle buses are operating at 70% or less occupancy, then Landlord may
discontinue the fourth shuttle bus, unless Tenant by notice to Landlord elects
to pay for the cost and expense of such fourth shuttle bus, in which case the
fourth shuttle bus will be operated until such time as Tenant by notice to
Landlord elect to cease paying for such cost and expense. This Lease does not
affect Landlord's right (without Tenant's request) to add shuttle bus service if
Landlord deems it appropriate based on demand and ridership, and include the
cost and expense thereof in Complex Operating Costs. If over a sustained
representative period of time there is a lessening in demand for the shuttle bus
services, such operations, including the schedule of such operations


                                       8

<PAGE>

may be altered provided Landlord notifies Tenant in writing no less than
fourteen Business Days in advance of such alteration. If over a two-week period
of time there is an increase in demand for the shuttle buses resulting in the
shuttle buses operating at full capacity between the hours of 8:00 a.m. and 9:00
a.m., and provided that such increase in demand is not the result of some
temporary condition, Tenant may thereafter notify Landlord of such increase in
demand, and Landlord, within a reasonable time after recipt of such notice, will
alter such operations to meet the increased demand. No fee shall be charged to
any passenger that boards a shuttle bus operated by Landlord under this Section
2.8, provided that all costs of operating such shuttle bus service shall be
included in Complex Operating Costs.

     Section 2.9. Second Floor Building 311 Premises. The Second Floor Building
311 Premises is currently leased to another tenant (the "EXISTING TENANT").
Existing Tenant is expected to vacate the Second Floor Building 311 Premises on
or before January 1, 2005. Upon Existing Tenant's vacating of the Second Floor
Building 311 Premises, Landlord shall send Tenant a notice stating the date upon
which the Landlord will deliver to Tenant possession of the Second Floor
Building 311 Premises and the Entry Premises, which date shall be no later than
five Business Days after the date that Existing Tenant vacates the Second Floor
Building 311 Premises (the "SECOND FLOOR, LEASE COMMENCEMENT DATE").

          2.9.1. Delayed Delivery Date. If the Second Floor Lease Commencement
Date occurs after January 1, 2005, the Rent Commencement Date with respect only
to portions of the Premises not occupied by Tenant as of July 1, 2005 (the
"Unoccu ied Space "), shall be postponed on a day by day basis for each day
after January 1, 2005 until the Second Floor Commencement Date. For example, if
the Second Floor Lease Commencement Date was January 15, 2005, the Rent
Commencement Date for the Unoccupied Space would be July 15, 2005, but the Rent
Commencement Date for the remaining Premises would be determined in accordance
with the definition of Rent Commencement Date set forth in Section 1.2. If the
Second Floor Lease Commencement Date has not occurred by January 30, 2005,
Landlord agrees to reimburse Tenant for any increase in the cost of Tenant's
Work directly attributable to the delivery of the Second Floor Building 311
Premises after January 1, 2005, provided that Tenant uses reasonable efforts to
minimize any such increased costs ("DELAY COSTS"). If the Second Floor Lease
Commencement Date has not occurred by March 1, 2005, Landlord will deliver to
Tenant a notice promptly thereafter setting forth the estimated Second Floor
Lease Commencement Date ("LANDLORD'S NOTICE"), and Tenant may elect, by delivery
of notice to Landlord within twenty days of Tenant's receipt of Landlord's
Notice, but prior to the Second Floor Lease Commencement Date ("TENANT'S
NOTICE"), to relocate Tenant's data center from the Second Floor Building 311
Premises to another portion of the Premises (the "DATA CENTER RELOCATION").
Tenant's Notice shall include change orders from the General Contractor
reflecting the cost of the Data Center Relocation ("DATA CENTER RELOCATION
COSTS"), and a revised construction schedule evidencing the number of days, if
any, that Tenant's construction schedule will be delayed as a result of the Data
Center Relocation ("DATA CENTER DELAY DAYS"). Landlord agrees to reimburse
Tenant for any Data Center Relocation Costs, provided that Tenant uses
reasonable efforts to minimize any such increased costs. Delay Costs and Data
Center Relocation Costs may be added to any Tenant's Statement submitted in
accordance with Section 5 of the Work Letter, and shall be payable in the same
manner as Landlord's Contribution. In addition, the Rent Commencement Date for
the Unoccupied Space shall be moved back on a day for day basis for each Data
Center Delay Day. For example, if the Data


                                       9

<PAGE>

Center Relocation results in 15 Data Center Delay Days, the Rent Commencement
Date for the Unoccupied Space would be July 15, 2005. Notwithstanding anything
herein to the contrary, until the occurrence of the Second Floor Lease
Commencement Date, the defined terms "Tenant's Share of Parking Spaces",
"Tenant's Operating Costs Share", and "Tenant's Tax Share" shall be deemed
revised to exclude the Second Floor Building 311 Premises.

     Section 2.10. Ancillary Uses of the Premises. Tenant shall have the right
to use a portion of the Premises for the following ancillary uses, provided such
ancillary uses shall not occupy more than 5% of the Premises: (i) a catered
cafeteria serving only Tenant's employees, business guests and invitees, and
(ii) a store for the sole purpose of selling athenathealth paraphernalia to
Tenant's employees, business guests and invitees.

     Section 2.11. Entry Premises and Terrace Premises. Tenant shall have the
right to use the Entry Premises solely as a reception area for visitors to
Tenant's offices, subject to the rights of other persons in Building 311 to
enter and exit Building 311 by the stairway that is located adjacent to the
Entry Premises. Tenant's use of the Entry Premises shall not at any time
interfere with the rights of others to use the stairway. Tenant shall have the
right to the exclusive use of the Terrace Premises solely as an outdoor terrace
and a seasonal lunch and break area for its employees, guests and invitees. The
Terrace Premises may include tables and chairs and the installation of lighting
and outdoor fixtures, all subject to the prior approval of Landlord pursuant to
the Work Letter. Any excavation or subsurface work in, on, or under the Terrace
Premises shall be performed in compliance with the Environmental Restrictions,
Legal Requirements, and the terms and conditions of this Lease.

                                ARTICLE 3. - RENT

     Section 3.1. Basic Rent. Tenant shall pay the Basic Rent, as set forth in
the table in Section 1.2 of the Lease, annually to Landlord during the Lease
Term commencing on the Rent Commencement Date, by equal monthly installment
payments in advance, on each Rent Payment Day. If the Rent Commencement Date
does not occur on the first day of a calendar month, the first monthly
installment of Basic Rent shall be appropriately prorated. If the Lease
Expiration Date does not occur on the last day of a calendar month, the
installment of Basic Rent for such partial month shall be prorated.

          3.1.1. Lease Year Defined. The term "LEASE YEAR" shall mean the period
running from the Lease Commencement Date to the first anniversary of the Rent
Commencement Date, and thereafter, a Lease Year shall mean each successive
year-long period commencing on an anniversary of the Rent Commencement Date.

          3.1.2. Late Payments, Additional Rent. If any installment of Rent is
not received by Landlord by the tenth day after the due date then, in such
event, as a late charge and as other additional rent hereunder, Tenant shall pay
to Landlord, together with such installment or payment an amount equal to five
percent of the installment of Rent that was not paid when due (the "LATE PAYMENT
PENALTY"). If any installment of Rent is not received by Landlord by the
thirtieth day after Tenant's receipt of a default notice from Landlord (the
"INTEREST GRACE PERIOD END DATE") then, in such event, as other additional rent,
Tenant shall pay to Landlord, together with such installment or payment and Late
Payment Penalty, interest on the unpaid


                                       10

<PAGE>

installment or payment at the Involuntary Rate, computed from the Interest Grace
Period End Date through the date that the installment or payment is received by
Landlord; provided, however, if Landlord sends two such default notices to
Tenant during the Lease Term, thereafter interest shall accrue on any unpaid
installment of Rent at the Involuntary Rate from the due date of such
installment until the date such installment is paid to Landlord. Tenant shall
not be required, however, to pay interest at a rate prohibited by applicable
law.

          3.1.3. Other Additional Rent. Unless otherwise expressly stated
herein, all payments due to Landlord from Tenant under this Lease, other than
Basic Rent and Additional Rent, are deemed to be "OTHER ADDITIONAL RENT."
Wherever in this Lease payments due Landlord from Tenant are other additional
rent, the same shall be due and payable in full on the next Rent Payment Day
except that one-time or non-recurring items that are charged as other additional
rent shall be due on the later to occur of thirty days after the date of written
demand or the next Rent Payment Date, unless otherwise expressly stated.

     Section 3.2. Expense Allocation. Tenant shall pay to Landlord as Additional
Rent with respect to each Lease Year, the Expense Allocation, as such term is
described in this Section 3.2.

     NOTWITHSTANDING REFERENCE IN THIS SECTION 3.2 OR IN ANY OTHER PROVISION OF
     THIS LEASE TO A COST, EXPENSE, OR DISBURSEMENT PAID BY OR INCURRED BY
     LANDLORD, LANDLORD SHALL HAVE NO OBLIGATION TO INCUR THE COST (OR TO
     PERFORM THE WORK OR OBLIGATION WITH REGARD THERETO) UNLESS SPECIFICALLY AND
     EXPRESSLY SET FORTH IN ARTICLE 9 OR OTHER PROVISION OF THIS LEASE.

     The following definitions are applicable to Section 3.2:

     "FISCAL YEAR": Landlord's fiscal year used for accounting purposes, being
Year-long periods beginning on July 1 and ending on the following June 30.

     "BASE COST YEAR": Fiscal Year 2006, commencing on July 1, 2005.

     "COST YEAR": A Fiscal Year for which the Expense Allocation is applicable.

     "TENANT'S OPERATING COSTS SHARE": 100% of Building Operating Costs for
Building 97 and 30.76% of Building Operating Costs for Building 311 (the
percentage calculated by dividing the rentable square feet of the Building 311
Premises (112,616) by the rentable square feet of Building 311 (366,112)).

     "EXPENSE ALLOCATION" shall mean, with respect to each Cost Year during the
Lease Term, an amount equal to Tenant's Operating Costs Share of the increase in
Building Operating Costs for such Cost Year over the Building Operating Costs
for the Base Cost Year.

     "INITIAL EXPENSE ALLOCATION" shall mean one-twelfth of Landlord's estimate
of Tenant's Operating Costs Share of the increase in Building Operating Costs
for Fiscal Year 2006 over the Building Operating Costs for the Base Cost Year.
Landlord shall provide Tenant with the amount of the Initial Expense Allocation
at least thirty days prior to the one-year anniversary of the Rent Commencement
Date.


                                       11

<PAGE>

          3.2.1. Expense Allocation Proration. The Expense Allocation will be
prorated for any partial Cost Year occurring within the Lease Term, or that
exists as a result of the earlier termination of this Lease.

          3.2.2. Complex Operating Costs Defined. "COMPLEX OPERATING COSTS"
shall include, without limitation, all expenses, costs, and disbursements of
every kind and nature (and taxes thereon (excluding any income taxes) that
Landlord shall pay or become obligated to pay during the Cost Year in question)
in connection with (i) the repair, safety, management, ownership, operation,
cleaning, equipping, protecting, insuring, lighting, repainting, and maintenance
of the Common Facilities, including the Parking Garage and the management
office, but exclusive of the Building and exclusive of the other buildings in
the Complex; (ii) the cost of operating any amenities in the Complex available
to all tenants of the Complex, including, without limitation, the Art/Theatre
Center Costs, transportation services, and any subsidy provided by Landlord for
or with respect to any such amenity; and (iii) the cost to maintain and repair
buildings within the Complex that are used exclusive by or partially in common
by all tenants or by Landlord or Landlord's agents in the management of the
Complex, including, without limitation, the Parking Garage, and the management
office. Complex Operating Costs include the following expenses, costs,
expenditures, and disbursements as calculated and reasonably allocated by
Landlord: salaries, but not for anyone above the level of property manager,
wages, and bonuses paid to, and any hospitalization, medical, surgical, union,
and general welfare benefits, group life insurance, pension, retirement, or life
insurance plans, and other benefits or similar expenses (collectively, "WAGES")
relating to employees of Landlord (or employees, agents, contractors,
subcontractors, or others whose Wages are chargeable to Landlord) engaged solely
in the operation, repair, safety, management, security, or maintenance of the
Complex or in the provision of any services provided to tenants or occupants of
the Complex, and social security, unemployment insurance contributions, and
other payroll taxes and disability and workmen's compensation coverage imposed
by any governmental law or regulation, union contract, or otherwise, with
respect to such employees; the cost of any management office maintained by
Landlord or Landlord's agents solely for and with respect to the management of
the Complex; the cost of gas, steam, water, sewer, heat, air conditioning,
ventilation, and other fuel and utilities, and the cost of electricity and
lighting furnished to the common areas of the Complex; the cost incurred by
Landlord in connection with any change of any company providing electricity
service, including maintenance, repair, installation, and service costs
associated therewith; the cost, premiums, and charges for public liability,
property damage, fire and extended coverage, rent, liquor liability, fidelity,
worker's compensation, boiler, plate glass, and any other insurance carried by
Landlord with respect to the Complex; and the costs of snow, ice, trash, and
rubbish removal; the cost of exterior landscaping, lawn mowing, hedge trimming,
fertilizing, replacing shrubs and other vegetation, seeding, weeding, sodding,
watering, and caring for the Complex; and the cost of cleaning, repairing,
maintaining, and replacing any sidewalks, driveways, and curbs adjacent to the
Complex; the cost of hand tools and other movable equipment used in the
operation, cleaning, repair, safety, management, security, or maintenance of the
Complex (collectively, the "TOOL EXPENSE"), provided that if the cost of all or
any portion of the Tool Expense should, in accordance with generally accepted
accounting principles, be depreciated or amortized rather than expended in the
Cost Year incurred, the Tool Expense or such portion thereof, shall be
depreciated or amortized, as the case may be, on a straight-line basis over its
useful life, with an interest factor equal to the Prime Rate plus two percentage
points (2.00%) existing at the time the Tool Expense or such portion is


                                       12

<PAGE>

incurred; the cost of rental of any tools and equipment; the cost of all repair,
and cleaning supplies and materials; the cost of uniforms, work clothes, and
laundering and dry cleaning; and the cost of telephone, computing, copying,
office supplies, and stationery; the cost of cleaning, guard, watchman, security
personnel, security service, or security system for the Complex; the cost of all
management, maintenance, alarm service, janitorial, elevator maintenance, window
cleaning, rubbish removal, landscaping service, and other service agreements;
and the charges of independent contractors and consultants performing work
included within this definition of Complex Operating Costs, including any
contractors or consultants performing work with respect to the furnishing of
electrical energy to the Complex or the computation of the cost thereof,
reasonable and customary management fees as may be charged by Landlord or
Landlord's managing agent; legal, accounting (including data processing
charges), auditing expenses only for the audit of operating expenses, and other
professional fees and disbursements incurred in connection with the ownership,
operation, and management of the Complex; the cost of applying for and pursuing
abatements of Real Estate Taxes; local association fees and dues; and the costs
of obtaining licenses and permits and making required filings with governmental
and financing entities; and the cost of capital expenditures for the common
areas of the Complex made (i) to maintain the condition of the Complex as a
first-class office park in suburban Watertown; or (ii) by reason of any Legal
Requirement or any Insurance Requirement, and the cost of capital expenditures
for the common areas of the Complex made that are intended or expected to reduce
or moderate the Complex Operating Costs may be added into.Complex Operating
Costs for the Cost Year in which incurred and in subsequent Cost Years, by
amortization on a straight-line basis over the estimated useful life of such
item as reasonably determined by Landlord in accordance with generally accepted
accounting principles, consistently applied, in effect at the time the capital
expenditure is incurred, with an interest factor equal to the Prime Rate plus
two percentage points (2.00%) existing at the time of the expenditure.
Notwithstanding the foregoing sentence, if Landlord reasonably concludes on the
basis of engineering estimates that a particular capital expenditure will effect
savings in Complex Operating Costs including, without limitation, energy-related
costs, and that such projected savings will, on an annual basis ("COMPLEX
PROJECTED ANNUAL SAVINGS"), exceed the amortization or depreciation of such
capital expenditure computed as aforesaid, then and in such events, for the
purposes of determining Complex Operating Costs, the depreciation or
amortization of such capital expenditure shall be accelerated to reflect an
annual amount equal to the Complex Projected Annual Savings; and in such
circumstances, the increased depreciation or amortization (in the amount of the
Complex Projected Annual Savings) shall be made for such period of time as it
would take to fully amortize the cost of the capital item in question, together
with interest as aforesaid. The allocation of Complex Operating Costs among the
various buildings in the Complex shall be on the basis of the ratio of the total
rentable square feet of each building in the Complex to the Rentable Square Feet
of the Complex.

          3.2.3. Building Operating Costs Defined. "BUILDING OPERATING COSTS"
shall include, without limitation, all expenses, costs, and disbursements of
every kind and nature (and taxes thereon (excluding any income taxes) that
Landlord shall pay or become obligated to pay during the Cost Year in question)
in connection with (i) the repair, safety, management, ownership, operation,
cleaning, equipping, protecting, lighting, painting, decorating, heating, air
conditioning, ventilating, and maintenance of the Buildings, and (ii) with
respect to Building 311, the costs of interior landscaping and elevator service,
and the provision of any services to tenants and occupants of Building 311.
Building Operating Costs include the cost of capital


                                       13

<PAGE>

expenditures for the Buildings made (i) to maintain the Buildings or (ii) by
reason of any Legal Requirement effective subsequent to the Lease Commencement
Date or any Insurance Requirement, and the cost of capital expenditures made
that are intended or expected to reduce or moderate the Building Operating Costs
may be added into Building Operating Costs for the Cost Year in which incurred
and in subsequent Cost Years, by amortization on a straight-line basis over the
estimated useful life of such item as reasonably determined by Landlord in
accordance with generally accepted accounting principles, consistently applied,
in effect at the time the capital expenditure is incurred, with an interest
factor equal to the Prime Rate plus two percentage points (2.00%) existing at
the time of the expenditure. Notwithstanding the foregoing sentence, if Landlord
reasonably concludes on the basis of engineering estimates that a particular
capital expenditure will effect savings in Building Operating Costs including,
without limitation, energy-related costs, and that such projected savings will,
on an annual basis ("BUILDING PROJECTED ANNUAL SAVINGS"), exceed the
amortization or depreciation of such capital expenditure computed as aforesaid,
then and in such events, for the purposes of determining Building Operating
Costs, the depreciation or amortization of such capital expenditure shall be
accelerated to reflect an annual amount equal to the Building Projected Annual
Savings; and in such circumstances, the increased depreciation or amortization
(in the amount of the Building Projected Annual Savings) shall be made for such
period of time as it would take to fully amortize the cost of the capital item
in question, together with interest as aforesaid. A portion of Complex Operating
Costs shall be included in Building Operating Costs in accordance with Section
3.2.2, provided that no cost is counted in both Complex Operating Costs and in
Building Operating Costs.

          3.2.4. Exclusions from Operating Costs. Notwithstanding anything to
the contrary set forth in the Lease, neither Complex Operating Costs nor
Building Operating Costs (collectively, "OPERATING COSTS") shall include the
following:

               (i) Any ground lease or underlying lease rental;

               (ii) Bad debt expenses and interest, principal, points and fees
on debts or amortization on any mortgage or other debt instrument encumbering
the Complex;

               (iii) Costs incurred by Landlord to the extent that Landlord is
reimbursed by insurance proceeds or is otherwise reimbursed by third-parties or
by other tenants;

               (iv) Depreciation, amortization, interest payments, or capital
expenditures, except as permitted in Sections 3.2.2, and 3.2.3;

               (v) Marketing costs, including lease commissions, attorneys' fees
(in connection with the negotiation and preparation of letters of intent,
leases, subleases and/or assignments), space planning costs, and other costs and
expenses incurred in connection with lease, sublease and/or assignment
negotiations and transactions with present or prospective tenants or other
occupants of the Complex, and costs incurred with respect to the installation of
other tenants' improvements;

               (vi) Expenses in connection with the enforcement of Landlord's
rights against Tenant or other tenants and occupants of the Complex;


                                       14

<PAGE>

               (vii) Costs incurred in connection with the sale, financing or
refinancing of the Buildings;

               (viii) Accounting costs for either the owner or property, IT
support, human resources support, or any other home office costs of the owner or
property manager, not related solely to the on-site operation of the Complex;

               (ix) Fines, interest, and penalties incurred due to the late
payment of real estate taxes, Complex Operating Costs, or Building Operating
Costs;

               (x) Expenses in connection with services or other benefits that
are not offered to Tenant or for which Tenant is charged for directly;

               (xi) Organizational expenses associated with the creation- and
operation of the entity which constitutes Landlord;

               (xii) Charitable contributions or other donations greater than
$5,000.00 in the aggregate per Cost Year;

               (xiii) Expenses in connection with the construction of new
buildings at the Complex; and

               (xiv) Expenses resulting from Landlord's gross negligence or
willful misconduct.

          3.2.5. Method of Payment. Payment of the Expense Allocation is
described below.

               3.2.5.1. Initial Method of Payment. Commencing on the one-year
anniversary of the Rent Commencement Date, Tenant shall pay one-twelfth of each
of the Initial Expense Allocation until Landlord furnishes to Tenant an Annual
Operating Estimate as described below.

               3.2.5.2. Annual Operating Estimate. Landlord will, within ninety
days of the end of each Fiscal Year after the Base Cost Year, furnish to Tenant
a written estimate ("ANNUAL OPERATING ESTIMATE") of the Building Operating Costs
for each of the Buildings and Expense Allocation for the current Fiscal Year.
During such Fiscal Year, commencing on the first day of the first calendar month
of the Fiscal Year after the Base Cost Year, Tenant shall pay each month on the
Rent Payment Day one-twelfth of the estimated Expense Allocation until Tenant
receives another Annual Operating Estimate. If the Annual Operating Estimate
shall be furnished to Tenant after the commencement of a Fiscal Year, then
Tenant shall promptly pay to Landlord an amount equal to the portion of such
increase allocable to the part of the current Cost Year that shall have elapsed,
and such payment shall be made within thirty days following the date that the
Annual Estimate is furnished to Tenant. At any time during a Cost Year (but no
more frequently than quarterly), Landlord shall be entitled to update and revise
the Annual Operating Estimate if there is an increase in the Building Operating
Costs during the Cost Year.


                                       15
<PAGE>

               3.2.5.3. Occupancy of Building and Complex. If the actual
percentage of occupancy of Building 311 or the Complex is less than one hundred
percent for any Cost Year, including the Base Cost Year, the Operating Costs
incurred shall be reasonably projected by Landlord to be the estimated Operating
Costs that would have been incurred if Building 311 and the Complex were one
hundred percent occupied for such Cost Year (with all tenants paying full rent,
as contrasted with free rent, half rent, or like rent concession), and with such
services and utilities being supplied to all tenants, and such projected amount
shall be included in Operating Costs for such Cost Year.

               3.2.5.4. Year-End Adjustments. Commencing with the end of the
Base Cost Year, Landlord shall within four months after the end of each Cost
Year furnish to Tenant a statement ("ANNUAL OPERATING STATEMENT") of the actual
Building Operating Costs for each of the Buildings and Complex Operating Costs
and, with respect to each Cost Year after the Base Cost Year, the Expense
Allocation for the Cost Year then ended. Landlord and Tenant shall annually make
such adjustments (described below) as may be necessary based on each such Annual
Operating Statement, so that for each respective Cost Year (a portion thereof in
the case of partial Lease Years, in which case as such amount shall be prorated)
Tenant will have paid the amount of the actual Expense Allocation for the Cost
Year, as follows:

     (a) Underpayment by Tenant. If the Expense Allocation for the Cost Year as
shown on the Annual Operating Statement exceeds the total payments made by
Tenant with respect to estimates of same for the Cost Year, then Tenant shall
pay Landlord the deficiency within thirty days after receipt of the Annual
Operating Statement.

     (b) Overpayment by Tenant. If the Expense Allocation for the Cost Year as
shown on the Annual Operating Statement is less than the total monthly payments
made by Tenant with respect to estimates of same for the Cost Year, Landlord
shall give Tenant a credit (in the amount of such excess) against Rent or other
payments next coming due, unless the Lease has expired, in which case Landlord
shall pay to Tenant, within thirty days of the date of delivery to Tenant of
such Annual Operating Statement, such excess after first deducting for any
unpaid Rent or other claims that Landlord may have against Tenant. If an Event
of Default exists under this Lease when this Lease terminates or expires, then
any adjustment payments to be made by Landlord to Tenant may be reduced by (and
Landlord may retain) any amounts owed by Tenant to Landlord, whether under this
Lease or otherwise.

               3.2.6. Record Keeping. Landlord shall keep full and accurate
books of account covering Operating Costs, and the Annual Operating Statement
shall accurately reflect same and Tenant's share thereof. The books of account
and all supporting documents shall be retained by Landlord for a period of at
least three years after the delivery to Tenant of each Annual Operating
Statement. Unless Tenant sends Landlord Tenant's Audit Notice in compliance with
Section 3.2.7, then Tenant shall be deemed to have waived its right to object to
the calculation of Expense Allocation for the year in question and the
calculation of the Expense Allocation set forth on such statement shall be
final.

               3.2.7. Inspection and Audit Rights. Upon Tenant's written request
given within sixty days after Landlord delivers to Tenant the Annual Operating
Statement ("TENANT'S AUDIT NOTICE"), Tenant shall have the right to inspect or
audit Landlord's books of account and all


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<PAGE>

supporting documents with respect to matters set forth in the Annual Operating
Statement. No audit or inspection shall extend to periods of time before the
Lease Commencement Date. Tenant's audit or inspection shall commence no later
than thirty days after Tenant's Audit Notice, and shall be conducted only at
Landlord's offices or the offices of Landlord's property manager during business
hours reasonably designated by Landlord, and shall be completed no later than,
120 days after Tenant's Audit Notice. However, any unreasonable delays by
Landlord shall extend the permitted time for the audit on a day for day basis.
Tenant shall pay all costs of such audit or inspection. An audit may be made
only by a reputable firm first approved by Landlord, which approval shall not be
unreasonably withheld. As a condition to performing any such inspection or
audit, Tenant and its examiners shall be required to execute and deliver to
Landlord an agreement, in form reasonably acceptable to Landlord, agreeing to
keep confidential any information that it discovers about Landlord, the
Buildings or the Complex in connection with such examination. Tenant may not
conduct an inspection or have an audit performed under this Section 3.2.7 more
than once with respect to any Fiscal Year. Landlord shall keep full and accurate
books of account covering the Building Operating Costs and the Annual Operating
Statement shall accurately reflect same and Tenant's share thereof.

               3.2.7.1. Results of Audit. If Tenant's inspection or audit
reveals an overcharge to Tenant of the greater of (i) more than five percent of
the annual Expense Allocation, and (ii) $1,500.00, then Landlord shall reimburse
Tenant for up to $5,000.00 of the reasonable costs of such audit or inspection
within thirty days of receipt of a reasonably detailed invoice therefor.
Landlord shall refund to Tenant any overpayment of Expense Allocation, and
Tenant shall pay to Landlord any underpayment of Expense Allocation as revealed
by such audit or inspection within thirty days after notification thereof, and
in each instance together with interest at the annual rate of the Prime Rate
plus three percent.

                ARTICLE 4. - REIMBURSEMENT FOR REAL ESTATE TAXES

     Section 4.1. Tenant to Reimburse Landlord for Real Estate Taxes. Tenant
covenants and agrees to pay to Landlord as Additional Rent during the Lease
Term, the Tax Reimbursement in accordance with this Article 4. The following
terms apply:

     (a) "TAX YEAR" means the tax fiscal year commencing on July 1 and ending on
the following June 30. If a taxing authority imposing real estate taxes adopts
some other tax fiscal year, the term "Tax Year" shall, as to that taxing
authority, mean such adopted tax fiscal year, and appropriate adjustments shall
be made by Landlord and Tenant with respect to the transition period.

     (b) "BASE TAX YEAR" means the tax Fiscal Year commencing on July 1, 2004
and ending on June 30, 2005.

     (c) "REAL ESTATE TAXES" means, as to any given Tax Year, the total of all
taxes (excluding any succession, transfer, or gift taxes and any income taxes,
franchise taxes, any taxes on rentals, inheritance taxes, estate taxes, excise
taxes, capital stock taxes, and excluding any penalties or interest incurred by
Landlord due to Landlord's failure to make timely payment of Real Estate Taxes)
and assessments, water, sewer, and other rents, rates, charges, excises, levies,
fees, and all other charges, that are for the Tax Year levied, assessed, or
imposed by any


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<PAGE>

governmental authority, upon, against or with respect to the Complex including
the buildings in the Complex, the Parking Garage, and the land and common areas
of the Complex or rentals, use, or occupancy of the same and, as to any of the
same for the first time levied, assessed, or imposed in the future, whether they
are in replacement, substitution, or addition of or to Real Estate Taxes
theretofore in effect. Landlord agrees to cause betterment assessments to be
paid over the longest period permitted by law, and, as to such betterment
assessments, only installments (together with any interest thereon) coming due
during the Tax Year in question shall be added into "Real Estate Taxes" for such
Tax Year. If during any Tax Year, Landlord makes payments as calculated under
that certain "Memorandum of Understanding with respect to Payment In Lieu of
Taxes," between the Town of Watertown and Landlord dated as of July 1, 2002, as
the same may be amended (the "MOU"), Real Estate Taxes shall mean the aggregate
payment made by Landlord under the MOU in such Tax Year, provided that the Base
Tax Year also includes the aggregate payment made by Landlord under the MOU in
the Base Tax Year.

     (d) "TENANT'S TAX SHARE" 17.98% (the percentage calculated by dividing the
rentable square feet of the Premises (133,616) by the Rentable Square Feet of
the Complex (743,176)). Tenant's Tax Share shall be adjusted proportionately if
the Rentable Square Feet of the Complex is increased or decreased.

     (e) "TAX REIMBURSEMENT" shall mean with respect to each Tax Year during the
Lease Term after the Base Tax Year, an amount equal to Tenant's Tax Share of the
increase in Real Estate Taxes for such Tax Year over Real Estate Taxes for the
Base Tax Year.

     Section 4.2. Payment of the Tax Reimbursement. Landlord shall annually
estimate the Tax Reimbursement and, commencing on the one-year anniversary of
the Rent Commencement Date, one-twelfth of the amount estimated shall be paid on
each Rent Payment Day, whether or not the Real Estate Taxes are due and payable
to the applicable taxing authority. Within sixty days after Landlord furnishes
Tenant with a copy of the bill(s) for real estate taxes for a Tax Year, Landlord
and Tenant shall make an adjustment, with payment to Landlord in the case that
Tenant owes additional amounts to Landlord, or with a credit given by Landlord
to Tenant against the Tax Reimbursement next coming due, so that Landlord shall
receive the entire amount of the Tax Reimbursement with respect to such Tax Year
and no more. If at the end of the Lease Term this Lease shall be in effect for
less than a full Tax Year, the Tax Reimbursement for that Tax Year shall be
prorated based on the number of days this Lease shall be in effect during such
Tax Year. If this Lease expires or is terminated during a Tax Year, the
adjustment referred to above shall occur upon such expiration or termination,
or, if necessary, as soon thereafter as accurate information as to the Real
Estate Taxes for the Tax Year is known, except that Landlord shall refund to
Tenant any such excess payment, but Landlord may deduct from any adjustment due
Tenant, any unpaid Rent or other claims that Landlord may have against Tenant.

     Section 4.3. Abatement. Nothing contained in this Lease shall obligate
Landlord to seek any abatement of Real Estate Taxes. If Landlord shall seek an
abatement (or otherwise contest with a taxing authority the Real Estate Taxes),
and if, after Tenant shall have made a payment to reimburse Landlord on account
of such Real Estate Taxes, Landlord shall receive a refund with respect to a Tax
Year of any portion of the Real Estate Taxes on which such payment shall have
been based, then of the net refund (i.e., the amount of the refund remaining


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<PAGE>

after deducting all expenses (including reasonable attorneys' fees and expenses)
incurred by Landlord in obtaining such refund), Landlord shall grant Tenant a
credit against Rent next coming due in the amount of Tenant's Tax Share;
provided, however, that Landlord need not pay Tenant as aforesaid more than the
amount paid by Tenant to Landlord under Section 4.2 for the Lease Year(s) in
question. If this Lease expires before Tenant realizes the benefit of the total
amount of the credit to which Tenant is entitled under this Section 4.3, then
Landlord shall pay Tenant the amount of the outstanding credit within thirty
days after the expiration of this Lease after first deducting for any unpaid
Rent or other claims that Landlord may have against Tenant, and, if Landlord
receives a refund of Real Estate Taxes after the expiration of this Lease that
would have resulted in a credit to Tenant under this Section 4.3, then Landlord
shall pay to Tenant the amount of such credit within thirty days after the date
that Landlord receives the refund from the taxing authority, after first
deducting for any unpaid Rent or other claims that Landlord may have against
Tenant.

     Section 4.4. Landlord's Right to Recover. Tenant covenants and agrees to
pay the Tax Reimbursement when due as provided in this Article 4, for any breach
of which Landlord shall have the rights and remedies set forth in Article 6.

                             ARTICLE 5. - COVENANTS

     Section 5.1. Tenant's Covenants. Tenant covenants and agrees that during
the Lease Term and such further time as Tenant holds any part of the Premises,
Tenant shall pay or perform, as the case may be, the following as set forth
below:

          5.1.1. Rent and other Payments; Independent Covenant. Tenant covenants
to pay when due (without any offset, deduction, or abatement whatever, except as
provided in this Lease in Section 8.2.3, Section 9.2.2, and Exhibits F and J)
the Rent, including all charges for electricity and other utilities and services
that are delivered or attributable to the Premises. The foregoing covenant of
Tenant is an independent covenant and Tenant shall have no right to withhold or
abate any payment of Rent or other payment, or to set off any amount against the
Rent or other payment then due and payable, except as provided in this Lease in
Section 5.2.2, Section 8.2.3, Section 9.2.2, and Exhibits F and J. Tenant hereby
acknowledges and agrees that it has been represented by counsel of its choice
and has participated fully in the negotiation of this Lease, that Tenant
understands that the remedies available to Tenant in the event of a default by
Landlord may be more limited than those that would otherwise be available to
Tenant under the common law in the absence of certain provisions of this Lease,
and that the so-called "dependent covenants" rule as developed under the common
law (including, without limitation, the statement of such rule as set forth in
the Restatement (Second) of Property, Section 7.1) shall not apply to this Lease
or to the relationship of landlord and tenant created hereunder.

          5.1.2. Care of Premises. Damage by fire, other casualty, eminent
domain, and reasonable wear and use excepted, Tenant covenants to keep the
Premises substantially in as good order, repair, and condition as the same are
in at the commencement of the Initial Lease Term, or may, in accordance with the
terms of this Lease, be put in thereafter, to keep the Premises clean and neat;
and to conform to Landlord's reasonable requests from time to time relating to
the appearance of the Premises, such requests to be reasonably consistent with
keeping the appearance of the Premises to the general standard of the Complex.
The exception


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<PAGE>

of reasonable wear and use contained in this Section 5.1.2 shall not be
construed to permit Tenant to maintain the Premises in anything less than good,
serviceable, and tenantable condition, damage by fire, other casualty or eminent
domain excepted. Tenant shall not cause damage to the Premises or the fixtures
and appurtenances therein, including, without limitation, the Building Systems
and Structural Components, and Tenant shall keep the Premises in a safe and
sanitary condition. Tenant shall not be required to make repairs, alterations,
or replacements to the Building Systems or Structural Components, except that if
such repairs, alterations, or replacements are required due to (i) Tenant's
negligence or wrongful acts or omissions, or (ii) the fact that Tenant has
caused or permitted use of or damage to Building Systems in violation of Legal
Requirements or Insurance Requirements, then in either such case Landlord may
cause such repairs, alterations, or replacements to be performed at Tenant's
sole expense. Tenant shall make, at Tenant's sole expense, all repairs,
alterations, and replacements to any Building Systems that are installed by
Tenant or at Tenant's direction, regardless of the event occasioning the need
therefor.

          5.1.3. Glass. Damage by fire or other insured casualty excepted,
Tenant covenants to keep all interior glass within the Premises, if any,
including that in doors, (but excluding glass that is part of demising walls in
the Building 311 Premises), whole and in good condition, and to replace promptly
any glass that Tenant may damage or break with glass of the same quality.

          5.1.4. Yielding Up of Premises on Termination or Expiration, Security
Interests. Tenant covenants that at the expiration or earlier termination of
this Lease, Tenant shall promptly remove Tenant's personal property, goods and
effects, (including any signage), and peaceably yield up immediately the
Premises (together with any additions and improvements made thereto, except for
items removed by Tenant in accordance with the terms of this Lease), clean, and
in good order, repair, and condition, damage by fire, other casualty, eminent
domain and reasonable wear and use (as described in Section 5.1.2) excepted. All
alterations and fixtures shall be left in the Premises at the expiration of the
Lease Term, except that with respect to alterations installed by Tenant pursuant
to 5.1.9, Landlord may, at the time of approval of such alterations, require
removal of such alterations, and with respect to alterations installed as part
of Tenant's Work, Landlord may require removal of such alterations by the terms
of Landlord's Approval Letter (see Exhibit F). If removal of any alterations or
fixtures or any of Tenant's other goods, effects, personal property or signage
causes any damage (other than minor damage due to removal of artwork,
decorations and work station and data fixtures) to the Premises, Tenant shall
promptly repair same, or, at Landlord's election, pay to Landlord money
sufficient to cover the cost (as reasonably estimated by Landlord) for restoring
the Premises. All goods, effects, or personal property remaining in or on the
Premises after the Tenant vacates the Premises or after the termination or
expiration of this Lease (whichever first occurs) shall be deemed abandoned, and
Landlord shall have the right to remove same at Tenant's expense and use, sell,
or destroy same as Landlord may elect. Tenant shall not grant security interests
in any alterations or fixtures.

          5.1.5. Overloading, Nuisance, Flammables, Increase in Insurance
Premiums. Tenant covenants not to injure, overload the capacity of the Building
Systems and Structural Components, or deface the Premises, the Buildings or any
part of the Complex, nor permit on the Premises any flammable fluids or
chemicals or any nuisance or emission from the Premises of any objectionable
noise or odor, nor permit any use of the Premises that is improper, contrary to


                                       20

<PAGE>

law or ordinance, or liable to invalidate (or increase the premiums for) any
insurance on the Buildings or its contents or liable to render necessary any
alterations or additions to the Buildings. Tenant shall not permit to be
released on the Premises, the Buildings, or any part of the Complex any
Hazardous Materials. If for any reason Tenant's particular manner of use of the
Premises (as opposed to office use generally) results in an increase of the
premiums for the insurance of Landlord, Tenant shall on demand reimburse
Landlord and such other tenants of the Buildings for all such insurance premium
increases.

          5.1.6. No Obstruction; Rules and Regulations. Tenant covenants not to
obstruct in any manner the lobbies, hallways, stairways, elevators, and other
common facilities in Building 311, or the sidewalks or other approaches to the
Buildings or any other Common Facilities of the Complex. Tenant covenants and
agrees to comply with the rules and regulations attached hereto as Exhibit A,
including such amendments thereto as Landlord may reasonably promulgate from
time to time with regard to the care and use of the Premises, the Buildings, the
Complex and the facilities, and approaches thereto. To the extent of any
inconsistencies between the rules and regulations, and the terms of this Lease,
the express terms of this Lease shall govern.

          5.1.7. Compliance with Laws: Safety; Health. Tenant covenants to keep
the Premises in a safe and sanitary condition and to comply with and to keep the
Premises in compliance with, all Legal Requirements and Insurance Requirements
now or hereafter existing that are required by or arise as a result of the
particular use made of the Premises by Tenant (as opposed to office use
generally). Without limiting Tenant's obligations existing under any other
provision of this Lease, if required by the foregoing sentence, Tenant covenants
and agrees to make all required repairs, alterations, replacements, or additions
in and to the Premises and to install any required devices or equipment.
Landlord represents and covenants that the Premises, and access thereto, are in
compliance with the Americans with Disabilities Act, 42 U.S. Code 12101 et seq.,
as it may be amended from time to time ("ADA") as of the Lease Commencement
Date. If any of Tenant's Work or any other work in the Premises performed by
Tenant, including any Construction Work, triggers the need for other alterations
under either the ADA or other Legal Requirement, such alterations shall be
performed by Tenant (or by Landlord, at Landlord's election, if the alterations
are needed in areas of Building 311 other than the Building 311 Premises) in
either case at Tenant's expense. Tenant is responsible for obtaining all permits
and licenses from Governmental Authorities that are needed for Tenant to use the
Premises.

          5.1.8. No Assignment or Subletting. As used in this Lease "SUBLETTING"
includes transactions creating or resulting in one or more subleases,
tenancies-at-will, licenses, concessions, or other occupancy arrangements. The
instrument evidencing the Subletting is referred to herein as the "SUBLEASE".
Except as permitted in Section 5.1.8.8 below, Tenant covenants not to engage in,
or permit the assignment, transfer, mortgage, alienation, or pledge
(collectively "ASSIGNMENT") of this Lease or any interest therein, nor engage
in, or permit any Subletting of all or any part of the Premises, nor suffer any
of the foregoing to occur, without Landlord's prior written approval in each
instance. Landlord agrees that, subject to the provisions of this Section 5.1.8,
including satisfaction of the conditions set forth in Section 5.1.8.5, and
subject to Landlord's rights under Section 5.1.8.2 below, Landlord will not
unreasonably withhold or delay its consent to a Subletting or Assignment and
shall notify Tenant in writing of its consent or refusal to consent within
eleven business days of receipt of Tenant's written notice


                                       21

<PAGE>

to assign or sublet, such notice shall identify (i) the space to be sublet, (ii)
the period of the sublet, and (iii) financial information for the proposed
subtenant in form satisfactory to Landlord. Notwithstanding anything contained
herein to the contrary, Landlord shall not be deemed to have acted unreasonably
in its election not to consent to any such action on the part of Tenant because
(i) an Event of Default shall have occurred and be continuing under this Lease
or Tenant shall otherwise be in default in the performance of the terms,
covenants or conditions contained in this Lease, (ii) the proposed assignee or
sublessee (the "PROPOSED TENANT") shall be an existing tenant or occupant of the
Complex, (iii) such assignment or subletting shall cause Landlord to be in
breach of any "exclusive use" or similar provision contained as of the Lease
Commencement Date in any other lease for space in the Complex, (iv) in the
reasonable judgment of Landlord, (x) the Proposed Tenant is of a character or is
engaged in a business that would be deleterious to the reputation of the
Complex, or (y) the Proposed Tenant is not sufficiently financially responsible
to perform its obligations under any such Assignment or Subletting, except that
the foregoing shall not be a condition to the approval of a Subletting for five
percent or less of the total rentable square feet of the then current Premises,
and for a term of five years or less, and, or (z) the Proposed Tenant or any of
its partners, members, shareholders, employees or affiliates, or the business
conducted by any of them, could pose a security risk for the Complex and/or its
occupants, (v) the Proposed Tenant is a Governmental Authority; (vi) the portion
of the Premises which Tenant proposes to Sublease including the means of ingress
and egress thereto and the proposed use thereof, and the remaining portion of
the Premises will violate any Legal Requirement, and (vii) the Proposed Tenant
is a party with whom Landlord is then negotiating a lease for space in the
Complex; provided, however, that the foregoing are merely examples of the
reasons for which Landlord may reasonably not consent to any such actions by
Tenant and shall not be deemed exclusive of any reason for reasonably making
such election, whether similar or dissimilar to the foregoing examples.

               5.1.8.1. Transfers of Interests in Tenant. Except for transfers
per Section 5.1.8.8, if at any time while this Lease is in effect, Tenant is a
corporation (excluding a corporation the outstanding voting stock of which is
listed on a recognized securities exchange), a trust (whether or not having
shares of beneficial interest), a partnership or association, or otherwise not a
natural person, and there shall occur any transfer (by one or more transfers) of
a controlling portion of or controlling interest in the stock, partnership,
membership, or beneficial interest, or other evidences of equity interests or
voting interest of Tenant, such change in identity shall also constitute an
Assignment for the purposes of this Section 5.1.8. The foregoing prohibition
against Assignment and Subletting shall include voluntary and involuntary
Assignment and Subletting, and Assignment and Subletting by operation of law,
including corporate mergers or consolidations, and (if Tenant is a corporation
or other entity) shall include Assignment of the controlling interest in the
Tenant, except that transfers of stock or membership interests of Tenant (or
other equity interest(s) tantamount to an equity interest) to members (who are
not under a legal disability so as to prevent such member from performing the
transferor's obligations) of the immediate families of the substantial owners of
Tenant shall be permitted if they occur either (a) by inter vivos transfer if
the transferor gives fourteen days prior written notice to Landlord of the
proposed transfer including with the notice true copies of all documents that
will evidence the transfer, the name, address, and family relationship of the
proposed transferee, and information in such detail as Landlord may request
about the transferee's creditworthiness and business experience or (b) by the
terms of the duly probated will of the transferor.


                                       22

<PAGE>

               5.1.8.2. Landlord's Recapture Right. (a) Tenant shall, prior to
offering or advertising (i) an Assignment, (ii) a Subletting of more than 40% of
the Premises, or (iii) a Subletting that when combined with other Subleases in
effect (but excluding Permitted Subleases), would result in more than 50% of the
Premises being sublet, give a written notice (the "RECAPTURE NOTICE") to
Landlord which: (i) states that Tenant desires to sublet all or any portion of
the Premises or assign its interest in the Lease, (ii) identifies the affected
portion of the Premises (the "RECAPTURE PREMISES"), (iii) identifies the period
of time (the "RECAPTURE PERIOD") during which Tenant proposes to sublet the
Recapture Premises or to assign its interest in the Lease, and (iv) offers to
Landlord the election either to terminate the Lease with respect to the
Recapture Premises, or to suspend the term of the Lease for the same period of
time as the Recapture Period (i.e., the term of the Lease in respect of the
Recapture Premises shall be terminated during the Recapture Period and Tenant's
rental obligations shall be reduced in proportion to the ratio of the total
rentable area of the Recapture Premises to the total rentable area of the
Premises then demised to Tenant). Landlord shall have fifteen Business Days from
Landlord's receipt of a Recapture Notice within which to respond to Tenant.

     (b) If Tenant does not enter into a Subletting or Assignment on the terms
and conditions contained in the Recapture Notice on or before the date which is
ninety days after the date of the Recapture Notice, then prior to entering into
any Subletting or Assignment after such ninety day period, Tenant must deliver
to Landlord a new Recapture Notice in accordance with Section 5.1.8.2(a) above.

     (c) If Landlord does not timely give written notice to Tenant accepting a
Recapture Offer or declines to accept the same, then Tenant may, subject to the
provisions of this Section 5.1.9, including satisfaction of the conditions set
forth in Section 5.1.9.5, enter into such Subletting or Assignment.

               5.1.8.3. Listing of Names. The listing of any name other than
that of Tenant, whether on the doors of the Premises or on a Building directory,
or otherwise, shall not operate to vest in any such other person, firm, or
corporation any right or interest in the Lease or in the Premises or be deemed
to effect or evidence any consent of Landlord, it being expressly understood
that any such listing is a privilege extended by Landlord revocable at will by
Landlord by written notice to Tenant.

               5.1.8.4. Additional Rent from Assignment or Subletting. Except
for Subletting or Assignment to Affiliates under Section 5.1.8.8, Tenant shall,
within thirty days of receipt thereof, pay to Landlord as other additional rent,
one hundred percent of any rent, sum, and other consideration to be paid or
given in connection with any Subletting or Assignment, either initially or over
time, after deducting the Deductible Costs in excess of Basic Rent attributed to
the portion of the Premises being sublet or assigned, as if such amount were
originally called for by the terms of this Lease. The term "DEDUCTIBLE COSTS"
shall mean (A) reasonable documented actual out-of-pocket expenses paid for (i)
legal services, including those incurred by Landlord and reimbursable pursuant
to Section 5.1.8.9, (ii) brokerage fees and (iii) advertising expenses,
architectural, engineering, third party project manager, and space planning
fees, Tenant improvements, cost of removal or installation of interior walls or
partitions, each as incurred by Tenant in connection with the Subletting or
Assignment, and (B) reasonable actual out-of-pocket construction costs necessary
in connection with the


                                       23

<PAGE>

Subletting or the Assignment, including costs of constructing demising walls
necessary to demise the subleased space from the Premises.

               5.1.8.5. Conditions to Subletting or Assignment. Notwithstanding
any contrary provision of this Lease, Tenant shall have no right to enter into a
Subletting or Assignment unless on both (i) the date on which Tenant notifies
Landlord of its intention to enter into a Subletting or Assignment and (ii) the
date on which such Subletting or Assignment is to take effect, no Breach or
Event of Default exists that, in either case, has not been cured. Any attempted
Assignment or Subletting in violation of any of the provisions of this Lease
shall be void; provided however that once Landlord consents in writing to an
Assignment or Subletting, such Assignment or Subletting cannot thereafter be
deemed void by reason of a Breach or Event of Default of Tenant existing on
either of the dates set forth in the preceding sentence. No Assignment or
Subletting shall in any way impair the continuing primary liability of Tenant
hereunder (which after any such Assignment or Subletting shall be joint and
several with the persons claiming under the Assignment or Subletting).

               5.1.8.6. Additional Provisions for Assignment. No Assignment
shall be effective unless and until Tenant delivers to Landlord duplicate
originals of the instrument of assignment (wherein the assignee assumes the
performance of Tenant's obligations under this Lease provided, however, such
assumption shall not relieve or reduce Tenant's obligations under this Lease)
and all related documents. In the event of an Assignment, Landlord and the
assignee thereunder may modify this Lease in any manner, without notice to
Tenant and without Tenant's prior consent; provided, however, that Tenant shall
not be liable for any such modified obligations.

               5.1.8.7. Additional Provisions for Subletting. No Subletting of
all or any part of the Premises shall be effective unless and until Tenant
delivers to Landlord duplicate originals of the Sublease and of all related
documents. Tenant shall also deliver to Landlord true, correct and complete
copies of any letters of credit held by Tenant under such Sublease. Any cash
security deposits held by Tenant under any Sublease shall be deposited into
trustee accounts and Tenant shall provide Landlord with the applicable account
information prior to commencement of the term of such Sublease. The term of any
Subletting shall expire no later than one day prior to the Lease Expiration
bate. Any Subletting shall (a) be subject and subordinate to this Lease; (b)
contain a provision prohibiting the subtenant from assigning the Sublease or
subletting all or any part of the subleased premises except in accordance with
the terms of this Lease; and (c) include an agreement by the subtenant and
Tenant that in the event this Lease is terminated, such subtenant shall, at
Landlord's request, attorn to Landlord on the terms of the Sublease, and the
letters of credit and cash deposits held in trustee accounts shall be delivered
in full to Landlord, and in such event such Sublease shall remain in full force
and effect between Landlord and such subtenant as if the Lease had not been
terminated, and such subtenant shall promptly execute such documents as Landlord
shall reasonably request.

               5.1.8.8. Affiliates. Notwithstanding the third sentence in
Section 5.1.8 or anything to the contrary in Section 5.1.8.1, Tenant may enter
into a Subletting or Assignment to Affiliates (as defined below) without
Landlord's consent, provided, however, that (i) Tenant must provide Landlord
with prior written notice of any proposed Subletting or Assignment to
Affiliates, and such notice shall include as an attachment a copy of the
proposed Sublease or


                                       24

<PAGE>
Confidential Materials omitted and filed separately with the Securities and
Exchange Commission. Asterisks denote omissions.

Assignment and a description of the relationship between Tenant and the
Affiliate, (ii) in all events Tenant shall remain primarily liable hereunder,
and (iii) the Affiliate must be capitalized sufficiently to meet the assignee or
subtenant obligations under the Assignment or Subletting as evidenced by a
recent financial statement prepared consistently with Tenant's Financial
Statement. Any Subletting or Assignment to an Affiliate will be subject to the
terms and provisions of this Section 5.1.8. The term "AFFILIATES" shall mean an
entity that is controlled by, is under common control with, or which controls
athenahealth, Inc. For the purposes of this Section, "control" shall mean the
ownership of more than fifty percent of the beneficial interest of the entity in
question, together with rights to exercise more than fifty percent voting
control over the entity. Tenant agrees to promptly provide Landlord with all
documentation reasonably requested by Landlord evidencing the relationship
between Tenant and the Affiliates, and current financial statements for the
Affiliate. Tenant may enter into an Assignment of the Lease to any successor of
Tenant by merger, consolidation or acquisition of all or substantially all the
stock or assets of Tenant; provided that (A) Tenant shall deliver to Landlord
reasonable advance notice of any such Assignment, (B) the net worth of Tenant's
successor (determined in accordance with generally accepted accounting
principles) immediately after such merger, consolidation or sale is equal to or
greater than Tenant's net worth as of the Lease Commencement Date; and (C) any
such Assignment shall comply with the terms and conditions in Sections 5.1.8.6,
and 5.1.8.9.

               5.1.8.9. Landlord's Expense. Tenant shall pay to Landlord,
promptly upon demand therefor, all reasonable costs and expenses (including,
without limitation, reasonable attorneys' fees and disbursements) incurred by
Landlord in connection with any Assignment or Subletting, provided that in no
event shall Tenant be liable to pay Landlord in excess of $* per assignment
or subletting under this Section 5.1.8.9.

          5.1.9. Landlord's Consent Required for Tenant's Alterations. Tenant
covenants not to make in or to the Premises or the Buildings any construction
work, alterations, or additions, or any holes in the walls, partitions,
ceilings, or floors or to paint or place therein or thereon any signs or to
place therein or thereon any awnings, aerials, flagpoles, or the like, or
install data/telecommunications cabling and related equipment in any area
outside of the Premises (collectively, "CONSTRUCTION WORK") without on each
occasion obtaining the prior written consent of Landlord. Landlord's consent
shall not be required in connection with hanging works of art or other
decorative items on wall or partitions. In addition, Tenant may make
non-structural alterations affecting only the interior of the Premises, and not
affecting Building Systems, costing less than $50,000 in any one instance (or in
the aggregate with respect to related alterations) without Landlord's prior
written consent but with prior written notice to Landlord and subject to the
provisions of this Lease, including this Section 5.1.9 (collectively, "PERMITTED
ALTERATIONS"). Landlord's consent and approval under this Section 5.1.9 shall
not be unreasonably withheld, conditioned or delayed, including any proposed
installation of tel/data cabling; except that any alterations or additions
affecting Structural Components or Building Systems, or visible from outside of
the Premises, or affecting the exterior of the Buildings or the Common
Facilities, shall be determined by Landlord in its sole discretion. Landlord's
consent may be subject to reasonable conditions deemed appropriate by Landlord,
including review of plans and specifications, reasonable approval of the
contractors and subcontractors, and architect's certificate that the work
complies with Legal Requirements, an architect's certificate of completion, and,
if required by Legal Requirements, a certificate of the city building inspector
of final completion. Tenant covenants to cause any Construction Work to be
performed


                                       25

<PAGE>

expeditiously, with first-class workmanship and materials and in compliance with
all applicable Legal Requirements and Insurance Requirements; to pay for the
same when due; to remove promptly (and not later than twenty-five days in any
event), or bond to Landlord's satisfaction, any materialmen's or mechanics liens
filed in connection therewith; and to save Landlord harmless and indemnified
from all injury, loss, claims, costs, or damage to any person or property
occasioned by or growing out of such Tenant Construction Work. If Landlord deems
it appropriate to supervise any of the Construction Work other than Tenant's
Work, Tenant shall pay the costs and expenses of such supervision, not to exceed
three percent of the cost of the Construction Work. Tenant shall cause
contractors employed by Tenant to carry worker's compensation insurance in
accordance with statutory requirements and commercial general liability
insurance and automobile liability insurance covering such contractors on or
about the Premises, and such other appropriate insurance coverage as Landlord
may require, in such reasonable amounts as Landlord shall reasonably require,
and Tenant shall submit certificates evidencing such coverage to Landlord before
the commencement of such Construction Work. Nothing in this Section 5.1.9 shall
be deemed to waive the requirement that Tenant obtain Landlord's prior written
consent to any such Construction Work except as otherwise set forth herein.
Tenant will provide to Landlord as-built plans of the Premises promptly after
the Construction Work is completed (except that asbuilt plans will not be
required for any Construction Work not requiring a building permit, and for
which no building permit was obtained, unless the work involves changes in
electrical, wiring, tel/data cabling, plumbing, chemical handling, access doors,
venting, or air handling systems, in which case as built plans shall be
provided). Tenant will pay all increases in Real Estate Taxes attributable to
the Construction Work.

          5.1.10. Licenses and Permits. Tenant covenants to procure, maintain,
and observe any and all licenses, permits, special permits, variances, or other
Authorizations required by reason of Tenant's use of the Premises or any
Construction Work by Tenant that has been consented to by Landlord, and Tenant
shall provide copies of same to Landlord. Landlord will cooperate reasonably
with Tenant in Tenant's applications for any Authorizations, but Landlord shall
not be obligated to incur expenses in connection therewith.

          5.1.11. Indemnification.

     (a) To the fullest extent permitted by law, Tenant covenants and agrees to
defend (at its own cost and expense and with counsel approved by Landlord), save
harmless, and indemnify Landlord:

               (i)  from all liability and claims of whatever nature

                    (1)  arising from or related to the omission, fault, act,
                    negligence, or misconduct (whether under this Lease or
                    otherwise) of Tenant or of any employee, agent, contractor,
                    licensee, or visitor of Tenant; or

                    (2)  arising from any accident, injury, or damage whatsoever
                    resulting to any person or property while on or about the
                    Premises (except to the extent arising from any omission,
                    fault, negligence,


                                       26

<PAGE>

                    or other misconduct of Landlord or of Landlord's agents,
                    contractors or employees); and

               (ii) from any actions, proceedings, judgments, expenses, and
costs in connection with matters described in Section 5.1.11(a)(i) above
(including reasonable attorneys fees and expenses), and including any claim of
an employee of Tenant (including the subrogated claim) who is covered (or who
should have been covered) in whole or in part by worker's compensation.

     (b) If Landlord is made a party or a third-party defendant to a legal or
administrative proceeding (because Landlord as lessor of the Premises is an
indispensable party or otherwise), which proceeding was initiated by Tenant
based on acts or omissions of others or initiated by others based on acts or
omissions of Tenant, Tenant shall reimburse Landlord, upon Landlord's request
therefor, for all damages and expenses, including reasonable attorneys fees and
expenses related thereto incurred by Landlord, and Landlord shall retain at all
times sole discretion to select and direct the attorney(s) to represent Landlord
in the proceeding.

     (c) The covenants and agreements set forth in this Section 5.1.11 shall
continue in full force and effect for the longest period of time permitted by
law, notwithstanding the expiration or termination of this Lease.

     (d) Provisions in this Lease that provide for Tenant's indemnity or
exoneration of Landlord from liability shall be applied to the fullest extent
permitted by law, and shall be construed or modified, as the case may be, so as
to be in conformity with, and not in violation of, applicable laws limiting
indemnities and exoneration.

          5.1.12. Enforcement Costs. Tenant covenants to pay as other additional
rent, Landlord's expenses (including reasonable attorneys' fees and expenses),
incurred in enforcing or demanding enforcement of any of Tenant's obligations
under this Lease, provided Landlord prevails in any judicial proceeding finally
adjudicating such enforcement action.

          5.1.13. No Interference. Tenant shall not permit employment of any
contractor, worker, or mechanic in the Premises, if such employment will
interfere, or cause any conflict, with other contractors, workers, or mechanics
engaged in work in the Buildings or in other parts of the Complex, and upon the
request of Landlord, Tenant shall cause all such contractors, workers, and
mechanics to leave the Buildings and Complex immediately. Tenant shall submit a
list of its proposed contractors to Landlord for approval, which approval shall
not be unreasonably withheld. Tenant shall not permit any auction sale on or in
the Premises or any other part of the Complex.

          5.1.14. Delivery of Financial Statements. Within one-hundred twenty
days after the end of each of Tenant's fiscal years occurring during the Lease
Term, Tenant shall deliver to Landlord, an annual financial statement of Tenant
("TENANT'S, FINANCIAL STATEMENT") for the then completed fiscal year prepared in
accordance with generally accepted accounting principles consistently applied
and certified by a nationally recognized accounting firm reasonably satisfactory
to Landlord.


                                       27

<PAGE>

          5.1.15. No Violation. Tenant covenants not to permit any servants,
licensees, employees, agents, invitees, or visitors of Tenant to violate any
covenant or obligation of Tenant hereunder, or any of the rules and regulations
from time to time promulgated by Landlord in such manner as Landlord may elect.
Nothing herein obligates Landlord to enforce the rules and regulations, or the
terms, conditions, or covenants of any lease as against any other tenant or
occupant of the Complex. Landlord shall not be liable to Tenant for violations
of such rules, regulations, terms, conditions, or covenants by any other tenant,
or any servant, employee, invitee, licensee, agent, or visitor of any other
tenant.

          5.1.16. Use. Tenant may not use all or any part of the Premises, the
Common Facilities, the Buildings or the Complex in any manner that in Landlord's
reasonable judgment would adversely affect the use and enjoyment of the Complex
by any other tenant, occupant, visitor, or invitee, the character or reputation
of the Complex.

          5.1.17. Keys. Upon expiration or termination of the Lease, Tenant
covenants to deliver the keys (which includes access cards) of the Premises to
Landlord. Tenant covenants not to change or replace any locks or any electronic
access system nor shall new locks or electronic access system be added by Tenant
without the written permission of Landlord, which permission shall not be
unreasonably withheld. Tenant agrees that any locks or electronic access system
so permitted to be installed shall become the property of Landlord and shall not
be removed by Tenant.

          5.1.18. Security Alarm. Tenant covenants not to install any security
alarms or systems without prior written consent from Landlord, which consent
will not be withheld unreasonably by Landlord, provided such devices and systems
are not incompatible with the Building's electronic card access system. Tenant
shall be responsible for all costs associated with any Tenant installed security
system. Tenant covenants to supply Landlord keys, devices, or instructions, as
the case may be, for deactivating said security alarms or systems. Any such
security alarms or systems shall become part of the real estate at the election
of Landlord.

          5.1.19. No Parking. Tenant covenants not to park automobiles,
motorcycles, other vehicles, or bicycles on any part of the Complex, except in
accordance with Section 2.7, provided that Landlord shall provide bike racks at
the Complex that are convenient to the Buildings.

          5.1.20. Insurance.

     (a) Types. Tenant covenants to maintain at all times during the Lease Term
for the mutual benefit of Landlord and Tenant with respect to the Premises and
Tenant's property therein a fully-paid commercial general liability insurance
policy written on an occurrence basis, with a so-called "broadening endorsement"
(or in the socalled "broad form") insuring, without limitation, contractual
liability, bodily injury (including death), personal injury, products liability
(and, if applicable, garage keepers liability, inn keepers liability, liquor
liability, fire legal liability, and, if there is an elevator in the Buildings,
elevator liability), with an endorsement deleting the "care, custody, and
control" exclusion and with a combined single limit equal to the Minimum
Liability Insurance Coverage (with an annual aggregate limit greater than two
times the Minimum Liability Insurance Coverage) with respect to bodily injury,
personal injury, and


                                       28

<PAGE>

property damage. If Tenant conducts business at locations other than the
Premises, the insurance policy shall contain an endorsement that the aggregate
limit in the policy shall apply to the Premises without regard to the Tenant's
other locations. Tenant shall also maintain at all times during the Lease Term
(i) an all-risk or special form coverage protecting Tenant against loss of or
damage to Tenant's alterations, improvements, inventory, and other personal
property situated in the Premises to the full replacement value of the property
so insured; and (ii) business interruption insurance with limits of liability
representing loss of at least approximately six months of income.

     (b) General Description. Each such commercial general liability insurance
policy (and any so-called "umbrella policy" carried by Tenant) shall name
Landlord as additional insured and Tenant as insured and shall be issued by
companies licensed to do business in Massachusetts having current A.M. Best and
Company ratings of A or better and financial size rating of class VIII or
higher, have deductibles satisfactory to Landlord, and be otherwise satisfactory
to Landlord, and with respect to Landlord shall be noncancellable and not
subject to modification without thirty days, prior written notice to Landlord by
registered or certified mail return receipt requested at the same address as
herein provided for notices from Tenant to Landlord. Tenant covenants to deliver
to Landlord, before the Lease Commencement Date, and before the commencement of
each Lease Year but in any event at least thirty days before the expiration date
of any existing policy (and before each renewal thereof), a certificate of
insurance for each policy describing the insurance that will be in effect for
such Lease Year, and if Tenant fails to do so, Landlord, without thereby waiving
or limiting any other right or remedy that Landlord may have, shall have the
right but not the obligation to obtain insurance for Tenant and the cost of
obtaining such insurance and the premiums therefor shall be other additional
rent. If the Initial Lease Term is extended pursuant to Article 10, the minimum
limits of such insurance policies for the Extension Term shall be increased as
Landlord may reasonably request from time to time. At any time, and from time to
time, upon Landlord's request, Tenant will forthwith deliver to Landlord a true
copy of each such insurance policy. Upon Landlord's request, Tenant shall
require Tenant's insurance company to explain to Landlord in writing the nature
and extent of the coverage and the exclusions, if any, provided by such policy
or policies.

     (c) Non-liability. Neither Landlord nor any of its affiliated or subsidiary
corporations, nor their respective agents, officers, members of governing
boards, or employees shall be liable to Tenant or Tenant's agents, officers,
directors, shareholders, partners, principals, invitees, contractors, licensees,
trespassers, or persons occupying or using the Premises, or persons claiming by
or through any of same, for injury, loss, or damage to person or property
(including Tenant's tenant improvements, betterments, fixtures, equipment,
appliances, personal property, and the like) including those resulting from any
accident or occurrence in or upon the Premises, Buildings or Complex, except to
the extent arising from the negligence of Landlord. If any property of Tenant is
entrusted to Landlord or Landlord's agent, such person shall be deemed to be
acting as Tenant's agent.

               5.1.20.1. Waiver of Subrogation. Subject to Section 5.1.20.2
below, any insurance policies carried by Tenant or by Landlord covering the
Premises, including policies covering contents, fire, and casualty insurance,
shall expressly waive any right on the part of the insurer against Tenant and
Landlord respectively by subrogation or otherwise. Tenant and Landlord agree
that its policies will contain such waiver clause or endorsement if such


                                       29

<PAGE>

waiver clause or endorsement is available from such insurer, whether or not an
additional premium is required. With respect to claims that Tenant may have
against Landlord for fire or casualty damage to any or all of the Premises,
property on the Premises, the Buildings, or other property in the Complex
(including business interruption caused thereby), which claims are covered by
insurance payable to and protecting Tenant, or would have been so covered had
Tenant obtained the insurance required under this Lease, Tenant hereby waives
all claims to the extent of Tenant's insurance coverage or to the extent of the
insurance coverage Tenant would have had if Tenant obtained the insurance
required under this Lease. The foregoing waiver shall apply to claims for damage
whether such damage is caused wholly or partially by Landlord or its agents,
employees, tenants, subtenants, licensees, or assignees.

               5.1.20.2. No Waiver of Subrogation for Harvard. Notwithstanding
the waiver of subrogation set forth above in Section 5.1.20.1, if President and
Fellows of Harvard College ("Harvard"), or any affiliate of, or related entity
to Harvard is the Landlord under this Lease, than with respect to claims that
Landlord may have against Tenant for fire or casualty damage to any or all of
the Premises, the Buildings, or the Complex, Landlord does not waive such claims
against Tenant, and Landlord expressly reserves and retains the right to recover
against Tenant such claims, provided, however, Landlord agrees that Tenant's
liability for any such claims shall not exceed the greater of (i) Tenant's
actual commercial general liability insurance coverage at the time of the claim,
or (ii) the commercial general liability insurance coverage that Tenant is
obligated to maintain pursuant to Section 5.1.20 above.

          5.1.21. Subordination. Tenant covenants that at the request of
Landlord from time to time, Tenant shall subordinate this Lease, and Tenant's
rights hereunder, to any mortgage, provided that the holder of such mortgage
enters into an SNDA Agreement (as defined below) with Tenant. Upon Landlord's
request, Tenant agrees to enter into an agreement with the holder of any
mortgage, on the mortgagee's customary form (an "SNDA AGREEMENT"). As of the
date of this Lease, there is no mortgage encumbering the Complex. The SNDA
Agreement shall provide that the holder agrees that, in the event of a
foreclosure of the mortgage, by entry or by sale, deed in lieu of foreclosure or
the holder or its successors otherwise obtaining possession of, or title to, the
Premises, Tenant, if Tenant is not then in default beyond applicable grace and
cure periods with respect to any of the covenants or conditions of this Lease to
be performed or observed by Tenant, shall peaceably hold and enjoy the Premises
and enjoy all of its rights hereunder for the remainder of the Lease Term upon
the same terms, covenants, and conditions as in this Lease contained and without
hindrance or interruption from such holder, and Tenant agrees, among other
things, that in the event of such entry or foreclosure, to recognize such holder
or any other person acquiring title to the Premises as Landlord hereunder for
the balance of the Lease Term. The SNDA Agreement shall also provide that no
said holder shall be deemed to be the owner of the Complex until said holder
shall have acquired title to the Complex or shall have entered the Complex as
mortgagee in possession or for the purposes of foreclosure.

          5.1.22. Harvard Name. Tenant covenants and agrees that unless Landlord
first gives its prior written consent, Tenant shall not (i) use the word
"Harvard" (whether alone or in combination with other words), (ii) display or
otherwise use the name, emblem, or logo (or any similar name, emblem, or logo)
of any school, department, or other component, constituent, or affiliate of
Landlord, or (iii) otherwise refer to Landlord or any school department, or
other component or affiliate of Landlord in or on any sign, advertisement
(including any newspaper,


                                       30

<PAGE>

television, or radio advertisement), commercial announcement, circular, flier,
or other publication.

          5.1.23. Tenant's Managers. Tenant covenants to deliver to Landlord at
Landlord's request, the name of the office manager employed on the Premises and
their contact information.

          5.1.24. Tenant's Expense, Personal Property Taxes. Performance by
Tenant of all of Tenant's covenants and agreements in this Lease, and observance
by Tenant of all terms and conditions in this Lease to be observed by Tenant,
shall be Tenant's sole responsibility and shall be at Tenant's sole cost and
expense, and Landlord shall bear no responsibility therefor. Tenant shall
promptly pay all taxes imposed on Tenant's personal property, trade fixtures,
and equipment.

          5.1.25. Hazardous Materials. Tenant may use only Hazardous Materials
such as adhesives, lubricants, ink, solvents, and cleaning fluids of the kind
and in amounts and in the manner customarily found and used in business offices
to conduct its business at the Premises, and to maintain and operate the
business machines located in the Premises (collectively "Permitted Hazardous
Materials"). Except as permitted by the preceding sentence, Tenant covenants not
to use, store, handle, treat, transport, release, or dispose of Hazardous
Materials on or about the Premises, the Buildings or the Complex. Any handling,
treatment, transportation, storage, disposal, or use of Permitted Hazardous
Materials by Tenant in or about the Premises shall comply with all applicable
Legal Requirements, Environmental Laws, and with the Environmental Restrictions.
Tenant shall, within ten Business Days of Landlord's written request therefor,
disclose in writing all Permitted Hazardous Materials that are being used by
Tenant in the Premises, the nature of such use, and the manner of storage and
disposal. Tenant shall indemnify, defend upon demand with counsel reasonably
acceptable to Landlord, and hold Landlord harmless from and against, any
liabilities, losses claims, damages, interest, penalties, fines, attorneys'
fees, experts' fees, court costs, remediation costs, and other expenses that
result from the use, storage, handling, treatment, transportation, release,
threat of release or disposal of Hazardous Materials in or about the Premises,
the Buildings or the Complex by Tenant or Tenant's agents, employees,
contractors, or invitees. Tenant shall give written notice to Landlord as soon
as reasonably practicable of any communication received by Tenant from any
Governmental Authority concerning Hazardous Materials that relates to the
Premises or the Complex. Attached hereto as Exhibit G is a list of documents
imposing environmental restrictions on the Complex (as the same may be amended
from time to time, collectively, the "ENVIRONMENTAL RESTRICTIONS"). Tenant
acknowledges that it has received a copy of the Environmental Restrictions
listed on Exhibit G. The Premises are leased subject to the Environmental
Restrictions. As used herein the term "Hazardous Material(s)" means any
hazardous or toxic substance, material, or waste or petroleum derivative that is
or becomes regulated by any Environmental Law. The term "Hazardous Material(s)"
includes all Permitted Hazardous Materials, and further includes any material or
substance that is (i) designated as a "hazardous substance" pursuant to Section
1311 of the Federal Water Pollution Control Act (33 U.S.C. Section 1317), (ii)
defined as a "hazardous waste" pursuant to Section 1004 of the Federal Resource
Conservation and Recovery Act, 42 U.S.C. Section 6901 et seq. (42 U.S.C. Section
6903), (iii) defined as a "hazardous substance" pursuant to Section 101 of the
Comprehensive Environmental Response, Compensation and Liability Act, 42 U.S.C.
Section


                                       31

<PAGE>

9601 et seq. (42 U.S.C. Section 9601), (iv) defined as "hazardous substance" or
"oil" under Chapter 21E of the General Laws of Massachusetts, or (v) defined as
hazardous chemicals under OSHA's Hazard Communication standards, 29 CFR
1910.1200. The term "Environmental Laws" includes Legal Requirements and the
laws listed in the preceding clauses (i) through (v) above. The provisions of
this Section 5.1.25 shall survive the expiration or earlier termination of this
Lease.

          5.1.26. Existing Environmental Conditions. Tenant shall (i) not be
liable for the removal or abatement of Hazardous Materials that exist in the
Premises as of the Date of this Lease, and (ii) not be responsible for, and
shall have no liability for, any violation of the Environmental Restrictions,
unless such violation is caused by Tenant or Tenant's agents, employees,
contractor or invitees. Landlord has received no written notice from any
Governmental Authority with respect to, the Complex regarding any violation of
Environmental Laws or the Environmental Restrictions. Landlord shall ensure
compliance with the Environmental Restrictions. Tenant's liability for Hazardous
Materials shall be as set forth in Section 5.1.25.

          5.1.27. Tenant's Business Name. Tenant agrees to provide Landlord with
prior written notice of any change in Tenant's Business Name.

     Section 5.2. Landlord's Covenants.

          5.2.1. Quiet Eniovment. Landlord covenants with Tenant that if and so
long as there is no Event of Default, Tenant may quietly hold occupy and enjoy
the Premises during the Lease Term, subject nonetheless, to all of the
provisions, terms, and conditions of this Lease; the easements, encumbrances,
restrictions, and rights referred to in Section 2.2; any Legal Requirements; the
Rules and Regulations; and any Insurance Requirements.

          5.2.2. Landlord's Default. Landlord shall not be deemed to be in
default in the performance of any of its obligations under this Lease unless
Landlord shall fail to use diligent efforts to perform such obligations, and
such failure shall continue for a period of thirty days (or such additional time
as is reasonably required to correct any such default) after written notice has
been given by Tenant to Landlord specifying the nature of Landlord's alleged
default (a "LANDLORD DEFAULT"). If Landlord's failure to perform its obligations
under this Lease represents an imminent threat of personal injury to persons in
the Premises or property damage to the Premises or Tenant's personal property in
the Premises (an "EMERGENCY DEFAULT"), the foregoing thirty-day period may be
accelerated if Tenant gives notice to Landlord of the Emergency Default, and
that immediate action is required by Landlord. Upon Landlord's receipt of the
notice described in the preceding sentence, Landlord shall promptly notify
Tenant that Landlord will undertake such cure. If Landlord fails to promptly
notify Tenant that Landlord will cure, or does not promptly take such immediate
action to commence such cure, then after notice to Landlord, Tenant may cure
such Emergency Default to the extent reasonably necessary to avoid such injury
or loss, and charge the documented out-of-pocket cost to Landlord, which if not
paid or disputed by Landlord within forty-five days thereafter, may be paid by
Tenant's offset of such amount (or such undisputed portion) from Basic Rent.
Tenant shall document to Landlord the actions so taken by Tenant in the event
Tenant undertakes to cure an Emergency Default pursuant to the preceding
sentence. Notices to either party in the event of an Emergency


                                       32

<PAGE>

Default shall be by telephone to numbers that Landlord and Tenant shall provide
to each other (and update as necessary) for emergency situations. Tenant shall
have the right to seek in a judicial proceeding any remedies available to Tenant
at law or in equity because of a Landlord Default or Emergency Default,
including the right to seek the termination of this Lease (notwithstanding
Tenant's independent covenant to pay rent under Section 5.1.1), provided that
such Landlord Default or Emergency Default renders the Premises untenable for
the purposes for which they are leased (a "CONSTRUCTIVE EVICTION ACTION"). If
Tenant prevails in a Constructive Eviction Action, the judge shall determine the
termination date of this Lease. In no event shall Landlord ever be liable to
Tenant for any indirect, special, or consequential damages suffered by Tenant
from whatever cause. Tenant further agrees that if Landlord shall have failed to
cure any such default (but excluding an Emergency Default) within thirty days of
such notice to Landlord (or if such default cannot be cured within said time,
then within such additional time as may be necessary to cure such default), then
the holder(s) of any mortgage(s) or the lessor under any ground lease entitled
to notice pursuant to Section 5.3 shall have an additional thirty days within
which to cure such default or if such default cannot be cured within that time,
then such additional time following the date that such holder or lessor becomes
entitled to cure such default as may be necessary to cure such default
(including commencement of foreclosure proceedings, if necessary to effect such
cure).

          5.2.3. Landlord's Insurance. Landlord shall insure the Buildings
against damage or destruction by fire or other casualties on an "all-risk" of
physical loss or damage basis, for full replacement cost value of the Buildings,
with an agreed amount endorsement to satisfy co-insurance requirements. If
President and Fellows of Harvard College ("Harvard"), or any affiliate of, or
related entity to, Harvard is the Landlord under this Lease, it shall have no
obligation to carry or maintain such insurance, and may self-insure for all or
any portion of the coverages required by this Section 5.2.3.

     Section 5.3. Notice to Mortgagee and Ground Lessor. After Tenant has been
delivered notice as herein specified of a mortgage or ground lease covering all
or part of the Premises, the Buildings, or the Complex, no notice from Tenant to
Landlord of a default by Landlord shall be effective unless and until a copy of
the same is given to the holder of the mortgage or ground lessor at the address
specified in the notice delivered by such holder or ground lessor as herein
required, as the case may be, and the curing of any of Landlord's defaults by
such holder or ground lessor shall be treated as performance by Landlord.

     Section 5.4. HIPAA. Landlord acknowledges that certain of the records and
documents in Tenant's care, custody and control in the Premises are subject to
the provisions of The Health Insurance Portability and Accountability Act of
1996 ("HIPAA"). No provision in this Lease shall operate or be deemed to operate
as (i) a disclosure of any information or documents protected or regulated by
HIPAA, (ii) a receipt by Landlord of any information or materials that are
protected or regulated by HIPAA, or (iii) an authorization to Landlord to
access, view or use materials or documents protected by HIPAA.

                          ARTICLE 6. - TENANT'S DEFAULT

     Section 6.1. Event of Default. The occurrence of any of the following shall
constitute an "EVENT OF DEFAULT" under this Lease:


                                       33

<PAGE>

     (a) if Tenant shall fail to pay to Landlord when due any payment of Basic
Rent or Additional Rent and such failure continues for ten days after receipt of
notice, provided, however, that if two such notices are sent to Tenant in any
twelve-month period during the Lease Term, thereafter it shall be an Event of
Default hereunder if Tenant shall fail to pay when due any payment of Basic Rent
or Additional Rent; or

     (b) if Tenant shall fail to pay to Landlord when due any payment of other
additional rent required by this Lease, and such failure continues for fifteen
days after receipt of notice, provided, however, that if two such notices are
sent to Tenant in any twelve-month period during the Lease Term, thereafter it
shall be an Event of Default hereunder if Tenant shall fail to pay within
fifteen days of when due, any payment of other additional rent required by this
Lease; or

     (c) if Tenant shall fail to maintain insurance as required by Sections
5.1.20, or shall fail to renew or reinstate the Letter of Credit as and when
required in Article 7, or shall enter into an Assignment or Subletting in
violation of this Lease; or

     (d) if Tenant shall fail to perform or observe any of Tenant's other
covenants herein (including the rules and regulations referred to in Section
5.1.6) (such failure being a "Breach") and such Breach shall continue

               (i) for thirty days after written notice of such Breach is given
to Tenant, or

               (ii) for more than the amount of time specified by Landlord to
Tenant in situations where more than thirty days are required to correct such
Breach, provided (A) Tenant promptly begins such correction after Landlord gives
written notice of such Breach, (B) Tenant gives Landlord notice before the end
of the thirty-day period describing progress made to date, justifying in
reasonable detail the need for more time and the steps needed to complete the
correction, and specifying an estimate of when the correction will be completed,
and (C) Tenant diligently prosecutes the correction to completion within the
time so specified;

provided, however, that if a Breach involving the same matter occurs repeatedly
(more than twice during any twelve-calendar-month period), and Landlord gives
Tenant notice of each such Breach, then if Landlord gives Tenant notice of a
third occurrence of a Breach involving the same matter, the same shall be an
Event of Default (without any further right to cure); or

     (e) for any Breach involving the disturbance (by noise, loud music, odors,
or nuisance) of another tenant in the Building or an abutter that results in a
formal or informal, oral or written complaint to Landlord by such tenant or
abutter or by a governmental official, if such Breach or a similar Breach
continues or occurs ten days after Landlord gives notice to Tenant of such
Breach, the same shall be an Event of Default (without any further right to
cure); or

     (f) if this Lease or the estate hereby granted or the unexpired balance of
the Lease Term should by operation of law or otherwise, be transferred to,
devolve upon, or pass to any person other than Tenant, except as is expressly
permitted by the provisions of Section 5.1.8; or

     (g) if the leasehold hereby created shall be taken either by execution
arising out of an action against Tenant, or by other process of law;


                                       34

<PAGE>

     (h) if any assignment shall be 'made of Tenant's property for the benefit
of creditors; or

     (i) if a receiver, guardian, conservator, or similar officer shall be
appointed to take charge of all or any part of Tenant's property by a court of
competent jurisdiction; or

     (j) if a petition or proceeding is filed against Tenant by others or is
filed by Tenant, or an order for relief is entered with respect to Tenant, under
any provision of the federal Bankruptcy Code, ll U.S.C. Sections 101-151326 &
app., or any similar provisions of any future federal bankruptcy law.

          6.1.1. Written Notice of Termination. If an Event of Default shall
occur, Landlord may immediately or at any time thereafter while such Event of
Default continues, terminate this Lease by five days prior written notice of
termination (or notice to quit) to Tenant, without prejudice to any remedies
(whether set forth in this Lease or provided for by law) that might otherwise be
used for arrearage of rent, for nonpayment of amounts required to be paid by
Tenant to Landlord under this Lease, or for preceding breaches of covenant, and
upon the giving of such notice of termination (or notice to quit), this Lease
shall terminate.

          6.1.2. Bankruptcy. In the case of an Event of Default under 6.1(j),
this Lease shall be deemed rejected if the trustee of Tenant shall fail to elect
to assume this Lease within sixty days (or the minimum period of time as may be
applicable under law or order of the applicable court) after the earlier to
occur of the date of the filing of the petition or the trustee's appointment (as
may be applicable). If this Lease is rejected by the trustee of the Tenant or
deemed to be rejected, then (i) Landlord shall immediately be entitled to
possession of the Premises without further obligation to Tenant or the trustee,
and this Lease shall be deemed terminated without prejudice to any remedies that
might otherwise be used for arrearage of Rent, for nonpayment of amounts
required to be paid by Tenant to Landlord under this Lease, or for preceding
breaches of covenant, and (ii) Landlord shall retain the right to be compensated
for damages in the bankruptcy proceeding. To be effective, any election by the
trustee of Tenant to assume this Lease must be in writing and addressed to
Landlord using the address set forth in Section 8.12 and be accompanied by the
trustee's commercially adequate assurance to Landlord of the future performance
and continuous performance of Tenant's obligations under this Lease; provided,
however, that the trustee first shall cure all defaults of Tenant under this
Lease and compensate all persons other than Landlord who have incurred or
suffered pecuniary losses due to Tenant's default under this Lease before the
trustee's assumption of this Lease shall be effective.

     Section 6.2. Tenant's Obligations After Termination. Tenant covenants that,
in case of termination of this Lease pursuant to the provisions of this Article
6, or in case of termination under the provisions of statute by reason of the
default of Tenant, Tenant will be obligated to pay and perform all of the
obligations described in (a), (b), and (c) below, and Landlord shall have the
right to elect to receive from Tenant either the Fixed Damages or alternatively,
the Incurred Loss; but if Landlord elects to receive the Incurred Loss payments,
Landlord shall have the right at any time thereafter during the Lease Term to
elect to receive instead Fixed Damages with respect to the remainder of the
Lease Term, and in any event, Landlord may elect that Tenant


                                       35

<PAGE>

quit the Premises. Landlord shall make such election within one year after the
termination of this Lease.

     (a) Fixed Damages. If Landlord by notice to Tenant so elects, Tenant shall
forthwith pay to Landlord as damages ("FIXED DAMAGES") a sum equal to the amount
(calculated on a present value basis using the Prime Rate as the discount rate)
by which the Basic Rent and other payments called for in this Lease for the
remainder of the Lease Term exceed the fair rental value of the Premises for the
remainder of the Lease Term.

     (b) Incurred Loss. If Landlord by notice to Tenant so elects, Tenant shall
continue to pay Landlord on the Rent Payment Day an amount (the "INCURRED LOSS")
equal to (i) the Rent to be paid under this Lease less (ii) the sum of any rent
collected from Landlord's reletting less the Reletting Expenses. The "RELETTING
EXPENSES" shall include reasonable attorneys' fees and expenses, brokerage fees,
and the reasonable cost and expense of putting the Premises into good order and
preparing the Premises for rental. Tenant shall indemnify Landlord during the
remainder of the Lease Term against all Incurred Loss suffered and expenses,
however caused, incurred by Landlord by reason of the termination of this Lease.
The Incurred Loss occurring during each calendar month during the remainder of
the Lease Term shall be due from Tenant to Landlord on the next Rent Payment
Day.

     (c) Surrender of Premises. If Landlord by notice to Tenant elects that
Tenant shall quit the Premises, then Tenant shall quit and peacefully surrender
the Premises to Landlord and remove Tenant's goods and effects and yield up the
Premises in accordance with Section 5.1.4 within five days after the date of
termination of this Lease. Landlord may upon, or at any time after any such
termination, without fu ther notice and without prejudice to any other rights
and remedies that Landlord may have at law or in equity, (1) enter the Premises
and possess itself thereof, by summary proceedings or otherwise, (2) dispossess
Tenant and remove Tenant and all other persons and property from the Premises,
and thereafter, Landlord may have, hold, and enjoy the Premises, and the right
to receive all rental income of and from the same; but, notwithstanding the
foregoing, Tenant shall remain liable to Landlord as provided in this Lease, and
Tenant shall be liable to Landlord for all costs incurred by Landlord under this
Section 6.2(c).

          6.2.1. Evidence of Value. If the Premises or any part thereof are
relet by Landlord before presentation of proof of liquidated damages to any
court commission or tribunal, the amount of rent reserved upon such reletting
shall be prima facie evidence of the fair rental value for the part or the whole
of the Premises so relet during the term of the reletting.

     Section 6.3. Other Matters Relating to Termination.

          6.3.1. Landlord's Right to Relet. At any time or from time to time
after any termination or Landlord's reentry pursuant to this Article 6, Landlord
shall use reasonable efforts to relet the Premises in the name of Landlord or
otherwise, for such term or terms (which may be greater or less than the period
that would otherwise have constituted the balance of the Lease Term) and on such
conditions (which may include concessions or free rent) as Landlord, in its
reasonable election, may determine, and Landlord may collect and receive the
rents therefor. Landlord shall in no way be responsible or liable for any
failure to relet the Premises or any part


                                       36

<PAGE>
Confidential Materials omitted and filed separately with the Securities and
Exchange Commission. Asterisks denote omissions.

thereof, or for any failure to collect any rent due upon any such reletting. If
Landlord is Harvard, Landlord may, at its election, relet all or any portion of
the Premises to Harvard's school or departments, and there shall be credited
against the Rent to be paid under this Lease, an amount representing the rental
value of the relet space less the Reletting Expenses.

          6.3.2. Landlord's Other Remedies. Nothing herein contained shall limit
or prejudice the right of Landlord to prove and obtain as damages by reason of
such termination, an amount equal to the maximum allowed by any statute or rule
of law in effect at the time when, and governing the proceedings in which, such
damages are to be proved, whether or not such amount be greater, equal to, or
less than the amount of the difference referred to above. In no event though
shall Tenant ever be liable to Landlord for consequential damages suffered by
Landlord, except that Landlord retains the right to seek consequential damages
caused by any holding over of Tenant in accordance with Section 8.10.

          6.3.3. Right to Equitable Relief. Landlord shall be entitled to enjoin
an Event of Default and shall have the right to invoke any right and remedy
allowed at law or in equity or by statute or otherwise as though re-entry,
summary proceedings, and other remedies were not provided for in this Lease.

          6.3.4. Landlord's Right To Cure Tenant's Default. If an Event of
Default shall occur, Landlord shall have the right, but shall not be obligated,
to enter upon the Premises, if necessary, and to cure such Event of Default. In
performing such cure, Landlord may make any reasonable payment of money or
perform any other reasonable act. Landlord may, in the event of danger to person
or property, the threat of cancellation of insurance, or other emergency,
exercise its right of self-help under this Section with only such notice of
default, oral or written, as is practicable in the circumstances,
notwithstanding a requirement, if any, for notice of default in any other
context. The aggregate of (i) all sums so paid by Landlord (including reasonable
counsel fees and expenses), (ii) interest (at the Involuntary Rate) on such sum,
and (iii) all necessary incidental costs and expenses in connection with the
performance of any such act by Landlord, shall be deemed to be other additional
rent under this Lease and shall be due and payable to Landlord immediately upon
demand. Landlord may exercise the foregoing rights without waiving any other of
its rights or releasing Tenant from any of Tenant's obligations under this
Lease.

                          ARTICLE 7. - LETTER OF CREDIT

     Section 7.1. Definitions. In this Article 7, the following definitions
apply:

     "ORIGINAL AMOUNT" means $* being the face amount of the original Letter of
Credit.

     "LETTER OF CREDIT" means the original Letter of Credit, and any substitute,
replacement, or additional letter of credit.

     Section 7.2. Requirements of Letter of Credit, Amount, Form. Simultaneously
with the execution of this Lease, Tenant shall deliver to and deposit with
Landlord an irrevocable, unconditional, absolutely "clean" Letter of Credit in
the face amount equal to the Original Amount running to Landlord as the sole
beneficiary. The Letter of Credit shall be in the form of


                                       37

<PAGE>
Confidential Materials omitted and filed separately with the Securities and
Exchange Commission. Asterisks denote omissions.

the letter of credit attached hereto as Exhibit C, or in any form substantially
similar as may be satisfactory to Landlord. Any Letter of Credit shall have a
stated duration of and shall be effective for at least one year with provision
for automatic successive annual one-year extensions for the Initial Lease Term
(and any renewal term or extension term) and for sixty days thereafter. The
Letter of Credit shall be automatically transferable without the issuer's
consent, and at no charge to Landlord. Tenant shall pay to Landlord, as other
additional rent, the amount of any fees charged by the issuer in connection with
a transfer of the Letter of Credit. Tenant shall keep the Letter of Credit in
force throughout the Lease Term and for sixty days after the Lease Expiration
Date or the earlier termination of the Lease Term, except that if such earlier
termination is based on Tenant's default, Tenant shall keep the Letter of Credit
in force until one hundred eighty days -after the termination of the Lease.
Tenant shall deliver to Landlord a renewal Letter of Credit no later than thirty
days prior to the expiration date of any Letter of Credit issued under this
Article 7, and if Tenant fails to do so, Landlord may draw the entire amount of
the expiring Letter of Credit and hold the proceeds in cash for the same
purposes as the Letter of Credit. The Letter of Credit shall be issued by a
commercial bank, reasonably satisfactory to and approved by Landlord, that has
capital assets of at least $250,000,000 and capital reserves of at least
$7,000,000, and that is a member of the Federal Reserve System. Landlord hereby
agrees that Silicon Valley Bank, and the form of Letter of Credit attached
hereto as Exhibit C-1 are satisfactory to Landlord for purposes of this Section
7.2. In no event will the Letter of Credit be deemed to be either prepaid rent
or a measure of liquidated damages.

     Section 7.3. Decrease in Amount of Letter of Credit. During each of the
second, third, and fourth Lease Years, Landlord will, within thirty days of
Landord's receipt of the Reduction Deliveries (pursuant to Section 7.3.1), and
provided that Landlord reasonably determines that Tenant is in compliance with
the terms of the Lease, and there is no Breach, and no Event of Default under
the Lease, and there has been no monetary Event of Default under the Lease (the
"REDUCTION CONDITION"), Landlord shall promptly send a notice to Tenant stating
that the Letter of Credit is eligible for reduction pursuant to the terms of
this Article 7 (the "REDUCTION NOTICE"). Notwithstanding the foregoing, Tenant's
inability to meet the Reduction Condition or deliver the Reduction Deliveries in
any one-year shall not prevent Tenant from being eligible for the applicable
reduction in subsequent years. The Reduction Notice will also state the amount
that the Letter of Credit may be reduced to as determined below. Within sixty
days of Tenant's receipt of a Reduction Notice (the "REDUCTION PERIOD"), Tenant
may, at its sole cost and expense, deliver an amendment to the Letter of Credit
reducing the face amount of the Letter of Credit (and Landlord shall join in any
reasonable documents as necessary) as follows:

          (A) During the second Lease Year, the face amount of the Letter of
Credit may be reduced to $*.

          (B) During the third Lease Year, the face amount of the Letter of
Credit may be reduced to $*.

          (C) During the fourth Lease Year, the face amount of the Letter of
Credit may be reduced to $*.

          7.3.1. Reduction Deliveries. "REDUCTION DELIVERIES" means Tenant's
delivery to Landlord of the following:


                                       38

<PAGE>

          (A) A copy of Tenant's then current annual financial statement audited
by a nationally recognized "Big Four" accounting firm, such as Deloitte Touche
Tohmatsu, Ernst & Young, KPMG, or PriceWaterhouseCoopers, and with a "no
on-going concern" opinion, and that no facts disclosed to the auditors have a
material adverse effect on Tenant's financial condition; and

          (B) A certification signed by Tenant's chief financial officer that
(i) there are no declared defaults by any of its lenders, and (ii) no monetary
defaults, or defaults under any of the financial covenants exist under any of
Tenant's loan arrangements.

          7.3.2. Amendment to Letter of Credit. Any such amendment reducing the
face amount of the Letter of Credit shall be on a commercially reasonable form.
If Tenant fails to deliver an amendment reducing the face amount of the Letter
of Credit on or before the expiration of a Reduction Period, Tenant shall
forfeit its option to reduce the Letter of Credit in accordance with such
Reduction Notice.

     Section 7.4. Landlord's Rights Upon an Event of Default. If, and as soon
as, there shall exist an Event of Default under this Lease (and on the occasion
of each Event of Default if there shall be more than one), Landlord may draw
upon the Letter of Credit at any time and from time to time in such amount or
amounts as may be necessary to cure the default or to reimburse Landlord for any
sums) that Landlord may have spent to cure the default(s) and if Landlord has
terminated this Lease for Tenant's default(s), Landlord may also draw upon the
Letter of Credit in such amount (or all) as may be necessary to obtain any
amounts from time to time owed to Landlord by Tenant after termination under
Article 6 or otherwise. In the case of each such drawing (except a drawing
occurring after termination or expiration of this Lease), Tenant shall,
immediately upon Landlord's demand, cause the Letter of Credit to be reinstated
to the full amount that was required by this Lease prior to the drawings, or
cause a similar Letter of Credit, aggregating said full amount, to be issued to
Landlord. Landlord shall have the right, in the Event of Default by Tenant, to
draw on all of the Letter of Credit and hold the proceeds thereof to be applied
from time to time against Fixed Damages, Incurred Losses (as described in
Section 6.2), and other costs arising under Section 6.2(c). If at the end of the
Lease Term, Tenant is in compliance with the terms of this Lease, the Letter of
Credit, or any balance thereof, shall be returned to Tenant, but not otherwise.

                          ARTICLE 8. - GENERAL MATTERS

     Section 8.1. Condition of Premises. SUBJECT TO LANDLORD'S OBLIGATION TO
DELIVER THE SERVICES SET FORTH IN SECTION 9, AND LANDLORD'S OBLIGATION TO ENSURE
COMPLIANCE WITH THE ENVIRONMENTAL RESTRICTIONS PURSUANT TO SECTION 5.1.26,
TENANT ACKNOWLEDGES THAT TENANT IS TAKING THE PREMISES IN ITS STRICTLY "AS-IS,
WHERE-IS" CONDITION. LANDLORD DISCLAIMS ANY WARRANTY OF SUITABILITY OF THE
PREMISES FOR USE BY TENANT. Tenant acknowledges that Landlord has not made any
representation or warranty, express or implied, as to the condition of the
Premises, the fitness of the Premises for any particular use, the exact floor
area of the Premises (whether in rentable square feet, usable square feet, or
some other measure), or the likelihood or ability of Tenant to obtain any
required Authorizations. Subject to Landlord's obligation to deliver the
services set


                                       39

<PAGE>

forth in Section 9, and Landlord's obligation to ensure compliance with the
Environmental Restrictions pursuant to Section 5.1.26, no variations of the
condition of the Premises from Tenant's expectations, nor any unfitness of the
Premises for any particular use (other than general office use) nor any
inability or failure of Tenant to obtain the Authorizations, shall entitle
Tenant to refuse to accept the Premises, or to quit, terminate, or surrender
this Lease, nor relieve Tenant from the obligation to pay the Rent in full
without offset or counterclaim, or from any of Tenant's other obligations under
this Lease. The initial work to be performed by Tenant to prepare the Premises
for Tenant's occupancy is set forth in the attached Exhibit F.

     Section 8.2. Casualty and Eminent Domain.

          8.2.1. Casualty, Partial Taking. During the Lease Term,

     (a) if, in Landlord's opinion, more than twenty-five percent of the
Premises or Building 311 is damaged by fire or any other cause, or

     (b) if, in Landlord's opinion, Building 311 or any part thereof shall be
damaged by fire or other cause to the extent that substantial alteration or
reconstruction of Building 311 shall be required (whether or not the Building
311 Premises shall have been damaged), or

     (c) if, in Landlord's opinion, title to, convenient access to, or use of
either the Building 311 Premises or Building 311, shall be taken or condemned in
any eminent domain, condemnation, compulsory acquisition, or like proceeding by
any Governmental Authority or conveyed under the threat thereof, for any public
or quasi public use or purpose (collectively hereinafter called a "TAKING"),

then in any such event this Lease shall be deemed to have terminated ninety days
after such event, unless Landlord, by notice given by Landlord to Tenant within
such ninety-day period, elects not to terminate this Lease. In addition if
Building 97 or any part thereof is damaged by fire or other cause to the extent
that substantial alteration or reconstruction of Building 97 shall be required
or if, in Landlord's reasonable opinion, title to, convenient access to, or use
of Building 97 shall be subject to a Taking, then in any such event this Lease
shall be deemed to have terminated with respect to the Building 97 Premises
only, ninety days after such event, unless Landlord, by notice given by Landlord
elects not to terminate this Lease with respect to the Building 97 Premises.
Whether or not Landlord elects not to terminate this Lease, Landlord shall be
entitled to receive directly from the Insurer (or the Taking authority) all
insurance proceeds (or Taking proceeds) resulting from or related to the
casualty (or the Taking).

          8.2.2. Total Taking/Partial Taking. If the entire Building 311
Premises shall be the subject of a Taking, this Lease shall terminate and the
effective date of termination shall be the earlier to occur of (i) the date when
physical possession of the Building 311 Premises is taken by the Taking
authority or (ii) the date that Tenant's use and occupancy of the Building 311
Premises is legally prohibited by final action of the Taking authority. If the
Building 97 Premises are the subject of a Taking, this Lease shall terminate
with respect to the Building 97 Premises and the effective date of termination
shall be the earlier to occur or (i) the date when physical possession of the
Building 97 Premises is taken by the Taking authority or (ii) the date that in
Landlord's sole opinion, Tenant's use and occupancy of the Building 97 Premises
is


                                       40

<PAGE>

legally prohibited by final action of the Taking authority. If a portion of the
Premises shall be the subject of a Taking, and the Taking (i) renders the
Premises no longer suitable for Tenant's conduct of its business, (ii)
materially impairs access to the Premises, or (iii) materially reduces Tenant's
Share of Parking Spaces, Tenant shall have the right to terminate this Lease by
notice given to Landlord within thirty days of the Taking.

          8.2.3. Restoration. Tenant's Right to Terminate. If this Lease is not
terminated under Section 8.2.1 or Section 8.2.2, Landlord shall use due
diligence to restore the Premises, or, in case of partial Taking, what may
remain thereof using compensation awarded to Landlord by the Taking authority,
(but Landlord shall not be obligated to restore any alterations, improvements or
equipment installed or paid for by Tenant or that Tenant may be required or
permitted to remove), to the condition existing prior to the casualty or Taking;
provided, however, that if Landlord has not restored the Premises within nine
months from the occurrence of the damage (or the effective date of the Taking),
Tenant shall have the right to terminate this Lease by notice to Landlord given
within thirty days after the expiration of such nine-month period. Any such
termination shall be effective thirty days after delivery of Tenant's notice of
termination, unless Landlord substantially completes the work before the end of
such thirty-day period, in which case Tenant's notice of termination shall be
void. During such restoration, a just proportion of the Basic Rent and
Additional Rent as determined in Landlord's reasonable opinion considering the
nature and extent of the damage or Taking, shall be abated. In the event of a
Taking, if less than all of the Premises are restored, a just proportion of the
Basic Rent and Additional Rent, similarly determined in Landlord's reasonable
opinion, shall be abated for the remainder of the Lease Term. Landlord shall not
be liable for any inconvenience or annoyance to Tenant or injury to the business
of Tenant resulting in any way from such damage or Taking or the repair or
restoration thereof. Landlord's obligations hereunder to restore shall be
subject to Landlord's ability to obtain materials or to install the same
strikes, labor difficulties, shortages of labor, or any cause beyond Landlord's
reasonable control. If during the last twelve months of the Lease Term, (i) the
Premises are materially damaged by fire or other casualty, (ii) either of the
Buildings is materially damaged by fire or other casualty that materially and
adversely affects Tenant's access to the Premises, or (iii) a Taking occurs,
Tenant shall have the right to terminate this Lease by notice to Landlord given
within thirty days of such fire, casualty, or Taking.

          8.2.4. Landlord's Right to Damages. Landlord reserves, and Tenant
hereby releases aid grants to Landlord, all rights to damages arising from any
Taking, except for damages specifically awarded to Tenant by the Taking
authority. Tenant reserves its right to seek a separate award from the Taking
authority for Tenant's relocation expenses.

     Section 8.3. Access to Premises; Landlord's Right to Repair and Alter.

          8.3.1. Viewing, Inspecting, Repairing. Landlord and Landlord's agents
shall have the right, without charge to Landlord and without reduction in Rent,
from time to time, at reasonable times after reasonable notice and to the extent
practicable (and in an emergency, at any time), to enter to view the Premises,
to inspect the Premises, to make such repairs to the Premises or the Buildings,
the Structural Components or Building Systems as Landlord elects, and to perform
environmental site inspections or soil investigations, or to inspect or repair
utilities, if any, located in, beneath, above, or adjacent to the Premises.
Landlord will to the


                                       41

<PAGE>

extent practicable, exercise its rights under this Section 8.3.1 in a manner
designed to avoid undue interference with the Premises and Tenant's use thereof.

          8.3.2. Landlord Alterations, Pest Extermination. Landlord reserves the
right, exercisable by Landlord or its agents or nominees, at any time and from
time to time, at reasonable times after reasonable notice without the same
constituting an actual or constructive eviction and without incurring any
liability to Tenant therefor or otherwise affecting Tenant's obligations under
this Lease, to make (whether or not required by a safety, insurance, or
Governmental Authority, or otherwise) such changes, alterations, additions,
improvements, repairs, renovations, or replacements in or to the Buildings and
the Premises and the fixtures and equipment thereof, as well as in or to the
Building Systems, Structural Components, and the Common Facilities, as Landlord
may reasonably deem necessary or desirable, and to install in the Premises (and
Landlord may thereafter use, maintain, repair, renovate, relocate, and replace),
pipes, ducts, wires, conduits, meters, fixtures, supporting columns, and other
installations generally, and to change the arrangement or location of entrances,
passageways, doors, doorways, corridors, elevators, stairs, toilets, or other
public parts of the Building, or any of the Common Facilities. Landlord agrees
to exercise all such reserved rights, to the extent practicable, in a manner
designed to avoid undue interference with Tenant's use of the Premises. Nothing
contained in this Section 8.3 shall be deemed to relieve Tenant of any duty,
obligation, or liability of Tenant with respect to making any repair,
replacement, renovation or improvement or complying with any law, order, or
requirements of any governmental or other authority, that would otherwise
expressly be the duty or liability of Tenant. Landlord reserves the right to
enter the Premises at reasonable times after reasonable notice to exterminate
insects, rodents, and other pests, and otherwise perform pest control measures,
and Landlord will, to the extent practicable, do so in a manner designed to
avoid undue interference with the Premises and Tenant's use thereof.

          8.3.3. Right to Remove Certain Items and Improvements. Landlord may
remove, at Tenant's expense (which expense shall be other additional rent),
alterations, additions, signs, awnings, aerials, flagpoles, or the like
installed by Tenant, and not consented to in writing by Landlord.

          8.3.4. Right to Affix "For Rent" Sign. Landlord may at reasonable
times and after reasonable notice show the Premises to prospective purchasers,
tenants, and mortgagees (but only during the last nine months of the Lease Term
with respect to prospective tenants) and may keep affixed to any suitable part
of the exterior of the Premises a notice for letting during the nine months
preceding the expiration of the Lease Term.

          8.3.5. Right to Modify Complex. Landlord expressly reserves the right
at any time, and subject to Landlord's obligation to maintain the Complex
pursuant to the terms of Section 9.5, (a) to add, modify, expand, remove,
diminish, reduce, relocate or reconfigure the building(s), vehicle parking areas
and other common areas and Common Facilities of the Complex, including the
location and dimensions of and exits and entrances to any common areas, or to
any buildings in the Complex, including, the Buildings, provided that Landlord
agrees not to reduce Tenant's Share of Parking Spaces; (b) to add or remove
contiguous parcels of real property to the area of the Complex; provided,
however, that the general location and size of the Premises and reasonable
access thereto shall not be materially impaired; (c) to rename the


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<PAGE>

Complex or any of the buildings, including the Buildings, and to change the
address of any of the buildings in the Complex, including the Buildings; and (d)
to convert any of the buildings (other than the Buildings) in the Complex to
residential purposes or to construct residential housing in the Complex.

     Section 8.4. Amendment, Severability. Neither this Lease nor any provision
thereof may be changed, waived, discharged, or terminated orally, but only by an
instrument clearly designated an amendment, duly executed by the party against
which the enforcement of the change, waiver, discharge, or termination is
sought. This Lease supersedes all prior agreements and understandings between
the parties concerning the subject matter hereof, and constitutes the complete
agreement and understanding between the parties. There are no oral statements or
oral agreements modifying or otherwise affecting the subject matter of this
Lease. If any one or more of the provisions of this Lease is finally determined
by a court of competent jurisdiction to be invalid or otherwise unenforceable,
such determination shall not affect the validity or enforceability of the
remaining provisions.

     Section 8.5. Cumulative Effect. Any and all rights, powers, and remedies
that either Landlord or Tenant may have under this Lease, at law, in equity and
by statute or otherwise shall be cumulative and shall not be deemed inconsistent
with each other, and any two or more of the same may be exercised at the same
time.

     Section 8.6. Estoppel Certificates. (A) Tenant shall, from time to time,
within twenty days after a written request by Landlord delivered in accordance
with the notice provisions of this Lease, execute and deliver to Landlord a
so-called "estoppel certificate," in form reasonably satisfactory to Landlord,
as to the status of (i)" this Lease, (ii) Rent and other payments due hereunder,
(iii) defaults hereunder, (iv) any claims or counterclaims, defenses, or offsets
that Tenant may have, and (v) all other matters reasonably required by any
mortgagee or prospective mortgagee or prospective purchaser, and such matters as
Landlord may reasonably request; and any such certificate may be relied upon by
Landlord, any prospective purchaser or mortgagee of the Buildings, any party
proposing to acquire any other interest in or with respect to the Buildings or
the Complex, and by any other person to whom the certificate is addressed.
Tenant acknowledges that time is of the essence to the delivery of such
certificates, and that Tenant's delay, failure or refusal to deliver such
certificates may cause substantial damages resulting from, for example, delays
in obtaining financing or selling the Complex, and therefore Tenant's failure to
deliver such an estoppel certificate within fifteen days after Landlord's
written request shall constitute an Event of Default under this Lease.

          (B) Landlord shall, from time to time, within twenty days after a
request by Tenant delivered in accordance with the notice provisions of this
Lease, execute and deliver to Tenant, a so-called "estoppel certificate" in form
reasonably satisfactory to Landlord as to the status of only the following: (i)
the Lease; (ii) Rent and other payments due hereunder; and (iii) any notices of
default sent by Landlord to Tenant; and any such certificate signed by Landlord
may be relied upon by Tenant, and any person to whom the certificate is
exhibited or delivered.

     Section 8.7. Brokers. Tenant and Landlord each warrants and represents to
the other that it has not dealt with any broker other than the Brokers in
connection with this transaction. In the event of any brokerage claims against
Landlord (excluding claims made by the Brokers) or


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<PAGE>

Tenant predicated on prior dealings by the other party hereto with the maker of
such claims, the party alleged to have had such prior dealings shall defend,
indemnify, and hold the other party harmless against all loss and expense
incurred by it. Landlord shall be responsible for any brokerage commission
payable to the Brokers pursuant to a separate agreement.

     Section 8.8. When Lease is Binding on Landlord. Neither the submission of
this Lease by Landlord to Tenant, nor Tenant's execution and delivery thereof to
Landlord, nor any communications to date between Landlord and Tenant, whether
oral or written, shall constitute, or evidence, any agreement on Landlord's part
or confer any rights on Tenant. The form of transmittal letter as attached
hereto as Exhibit B shall be used by Tenant to transmit to Landlord the Lease
after it has been executed and acknowledged by Tenant, together with all
authorizations, certificates of insurance, and other certificates referred to in
Exhibit B. Landlord is to be bound to Tenant with respect to this Lease and the
Premises only if and when Landlord delivers to Tenant a copy of this Lease
executed by Landlord, and Tenant has delivered to Landlord, and Landlord has
accepted the Letter of Credit.

     Section 8.9. Transfer of Complex. If in connection with or as a consequence
of the sale, transfer, or other disposition of the Complex (or the Buildings,
either or both, as the case may be), Landlord ceases to be the owner of the
reversionary interest in the Premises, Landlord shall thereafter be entirely
freed and relieved from the performance and observance thereafter of all
covenants and obligations hereunder on the part of Landlord to be performed and
observed, it being understood and agreed in such event (and it shall be deemed
and construed as a covenant running with the land) that the person succeeding to
Landlord's ownership of said reversionary interest shall thereupon and
thereafter assume, perform, and observe, any and all of such covenants and
obligations of Landlord.

     Section 8.10. Holding Over. If Tenant occupies (or claims the right to
occupy) the Premises or any portion of the Premises after the Lease Expiration
Date (or earlier termination of this Lease) without having entered into a new
lease of the Premises with Landlord, Tenant shall be a tenant-at-sufferance
only, shall be subject to all of the terms and provisions of this Lease, and
shall pay as use and occupation each month an amount equal to one and one-half
times the monthly Rent payments in effect for the last full calendar month
preceding the Lease Expiration Date (or the date of earlier termination). Such a
holding over, even if with the consent of Landlord, shall not constitute a
tenancy at will or an extension or renewal of this Lease, and shall not diminish
or affect Landlord's right to recover possession of the Premises by self help,
re-entry by summary proceedings or otherwise, the provisions of this Lease,
judicial process, or otherwise. Tenant shall save Landlord harmless and will
exonerate, defend, and indemnify Landlord from and against any and all damages
that Landlord suffers on account of Tenant's holding over in the Premises after
the expiration or sooner termination of the term of this Lease.

     Section 8.11. Captions; Rules of Construction. The captions in this Lease
are for convenience of reference only and shall not define or limit the contents
of this Lease nor be used in construing this Lease. Unless repugnant to the
context, the words "Landlord" and "Tenant" appearing herein shall be construed
to refer to the person or persons, natural or corporate, named above as Landlord
or as Tenant, as the case may be, and the heirs, executors, administrators,
successors, and assignees of such person or persons and those claiming through
or under them or any of them. If Tenant consists of more than one person, the
obligations of all such persons as


                                       44

<PAGE>

Tenant are joint and several. References to an Article, include all Sections of
the Article; references to a Section (e.g., Section 6.1) include all subsections
(e.g., 6.1.1, 6.1.2, 6.1.3) thereof. Wherever in this Lease it is provided that
Landlord's consent or approval is required, Landlord shall have the right to
withhold such consent or approval arbitrarily unless otherwise specifically
provided to the contrary. In this Lease (a) the use of the terms "include,"
"includes," or "including" means "include without limitation," "includes without
limitation," or "including without limitation," respectively, as the case may
be; (b) the word "or" is used in its inclusive sense, i.e., when the word "or"
is used in this Lease to describe a result occasioned by the occurrence of any
of multiple specified events or conditions, the result shall also be occasioned
by the occurrence of more than one of the events or conditions, unless the
context otherwise indicates; (c) "may" is used in the permissive sense, creates
discretionary authority, and does not impose a duty; (d) "shall" is used in the
imperative sense and imposes a duty; (e) a statement or definition followed by a
listing of examples shall not invoke ejusdem generis, i.e., the examples -are
descriptive only and shall not limit the generality of the statement or
definition; and (f) where a general category is described by specific examples
introduced by "including," the listing of the specific examples shall not be
interpreted to be exhaustive.

     Section 8.12. Notices. Unless otherwise specified herein, any notice or
demand to be given hereunder shall be in writing and signed by the party or the
party's attorney and shall be deemed to have been given (a) when delivered, if
delivered by hand, or (b) two calendar days after it is mailed, if mailed by
U.S. mail, postage prepaid, registered or certified mail, return receipt
requested, or (c) one business day after deposit with a nationally recognized
overnight courier service (e.g., Federal Express) provided that evidence of
delivery is obtained, addressed in each such case as follows:

if to Landlord, at Landlord's address as follows:

     President and Fellows of Harvard College
     c/o Harvard Real Estate Services
     1350 Massachusetts Avenue
     Holyoke Center, Suite 800
     Cambridge, Massachusetts 02138-3826

with a copy to Landlord's attorney:

     Office of the General Counsel
     Harvard University
     1350 Massachusetts Avenue
     Holyoke Center, Suite 980
     Cambridge, Massachusetts 02138-3834
     Attention: Robert E. McGaw, University Attorney


                                       45

<PAGE>

with a copy to:

     Beal & Company, Inc.
     177 Milk Street
     Boston, Massachusetts 02109
     Attention: Vice President Property Manager

if to Tenant, at Tenant's address as follows:

     prior to the Occupancy Date:
     Tenant's Mailing Address set forth in Article 1
     Attention: General Counsel

from and after the Occupancy Date:

     300 North Beacon Street
     The Arsenal on the Charles
     Watertown, Massachusetts 02472
     Attention: General Counsel

with a copy to:

     Holland & Knight LLP
     10 St. James Avenue
     Boston, Massachusetts 021116
     Attention: Kenneth B. Hoffman, Esq.

By such notice, either party or such party's attorney may specify a new address,
which thereafter shall be used for subsequent notices. Any mailed notice by
certified or registered mail shall be deemed mailed on the date of postmark of
the mailing of the same. Service by constable showing delivery to the address
stated above of Landlord or Tenant, as the case may be, shall also be an
acceptable method of giving notice. Notice may also be given by a sheriff or
constable in the same manner as provided under the Massachusetts Rules of Civil
Procedure for the service of process.

     Section 8.13. No Waiver, No Exhaustion of Rights. No consent or waiver,
express or implied, by either Landlord or Tenant, to or of any breach of any
covenant, condition, or duty of the other party, shall be construed as a consent
to or waiver of any other breach of the same or any other covenant, condition,
or duty. No consent or waiver by either Landlord or Tenant to any breach of any
covenant, condition, or duty of the other party shall be effective unless it is
in writing and signed by the non breaching party. If for any reason Landlord
consents to or acquiesces to an act of or request of Tenant that is prohibited,
restricted, or governed by law or this Lease, the exercise of the right (or
acquiescence) shall not exhaust the right; rather, Landlord shall continue to
have, enjoy, and be able repeatedly and from time to time to exercise (or
withhold exercise of) its rights to give or withhold consents to, or to
prohibit, as the case may be, similar acts or requests including the right to
prohibit Assignment and Subletting. Landlord's failure to enforce any of the
rules and regulations against Tenant or any other tenant or occupant of the
Building or Complex shall not be deemed a waiver of the rules and regulations or
right to


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<PAGE>

enforce same. The delivery of keys to Landlord shall not operate as a
termination of this Lease or a surrender of the Premises. No act by Landlord or
any agent or employee of Landlord shall be deemed an acceptance or a surrender
of the Premises, except for a written agreement that is clearly designated an
acceptance of surrender of the Premises, duly executed by the authorized
officers of Landlord.

     Section 8.14. Representative Capacity. The obligations of parties hereto
shall run with the land and be binding upon their respective successors and
assigns. In the event of any transfer of title to the Complex or the Buildings
by Landlord, Landlord shall thereafter be released from the performance and
observance of all covenants and obligations under this Lease occurring after the
date of such transfer. None of Landlord's agents, managers, partners, trustees,
stockholders, officers, members of a governing board, directors, employees, or
beneficiaries of Landlord shall be personally liable under this Lease nor shall
any of their assets be subject to levy, execution, or other enforcement
procedure for the satisfaction of the Tenant's remedies arising under this Lease
or in connection with Tenant's use or occupancy of the Premises. Tenant shall
look solely to Landlord's interest in the Premises for satisfaction of any
liability of Landlord under this Lease.

     Section 8.15. No Invalidity. If any term of this Lease, or the application
thereof to any persons or circumstances, shall to any extent be invalid or
unenforceable, the remainder of this Lease or the application of such term to
persons or circumstances other than those as to which it is invalid or
unenforceable, shall not be affected thereby, and each term of this Lease shall
be valid and enforceable to the fullest extent permitted by law.

     Section 8.16. No Recording. Tenant shall not record this Lease. Landlord
agrees, at the request of Tenant, to execute a notice of lease in accordance
with the provisions of M.G.L. c. 183, s. 4, and Tenant may record such notice of
Lease.

     Section 8.17. Time to Commence Actions; No Jury Trial. Any claim, demand,
right, or defense by Tenant that arises out of this Lease or the negotiations
that preceded this Lease shall be barred unless Tenant commences an action
thereon, or interposes a defense by reason thereof, within one year after the
date of the inaction, omission, event, or action that gave rise to such claim,
demand, right, or defense. Tenant waives all right to a jury trial in any
proceeding brought by Landlord for possession of the Premises, nonpayment of
rent, or other default by Tenant under this Lease.

     Section 8.18. Landlord's Right to Erect Obstructions. Landlord reserves the
right to erect any gate, chain or obstruction to close off any portion of the
Buildings and the Complex to the public at any time and to the extent necessary
to prevent dedication thereof to public use or to prevent an acquisition of
private rights and easements by prescription or adverse possession. Landlord
will to the extent practicable exercise its rights under this Section 8.18 in a
manner designed to avoid undue interference with the Premises and Tenant's use
thereof.

     Section 8.19. Effect of Unavoidable Delays. If either party to this Lease,
as the result of any (i) strikes, lockouts, or labor disputes; (ii) inability to
obtain labor or materials, or reasonable substitutes therefor; (iii) acts of
God, governmental action, condemnation, civil commotion, fire, or other
casualty, (iv) trouble in obtaining fuel, electricity, water, sewer, or
telecommunication


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<PAGE>

services or supplies from sources from which they are usually obtained for the
Buildings; or (v) other conditions similar to those enumerated in this Section
beyond the reasonable control of the party obligated to perform, fails to
perform punctually any obligation on its part to be performed under this Lease
(collectively, "Force Majeure"), then such failure shall be excused and not be a
breach of this Lease by the party in question, but only to the extent occasioned
by such event. If any right or option of either party to take any action under
or with respect to this Lease is conditioned upon the same being exercised
within any prescribed period of time or at or before a named date then such
prescribed period of time and such named date shall be deemed to be extended or
delayed, as the case may be, for a period equal to the period of the delay
occasioned by any event described above. The provisions of this Section 8.19
shall not be applicable to Tenant's obligation to pay Rent.

     Section 8.20. No Representations or Inducements. In entering into this
Lease, Tenant acknowledges that Tenant is not relying on any representations,
agreements, or promises of Landlord, or any inducements offered by Landlord to
Tenant, not expressly set forth in this Lease.

     Section 8.21. Formalities of Execution. This Lease is executed in multiple
counterpart copies, each being deemed an original and all of which shall be
deemed to constitute one instrument, to be governed by and construed in
accordance with the laws of The Commonwealth of Massachusetts, to take effect as
a SEALED INSTRUMENT.

     Section 8.22. Community Outreach Agreement. Tenant acknowledges that
Landlord is obligated, under a certain affirmative community outreach agreement
by and between Landlord and Watertown Arsenal Development Corporation ("WADC")
dated as of the first day of December, 1998, to cause every person and entity
conducting a business located in whole or in part in or on the Complex to make
reasonable efforts, in employing persons for such business, to give equal
opportunity to residents of Watertown, Massachusetts. Tenant agrees to make
known to Landlord any employment opportunities within Tenant's business at the
Premises (to the extent that such job openings are not being filled from within
the Tenant's business), and authorizes Landlord to advertise those employment
opportunities, such that residents of Watertown, Massachusetts will be aware of,
and can make application to be considered for, such employment opportunities.
Tenant also agrees that if the Tenant advertises any such employment
opportunities in any trade publication or in any newspaper, that Tenant shall
also concurrently advertise such positions in a similar form, content and size
in at least one newspaper based in Watertown with a general circulation
throughout Watertown.

     Section 8.23. Patriot Act. Executive Order No. 13224 on Terrorist
Financing, effective September 24, 2001 (the "Executive Order"), and the Uniting
and Strengthening America by Providing Appropriate Tools Required to Intercept
and Obstruct Terrorism Act of 2001 (Public Law 10756, the "Patriot Act")
prohibit certain property transfers. Tenant shall comply with all applicable
provisions of the Patriot Act. If required by the Patriot Act, Tenant shall from
time to time, within ten days after request by Landlord, deliver to Landlord a
certification confirming Tenant's compliance with the applicable provisions of
the Patriot Act.


                                       48
<PAGE>

                       ARTICLE 9. - ADDITIONAL PROVISIONS

     Section 9.1. Services to the Premises. If Landlord is required under this
Lease to provide or furnish services or utilities to the Premises, such
obligation to be binding on Landlord must be set forth in this Article 9 or
specifically elsewhere in this Lease, and Landlord shall not be under any duty
to supply or continue at any time any heat, light, electricity, water, gas,
elevator, janitor, or other services to the Premises or the Buildings, except as
may be expressly agreed herein. All charges for utility or other services under
this Article 9, except to the extent included in Additional Rent under Section
3.2, shall be deemed other additional rent.

     Section 9.2. Electricity. From and after the Lease Commencement Date,
Tenant shall pay all charges for its use of electricity in the Premises.
Electricity will be provided to the Premises in accordance with the Base
Building Specifications attached hereto as Exhibits I-1 (the "BUILDING 97 BASE
BUILDING SPECIFICATIONS") and Exhibit I-2 (the "BUILDING 311 BASE BUILDING
SPECIFICATIONS"). Electricity charges for the Building 311 Premises will be
determined by Landlord based upon the check meters installed in Building 311.
Electricity charges for the Building 311 Premises will be billed to Tenant in
arrears on a monthly basis and shall be due on the next Rent Payment Date after
the date of such invoice. Building 97 is separately metered for electricity, and
Tenant shall pay all electricity charges for Building 97 directly to the
applicable service provider. Tenant, at Tenant's expense, shall maintain the
metering equipment in Building 97.

          9.2.1. Replacement Lamps/Bulbs. Landlord, at Tenant's sole cost and
expense and upon Tenant's request, shall purchase and install all replacement
lamps of types generally commercially available (including, but not limited to,
incandescent and fluorescent) and used in the Premises. Tenant, at Tenant's sole
cost and expense, shall purchase all replacement bulbs (as approved by Landlord)
used in the Premises. Tenant may install such replacement bulbs, or Tenant may,
at Tenant's expense, request that Landlord install such replacement bulbs, in
which case Landlord shall install the same at Tenant's expense.

          9.2.2. Selection of Power Providers/Interruption of Utility Service.
If permitted by Legal Requirements, Landlord shall have the right, exercisable
solely by Landlord but at any time and from time to time while this Lease is in
effect, to select and contract with (and change) such provider of electric
service ("POWER PROVIDER") as Landlord deems appropriate to provide electric
power to the Premises, and in connection therewith, Landlord, the applicable
electric utility company, and any such Power Provider, shall have the right of
reasonable access to the Premises to install, maintain, or change such apparatus
and appurtenances thereto as are needed in connection with the provision of
electric power to the Premises by such Power Provider or the applicable electric
utility company. Notwithstanding the foregoing sentence, Landlord shall not be
liable or responsible for any loss, damage, or expense that Tenant may sustain
by reason of any change, failure, interference, disruption, or defect in the
supply or character of the electric energy or any other utility or service
furnished to the Premises, or if the quantity or character of the electric
energy supplied by the applicable Power Provider or electric utility company is
no longer available or suitable for Tenant's requirements, and no such change,
failure, interference, disruption, defect, unavailability, or unsuitability
shall constitute an actual or constructive eviction, in whole or in part, or
entitle Tenant to any abatement of rent, or relieve Tenant from any of Tenant's
obligations under this Lease; provided, however, that if


                                       49

<PAGE>

               (i) the electrical, water or heat service that Landlord is
required hereunder to provide to Tenant is interrupted, or Tenant's data lines
are disrupted resulting in Tenant being unable to send or receive data over all
or a substantial portion of its data lines in the Buildings, and such
interruption or disruption is caused by the negligence or willful misconduct of
Landlord (a "SERVICE FAILURE"), and

               (ii) Tenant promptly gives written notice to Landlord of the
existence of such Service Failure ("TENANT'S OUTAGE NOTICE"), and

               (iii) such service is not restored within five Business Days of
Landlord's receipt of Tenant's Outage Notice, subject to the provisions of
Section 8.19 hereof ("OUTAGE NOTICE PERIOD"), and

               (iv) such Service Failure results in Tenant being unable to
conduct its normal business operations, and Tenant, in fact, shuts-down all or a
portion of its normal business operations in the Premises for the entire Outage
Notice Period, and

then Tenant shall be entitled to an abatement of Rent, in an amount
proportionate to the portion of the Premises so rendered unusable or the portion
of Tenant's normal business operations in the Premises shut-down as a result of
the Service Failure, for the period commencing on the day following the
expiration of the Outage Notice Period, and continuing until the Service Failure
is remedied. Except as set forth in this Section 9.2.2, Landlord shall not in
any way be liable or responsible to Tenant for any loss, damage, or expense that
Tenant may sustain or incur if the quantity, character, or supply of electrical
energy as stated in the Base Building Specifications subsequently becomes no
longer available or suitable for Tenant's requirements.

          9.2.3. Alterations to Electrical Equipment. Tenant will not make any
material alteration or material addition to the electrical equipment or
appliances in the Premises that would adversely affect any Building Systems or
electrical equipment without the prior written consent of Landlord in each
instance, and will promptly advise Landlord of any other alteration or addition
to such electrical equipment and/or appliances.

          9.2.4. Additional Electricity Requirements. If Tenant shall
subsequently require electric current for use in the Premises in excess of the
capacity set forth in the Base Building Specifications for either of the
Buildings, and if in Landlord's reasonable judgment, (i) Landlord's facilities
are inadequate for such excess requirements, or (ii) such excess use shall
result in an additional burden on the Building air conditioning systems and
additional cost to Landlord on account thereof then, as the case may be,
Landlord, upon written request and at the sole cost and expense of Tenant, will
furnish and install such additional wire, conduits, feeders, switchboards, and
appurtenances as reasonably may be required to supply such additional
requirements of Tenant if current therefor is available to Landlord, provided
that the same (v) shall be permitted by Legal Requirements and Insurance
Requirements, (w) shall not cause damage to the Buildings or the Premises, (x)
shall not cause or create a dangerous or hazardous condition, (y) shall not
entail excessive or unreasonable alterations or repairs, and (z) shall not
materially interfere with or disturb other tenants or occupants of the
Buildings. Tenant shall reimburse Landlord for such additional cost within
thirty days of demand therefor.


                                       50

<PAGE>

     Section 9.3. Water. Hot and cold water for ordinary office occupancy will
be provided to the Premises. Costs for water and sewer provided to the Premises
shall be included in Building Operating Costs.

     Section 9.4. Elevators, Heat, Air Conditioning, Cleaning.

          9.4.1. Elevators. Passenger elevator service will be provided to
Building 311 in accordance with the Building 311 Base Building Specifications.
Freight elevator service is also available to the tenants and occupants of
Building 311, subject to prior reservation with Landlord.

          9.4.2. Heating, Venting and Air Conditioning: for the Building 97
Premises. Heating, venting, and air conditioning ("HVAC") will be provided to
the Building 97 Premises in accordance with the Building 97 Base Building
Specifications, and including the additional HVAC unit described in the Work
Letter. Tenant shall have control over the thermostat regulating the HVAC
equipment servicing the Building 97 Premises, and commencing on the Lease
Commencement Date, Tenant shall be responsible for payment of all charges for
HVAC service to the Building 97 Premises directly to the applicable utility
service providers.

          9.4.3. Heating, Venting and Air Conditioning for the Building 311
Premises. HVAC will be provided to the Building 311 Premises in accordance with
the Building 311 Base Building Specifications during business hours. During
non-business hours, Landlord will provide after-hours HVAC service to the
Building 311 Premises if Tenant requests after-hours HVAC service by contacting
Landlord's property management office by 1:00 p.m. on the day service is
required. Tenant shall pay all charges for HVAC services provided to the
Premises, or any portion thereof, during nonbusiness hours, such charges to be
determined based on Landlord's actual cost of providing such HVAC service. The
current after-hours HVAC charge is $.60 per 1,000 rentable square feet per hour.

          9.4.4. Cleaning. Commencing on the Occupancy Date, Landlord shall
cause the common areas of Building 311, and the portions of the Premises used
for offices, to be cleaned Monday through Friday. Except as specified in Exhibit
H the cleaning standards generally prevailing in first-class office parks in
suburban Watertown, shall represent substantially the extent and scope of the
cleaning to be provided by Landlord pursuant to this Section 9.4.4.

          9.4.5. Common Area Maintenance/Repairs. Landlord shall keep and
maintain the Structural Components, Building Systems, and Common Facilities of
the Complex in good order, condition and repair consistent with first-class
office parks in suburban Watertown, to include, but not limited to, landscaping
of outdoor common areas of the Complex, and snow and ice removal from the access
roads, driveways, parking areas, and pedestrian sidewalks located within the
Complex. All costs incurred by Landlord in connection with the foregoing, and in
connection with complying with Legal Requirements that are not Tenant's
obligations, shall be included in Complex Operating Costs or Building Operating
Costs, as applicable, to the extent provided in Sections 3.2.2 and 3.2.3.
Landlord shall not be responsible for making any improvements or repairs to the
Buildings or the Complex other than as expressly set forth in this Section 9.5,
or as expressly provided otherwise in this Lease. Landlord shall never be liable
for any failure to make repairs that Landlord has undertaken to make under the
provisions of this


                                       51

<PAGE>

Section 9.5 or elsewhere in this Lease, unless Tenant has given notice to
Landlord of the need to make such repairs, and Landlord has failed to commence
to make such repairs within a reasonable time after receipt of such notice, or
fails to proceed with reasonable diligence to complete such repairs. Only a
Governmental Authority (and not Tenant) shall have the right to compel Landlord
to comply with a Legal Requirement.

     Section 9.5. Energy Conservation. Notwithstanding anything to the contrary
contained herein, Landlord may institute upon written notice to Tenant such
policies, programs, and measures as may be necessary, required, or expedient for
the conservation or preservation of energy or energy services (collectively, the
"CONSERVATION PROGRAM"), provided however, subject to Legal Requirements, that
the Conservation Program does not, by reason of such policies, programs, and
measures, reduce the level of energy or energy services being provided to the
Premises immediately prior to the institution of such policy, program, and/or
measure. Upon receipt of such notice, Tenant shall comply with the Conservation
Program.

     Section 9.6. Premises Population. Other than parking, all services provided
by Landlord to Tenant are based upon an assumed maximum Premises population
(i.e., occupancy) of one person per 150 rentable square feet of the Premises,
which limit Tenant shall in no event exceed. Tenant acknowledges that if it
exceeds the foregoing limitation, Landlord may incur costs including, without
limitation, additional costs due to the additional load on Building Systems.
Tenant agrees to reimburse Landlord for the amount of such additional costs (if
any), as reasonably determined by Landlord, due to a Premises population that is
in excess of the foregoing maximum.

     Section 9.7. Security. Landlord shall provide security services to the
Complex and to Building 311. Security to the common areas of the Complex is
currently provided from 6:00 a.m. to 11:00 p.m. on Business Days and 24 hours a
day on non-Business Days. Security to Building 311 is currently provided from
3:00 p.m. - 7:00 a.m. during Business Days and 24 hours a day on non Business
Days. Tenant shall be responsible for the security of the Premises, including
Building 97, and for any security system that it may choose, as its sole
expense, to install therein in accordance with the provisions of this Lease.
Landlord shall not be liable for damage to property of Tenant in the Premises or
for injury to persons except to the extent such damage or injury is caused by
the negligence of Landlord. All exterior doors of Building 311, with the
exception of the main lobby door, are locked and provide card access. Landlord
will provide Tenant, at no charge, up to one access card for the Building 311
security system for each employee of Tenant employed at the Building 311
Premises as of the Occupancy Date. Additional and replacement access cards will
be provided by Landlord and paid for by Tenant as other additional rent.

     Section 9.8. Loading Docks. Tenant shall have the right to use in common
with other tenants and occupants of Building 311, Building 311's loading docks.
Tenant's use of the loading docks shall be subject to Landlord's reasonable
rules and regulations. Tenant shall also be permitted to install a secure fence
around an approximately 200 square foot portion of the Building 311 loading dock
in an area designated by Landlord in order to comply with HIPAA requirements.
The design of such fence shall be subject to Landlord's reasonable prior
approval.


                                       52

<PAGE>

     Section 9.9. Telecommunication Service Provider. Tenant shall have the
right to choose its telecommunications service provider and Landlord shall, at
no expense to Landlord, cooperate with such provider in providing access to the
Buildings. Except as otherwise required by law, Landlord has no obligation to
allow any particular telecommunication service provider to have access to the
Buildings or to the Premises, provided that Landlord agrees not to act
unreasonably in connection with allowing access by telecommunications providers
selected by Tenant, and if Landlord permits such access, Landlord may condition
such access upon the payment to Landlord by the service provider of one-time or
recurring fees assessed by Landlord in such amounts as Landlord may determine,
and in addition the service provider shall reimburse Landlord for any costs
incurred by Landlord (including reasonable attorneys fees) in connection with
allowing such access.

     Section 9.10. Signage. Landlord shall, at Landlord's expense, (i) include
Tenant's name on the common directory sign in the interior lobby of Building
311; and (ii) cause one interior entry suite sign to be installed at the
entrance to the Building 311 Premises (the "TENANT INTERIOR SIGNS"). Tenant may,
at Tenant's expense, install an interior sign in the Entry Premises (the "TENANT
ENTRY SIGN"). Tenant, at Tenant's sole cost and expense, and provided Tenant has
obtained all Governmental Authority approvals and permits, shall be permitted to
install (a) two signs on the exterior of Building 311, one on the north side of
Building 311 along Arsenal Street and the other facing the fountain, (b) two
signs on the exterior of Building 97, and (c) one flag on the exterior of
Building 97, all in a location mutually acceptable to Landlord and Tenant
(collectively, the "TENANT EXTERIOR SIGNS"). The location and design of Tenant's
Exterior Signs shall be subject to subject to Landlord's written approval, such
approval not to be unreasonably withheld or delayed. Tenant shall, at Tenant's
sole cost and expense, comply with all Legal Requirements applicable to Tenant's
Exterior Signs, and shall be responsible for all maintenance and lighting of
Tenant's Exterior Signs. Landlord may, at Tenant's expense, remove any sign,
including Tenant's Entry Sign and Exterior Signs, that are not in compliance
with the terms of this Lease. Any sign installed by Tenant shall be removed by
Tenant at the end of the Lease Term in accordance with the terms of Section
5.1.4. All Tenant Interior Signs and Tenant Exterior Signs shall be consistent
with building standard signage.

     Section 9.11. Rooftop Equipment and Communication Devices. Tenant shall
have the right to install Communication Devices (as defined in Exhibit K), and a
back-up generator on the roof of Building 311, subject to compliance with the
'terms and conditions set forth in Exhibit K.

                   ARTICLE 10. - OPTION TO EXTEND LEASE TERM

     Section 10.1. Tenant's Option to Extend. On the conditions (which
conditions Landlord may in its sole discretion waive by notice to Tenant at any
time) that (i) Tenant is in compliance with the terms of this Lease and no Event
of Default exists, and (ii) Tenant is occupying at least 60% of the Premises
originally demised by this Lease, in the case of each such condition, both as of
the time of the exercise of the Tenant's rights in this Article 10, and as of
the commencement of the Extension Term, Tenant shall have the option to extend
this Lease for each Extension Term. Tenant may exercise each Extension Term by
giving written notice ("EXTENSION NOTICE") to Landlord at least nine months
before the Lease Expiration Date. Time shall be of the essence in this Article
10.


                                       53

<PAGE>

     Section 10.2. Determination of Rent for the Extension Term. The Basic Rent
for the first Lease Year of each Extension Term shall be equal to the greater of
the following:

               (i) the amount of the Basic Rent for the last year of the
preceding Lease Term, or

               (ii) 95% of the Market Rent.

The term "MARKET RENT" shall mean the fair market rental value of the Premises
for each Lease Year of the Extension Term calculated as of the commencement of
the Extension Term, based on the length of such Extension Term, and the value of
similar office space in the Complex and in the Waltham, Newton, Watertown and W.
Cambridge area, and after adjustment for the then current operating expenses,
additional rent, real estate taxes, and other amounts payable by Tenant, the
condition of the Buildings and the Complex, and the governing provisions of this
Lease. Market Rent shall be calculated on the then "as-is" condition of the
Premises, taking into account current market conditions relative to tenant
improvement allowances, leasing commissions and other costs being paid by
landlords to sign leases with renewal tenants for space similar to the Premises.
If Tenant extends its Lease pursuant to this Article 10, the base years for
operating expenses and taxes will be the calendar and fiscal years,
respectively, in which the extension takes place. The Market Rent shall be
determined as follows:

     (a) Landlord shall reasonably determine Market Rent and shall set forth its
determination in a notice given to Tenant within sixty days after Tenant gives
the, Extension Notice.

     (b) If Tenant accepts Landlord's determination, Tenant shall give Landlord
a notice stating Tenant's acceptance within thirty days of receipt of Landlord's
notice sent in Section 10.2(a) (an "ACCEPTANCE NOTICE"). If Tenant in good faith
disagrees with Landlord's determination, Tenant shall within thirty days after
the receipt of Landlord's notice give Landlord written notice of Tenant's
disagreement with Landlord's determination, detailing Tenant's basis for
disagreement. If Tenant fails to give Landlord a notice during such thirty-day
period, it shall be deemed that Tenant irrevocably accepted Landlord's
determination.

     (c) In the event that Tenant gives such notice of disagreement, and
Landlord and Tenant do not resolve by negotiation the Market Rent within thirty
days after Tenant gives said notice of disagreement, the Market Rent shall be
determined by appraisal as provided below.

     (d) If Market Rent is to be determined by appraisal, then within ten days
after the expiration of the thirty-day negotiation period referred to in Section
10.2(c), Landlord and Tenant shall each appoint as an appraiser a real estate
appraiser experienced in appraising space similar to the Premises in the market
or neighborhood area of the Premises, and give notice of such appointment to the
other party. If either Landlord or Tenant shall not so appoint such an
appraiser, then the appointed appraiser shall select the second appraiser within
ten days after the failure of Landlord or Tenant, as the case may be, to
appoint. Such two appraisers shall, within 'thirty days after the appointment of
the latter of them to be appointed complete their determination of the Market
Rent based on the standards set forth in this Section 10.2, and submit their
appraisal reports simultaneously in writing to each of Landlord and Tenant. If
their


                                       54

<PAGE>

valuations vary by five percent or less from their arithmetic average, the
Market Rent shall be the arithmetic average of the two valuations. If the
valuations vary by more than five percent from their arithmetic average, the two
appraisers shall, within ten days after submission of the last submitted
appraisal report, appoint a third appraiser who shall be similarly qualified. If
the two appraisers are unable to agree timely on the selection of the third
appraiser, then either appraiser, on behalf of both, may request such
appointment by the President of the Boston Bar Association. Within thirty days
after the appointment of the third appraiser, the third appraiser shall
determine Market Rent and give notice to Landlord and Tenant of such
determination together with a copy of the appraisal report. The Market Rent
shall be as determined by the third appraiser, (y) unless it is less than the
valuation set forth in the lower of the first two appraisals previously
obtained, in which case the valuation set forth in the lower appraisals shall be
controlling, or (z) unless it is greater than the valuation set forth in the
higher of the first two appraisals previously obtained, in which case the
valuation set forth in the higher of the first two appraisals shall be
controlling.

     (e) If the three appraisers have not established the Market Rent before the
Lease Expiration Date, then the Basic Rent for the first Lease Year of the
Extension Term shall be calculated under clause (i) of the first sentence of
this Section 10.2, until the Market Rate is determined by the appraisers, and
then the parties shall adjust for over or under-payments within ten days after
notice of the decision of the appraisers finally establishing the Market Rent is
given to Tenant and Landlord.

     Section 10.3. Costs and Expenses. Landlord and Tenant shall each pay the
fees of their respective appraisers and the fees of the third appraiser shall be
paid one-half by Landlord and one-half by Tenant; provided, however, that if the
Market Rent as finally determined is more than ten percent above the lower
appraisal previously obtained, the fees of all appraisers shall be borne by the
party appointing the appraiser responsible for the lower appraisal, and if the
Market Rent as finally determined is more than ten percent below the higher
appraisal previously obtained, the fees of all appraisers shall be borne by the
party appointing the appraiser responsible for the higher appraisal.

     Section 10.4. Continuation of Terms and Conditions. All of the terms,
covenants, and agreements contained in this Lease shall continue during the
Extension Term, except that the Basic Rent shall be as set forth in Section
10.2.

     Section 10.5. Definition. If this Lease is extended as provided herein, the
phrase "Lease Expiration Date" shall mean the last day of the Extension Term.

     IN ENTERING INTO THIS LEASE, TENANT ACKNOWLEDGES THAT TENANT IS NOT RELYING
ON ANY REPRESENTATIONS, AGREEMENTS, INDUCEMENTS, OR PROMISES OF LANDLORD NOT
EXPRESSLY SET FORTH IN THIS LEASE.

                   [Balance of Page Intentionally Left Blank]


                                       55

<PAGE>

EXECUTED as of the date first above written.

                                        LANDLORD:

                                        PRESIDENT AND FELLOWS
                                        OF HARVARD COLLEGE


                                        By: Illegible
                                            ------------------------------------


                                        By: Illegible
                                            ------------------------------------


                                        TENANT:

                                        ATHENAHEALTH, INC.


                                        By: /s/ Carl Byers
                                            ------------------------------------
                                        Name: Carl Byers
                                        Title: CFO


                                       56

<PAGE>
*Exhibit has been omitted pursuant to request for CTR
**Portion of Exhibit has been omitted pursuant to request for CTR


                                    EXHIBITS

  Exhibit A  Rules and Regulations
  B          Form of Transmittal Letter
**C          Form of Letter of Credit
  C-1        Approved Form of Letter of Credit
 *D          Floor Plan of Premises
 *D-1        Floor Plan of Building 97 Premises
 *D-2        Floor Plan of Building 311 Premises
  E          Site Plan
**F          Work Letter
  G          List of Environmental Restrictions
  H          Cleaning Specifications
  I          Base Building Specifications
  I-1        Building 97 Base Building Specifications
  I-2        Building 311 Base Building Specifications
**J          Existing Lease Obligations
  K          Lease Rider
  L          Shuttle Bus Schedule
  L-1        4th Shuttle Bus Schedule


                                       57
<PAGE>
                        EXHIBIT A: RULES AND REGULATIONS

              PRESIDENT AND FELLOWS OF HARVARD COLLEGE ("Landlord")

                        RULES AND REGULATIONS FOR TENANTS

    [Capitalized terms herein have the meanings set forth in Tenant's Lease].

                                  Introduction

      The following rules and regulations have been formulated for the safety
and well-being of all tenants and to ensure compliance with all governmental,
insurance, and other requirements. Strict adherence to these rules and
regulations is necessary so that each and every tenant will enjoy a safe and
unannoyed occupancy in their respective premises in accordance with their lease.
It should be apparent that in some cases some of the rules and regulations will
be by their terms inapplicable to a specific building or to a specific tenant's
premises, and in these cases these rules and regulations shall be interpreted by
reference to the specific circumstances involved.

      Landlord reserves the right to reasonably amend or rescind, from time to
time, any of these rules and regulations and to make such other and further
reasonable rules and regulations as in its judgment shall, from time to time, be
required for the safety, protection, care, and cleanliness of the buildings and
the Complex, the operation thereof, the preservation of good order therein, and
the protection and comfort of the tenants and their agents, employees, and
invitees. Such rules and regulations need not be uniform for all tenants in a
building, and Landlord is under no obligation to enforce any of the rules and
regulations or to enforce any of them uniformly, provided, however, that
Landlord shall endeavor to enforce the rules and regulations in a
non-discriminatory manner. Such rules and regulations, when made, amended, or
rescinded and written notice thereof is given to a tenant, shall be binding upon
the tenant. If President and Fellows of Harvard College ("Harvard"), or any
affiliate of, or related entity to Harvard, occupy any portion of the Complex
they shall not be deemed "tenants" for purposes of these Rules and Regulations.

      Landlord may, upon request by any tenant waive compliance by such tenant
to any of these rules and regulations, provided that (a) no waiver shall be
effective unless in writing and signed by Landlord, (b) any such waiver shall
not relieve such tenant from the obligation to comply with such rule or
regulation in the future unless expressly consented to by Landlord, (c) no
waiver granted to any tenant shall relieve any other tenant from the obligation
of complying with the rules and regulations unless such other tenant has
received a similar waiver in writing from Landlord, and (d) any such waiver by
Landlord shall not relieve the tenant from any obligation or liability of tenant
to Landlord pursuant to the Lease for any loss or damage occasioned as a result
of the Tenant's failure to comply with any such rule or regulation.

      To the extent of any inconsistencies between these rules and regulations
and any rules and regulations hereafter promulgated and the terms of the Lease,
the express terms of the Lease shall govern.

<PAGE>

                         Specific Rules and Regulations

      1. The sidewalks, driveways, entrances, passages, courts, elevators,
vestibules, stairways, corridors, halls, fire escapes, or other parts of the
Complex or the buildings not occupied by any tenant shall not be obstructed by
any tenant or used for any purpose other than ingress and egress to and from the
tenant's premises. Landlord shall have the right to control and operate the
public portions of the Complex and the buildings and the facilities furnished
for common use of the tenants in such manner as Landlord deems best for the
benefit of the tenants generally. No tenant shall permit the visit to the
tenant's premises (or to other premises or to any space, in the buildings) of
persons in such numbers or under such conditions as to interfere with the use
and enjoyment by other tenants of the entrances, corridors, elevators, and other
public portions or facilities of the building.

      2. No awnings, signs, or other projections shall be attached to the
outside walls of the building without the prior written consent of Landlord. No
drapes, blinds, shades, or screens shall be attached to or hung in, or used in
connection with, any window or door of a tenant's premises, without the prior
written consent of Landlord which consent shall not be unreasonably withheld.
Such awnings, projections, curtains, blinds, shades, screens or other fixtures
must be of a quality, type, design; and color, and attached in the manner,
approved by Landlord in its reasonable discretion. No tenant shall throw
anything out of the doors or windows or down the corridors, stairs, or air
shafts.

      3. No showcases or other articles shall be put outside, in front of, or
affixed to any part of the exterior of the building, nor placed in the halls,
corridors, or vestibules without the prior written consent of Landlord.

      4. The water, toilets, wash closets, and other plumbing fixtures shall not
be used for any purposes other than those for which they were constructed, and
no sweepings, rubbish, cooking oils, grease, cleaning solvents, rags, chemicals,
paints, cleaning fluids, or other substances shall be put therein. All fines,
penalties, and damages resulting from any misuse of the fixtures shall be borne
by the tenant who, or whose servants, employees, agents, visitors, or licensees,
shall have caused the same, and Landlord in no case shall be responsible
therefor.

      5. There shall be no marking, painting, drilling into, or in any way
defacing the building or any part of tenant's premises visible from public areas
of the building. Tenants shall not construct, maintain, use, or operate within
the tenant's premises any electrical device, wiring, or apparatus in connection
with a loud speaker system or other sound or alarm system except as reasonably
required for its communication or security system and approved by Landlord
before the installation thereof. The tenant shall bear all costs and pay all
fines in connection with any malfunctioning system. If in the reasonable opinion
of Landlord, the system becomes a nuisance or creates an unreasonable
disturbance, the tenant shall promptly remedy or remove same as Landlord may
request. No such loud speaker or sound system shall be constructed, maintained,
used, or operated outside of tenant's premises.

      6. No bicycles, vehicles, or animals, birds, or pets of any kind (except
for seeing-eye dogs) shall be brought into or kept in or about public areas,
common areas of the building, or a tenant's premises and no cooking shall be
done or permitted by any tenant in the tenant's

                                        2
<PAGE>

premises, except, tenants may heat or reheat foodstuff in microwave or toaster
ovens located within a tenant's premises. Tenants shall not cause or permit any
unusual or objectionable odors to be produced upon or permeate from the tenant's
premises.

      7. No space in the building shall be used by a tenant for manufacturing of
goods for sale in the ordinary course of business, for the storage in bulk of
merchandise or for the sale at auction of merchandise, goods, or property of any
kind.

      8. No tenant shall unreasonably disturb or interfere with occupants of the
building or neighboring buildings or premises or those having business with them
whether by the use of any musical instrument, radio, talking machine, unmusical
noise, whistling, singing, or in any other way.

      9. No flammable, combustible, radioactive, infectious, or explosive fluid,
chemical, or substance shall be brought or kept upon a tenant's premises.

      10. No additional locks or bolts of any kind shall be placed upon any of
the doors or windows by any tenant, nor shall any changes by made in existing
locks or the mechanism thereof without the prior written consent of Landlord.
All locks for doors in tenant's premises shall be "building standard." If a
tenant desires to change the existing locks or the mechanism thereof, the tenant
shall first obtain the approval of Landlord and then shall provide copies of the
keys to such new or changed locks to Landlord immediately upon installing such
new locks or changing the mechanism of existing locks. All requests for
duplicate keys shall be made through Landlord and charged to tenant. The doors
leading to the corridors or main halls shall be kept closed during business
hours except as they may be used for ingress or egress. Corridor doors, when not
in use, shall be kept closed. Tenants shall, and shall cause their employees to,
lock the doors to the tenant's premises as tenant and tenant's employees leave
at the end of each working day and after ordinary business hours, ascertain that
the doors of the building by which it and they leave are locked securely. Each
tenant shall, upon the termination of its tenancy, restore to Landlord all keys
of stores, offices, storage, and toilet rooms either furnished to or otherwise
procured by such tenant. In the event of the loss of any keys so furnished, such
tenant shall pay to Landlord the cost thereof.

      11. Landlord reserves the right to inspect all freight to be brought into
the building and to exclude from the building all freight that violates any of
these rules and regulations.

      12. No tenant shall pay any employees on the tenant's premises, except
those actually working for such tenant on the tenant's premises.

      13. Landlord reserves the right to exclude from the building at all times
any person who is not known or does not give proper and satisfactory
identification to the Complex or building management. Tenants will comply with
any reasonable measures instituted for the security of the building, which may
include the signing in or out in a register in the building lobby after hours
and on weekends and holidays. Each tenant shall be responsible for all persons
for whom it authorizes entry into or exit out of the Complex or the building,
and shall be liable to Landlord for all acts or omissions of such persons.

                                        3
<PAGE>

      14. A tenant's premises shall not, at any time, be used for lodging or
sleeping or for any immoral or illegal purpose.

      15. Each tenant, before closing and leaving its premises at any time,
shall see that all windows are closed and all lights other than emergency lights
and security lights are turned off.

      16. Landlord's employees shall not perform any work or do anything outside
of their regular duties, unless under special instruction from the management of
the Complex. The requirements of tenants will be attended to only upon
application to Landlord and any such special requirements shall be billed to the
tenant (and paid with the next installment of rent due) at the schedule of
charges maintained by Landlord (which will be provided to the tenant upon the
tenant's request) from time to time or at such charge as is agreed upon in
advance by Landlord and the requesting tenant.

      17. Canvassing, soliciting, and peddling in the Complex and the building
is prohibited and each tenant shall cooperate to prevent the same.

      18. There shall not be any hand trucks used in any tenant's premises, or
in the public halls of the building, either by any tenant or by jobbers or
others, in the delivery or receipt of merchandise, except those equipped with
rubber tires and side guards. Tenants shall be responsible to Landlord for any
loss or damage resulting from any deliveries to tenants.

      19. Mats, boxes, trash, or other objects shall not be placed in the public
corridors. Trash shall be stored and disposed of only in accordance with
Landlord's instructions.

      20. No one except Landlord and its employees and agents shall be allowed
on the roof of the building, in utility or janitor's closets, or in any basement
areas except those areas specifically leased to a tenant or otherwise expressly
designated for the tenant's use.

      21. No tenant shall place any sign or advertising notice in any part of
the building or any part of the Complex except as approved by Landlord, or use
any advertising or take any other action that in Landlord's judgment might tend
to affect adversely the reputation of the Complex or the building and its
desirability as a building for laboratory space and offices.

      22. Movement of furniture or office equipment, or dispatch or receipt by
tenants of any bulky material, merchandise, or materials that requires use of
elevators or stairways, or movement through the building entrances or lobby,
shall be restricted to such hours as Landlord may reasonably designate, and such
movement shall be subject to reasonable control of Landlord.

      23. Landlord shall have the authority to limit the weight and prescribe
the manner that safes, file cabinets, and other heavy equipment are positioned.

      24. Any passenger elevators are to be used only for the movement of
persons and routine deliveries to a tenant's premises, unless an exception is
first approved by Landlord in writing.

                                        4
<PAGE>

      25. Tenants shall not tamper with or attempt to adjust temperature control
thermostats in their respective premises with respect to base building systems.
A tenant shall request Landlord to adjust thermostats to maintain required
temperatures for heating, ventilating, and air conditioning.

      26. No vending or coin- or token-operated machines of any type shall be
allowed in a tenant's premises (or any common area) without the prior written
consent of Landlord.

      27. Landlord shall not be responsible for lost or stolen personal
property, money, or jewelry from a tenant's premises, the common areas, or any
public areas regardless of whether such loss occurs when area is locked against
entry or not.

      28. Tenants shall participate and shall ensure that the tenant's employees
participate in all safety programs, practices, and drills, relating to emergency
evacuation of the building. Tenants shall ensure that tenant's employees are
appropriately instructed and informed. Tenants shall provide appropriate
evacuation monitors, assistants, and wardens as necessary to assist in
evacuations.

                                        5
<PAGE>

                      EXHIBIT B: FORM OF TRANSMITTAL LETTER

                   [ to be retyped onto letterhead of Tenant ]

President and Fellows of Harvard College
c/o Harvard Real Estate Services
Holyoke Center, Suite 800
Cambridge, Massachusetts 02138-3826

Greetings:

      We deliver herewith three copies of a proposed lease dated as of
______________ (hereinafter the "Lease"), between President and Fellows of
Harvard College ("Harvard") as Landlord and the undersigned athenahealth, Inc.
(hereinafter "Tenant"), as lessee, of certain premises at Building 311 and
Building 97, all of which have been executed by Tenant; a Clerk's Certificate
authorizing Tenant's entry into this Lease, a recent certificate of legal
existence for Tenant issued by the [Secretary of State of the Commonwealth of
Massachusetts], the Letter of Credit, and one or more certificates of insurance
as required by Section 5.1.20 of the Lease.

      This delivery to Harvard of the enclosed documents constitutes an offer by
Tenant to Harvard to enter into the Lease and to have the letter of credit held
pursuant to the Lease. Harvard may accept this offer by executing one of the
enclosed copies of the Lease within ten Business Days of the date of this letter
and delivering the executed Lease to Tenant at the address first above listed or
at our counsel's office. Delivery may be by delivery in hand or mailing and if
mailed, delivery shall be deemed effective upon mailing. This offer is
irrevocable through ten Business Days after the date hereof. Thereafter this
offer shall be deemed continuing and may be revoked by either Landlord or Tenant
in writing delivered to the other party, which revocation shall be effective
upon receipt by the other party.

      The documents delivered herewith are delivered subject to, and Tenant
agrees that Tenant's relations with Harvard are in all respects subject to,
Section 8.8 of the Lease and that, without limiting the foregoing, Harvard shall
be bound with respect to the Lease and the Premises demised thereunder only if
and when Harvard delivers an executed Lease as described above, Tenant delivers
the Letter of Credit to Harvard, and Harvard has accepted the Letter of Credit
in accordance with the foregoing and the terms of the Lease.

<PAGE>

      EXECUTED UNDER SEAL this ____ day of _______.

                                            athenahealth, Inc.

                                            By:_________________________________
                                            Name:_______________________________

Enclosures:
Lease (executed by Tenant in triplicate)
Clerk's Certificate
Certificate of Legal Existence
Letter of Credit
Certificate(s) of Insurance

                                        2
<PAGE>
Confidential Materials omitted and filed separately with the Securities and
Exchange Commission. Asterisks denote omissions.

                       EXHIBIT C: FORM OF LETTER OF CREDIT
                      (Name or letterhead of issuing bank)

$_________________________

LETTER OF CREDIT NO. ____________                           DATE:_______________

President and Fellows of Harvard College
c/o Deputy Director of Finance/Controller
Harvard Real Estate Services
Holyoke Center, Suite 800
Cambridge, Massachusetts 02138-3826

Gentlemen:

      We hereby open our IRREVOCABLE LETTER OF CREDIT in your favor available by
your draft(s) drawn on OURSELVES at sight for any sum or sums not exceeding in
total [$*] for account of athenahealth, Inc. It is a condition of this Letter of
Credit that on each anniversary hereof, this Letter of Credit shall be deemed
automatically extended without amendment for an additional year, but not beyond
insert the date that is sixty days after the Lease Expiration Date), unless
thirty days prior to any such anniversary hereof we shall notify you by
registered letter, return receipt requested, that we elect not to consider this
Letter of Credit extended. Notwithstanding the giving of such notice, you are
authorized to draw hereunder during such thirty-day period by means of your
sight draft(s) on us.

      Each draft must bear upon its face the clause "Drawn under Letter of
Credit No. dated (insert issue date) of (insert name of issuing bank)."

      This Letter of Credit is transferable in its entirety for the then
available amount at the time of transfer. Cost and expense of such transfer
shall be at expense of applicant.

      Except so far as otherwise expressly stated herein, this Letter of Credit
is subject to the "Uniform Customs and Practice for Documentary Credits (1993
Revision), International Chamber of Commerce Publication No. 500."

      We hereby agree with you that drafts drawn under and in compliance with
the terms of this Letter of Credit will be duly honored if presented to us on or
before insert the date of the first anniversary of issue date) or any
automatically extended date, whichever is later, as above provided.

                                           Very truly yours,

                                           (Name of issuing bank)

                                           By __________________________________
                                              Authorized Official
<PAGE>
                 EXHIBIT C-1: Approval Form of Letter of Credit


               STANDBY LETTER OF CREDIT DRAFT FOR REGIONAL OFFICES

IRREVOCABLE STANDBY LETTER OF CREDIT NO. SVBSFXXXXXX

DATE:

BENEFICIARY:
PRESIDENT AND FELLOWS OF HARVARD COLLEGE
C/O DEPUTY DIRECTOR OF FINANCE/CONTROLLER
HARVARD REAL ESTATE SERVICES
HOLYOKE CENTER, SUITE 800
CAMBRIDGE, MA 02138-3826

APPLICANT:

WATERTOWN, MA 02472

AMOUNT:

EXPIRATION DATE:_______________, 2004

LOCATION: AT OUR COUNTERS IN SANTA CLARA, CALIFORNIA

DEAR SIR/MADAM:

      WE HEREBY ESTABLISH OUR IRREVOCABLE STANDBY LETTER OF (SIT NO. SVBSFXXXXXX
IN YOUR FAVOR AVAILABLE BY YOUR DRAFT DRAWN ON US AT SIGHT IN THE FORM OF
EXHIBIT "B" ATTACHED AND ACCOMPANIED BY THE FOLLOWING DOCUMENTS:

      1. THE ORIGINAL OF THIS LETTER OF CREDIT AND ALL AMENDMENT(S), IF ANY.

      2. A DATED CERTIFICATION FROM THE BENEFICIARY SIGNED BY AN AUTHORIZED
OFFICER, FOLLOWED BY ITS DESIGNATED TITLE, STATING THE FOLLOWING:

      (A)   "An Event of Default exists under that CERTAIN LEASE BY AND BETWEEN
            BENEFICIARY, AS LANDLORD, AND APPLICANT, AS TENANT or Beneficiary is
            otherwise entitled to draw under this Letter of Credit pursuant to
            the terms of the Lease."

                                       OR

      (B)   "WE HEREBY CERTIFY THAT WE HAVE RECEIVED NOTICE FROM SILICON VALLEY
            BANK THAT LETTER OF CREDIT NO. SVBSFXXXXXX WILL NOT BE RENEWED, AND
            THAT WE HAVE NOT RECEIVED A REPLACEMENT OF THIS LETTER OF CREDIT
            FROM

                                  PAGE 1 of 2

<PAGE>

IRREVOCABLE STANDBY LETTER OF CREDIT NO. SVBSFXXXXXX
DATE:

            APPLICANT SATISFACTORY TO US AT LEAST THIRTY (30) DAYS PRIOR TO THE
            EXPIRATION DATE OF THIS LETTER OF CREDIT."

      PARTIAL AND MULTIPLE DRAWS ARE ALLOWED. THIS LETTER OF CREDIT MUST
ACCOMPANY ANY DRAWINGS HEREUNDER FOR ENDORSEMENT OF THE DRAWING AMOUNT AND WILL
BE RETURNED TO THE BENEFICIARY UNLESS IT IS FULLY UTILIZED.

      DRAFT(S) AND DOCUMENTS MUST INDICATE THE NUMBER AND DATE OF THIS LETTER OF
CREDIT.

      THIS LETTER OF CREDIT SHALL BE AUTOMATICALLY EXTENDED FOR AN ADDITIONAL
PERIOD OF ONE YEAR, WITHOUT AMENDMENT, FROM THE PRESENT OR EACH FUTURE
EXPIRATION DATE UNLESS AT LEAST SIXTY (60) DAYS PRIOR TO THE THEN CURRENT
EXPIRATION DATE WE NOTIFY YOU BY REGISTERED MAIL/OVERNIGHT COURIER SERVICE AT
THE ABOVE ADDRESSES THAT THIS LETTER OF CREDIT WILL NOT BE EXTENDED BEYOND THE
CURRENT EXPIRATION DATE. IN NO EVENT SHALL THIS LETTER OF CREDIT BE
AUTOMATICALLY EXTENDED BEYOND___________________.

      THIS LETTER OF CREDIT MAY ONLY BE TRANSFERRED IN ITS ENTIRETY BY THE
ISSUING BANK UPON OUR RECEIPT OF THE ATTACHED "EXHIBIT A" DULY COMPLETED AND
EXECUTED BY THE BENEFICIARY AND ACCOMPANIED BY THE ORIGINAL LETTER OF CREDIT AND
ALL AMENDMENTS, IF ANY, WITH THE APPLICANT'S PAYMENT OF OUR TRANSFER FEE OF 1/4
OF 1% OF THE TRANSFER AMOUNT (MINIMUM USD250.00I).

      ALL DEMANDS FOR PAYMENT SHALL BE MADE BY PRESENTATION OF THE ORIGINAL
APPROPRIATE DOCUMENTS PRIOR TO 10:00 A.M. CALIFORNIA TIME, ON A BUSINESS DAY AT
OUR OFFICE M IE "BANK'S OFFICE") AT: SILICON VALLEY BANK, 3003 TASMAN DRIVE
SANTA CLARA, CA 95054, ATTENTION: STANDBY LETTER OF CREDIT NEGOTIATION SECTION
OR BY FACSIMILE TRANSMISSION AT: (408) 6546211 OR (408) 496-2418; AND
SIMULTANEOUSLY UNDER TELEPHONE ADVICE TO: (408) 654-7120 OR (408) 654-3052),
ATTENTION: STANDBY LETTER OF CREDIT NEGOTIATION SECTION WITH ORIGINALS TO FOLLOW
BY OVERNIGHT COURIER SERVICE; PROVIDED, HOWEVER, THE BANK WILL DETERMINE HONOR
OR DISHONOR ON THE BASIS OF PRESENTATION BY FACSIMILE ALONE, AND WILL NOT
EXAMINE THE ORIGINALS.

      PAYMENT AGAINST CONFORMING PRESENTATIONS HEREUNDER SHALL BE MADE BY BANK
DURING NORMAL BUSINESS HOURS OF THE BANK'S OFFICE WITHIN TWO (2) BUSINESS DAYS
AFTER PRESENTATION.

      WE HEREBY AGREE WITH THE DRAWERS, ENDORSERS AND BONAFIDE HOLDERS THAT THE
DRAFTS DRAWN UNDER AND IN ACCORDANCE WITH THE TERMS AND CONDITIONS OF THIS
LETTER OF CREDIT SHALL BE DULY HONORED

<PAGE>

IRREVOCABLE STANDBY LETTER OF CREDIT NO. SVBSFXXXXXX
DATE:

UPON PRESENTATION TO THE DRAWEE, IF NEGOTIATED ON OR BEFORE THE EXPIRATION DATE
OF THIS CREDIT.

      THIS LETTER OF CREDIT IS SUBJECT TO THE UNIFORM CUSTOMS AND PRACTICE FOR
DOCUMENTARY CREDITS (1993 REVISION), INTERNATIONAL CHAMBER OF COMMERCE,
PUBLICATION NO. 500.

_________________________________               ________________________________
AUTHORIZED SIGNATURE                            AUTHORIZED SIGNATURE

<PAGE>

                                   PAGE 2 of 2

                                   EXHIBIT "A"

DATE:

TO: SILICON VALLEY BANK                               RE STANDBY LETTER OF
    3003 TASMAN DRIVE                                    CREDIT NO. ISSUED BY
    SANTA CLARA, CA 95054                                SILICON VALLEY BANK,
    ATTN: INTERNATIONAL DIVISION.                        SANTA CLARA L/C AMOUNT:
          STANDBY LETTERS OF CREDIT

GENTLEMEN:

FOR VALUE RECEIVED, THE UNDERSIGNED BENEFICIARY HEREBY IRREVOCABLY TRANSFERS TO:

(NAME OF TRANSFEREE)
(ADDRESS)

      ALL RIGHTS OF THE UNDERSIGNED BENEFICIARY TO DRAW UNDER THE ABOVE LETTER
OF CREDIT UP TO ITS AVAILABLE AMOUNT AS SHOWN ABOVE AS OF THE DATE OF THIS
TRANSFER.

      BY THIS TRANSFER, ALL RIGHTS OF THE UNDERSIGNED BENEFICIARY IN SUCH LETTER
OF CREDIT ARE TRANSFERRED TO THE TRANSFEREE. TRANSFEREE SHALL HAVE THE SOLE
RIGHTS AS BENEFICIARY THEREOF, INCLUDING SOLE RIGHTS RELATING TO ANY AMENDMENTS,
WHETHER INCREASES OR EXTENSIONS OR OTHER AMENDMENTS, AND WHETHER NOW EXISTING OR
HEREAFTER MADE. ALL AMENDMENTS ARE TO BE ADVISED DIRECT TO THE TRANSFEREE
WITHOUT NECESSITY OF ANY CONSENT OF OR NOTICE TO THE UNDERSIGNED BENEFICIARY.

      THE ORIGINAL OF SUCH LETTER OF CREDIT IS RETURNED HEREWITH, AND WE ASK YOU
TO ENDORSE THE TRANSFER ON THE REVERSE THEREOF, AND FORWARD IT DIRECTLY TO THE
TRANSFEREE WITH YOUR CUSTOMARY NOTICE OF TRANSFER.

SINCERELY,

_____________________________________
        (BENEFICIARY'S NAME)

_____________________________________
      SIGNATURE OF BENEFICIARY

<PAGE>

SIGNATURE AUTHENTICATED

_____________________________________
           (NAME OF BANK)

_____________________________________
        AUTHORIZED SIGNATURE

<PAGE>

                                   EXHIBIT "B"

DATE: ______________________                         REF. NO. __________________

AT SIGHT OF THIS DRAFT

PAY TO THE ORDER OF ____________________________________  US$ __________________

USDOLLARS_______________________________________________________________________
________________________________________________________________________________

DRAWN UNDER SILICON VALLEY BANK, SANTA CLARA, CALIFORNIA, STANDBY LETTER OF
CREDIT NUMBER NO. ___________________   DATED  ___________________

TO: SILICON VALLEY BANK
    3003 TASMAN DRIVE                                 __________________________
    SANTA CLARA, CA 95054                                (BENEFICIARY'S NAME)

                                                      __________________________
                                                         Authorized Signature

                         GUIDELINES TO PREPARE THE DRAFT

1.    DATE: ISSUANCE DATE OF DRAFT.

2.    REF. NO.: BENEFICIARY'S REFERENCE NUMBER, IF ANY.

3.    PAY TO THE ORDER OF: NAME OF BENEFICIARY AS INDICATED IN THE L/C (MAKE
      SURE BENEFICIARY ENDORSES IT ON THE REVERSE SIDE).

4.    US$: AMOUNT OF DRAWING IN FIGURES.

5.    USDOLLARS: AMOUNT OF DRAWING IN WORDS.

6.    LETTER OF CREDIT NUMBER: SILICON VALLEY BANK'S STANDBY L/C NUMBER THAT
      PERTAINS TO THE DRAWING.

7.    DATED: ISSUANCE DATE OF THE STANDBY L/C.

8.    BENEFICIARY'S NAME: NAME OF BENEFICIARY AS INDICATED IN THE L/C.

9.    AUTHORIZED SIGNATURE: SIGNED BY AN AUTHORIZED SIGNER OF BENEFICIARY.

IF YOU NEED FURTHER ASSISTANCE IN COMPLETING THIS DRAFT, PLEASE CALL OUR L/C
PAYMENT SECTION AND ASK FOR:

ALICA DA LUZ: 408-654-7120
CESAR AGONCILLO: 408-654-3052

<PAGE>
Confidential Materials omitted and filed separately with the Securities and
Exchange Commission. Asterisks denote omissions.




                       EXHIBIT D: FLOOR PLAN OF PREMISES





                                        *
<PAGE>
Confidential Materials omitted and filed separately with the Securities and
Exchange Commission. Asterisks denote omissions.




                           EXHIBIT D-1: FLOOR PLAN OF
                              BUILDING 97 PREMISES





                                        *

<PAGE>
Confidential Materials omitted and filed separately with the Securities and
Exchange Commission. Asterisks denote omissions.




                           EXHIBIT D-2: FLOOR PLAN OF
                             BUILDING 311 PREMISES





                                        *
<PAGE>

                              EXHIBIT E: SITE PLAN

<PAGE>

                                  [SITE PLAN]

<PAGE>

                                    EXHIBIT F

                                   WORK LETTER

      LANDLORD:         President and Fellows of Harvard College

      TENANT:           athenahealth, Inc.

1. DEFINITIONS. Capitalized terms used in this Exhibit and not otherwise defined
shall have the meanings set forth in the Lease. The following capitalized terms
shall have the meanings set forth below:

      A&E GUIDELINES: The architectural and engineering guidelines for Building
311 attached hereto as Schedule C.

      ARCHITECT: Marguiles & Associates.

      BUILDING PERMIT: A building permit issued by the Town of Watertown on the
basis of Tenant's Plans.

      CERTIFICATE OF OCCUPANCY: A certificate of occupancy for the Premises
issued by the Town of Watertown.

      CONSTRUCTION BUDGET: A written budget for the Tenant's Work that contains
a detailed line by line breakdown of all hard and soft costs (including but not
limited to the Construction Contract, furniture, fixture, and equipment needed
to operate the completed facility, architectural, engineering fees, and all
requisite consulting fees, construction manager's expenses, permit fees, legal
costs, insurance premiums, payment, performance, and lien bond premiums,
contingency and construction change order allowances, material testing,
equipment start-up and building commissioning costs, utility company billings,
including construction back-charges, pest and vermin control measures, premium
work costs as may be needed to ameliorate disruption to existing tenants in the
Complex), and all other costs needed to construct Tenant's Work.

      CONSTRUCTION CONDITION PRECEDENT: See Section 2.2. Construction Rent: See
Section 5.2.

      CONSTRUCTION RENT: See Section 5.2.

      DESIGN/DEVELOPMENT PLANS: A set of design/development plans to be more
particularly described in Schedule A attached hereto.

      ENGINEERS: Collectively, all structural, heating, ventilation, air
conditioning, plumbing, fire protection, civil and electrical engineers licensed
in The Commonwealth of Massachusetts retained by Tenant, Architect or General
Contractor to design, supervise or perform the Tenant's Work. All Engineers
shall be approved by Landlord.

      FINAL CONSTRUCTION DRAWINGS: A full set of final construction drawings for
Tenant's Work prepared by the Architect and identified in the Landlord Approval
Letter.

<PAGE>
Confidential Materials omitted and filed separately with the Securities and
Exchange Commission. Asterisks denote omissions.



      FINAL PAYMENT CONDITIONS: See Section 5.3.

      GENERAL CONTRACTOR: A licensed general contractor to be approved by
Landlord, such approval not to be unreasonably withheld. Tenant intends to
engage Columbia Construction.

      LANDLORD APPROVAL LETTER: A letter agreement between Landlord and Tenant
approving the Final Construction Drawings in the form attached hereto as
Schedule B.

      LANDLORD'S ADDITIONAL CONTRIBUTION: Funds of up to a maximum amount of $ *
($ * per rsf) that Landlord has agreed to provide to Tenant subject to the terms
and conditions set forth in Section 6 below, provided, however, that until the
occurrence of the Second Floor Lease Commencement Date, Landlord's Additional
Contribution shall not exceed $ * .

      LANDLORD'S CONTRIBUTION: An allowance of up to a maximum amount of $ *
($ * per rsf plus $ * for bathroom work) that Landlord shall provide to Tenant
for reimbursement of costs in connection with Tenant's Work, subject to the
terms and conditions set forth Section 5 below, provided, however, that until
the occurrence of the Second Floor Lease Commencement Date, Landlord's
Contribution shall not exceed $ * .

      LANDLORD'S WORK: The installation of a 20-ton HVAC unit in Building 97.

      LIEN BOND: A statutory lien bond obtained by the General Contractor to be
recorded against the Complex in the amount of the construction contract.

      OUTSIDE WORK COMPLETION DATE: January 1, 2006.

      PAYMENT AND PERFORMANCE BOND: A payment and performance bond obtained by
the General Contractor and naming Landlord as Owner/Obligee in the amount of the
construction contract.

      SUBSTANTIAL COMPLETION CERTIFICATE: A certificate signed by the Architect
stating that Tenant's Work has been substantially completed in accordance with
the Final Construction Drawings, with the exception of minor items of incomplete
work and so-called "punchlist" items.

      SUBSTANTIAL COMPLETION DATE: The later of the (i) the date that the
Architect delivers the Substantial Completion Certificate to Landlord; or (ii)
the date the Certificate of Occupancy for the Premises is issued.

      TENANT'S FINANCED PERSONALTY: See Section 6.1. Tenant's Permitted
Expenses: See Section 5.1.

      TENANT'S PLANS: Collectively, the Design/Development Plans and the Final
Construction Drawings. The term "Tenant's Plans" shall also include any
revisions to those plans approved by Landlord in accordance with Section 2.1
below.

                                       2
<PAGE>

      TENANT'S WORK: The leasehold improvement work necessary to prepare the
Premises for occupancy by Tenant, including, the installation of
data/telecommunications conduit and cabling, and related equipment, all as
described in Tenant's Plans.

      TOTAL FIT-UP COSTS: The total cost to perform all of Tenant's Work, which
total cost is identified on the Construction Budget.

2.    TENANT'S PLANS.

      2.1 Tenant's Plans. In connection with the performance of Tenant's Work,
Tenant will submit to Landlord for Landlord's written approval a set of the
Design/Development Plans by no later than November 10, 2004. Landlord may list
any comments it has on the Design Development Plans on Schedule A attached
hereto. Tenant shall submit to Landlord for Landlord's written approval, the
Final Construction Drawings by no later than January 1, 2005. Landlord shall
either approve or disapprove of such Final Construction Drawings within 10
Business Days of Landlord's receipt thereof and, in the event of any
disapproval, Landlord will provide Tenant with a summary of the material reasons
for disapproval, and of the changes that will be required before Landlord will
reconsider approving the same. If necessary, Tenant shall promptly cause such
Final Construction Drawings to be modified in accordance with Landlord's
reasonable requests within 10 Business Days of Tenant's receipt of Landlord's
comments. Landlord's approval of the Final Construction Drawings shall not be
unreasonably withheld, conditioned or delayed, provided that they are consistent
with the Design/Development Plans and the A&E Guidelines. At such time as the
Final Construction Drawings are completed and approved by Landlord, Landlord and
Tenant shall each execute and deliver the Landlord Approval Letter, reciting
such approval and definitively identifying the Final Construction Drawings so
approved, and a copy of such letter shall be appended to each counterpart of the
Lease. The Landlord Approval Letter shall also list any elements of Tenant's
Work that must be removed at the end of the Lease Term in accordance with
Section 5.1.4. of the Lease. After execution of the Landlord Approval Letter,
any material changes to Tenant's Plans shall require Landlord's prior written
approval, such approval to follow the procedure outlined in this Section above.
Upon issuance of the Landlord Approval Letter, Tenant shall obtain the Building
Permit.

      Any approval granted by Landlord under this Section 2 shall be granted
solely for the benefit of Landlord, and neither Tenant nor any third party shall
have the right to rely upon Landlord's approval of any of the Tenant's Plans for
any other purpose whatsoever. Without limiting the foregoing, Tenant shall be
responsible for all elements of the design of Tenant's Work (including, without
limitation, the compliance of the Tenant's Work and Tenant's Plans with Legal
Requirements, functionality of design, the structural integrity of the design,
the configuration of the Premises, the demising of the Premises, and the
placement of Tenant's furniture, appliances and equipment), and Landlord's
approval of the Tenant's Plans shall in no event relieve Tenant of the
responsibility therefore.

      2.2 Cost of Initial Fit-Up Work. Prior to commencing construction of
Tenant's Work, Tenant shall submit to Landlord for Landlord's written approval,
such approval not to be unreasonably withheld or delayed, (i) the Construction
Budget; and (ii) evidence reasonably satisfactory to Landlord that Tenant has
cash on hand sufficient to pay the excess if any, in the

                                       3
<PAGE>

Total Fit-Up Costs over Landlord's Contribution plus Landlord's Additional
Contribution (the "CONSTRUCTION CONDITION PRECEDENT").

3.    TENANT'S WORK.

      3.1 Commencement of Tenant's Work/Delivery of Bonds. Tenant shall not
commence construction of Tenant's Work until (i) the Building Permit is issued,
and a copy provided to Landlord; (ii) the Construction Condition Precedent is
satisfied, (iii) Tenant has delivered to Landlord (x) certificates of insurance
evidencing that the General Contractor is carrying all coverages required to be
carried by contractors employed by Tenant under the Lease; and (y) the original
Payment and Performance Bond and the Lien Bond. Landlord will arrange the
recording of the Lien Bond.

      3.2 Performance and Quality of the Tenant's Work. Except for Landlord's
Contribution, all of Tenant's Work shall be performed by Tenant at Tenant's sole
cost and expense. All construction work conducted in connection with the
Tenant's Work shall be done in a good and workmanlike manner with new,
first-class materials, in a lien-free manner and in compliance with all Legal
Requirements, and with the A&E Guidelines, and all requirements of public
authorities and insurance bodies related to, or arising out of the performance
of, such construction work. Tenant shall diligently pursue construction of
Tenant's Work. Landlord shall have the right to inspect such construction work
at any time, provided that Landlord shall use reasonable efforts to give Tenant
prior notice of any such inspections.

      3.3 Completion of the Tenant's Work/Default. Tenant shall cause the
Substantial Completion Certificate to be issued to Landlord on or before the
Outside Work Completion Date. Within fifteen days after the Substantial
Completion Date, Tenant shall record against title to the Complex a Notice of
Substantial Completion signed by the General Contractor that meets the
requirements set forth in M.G.L. c. 254, s. 2A. Tenant shall obtain the
Certificate of Occupancy at the earliest date possible following completion of
Tenant's Work, and shall then occupy the Premises for the conduct of the
Permitted Use within 45 days of the Substantial Completion Date. Any (i)
suspension of construction of Tenant's Work for more than 15 consecutive days or
for more than 20 days in the aggregate, (ii) failure by Tenant to cause Tenant's
Work to be substantially completed by the Outside Work Completion Date, or (iii)
breach of any other of the terms and conditions of this Exhibit F that is not
cured within 10 days after written notice to Tenant thereof, and provided that
the foregoing defaults are not the result of Landlord's failure to pay Tenant a
Landlord Payment (as defined in Section 9), shall in each case be deemed to
constitute an Event of Default under the Lease entitling Landlord to exercise
Landlord's remedies under the Lease, including the right to draw down on the
Letter of Credit to cure any such Event of Default, and the rights set forth in
Section 6 below. Within 30 days after the Substantial Completion Date, Tenant
shall, at Tenant's sole expense, deliver to Landlord a complete set of as-built
plans for the Tenant Work, certified as being accurate and complete by the
Architect. Such plans shall be in so-called "computer assisted design" or "CAD"
format if requested by Landlord.

4. LANDLORD'S WORK. Landlord shall, at Landlord's sole cost and expense,
complete Landlord's Work prior to the Substantial Completion Date. Landlord's
Work shall be performed in compliance with all applicable Legal Requirements.
Tenant may at any time prior to the

                                       4
<PAGE>
Confidential Materials omitted and filed separately with the Securities and
Exchange Commission. Asterisks denote omissions.

issuance of the Landlord Approval Letter, by delivery of notice to Landlord,
elect, in lieu of Landlord performing Landlord's Work, to increase Landlord's
Contribution by an additional $*, and Landlord shall then be released from the
obligation to perform Landlord's Work.

5.    LANDLORD'S CONTRIBUTION.

      5.1 Permitted Expenses. As an inducement to Tenant's entering into the
Lease, and subject to the terms and conditions set forth in this Work Letter,
Landlord shall provide to Tenant Landlord's Contribution. Landlord's
Contribution shall be used by Tenant to pay only for the following costs in
connection with Tenant's Work: general construction costs;
data/telecommunications cabling and related equipment costs; architectural
services, including space plans, as-built plans, and mechanical, electrical and
plumbing work; and construction management fees (collectively, "Tenant's
Permitted Expenses"). Notwithstanding anything herein to the contrary, not more
than $11,011 of Landlord's Contribution shall be used for architectural services
related to the Design/Development Plans.

      5.2 Periodic Payment. Upon commencement of the construction of Tenant's
Work, Tenant shall have the right to obtain periodic payments (but not more than
once a month) of up to 87.5% of Landlord's Contribution (collectively, the
"PERIODIC PAYMENTS") by submitting to Landlord (i) a statement (hereinafter
"TENANT'S STATEMENT"), including requisitions from Tenant's contractors with
retainage of not less than 10% of the amount of such requisition, third party
invoices, and other documentation reasonably requested by Landlord showing in
reasonable detail the cost of all such Tenant's Permitted Expenses and (ii) lien
waivers with respect to work set forth on Tenant's Statement. For the Periodic
Payments, Landlord shall pay to Tenant within 30 days of Landlord's receipt of
Tenant's Statement, the lesser of (i) Tenant's Permitted Expenses as detailed on
Tenant's Statement, or (ii) 87.5% of Landlord's Contribution minus amounts
previously paid to Tenant.

      5.3 Final Payment. Tenant shall have the right to obtain payment of the
unpaid balance of Landlord's Contribution at any time after the Final Payment
Conditions are satisfied but prior to the date that is 90 days after the
issuance of the Certificate of Occupancy (the "FINAL PAYMENT"), by submitting to
Landlord (x) Tenant's Statement in accordance with Section 5.2 above; and (y)
final lien waivers relating to items, services and work performed in connection
with all phases and portions of Tenant's Work. The "FINAL PAYMENT CONDITIONS"
shall mean (i) Landlord has received the Substantial Completion Certificate and
a copy of the final Certificate of Occupancy; and (ii) Tenant is occupying the
Premises for the Permitted Use. For the Final Payment, Landlord shall pay to
Tenant within 30 days of the date of Landlord's receipt of Tenant's Statement
and the lien waivers in compliance with the terms of this Section 5, the lesser
of (i) an amount equal to Tenant's Permitted Expenses as detailed on Tenant's
Statement, or (ii) an amount equal to the unpaid balance of Landlord's
Contribution.

      5.4 Additional Conditions. Landlord shall have the right, upon reasonable
advance notice to Tenant, to inspect Tenant's books and records relating to
Tenant's Statement in order to verify the amount thereof. Except with respect to
work and/or materials previously paid for by Tenant, as evidenced by paid
invoices and written lien waivers provided to Landlord, Landlord shall have the
right to have Landlord's Contribution paid directly to Tenant's contractor(s),
consultants, service providers, and vendor(s). Notwithstanding anything to the
contrary

                                       5
<PAGE>

contained in the Lease: (i) Landlord shall have no obligation to pay any portion
of Landlord's Contribution (including the Final Payment) requested under any
Tenant's Statement that is submitted to Landlord after the Outside Work
Completion Date; (ii) Landlord's obligation to pay any portion of Landlord's
Contribution shall be conditioned upon Tenant being in compliance with the terms
of this Lease, and there existing no default by Tenant in its obligations under
the Lease at the time that Landlord would be required to make such payment; and
(iii) Landlord shall have no obligation to advance any funds or pay any amounts
on account of Tenant's Work in excess of Landlord's Contribution.

6.    LANDLORD'S ADDITIONAL CONTRIBUTION/CONSTRUCTION RENT.

      6.1 Landlord's Additional Contribution. Tenant shall have the right, at
Tenant's election, to increase Landlord's Contribution in an the amount up to
Landlord's Additional Contribution. Landlord's Additional Contribution shall be
used by Tenant to pay only for the following costs (collectively, "TENANT'S AC
PERMITTED EXPENSES") (i) Tenant's Permitted Expenses, or (ii) furniture,
furnishings or equipment purchased by Tenant and to be installed in the Premises
("TENANT'S FINANCED PERSONALTY"), or (iii) moving costs associated with Tenant's
relocation to the Premises ("MOVING COSTS"). Tenant's Financed Personalty shall
not include any furniture, furnishings or equipment leased by Tenant or that is
subject to any other security interest. Landlord's Additional Contribution shall
be payable to Tenant in the same manner, and subject to all of the terms and
conditions applicable to Landlord's Contribution set forth in Section 5 above,
except that all references to Tenant's Permitted Expenses shall mean Tenant's AC
Permitted Expenses. Tenant shall exercise its election to use Landlord's
Additional Contribution by submitting to Landlord Tenant's Statement in
accordance with Section 5.2, and identifying in Tenant's Statement (i) the
Tenant's AC Permitted Expenses for which Tenant is requesting payment from
Landlord's Additional Contribution, and (ii) an itemized listing of all included
Tenant's Financed Property, describing such personalty in reasonable detail (a
"PERSONALTY LIST"). If Tenant elects to use any portion of Landlord's Additional
Contribution, Tenant shall pay Construction Rent in accordance with Section 6.2
below.

      6.2 Construction Rent. If Landlord provides any Landlord's Additional
Contribution then Tenant shall pay to Landlord, as Additional Rent, Construction
Rent, as hereinafter defined. Construction Rent shall commence as of the Rent
Commencement Date and shall continue on each Rent Payment Date thereafter.
"CONSTRUCTION RENT" shall mean a monthly sum equal to the amount of equal
monthly payments of principal and interest which would be necessary to repay a
loan in the amount of Landlord's Additional Contribution paid to Tenant,
together with interest at the rate of eight (8%) percent per annum, on a level
direct reduction basis over the Initial Lease Term (commencing as of the Rent
Commencement Date). Construction Rent shall be treated as Additional Rent under
the Lease. Landlord will deliver to Tenant a statement setting forth the
Construction Rent. Construction Rent shall not be abated or reduced for any
reason whatsoever (including, without limitation, termination of the Lease). In
the event of any termination of this Lease, the outstanding balance of
Landlord's Additional Contribution, plus all unpaid interest earned thereon
shall become automatically due and payable as of the date of such termination.

7. LANDLORD'S CONTRIBUTION, CONSTRUCTION RENT/EVENT OF DEFAULT. Landlord has
agreed to provide Landlord's Contribution and Landlord's Additional Contribution
on the terms and

                                       6
<PAGE>

conditions set forth in this Work Letter as an inducement for Tenant to
faithfully perform its obligations under the Lease. If an Event of Default
occurs (i) Landlord's obligation to provide Landlord's Contribution or
Landlord's Additional Contribution shall, at Landlord's option, cease as of the
date of the occurrence of the Event of Default, and (ii) immediately upon
demand, Tenant shall pay to Landlord an amount equal to the sum of (x) the
unamortized balance of Landlord's Additional Contribution, and all interest
earned thereon, plus (y) the unamortized balance of Landlord's Contribution
(calculated on a level direct reduction basis over the Initial Lease Term). The
provisions of this Section 7 shall apply whether or not Tenant thereafter
remedies such default, and shall be in addition to all other rights and remedies
of Landlord in the event of a default of Tenant under the Lease. Tenant shall
not be entitled to any credit or reduction in the amount owed Landlord pursuant
to this Section 7 based upon amounts collected by Landlord as either Fixed
Damages or from reletting the Premises after an Event of Default.

8. SECURITY INTEREST. To secure the payment of Construction Rent, Landlord shall
have, and Tenant grants to Landlord, a continuing security interest in all of
Tenant's Financed Personalty that has been paid for or purchased, in part or in
whole with Landlord's Additional Contribution, and such property shall not be
removed from the Premises without the consent of Landlord until all Construction
Rent has been paid in full. Upon the occurrence of an Event of Default, Landlord
shall have, in addition to any other remedies provided in this Lease or by law,
all rights and remedies under the Uniform Commercial Code, including, the right
to sell the property at public or private sale upon five days notice to Tenant.
Landlord may file any financing statements necessary to perfect its security
interest under this Section 8, and Tenant shall execute any instruments as shall
be necessary or desirable in Landlord's discretion to perfect the security
interest hereby created; provided, however, any such financing statements shall
include only items listed on a Personalty List. Upon the repayment of all
Construction Rent, Landlord shall cause such instruments to be terminated.

9. DEFAULT. If Landlord defaults in its agreement to pay any payment of
Landlord's Contribution or Landlord's Additional Contribution that Landlord is
obligated to pay hereunder (a "LANDLORD PAYMENT"), and such default continues
for ten business days after Landlord's receipt of notice from Tenant setting
forth such default, then Tenant may, after the expiration of the ten business
day period, set-off against its next payments of Basic Rent due under the Lease,
the amount of the Landlord Payment.

10. NOTICE. Any notice required or permitted to be given pursuant to the
provisions of this Exhibit F shall be given in accordance with the provisions
set forth in the Lease.

                  [Remainder of Page Left Intentionally Blank]

                                       7
<PAGE>

                                   SCHEDULE A

                            DESIGN/DEVELOPMENT PLANS

A.    Initial Design/Development Plans

      Plans prepared by the Architect and attached hereto.

B.    Landlord's Comments on Initial Design/Development Plans

<PAGE>

                                   SCHEDULE B

                            LANDLORD APPROVAL LETTER

                          ______________________, 2004

athenahealth, Inc.

Attn:______________________

      Re:   BUILDING 97 AND BUILDING 311, THE ARSENAL ON THE CHARLES WATERTOWN,
            MASSACHUSETTS (THE "PREMISES")

Ladies and Gentlemen:

      Reference is made to that certain Lease, dated as of ___________, 2004,
between President and Fellows of Harvard College, as Landlord, and athenahealth,
Inc., as Tenant, with respect to the Premises. In accordance with Section 2.1 of
Exhibit F to the Lease, this is to confirm that the Final Construction Drawings
referred to in such Exhibit F are those drawings prepared by ___________________
and described as follows:

<TABLE>
<CAPTION>
DATE                               TITLE                         #PAGES
----                               -----                         ------
<S>                                <C>                           <C>
</TABLE>

      Landlord confirms that it has approved the Final Construction Drawings.

      Landlord hereby requires that the following elements of Tenant's Work
shall be removed by Tenant at the expiration of the Lease Term in accordance
with Section 5.1.4 of the Lease:

                        [LIST ALL ELEMENTS TO BE REMOVED]

      If the foregoing is in accordance with your understanding, would you
kindly execute this letter in the space provided below and return the same to
us, whereupon it will become a binding agreement between us.

<PAGE>

                                                Very truly yours,

                                                PRESIDENT AND FELLOWS
                                                OF HARVARD COLLEGE

                                                By:_____________________________

Accepted and Agreed:

athenahealth, Inc.

By:_______________________________
Name:_____________________________
Title:____________________________

                                       2
<PAGE>

                                   SCHEDULE C

            ARCHITECTURAL AND ENGINEERING GUIDELINES FOR BUILDING 311

<PAGE>

                    ARCHITECTURAL AND ENGINEERING GUIDELINES
                                  TENANT SPACES
                          311 ARSENAL STREET, WATERTOWN

This memorandum will summarize the basic requirements of the Sixth Edition of
the Massachusetts State Building Code (MSBC) applicable to the building at 311
Arsenal Street, Watertown. It includes the conditions imposed by MSBC Appeal
Board in its decision to permit the roof trusses of the building to remain
without fire rating.

BASIC BUILDING CODE REQUIREMENTS

The basic requirements of the MSBC applicable to this building are summarized in
Table No. 1. The occupancy and building characteristic that are the basis for
those requirements are identified at the beginning of that table. Any deviation
from those characteristics including changes of occupancy must be made in
compliance with the building code and the intent of the variance which was
granted with respect to the roof assembly.

CONDITIONS ON THE VARIANCE

Two sets of conditions have been imposed on the design and construction of the
building in order to justify the variance to permit the roof trusses and deck to
be unrated. These are in addition to the standard features of the building
required by the building code based on its occupancy and physical
characteristics. Those requirements are summarized in Table No. 1.

First, in the presentation of technical arguments for the variance, it was
represented that the following fire protection features would be provided in the
building:

      1.    One connection to the site water mains which are supplied from the
            Watertown municipal water system.

      2.    A fire pump to boost system pressures to required levels.

      3.    A standby power supply for the fire pump.

      4.    A system of combined standpipe risers to supply sprinkler systems of
            each floor as well as hose connections within exit stairs.

      5.    Three sprinkler systems per floor with each arranged to be supplied
            from two separate standpipes.

      6.    Complete supervision of all operating characteristics and components
            of the sprinkler and standpipe systems.

      7.    Complete coverage of all levels of the building with automatic smoke
            detectors.

All of these features have been provided as part of the base building except
that tenant sprinkler systems must be arranged to be supplied from two separate
standpipes and tenant space fire alarm systems must include complete coverage
with an addressable automatic smoke detection system.

Second, two conditions ware imposed on the building by the Appeal Board in its
decision. One condition requires that ceilings, where provided, have a one hour
fire rating. This requirement may be applicable to fully enclosed offices,
toilet rooms, storage rooms, equipment rooms and similar spaces which are
provided with ceilings suspended or framed below the roof trusses. The

<PAGE>

decision also required that sprinklers be installed both above (in the truss
space) and below the ceilings (in the use space), where ceilings are provided.

The requirement for a one hour ceiling may be satisfied by installation of a
ceiling assembly which has a one hour "finish rating" by standard Underwriters
Laboratories' test criteria. Such a ceiling will typically require two layers of
5/8 inch Type X gypsumboard appropriately attached to framing above. The ceiling
membranes of UL Floor/Ceiling Assembly Design No. L532 or L505 would be
appropriate for this purpose. The intended fire rating will only be achieved if
the ceiling membrane is provided with connections and support equal to that
provided by the floor assembly to which it is attached in the UL Design (ie.
spacing of framing, frequency of fasteners, etc.).

                                       2
<PAGE>

                      SUMMARY OF BUILDING CODE REQUIREMENTS
                MASSACHUSETTS STATE BUILDING CODE - SIXTH EDITION

                        311 ARSENAL STREET, WATERTOWN, MA

This Code Summary is based upon the Sixth Edition of the Massachusetts State
Building Code (MSBC) and the following assumptions concerning the building and
its occupancy.

The existing single story building will be modified to have four stories above
grade within the existing building envelope. The height to the midpoint of the
sloped roof of the building will be approximately 58 ft. above average grade.
The building area will be approximately 147,000 sf based on the footprint area
of the First Floor.

The building will be utilized for offices classified as a business occupancy in
Use Group B, Business.

Basic requirements of the MSBC under these circumstances are identified below.
The details of the requirements affecting specific building features shall be
determined from the Code as required.

CONSTRUCTION TYPE

(1) Utilize modified Type 1B construction. (T-503)

Type 1B or better construction is required by Table 501 to satisfy the height
and area limitations for a building of B occupancy which is 4 stories in height
and has an area of 147,000 sf and is not subdivided by fire walls. That type of
construction permits such a building to be of unlimited height and area.

The existing unprotected, noncombustible roof assembly will be retained rather
than provide the required 1-1/2 hour fire rated assembly required for Type 1B
construction. A conditional variance from the MA Board of Building Regulations
and Standards Appeal Board will allow the roof trusses and deck to remain
unprotected. Where ceilings are to be provided above specific rooms or spaces of
the top story of the building, those ceilings are required by that decision to
have a one hour fire rating.

OCCUPANCY SEPARATIONS

None required.

FLOOR SYSTEMS

(2) Provide 2 hour fire ratings for floor/ceiling assemblies as required for
construction Type 1B. (T-602)

(3) Provide multiple floor openings arranged as an atrium having features as
summarized in Table No. 1. (713.3, Exception 5, 404.0)

                                       3
<PAGE>

INTERIOR WALLS AND PARTITIONS

(4) Provide unrated partitions for enclosure of exit access corridors. (1011.4)

(5) Provide one hour rated partitions as tenant-to-tenant separation walls.
(T-602)

(6) Provide two hour fire enclosures for stairway, elevator and mechanical
shafts which connect more than three stories and one hour fire rated enclosures
for stairway and mechanical shafts which connect three stories or less. (T-602,
1014.11, 710.3)

(7) Provide 2 hour fire rated enclosures of all rooms, shafts and closets
containing equipment and wiring for emergency power distribution and control.
(MA Electrical Code, 700-10)

(8) Provide one hour fire rated walls with 3/4 hour opening protectives around
the following specific occupancy areas:

            -     Trash rooms

            -     Physical Plant and Maintenance Shops

(302.1.1, T-302.1.1)

(9) Provide smoke partitions designed to resist the passage of smoke constructed
of combustible or non-combustible materials which extend from the floor below to
the underside of the floor or roof above around the following specific occupancy
areas:

            -     Storage rooms over 50 sf in area

(302.1.1, T-302.1.1)

(10) Provide doors to the areas identified in Item 9 which are self closing or
arranged for automatic closing upon detection of smoke. (302.1.1.1)

EXTERIOR WALLS AND ROOF

(11) Provide three hour fire ratings for interior and exterior columns
supporting more than one floor and two hour fire ratings for columns supporting
only one floor or the roof. (T-602)

(12) Provide unrated non-bearing exterior wall components for the building
walls. (705.2, T-705.2)

(13) Utilize unlimited-openings in exterior walls. (705.3, T-705.3)

No rating is required for exterior walls of a sprinklered building of Use Group
B occupancy when the fire separation distance for the wall is greater than 5
feet. Unlimited exterior wall openings are permitted in such a wall when the
wall has a fire separation distance of more than 20 feet.

                                       4
<PAGE>

The fire separation distance of the Arsenal Street wall measured to the
centerline of Arsenal Street is 48 feet. The fire separation distances of walls
not facing immediately adjacent buildings are well in excess of 20 feet.

The physical distance between Building 311 and the Harvard Printing Building is
approximately 37 feet. A fire separation distance of greater than 15 feet for
the Harvard Printing Building permits that building to have an unrated exterior
wall with not more than 70% openings. The remaining 22 feet is considered the
fire separation distance for Building 311. That distance allows the unrated
exterior wall with essentially 100% openings that are provided on Building 311.

The physical distance between Building 311 and the adjacent parking garage is
approximately 55 feet. That physical distance permits a fire separation distance
of greater than 30 feet for the parking garage and greater that 20 feet for
Building 311. In that situation, the exterior wall of Building 311 is permitted
to be unrated and have unlimited exterior openings.

(14) Do not provide fire rated exterior walls for exit stair enclosures or for
the exterior walls of use spaces adjacent to exterior walls of exit stairs.
(Compliance alternative 1014.11.1)

MSBC Section 1014.11.1 requires that either the exterior walls of exit stair
enclosures have a one hour rating and have protected openings or that the
exterior walls of adjacent use spaces within 10 feet of the stair enclosure be
treated in that manner.

As a compliance alternative to strict compliance with the requirement for
exterior wall rating and opening protectives either within or adjacent to an
exit stair, close spaced automatic sprinklers will be provided to protect the
exterior glass of the stair enclosure. Those sprinklers will help to maintain
the integrity of the stairway windows under potential fire exposure.

(15) Do not provide opening protection for any exterior wall openings in this
fully sprinklered building. (705.3.1)

(16) Do not provide a fire rated spandrel panel or wall on this fully
sprinklered building. (705.4, Exception 2)

FIRE ALARM SYSTEM

(17) Provide a fire alarm system having the basic features required by Section
917 and additional features required by the atrium Section 404.0. (917.4.2)

(18) Provide addressable system connected automatic smoke detectors throughout
all levels of the building. (NR/Condition of variance)

Complete coverage of the building with addressable type smoke detectors was
offered as part of the justification of the requested variance from fire rating
requirements applicable to the roof assembly. Such protection is considered a
condition of the variance.

(19) Activate the fire alarm system using manual pull stations, waterflow
detectors of the sprinkler system and smoke detectors of the atrium exhaust
system. (917.7.1)

                                       5
<PAGE>

MEANS OF EGRESS

(20) Provide 2 doors to the corridor system from all rooms or spaces with an
occupant load of more than 50 persons or in which the travel distance exceeds 75
ft. (T-1017.2)

(21) Install doors which serve rooms with occupants loads of 50 or more persons
so as to swing in the direction of egress travel. (1017.4)

(22) Where two exit or exit access doors are required from a room or other
space, separate the doors by a distance equal to or greater than one quarter of
the longest diagonal of the area served. (1006.4.1)

(23) Limit dead ends of corridors to not more than 20 ft. (1011.2)

(24) Limit the length of a common path of travel in the Use Group B spaces to
not more than 100 ft. (1011.2.1)

(25) Provide unrated exit access corridor enclosures. (1011.4)

(26) Provide unrated corridor doors. (1011.4.2)

(27) Provide corridors with a minimum clear width of 44 inches. (1011.3)

(28) Utilize interior exit stairs designed in accordance with MSBC Section
1014.0 as the required exits of the building. (1014.0)

(29) Provide sufficient egress capacity for the occupant load of each floor of
the building separately. (1009.1, 1009.3)

At the code specified area allowance of 100 square feet per person and with an
area of not more than 147,000 sf, the occupant load of the largest floor of the
building will be 1,470 persons. There will be four 44 inch wide exits stairs and
seven 48 inch wide exit stairs provided from the upper stories of the building
will each have a capacity of 220 persons. The total capacity available from
those stairs at an allowance of 0.20 inches per person will be 2,560 persons,
well in excess of the project population.

(30) Locate exits as required to limit travel distances to less than 150 ft. in
spaces not separated from the atrium and 250 ft. in spaces separated from the
atria. (404.7, T-1006.5)

(31) Provide exit discharge from exit stairs directly to the outside, through
rated passageways, sprinklered lobbies or small vestibules. (1020.0)

ELEVATORS

(32) Provide all elevators having a travel of 25 feet or more with
characteristics and controls for fire emergency use in accordance with the MA
Elevator Code. (MA Elevator Code, 17.39)

                                       6
<PAGE>

(33) Provide one elevator which serves all floors of the building with
characteristics and controls to permit emergency medical use in accordance with
the MA Elevator Code. (MA Elevator Code, 17.40)

SPRINKLER SYSTEMS

(34) Provide a complete automatic suppression system in all portions of the
building in accordance with the requirements of Article 9. (904.2, 404.2)

STANDPIPE

(35) Provide fire standpipes in the building with hose connections located in
accordance with the criteria of NFPA 14. (914.4, 914.5)

WATER SUPPLY

(36) Provide water supplies for the sprinkler and standpipe systems using a
connection to the municipal water supply system. (NFPA 13, 14)

(37) Size the supply piping of the combined sprinkler and standpipe water supply
system in accordance with the criteria. of NFPA 14. (914.3)

(38) Provide connections of each sprinkler system to two separate standpipe
risers. (NR/Condition of variance)

EMERGENCY POWER

(39) Provide an emergency generator to provide standby power for the fire alarm
system, exit signs, emergency lights, the atria smoke control systems and the
fire pump. (917.6, 1023.4, 1024.4, 921.5, Condition of variance)

The provisions of standby power for the fire pump was a condition of the
variance from the requirements for fire rating of the roof assembly.

INTERIOR FINISH

(40) Utilize interior finish as follows:

                  -     Class I interior finish within all exit stairs.

                  -     Class II or better interior finish in exit access
                        corridors serving only office areas.

                  -     Class III or better interior finish within rooms or
                        spaces of assembly and office areas.

                        (T-803.4)

                                       7
<PAGE>

(41) Utilize traditional floor coverings such as wood, vinyl, linoleum, terrazzo
or other resilient floor finish materials or carpeting which complies with the
DOC FF-1 "pill test" (CPSC 16 CFR, Part 1630) in all spaces including exits and
exit access corridors. (805.3, Exception)

                                       8
<PAGE>

                                   TABLE NO. 1
                         SUMMARY OF ATRIUM REQUIREMENTS
                MASSACHUSETTS STATE BUILDING CODE - SIXTH EDITION

(1)   Classify any openings in the floor systems connecting two or more stories
      as an atrium. (404.1)

(2)   Provide a complete automatic suppression system in the portions of the
      building not separated from the atrium by two hour fire separation
      partition and floor assemblies. (404.2)

(3)   Limit the use of the floor of the atrium low hazard uses with approved
      materials and decorations unless appropriately protected with automatic
      fire suppression system. (404.3)

(4)   Allow exit discharge through the atrium in accordance with the rules for
      exit discharge through a lobby in Section 1020.0. (404.3.1)

(5)   Provide a smoke control system as required by Section 921.0. (404.4)

(6)   Separate the atrium from adjacent spaces by 1-hour fire separation walls,
      fire rated windows or tempered, wired or laminated glass walls constructed
      as required by Section 404.5 [Exception 2] except as noted in Item 7
      below. (404.5)

(7)   Allow up to three levels of the building to be open to the atrium without
      the separation required by Item 6. (404.5, Exception 3])

Only limited portions of the First Floor of the building will be open to the
atrium. Most spaces will be separated from the atrium spaces by glass walls
protected by closely spaced sprinklers.

(8)   Provide automatic smoke detectors within and at the perimeter of the
      atrium and on the ceilings of spaces not separated from the atrium
      (404.6).

The extent of coverage by smoke detectors is not explicitly stated in the code.
Coverage should be provided in the area immediately surrounding the atrium and
all corridors which are open to the atrium. The specific extent of coverage
should be determined in discussions with the authorities having jurisdiction.

(9)   Arrange automatic smoke detectors within the atrium space to sound fire
      alarms upon activation of any two or more of the detectors. (Not required)

No explicit requirement that two or more smoke detectors be required to operate
before fire alarms are sounded is found in the current edition of the code.
However, that means of operation is one reasonable approach to limiting the
effect of false alarms from smoke detectors. (Such a requirement did appear in
previous editions of the NBC.) Other technical approaches to limiting the false
alarm problem are available such as addressable detectors and alarm confirmation
circuits. The specific arrangement of the detection system in this facility
should be determined in discussions with the authorities having jurisdiction.

                                       9
<PAGE>

(10)  Activate the fire alarm system using signals from sprinkler system
      waterflow detectors and manual pull stations. (406.6 and 917.7,1)

(11)  Utilize a voice or non-voice alarm system which complies with the detailed
      provisions of Section 917.9. (404.6)

(12)  Limit the distance of exit access travel within the atrium on other than
      the lowest levels of the building to not more than 150 ft. (404.7)

                                       10
<PAGE>

                      EXHIBIT G: ENVIRONMENTAL RESTRICTIONS

1.    Grant of Environmental Restrictions and Easements dated as of August 9,
      1998 from the United States of America acting by and through the Secretary
      of the Army as Grantor to the Massachusetts Department of Environment
      Protection as Grantee, recorded with the Middlesex South District Registry
      of Deeds in Book 28978, Page 549, as amended by a First Amendment to Grant
      of Environmental Restrictions and Easements dated February 9, 1999
      recorded with said Deeds in Book 29779, Page 359, a Second Amendment to
      Grant of Environmental Restrictions and Easement recorded with said Deeds
      in Book 30066, Page 116, a Partial Release of Grant of Environmental
      Restrictions and Easement recorded with said Deeds in Book 30278, Page
      511, a Third Amendment to Grant of Environmental Restriction and Easement
      recorded with said Deeds in Book 30278, Page 513, and a Fourth Amendment
      to Grant of Environmental Restriction and Easement recorded with said
      Deeds in Book 31682, Page 99 (the "Grant of Environmental Restriction").

2.    Notices of Activity and Use Limitation under M.G.L. c.21E recorded with
      said Deeds in Book 28959, Page 92 (the "Well C-2 Area AUL").

3.    Notice of Activity and Use Limitation under M.G.L. c.21E recorded with
      said Deeds in Book 29766, Page 17.

4.    Notice of Activity and Use Limitation under M.G.L. c. 21E recorded with
      said Deeds in Book 28959, Page 190, as amended by a First Amendment
      recorded with said Deeds in Book 30801, Page 319 (the "Building 60/227
      Area").

5.    Quitclaim Deed dated as of August 20, 1998 from United States of America
      acting by and through the Secretary of the Army to the Watertown Arsenal
      Development Corporation, recorded with the Middlesex South District
      Registry of Deeds in Book 29012, Page 240 (the "Army Deed").

6.    Plan entitled "Army Materials Technology Laboratory, Watertown,
      Massachusetts, Center Wing of Building 313 Area and Portion of Southerly
      Wing of Building 313 Area," dated June 2, 1999, as revised on June 3,
      1999, prepared by Dunn McKenzie, Inc., recorded as Plan No. 614.

7.    Finding of Suitability to Transfer dated July 30, 1998, prepared for the
      United States Department of the Army by the United States Army Corps of
      Engineer.

      INCLUDING ANY AND ALL AMENDMENTS OR MODIFICATIONS TO THE FOREGOING
      INSTRUMENTS.

<PAGE>

                       EXHIBIT H: CLEANING SPECIFICATIONS

<PAGE>

                               TASK SPECIFICATIONS

LOBBIES & COMMON AREAS
DAILY:

-     Empty all waste receptacles and replace liners (to be supplied by
      Customer).

-     Remove dust from all furniture, window ledges, radiators, coat racks,
      artificial plants, paintings and other wall decorations using chemically
      treated cloths.

-     Completely wipe all furniture.

-     Spot clean doors and walls especially around door-frames and light
      switches.

-     Completely wash all glass.

-     Clean and polish all elevator doors, walls, etc.

-     Thoroughly vacuum all carpeting including edges.

-     Thoroughly sweep and damp mop all hard surface. floors..

-     Spot clean all carpeting.

WEEKLY:

-     Spray-buff or hi-speed burnish all hard surface floors (three times per
      week).

-     Vacuum all upholstered furniture.

-     Render all dusting of accessible surfaces not reached by daily cleaning.

-     Clean and polish elevator tracks.

MONTHLY:

-     Dust or vacuum all ceiling vents.

TWICE PER YEAR:

-     Strip and refinish all hard surface floors. As Necessary:

AS NECESSARY:

-     Shampoo all carpeting using a rotary and extraction method.

GENERAL OFFICE AREAS

DAILY:

-     Empty all waste receptacles and replace liners (to be supplied by
      Customer).

-     Empty all recyclable materials, if any, and dispose of in designated
      recycling containers.

-     Remove dust from all furniture, window ledges, radiators, etc.

-     Spot clean all doors and walls especially around door-frames and light
      switches.

-     Spot clean all glass doors, partitions and glass walls that may exist.

-     Thoroughly vacuum all carpeting.

-     Thoroughly sweep and damp mop all hard surface floors.

WEEKLY:

<PAGE>

-     Completely wash all glass doors, partitions and glass walls that may
      exist.

-     Vacuum or wipe clean conference room chairs.

-     Spray-buff or hi-speed burnish all hard surface floors (Tuesdays &
      Thursdays).

MONTHLY:

-     Render all dusting of accessible surfaces not reached by daily cleaning.

QUARTERLY:

-     Dust all ceiling vents.

TWICE PER YEAR:

-     Strip and refinish all hard surface floors.

KITCHENETTES

DAILY:

-     Pull all trash and replace liners (to be supplied by Customer).

-     Remove dust from all furniture, window ledges, radiators, coat racks,
      artificial plants, paintings and other wall decorations.

-     Thoroughly wipe down all tables, and chairs.

-     Wipe down all trash containers.

-     Spot clean doors and walls especially around and behind trash receptacles.

-     Thoroughly vacuum all carpeting.

-     Spot clean all carpeting.

-     Thoroughly dry-mop and damp mop all hard surface floors.

WEEKLY:

-     Spray-Buff or hi-speed burnish all hard surface floors.

QUARTERLY

-     Vacuum all ceiling vents.

TWICE PER YEAR

-     Thoroughly scrub, seal and wax all hard surface floors.

                                       2
<PAGE>

                     EXHIBIT I: BASE BUILDING SPECIFICATIONS

<PAGE>

              EXHIBIT I-1: BUILDING 97 BASE BUILDING SPECIFICATIONS

                                       2
<PAGE>

                          BASE BUILDING SPECIFICATIONS

HVAC System - There is one 20-ton Trane air handler dedicated to this space with
it's own thermostat.

Plumbing - Each floor contains two-finished common area Men and Women's
handicapped bathroom. Each floor also contains a drinking fountain.

Sprinkler System - The building is 100% protected by a wet fire protection
sprinkler system.

Electrical System - The building contains a 1,600A, 480V 3-phase 4-wire service
that is currently metered by only one meter.

Fire Alarm - The building contains a fully addressable system through out.

Telecommunications and Data capabilities include RCN Fiber 288count, Verizon
connections & Video/Broadband in the building.

A common area directory will be installed in the first and second floors of the
building.

<PAGE>

             EXHIBIT I-2: BUILDING 311 BASE BUILDING SPECIFICATIONS

                                       2
<PAGE>

                                     EXHIBIT

                 311 ARSENAL STREET - BASE BUILDING DESCRIPTION

311 Arsenal Street (the "Building"), contains 366,112 square feet of rentable
floor divided into two symmetrical multi-level sections, Segment A and Segment
B, centered on a full -height central atrium / circulation core. Each of the two
sections contain two high-bay laboratory floors, totaling approximately 103,080
rentable square feet, adjacent to four levels of executive office / research
laboratory areas totaling approximately 263,032 rentable square feet An enclosed
six-level garage immediately adjacent to the Building provides 1,100 automobile
parking spaces for tenants and visitors.

SITE DEVELOPMENT:

a.    The perimeter of the 311 Arsenal Street building site is improved with
      concrete sidewalks, irrigated landscape areas and site lighting in keeping
      with its historic business environment.

b.    Specimen trees, ground coverings directional signage, flags and banners
      complement the Building's primary street frontages along with its surface
      parking areas and the adjacent parking garage.

STRUCTURAL SYSTEM:

a.    The Building was originally constructed in two separate sections, Segment
      A in 1942 and Segment B including the central atrium, in 1917. The entire
      Building was restored, renovated and modernized in 2000.

b.    Building foundations are reinforced concrete spread footings and perimeter
      concrete foundation walls. The first floor is a concrete slab-on-grade.
      There is no basement in the Building.

c.    All elevated floors in the Building, two in the high bay area and four in
      the office / laboratory area, are reinforced cast-in-place concrete on a
      metal deck flooring system spanning between structural steel beams and
      girders which frame into steel columns with moment-resisting frames at the
      floor levels to resist lateral loads.

d.    Exposed steel trusses support the Building's pre-cast concrete and gypsum
      plank roof components, portions of which are structurally-reinforced to
      accommodate current Building and future tenant equipment supports. A
      portion of the roof area is provided with an enclosed penthouse to house
      Building and (as space allows) future tenant mechanical and electrical
      equipment installations.

e.    Floor-to-floor elevations are 20'-0" in the two-level high-bay laboratory
      section of the building and 13'-4"on the four-level office / research
      floors. Live load carrying capacities of the elevated floors are rated at
      100 pounds per square foot.

BUILDING EXTERIOR:

<PAGE>

a.    The building's exterior walls are constructed of solid brick masonry. Cast
      stone window-sills and steel window lintels surround original and replaced
      segmented window units which maintain the historic appearance and ambiance
      of the Building,

b.    All original window units on the east and west Building elevations, at the
      corners and at the central entrances have been replaced with
      double-glazed, insulated glass units set in either the original steel
      encasement frames or in new aluminum frames.

c.    Roofing consists of a single-ply Firestone EPDM membrane system
      directly-applied over rigid insulation atop gypsum and concrete roof deck
      materials.

LOADING DOCK:

a.    The Building's interior enclosed Receiving area is equipped with a Mail
      Room, Supply Room and is immediately adjacent to an elevator unit serving
      all floors of the Building

ELEVATORS:

a.    Eight electric-powered hydraulic elevators rated at 3,500 pound capacity /
      150 feet per minute travel speed serve all sections of the Building.

INTERIOR FINISHES:

a.    The main entrance lobby of the Building is directly accessible, at its
      north entrance, to a scheduled public transportation stop on Arsenal
      Street and, at its south entrance, to surface parking lots and the
      adjacent parking garage on Wooley Avenus. The lobby's dramatic four-story
      atrium serves as the central focus for the building's reception,
      circulation and vertical transportation systems. Lobby finishes center on
      exposed structural steel framing, industrial cranes, full-height
      steel-framed windows and lighting reminiscent of the Building's historic
      heavy industrial use, accented with modem cork wall coverings and interior
      glass curtain walls at the tenant spaces.

b.    Acoustical ceilings at toilet rooms and other building shell & core areas
      are 2' x 2' x 5/8" acoustical ceiling tile (moisture-resistant where
      applicable), similar to Armstrong Designer Series, set in 15/16" exposed
      metal grid

c.    Interior wall partitions are 5/8" gypsum wallboard on 35/8" metal studs
      (fire rating per Code); toilet rooms and core area mechanical shaft ways
      and rooms are insulated full-height partitions (slab-to-slab). Interior
      surfaces of building core walls to be 5/8" gypsum wallboard taped,
      spackled and ready to receive tenant's application of interior
      wall-covering materials.

d.    Elevator lobby areas are finished with carpet and vinyl base. Concrete
      floors in Tenant fit-up areas are clean and ready to receive Tenant
      carpeting materials.

e.    Toilet Rooms/Locker Rooms: Ceramic tile is installed on floors and wet
      walls of toilet rooms. Lavatory counters are plastic laminate surfacing
      with under-slung. bowls and full-height frame-less wall mirrors above the
      counters. Metal toilet enclosures are ceiling

                                       2

<PAGE>

      mounted with baked enamel finishes. Installation of Toilet and Locker Room
      accessories comply with requirements of the Massachusetts Architectural
      Access Board and ADA recommendations.

SPECIALTIES AND EQUIPMENT:

a.    A uniform Building graphics system, consisting of interior core area
      signage and a building directory is provided.

HEATING, VENTILATING & AIR CONDITIONING:

A.    BASE BUILDING SYSTEMS

      1. Heating System. The Building's heating system consists of two 250
horsepower and one 100 horsepower gas-fired water-tube boilers located in the
Building's first floor Mechanical Room #3 The 100 horsepower boiler is intended
as a backup for cool summer days that may require heat. The boilers are designed
to deliver 190 degree (F) hot water with 20 degree (F) temperature differential
and have an overall capacity of 55 BTH available heating per rentable square
foot for the Building's 366,112 rsf area. The boilers provide hot water to
perimeter heating units and to constant-volume and variable-volume terminal box
reheat coils located throughout the Building. The heating system is designed to
maintain the interior temperature of the Building at 72 degrees (F) with an
outdoor design temperature of 0 degrees (F

      2. Cooling System. The Building's cooling system consists of two 775 ton
and one 250 ton electric-fired centrifugal chillers located in the Building's
first floor Mechanical Room #3. The 250 ton chiller is intended as a backup for
warm winter days that may require mechanical cooling: Three 600 ton cooling
towers, one of which is outfitted for winter operation with the 250 ton chiller,
are located within a screened enclosure on the roof of the Building, Chilled
water is pumped to air handling units located on the Building's first, second
and third floors. The cooling system is designed to maintain the interior
temperature of the Building at 75 degrees (F) / 50% relative humidity with
outdoor design conditions of 88 degrees (F) dry bulb / 74 degrees (F) wet bulb.

      3. Supply Air System. Sixteen air handling units, totaling 487,000 cubic
feet per minute, located in mechanical rooms on the first, second and third
floors of the Building, provide an average airflow rate, varying throughout the
Building, of 1.3 cubic feet per minute per rentable square foot for the
Building's 366,112 rsf area. Each air handling units is sized for 10% outdoor
air with 2" thick 30% efficient pleated air filters and incorporates an
economizer cycle to provide free cooling air during fall, winter and spring
months. The system's outdoor air capacity is in compliance with the
Massachusetts State Building Code for office occupancy of one person per 143
rentable square feet Tenant requirements in excess of this occupancy and zone
control within tenant areas can be provided by supplemental tenant-installed
ventilation equipment.

      4. Exhaust Systems. The Building contains two exhaust systems, one for the
Building toilet rooms and one for the central atrium's emergency smoke exhaust
system. The toilet rooms' makeup air is provided by adjacent tenant supply air
distribution systems The atrium wings to the east and west of the central atrium
enclosure receive makeup air during

                                       3

<PAGE>

emergency conditions from adjacent tenant areas via transfer grilles connecting
tenant ceiling plenums to the atrium spaces.

      5. HVAC Control Systems. HVAC systems within the Building are controlled
by a distributed direct digital control system manufactured by the Johnson
Control Company and equipped with adequate add-on capacity for tenant controls
to ensure that a single, Building-wide environmental control system can be
monitored, supervised and maintained by the Landlord.

B.    TENANT OPTIONS

      1. The Building's HVAC system is designed and constructed in anticipation
of office occupancy loads. However the capacity of the cooling and heating
systems and a portion of the air handling system have the capability to support
a limited amount of more-intense heating and cooling requirements, including
laboratory occupancies.

      2. Landlord's engineers estimate that the Building's existing heating and
cooling systems (boiler and chiller equipment) have the capacity to support up
to 100,000 rentable square feet of laboratory uses. Additional heating and
cooling units, as may be required to support tenant laboratory occupancies in
excess of 100,000 rsf, can be installed as-needed within, and adjacent to,
existing first floor mechanical rooms or on the Building roof.

      3. Should a tenant have need for increased quantities of supply or exhaust
air, tenant can install additional 100% outside air handling units within its
premises and additional exhaust fans on the Building roof. Vertical shaft space
for supplemental tenant supply or exhaust risers are subject to Landlord
approval and other tenant spaces through which the shafts would be routed.

PLUMBING:

A.    BASE BUILDING SYSTEMS

      1. Domestic Cold Water System. A 75 psig, 6" diameter water service main
enters the west end of the Building at the Fire Pump Room where it passes
through a water meter and backflow preventer. From this point, the domestic
water distribution piping extends across the Building to the Building's toilet
room risers, the main mechanical room and the exterior wall hydrants. The
Building's plumbing fixtures are water saving type in compliance with the
Massachusetts State Building Code water conservation guidelines.

      2. Domestic Hot Water System. 6 KW electric point-of-use hot water
heaters, rated at 30 gallons per hour, are located above the ceilings of each
Building toilet room and janitor closet. Toilet Room fixturing is sized for one
person per 175 sq ft of occupied area (50% men / 50% women).

      3. Sanitary Drainage. Multiple 4" and 6" diameter sanitary sewer drains
extend from the Building's toilet and mechanical rooms through ten house drains
traversing the Building, at equidistant points north-to-south, to connection
points at the Town's municipal sewer main in Wooley Avenue. Each sanitary house
drain is equipped to provide access points for future tenant connections.

                                       4

<PAGE>

      4. Storm Water Drainage. Roof areas are drained via exterior and interior
rainwater conductors to ground level storm drainage collection mains.

      5. Natural Gas. A 4-inch diameter natural gas service line enters
Mechanical Room #3 to serve the Building's hot water boiler equipment with an
8-inch capped tee for future connection to tenant standby generator needs
(Tenant to make separate installation and metering / payment arrangements with
KeySpan Gas Company).

B.    TENANT OPTIONS

      1. The Building's plumbing system is designed for office occupancy.
However a tenant has the opportunity to install supplementary systems for its
special occupancy needs, including research laboratories. Hot water generating
systems for laboratories or kitchens, vacuum, gas, pure water, non-potable
water, and laboratory waste collection, treatment and ph-monitoring systems can
be installed in the Building at tenant cost with landlord approval.

FIRE PROTECTION:

A.    BASE BUILDING SYSTEMS

      1. A combined fire standpipe and wet-type sprinkler system protects the
entire Building which is divided into three fire suppression zones, west,
central and east. Each zone includes a 6" diameter cross main originating from
its zone valve in the Fire Pump Room; A common 4" diameter Fire Department
connection cross main runs the length of the Building from Fire Department
siamese connection points at the east and west ends of the Building.

      2. An 8" diameter water main, with a 75 psi residual pressure, enters the
Fire Pump Room at the west end of the Building. There, a 100 horsepower
electric-drive fire pump with jockey pump and :test manifold, boosts the water
pressure in the Building to firefighting requirements. The system is
hydraulically-designed to deliver 350 gallons per minute with a 70 psig residual
pressure at the ground-level base of each interior standpipe.

      3. The Building's sprinkler systems are sized in accordance with NFPA #
13, using Ordinary Hazard densities of 0.20 gallons per minute over 1,500 square
feet in storage areas and Light Hazard densities of 0.10 gallons per minute over
1,500 square feet in office areas.

B.    TENANT OPTIONS

      1. The Building sprinkler system may be modified by a tenant to suit its
particular occupancy needs and hazard levels within the capability of the
Building's fire pump and piping systems. These modifications, taken after
receipt of approval of the Building owner and insurance underwriter, may include
changes in type, or re-locations, of sprinkler heads, changes in density of
coverage (e.g laboratory occupancies may require increasing sprinkler density to
Ordinary Hazard Group 1) and the like.

ELECTRICAL:

A.    BASE BUILDING SYSTEMS

                                       5

<PAGE>

      1. The Building is serviced by three (two 3,000 amp; one 4,000 amp) 480
volt, 3 phase, 4 wire incoming electric services from three separate
NStar-provided pad-mounted transformers.

      2. The Building's main electric switchboards, located in the first floor
Electric Room, provide 18.1 volt-amperes per square foot of Building area at a
rating of 50% of the main switchboard disconnect.

      3. Separate east and west services, each rated at 3,000 amps, feed into
two 1,000 amp buss duct risers to the fourth floor for both Building needs and
future tenant connections. These four risers provide an average 8 watts
available electric power per rentable square foot for the Building's 366,112 rsf
area. Electric closets are located on each floor for tenant distribution panels
and step-down transformers. Monthly NStar utility bills for electric consumption
within the Building will be allocated to tenants via consumption check meters
installed by Landlord.

      4. Additional power, as may be needed for higher density tenant
requirements, may be distributed by tenants from the Building's main
switchboards on a case-by-case basis as available.

                                       6
<PAGE>

                     EXHIBIT J - EXISTING LEASE OBLIGATIONS

As used herein, the following terms have the following meanings:

Conditions Precedent:        Landlord's obligations under this Exhibit J
                             are subject to satisfaction at all times of the
                             following conditions precedent:

                             1.    There is no Event of Default under the Lease;

                             2.    Tenant is in compliance with the terms of
                                   this Lease;

                             3.    Tenant is in compliance with the terms and
                                   conditions of the Existing Leases; and

                             4.    Landlord has received the Estoppel
                                   Certificates.

                             Landlord, at its option, may waive any of the
                             Conditions Precedent listed above.

Main Street Landlord:        Skorz/Waltham, LLC

Main Street Lease:           Sublease between Syncra Systems, Inc., as
                             sublessor, and Tenant, as sublessee, dated April
                             9, 2003 (the "Sublease") for space in the building
                             located at 716 Main Street, Waltham, Massachusetts,
                             as amended by an Amendment and Assumption of
                             Sublease with an effective date of May 1, 2004 (the
                             "Assumption"), between Main Street Landlord and
                             Tenant, pursuant to which the Sublease became a
                             direct lease.

Main Street Rent:            All Base Rent, Electricity Rent, and Additional
                             Rent as set forth in Sections 4 and 5 of the
                             Sublease, and as amended by the Assumption, to be
                             paid by or on behalf of Tenant for the period from
                             March 1, 2005 through November 30, 2005.

Main Street Termination:     Tenant's right to terminate the Main Street Lease
                             by delivery of notice to Main Street Landlord on
                             September 2, 2005.

Moody Street Landlord:       One Moody Realty, LLC.

Moody Street Lease:          Amendment and Restatement of Lease dated as .of
                             February 1, 2000 between Moody Street Landlord and
                             Tenant for space in the building located at One
                             Moody Street, Waltham, Massachusetts, as amended
                             by a First Amendment to Lease dated October 31,
                             2000 and a Second Amendment to Lease dated February
                             22, 2002.

Moody Street Rent:           All Annual Fixed Rent (as defined in the Moody
                             Street Lease),


<PAGE>
Confidential Materials omitted and filed separately with the Securities and
Exchange Commission. Asterisks denote omissions.




                             and the additional rent under Sections 2.6, 2.7,
                             and 2.8 of the Moody Street Lease to be paid by or
                             on behalf of Tenant for the period from March 1,
                             2005 through the expiration date of the Moody
                             Street Lease.

EL Modifications:            See Section 5.

Estoppel Certificates:       Estoppel Certificates on the forms attached hereto
                             as Schedule B executed by Tenant, Main Street
                             Landlord and Moody Street Landlord.

Existing Landlords:          Collectively, the Main Street Landlord, and the
                             Moody Street Landlord.

Existing Leases:             Collectively, the Main Street Lease, and the
                             Moody Street Lease.

Existing Lease Additional    See Section 2 below.
Rent:

Existing Rents:              Collectively, the Main Street Rent, and the Moody
                             Street Rent.

Existing Rent Schedule:      The schedule attached hereto as Schedule A setting
                             forth the Existing Rents (but not including an
                             estimate of any additional rent).

Landlord's Rent              See Section 1 below.
Contribution

Landlord's Main Street       $ * (or * % of $ * ).
Rent Share:

Tenant's Main Street         An amount equal to the Main Street Rent minus
Rent Share:                  Landlord's Main Street Rent Share.

Landlord's Moody Street      $ * (or * % of $ * ).
Rent Share:

Tenant's Moody Street        An amount equal to the Moody Street Rent minus
Rent Share:                  Landlord's Moody Street Rent Share

Tenant's Maximum             With respect to either the Main Street or the
Rent Share:                  Moody Street Lease, the amount that Tenant would
                             pay to Landlord if the Existing Lease Additional
                             Rent was in an amount equal to Tenant's Moody
                             Street Rent Share or Tenant's Main Street Rent
                             Share, as the case may be, the interest rate was *%
                             , and Tenant made equal monthly installments of
                             Existing Lease Additional Rent and interest
                             sufficient to fully amortize the Existing Lease
                             Additional Rent over the period beginning on the
                             First Payment

<PAGE>

                             Date and ending on the Maturity Date
                             (as defined in Section 2 below). An estimate of
                             Tenant's Maximum Rent Share for both the Main
                             Street Lease and the Moody Street Lease (but not
                             including an estimate of any additional rent) is
                             set forth on Schedule A.

      1. REIMBURSEMENT FOR RENTS. As an inducement for Tenant to faithfully
perform its obligations under the Lease, and subject to the terms and conditions
set forth herein, and to Landlord's determination that the Conditions Precedent
are satisfied, Landlord shall, commencing on March 1, 2005, pay the Existing
Rents directly to the Main Street Landlord and the Moody Street Landlord,
respectively, and in accordance with the terms of the Existing Leases
("Landlord's Rent Contribution"). If Landlord at any time determines that the
Conditions Precedent are not satisfied, and as a result Landlord does not make
an Existing Rent payment (a "Missed Payment"), and if Landlord later determines
that Tenant has satisfied such Conditions Precedent, Landlord will pay to the
applicable Existing Landlord the Missed Payment, or in the event Tenant has paid
the Missed Payment directly to such Existing Landlord, Landlord will reimburse
Tenant for the Missed Payment as Landlord's Rent Contribution.

      2. EXISTING LEASE ADDITIONAL RENT., Any amounts paid by Landlord as (i)
Landlord's Rent Contribution to the Main Street Landlord in excess of Landlord's
Main Street Rent Share; and (ii) Landlord's Rent Contribution to the Moody
Street Landlord in excess of Landlord's Moody Street Rent Share, shall
constitute Additional Rent payable by Tenant to Landlord as set forth herein
(the "Existing Lease Additional Rent"). The following terms as used herein shall
have the following meanings:

      Interest Rate:  8% per annum, compounded monthly.
      Maturity Date:  The date that is ten years after the Rent Commencement
      Date.
      Payments: Tenant shall pay to Landlord monthly payments of Existing Lease
Additional Rent and interest at the Interest Rate beginning on January 1, 2006
("First Payment Date"), sufficient to fully amortize the aggregate of all
Existing Lease Additional Rent on the Maturity Date. Existing Lease Additional
Rent payments shall be made on Rent Payment Dates.

      The "Existing Lease Additional Rent Start Date" shall mean the date that
any Landlord's Rent Contribution first constitutes Existing Lease Additional
Rent pursuant to the foregoing, or at the time Landlord makes any Termination
Payment pursuant to Section 5. Landlord will deliver notice to Tenant of the
Existing Lease Additional Rent Start Date. Existing Lease Additional Rent will
accrue interest at the Interest Rate as of the Existing Lease Additional Rent
Start Date, and all interest accrued on Existing Lease Additional Rent for the
period from the Existing Lease Additional Rent Start Date until the First
Payment Date shall be added to Existing Lease Additional Rent. Prior to the
First Payment Date, and each month during the Initial Lease Term thereafter,
Landlord will send to Tenant an invoice indicating the outstanding amount of
Existing Lease Additional Rent, and the payment due Landlord thereunder,
provided, however, that Landlord will make any necessary reduction in the
monthly payments so that the scheduled payments will not result in Tenant
repaying more than Tenant's Maximum Rent Share. If Existing Lease Additional
Rent payments will be constant over the balance of the Initial Lease Term,
Landlord will not provide Tenant with a monthly statement, and Tenant shall pay
such constant amount on Rent Payments Dates. All payments of Existing Lease
Additional Rent shall

<PAGE>

constitute Additional Rent under the Lease. The occurrence of an Event of
Default under the Lease shall automatically entitle Landlord to accelerate the
remaining payments of Existing Lease Additional Rent, and any default in any
payment of Existing Lease Additional Rent shall cause an Event of Default under
the Lease. In the event of any termination of this Lease, the aggregate
outstanding amount of Existing Lease Additional Rent, plus all unpaid interest
earned thereon shall become automatically due and payable as of the date of such
termination. Tenant may at any time pay to Landlord the outstanding balance of
Existing Lease Additional Rent together with all unpaid interest earned thereon.

      3. MAIN STREET TERMINATION. Tenant shall exercise the Main Street
Termination on September 2, 2005, and shall provide Landlord with a copy of the
notice of termination no later than August 15, 2005, for review by Landlord.
Landlord's obligation to pay Landlord's Rent Contribution with respect to the
Main Street Lease shall terminate on December 1, 2005.

      4. EVENTS OF DEFAULT. In addition to the terms set forth in Section 2
above, if an Event of Default occurs (i) Landlord's obligation to provide
Landlord's Rent Contribution shall, at Landlord's option, cease as of the date
of the occurrence of such Event of Default, and (ii) if Landlord exercises its
right to terminate this Lease in accordance with the provisions of Section 6.1.1
of the Lease, Landlord shall be entitled recover from Tenant, in addition to the
other amounts set forth in Article 6, the entire amount of Landlord's Rent
Contribution paid by Landlord, as reduced by the aggregate of Existing Lease
Additional Rent paid by Tenant, and all unpaid interest earned on Existing Lease
Additional Rent, immediately on delivery of written notice to Tenant requesting
the same. Tenant shall not be entitled to any credit or reduction in the amount
recoverable by Landlord pursuant to this Section 4 based upon amounts collected
by Landlord as either Fixed Damages or from reletting the Premises after an
Event of Default.

      5. MODIFICATIONS TO EXISTING LEASES. Landlord and Tenant shall work
together to obtain mutually agreeable (i) early termination agreements for the
Existing Leases with the Existing Landlords ("EL Terminations"), or (ii)
subleases for all or portions of the Existing Lease space ("EL Subleases").
Tenant agrees to execute any documents necessary to effect any EL Terminations
or EL Subleases, and if Tenant fails to execute any such documents, and such
failure continues for ten days after receipt of notice from Landlord, it shall
constitute an Event of Default under this Lease. In the event of an EL
Termination, Landlord agrees to make any termination payment required by an EL
Termination (a "Termination Payment") provided Landlord determines the
Conditions Precedent are satisfied. Any Termination Payment paid by Landlord
shall be allocated as follows: (i) if the Termination Payment exceeds Tenant's
Main Street Rent Share or Tenant's Moody Street Rent Share, as applicable, the
portion of the Termination Payment in excess of such applicable Tenant's Main
Street Rent Share or Tenant's Moody Street Rent Share, as applicable, shall
constitute Landlord's Main Street Rent Share or Landlord's Moody Street Rent
Share, as applicable, and the balance of the Termination Payment shall
constitute Existing Lease Additional Rent payable in accordance with Section 2;
and (ii) if the Termination Payment is equal to or less than Tenant's Main
Street Rent Share or Tenant's Moody Street Rent Share, as applicable, the
Termination Payment shall constitute Existing Lease Additional Rent payable in
accordance with Section 2. For the purpose of the foregoing allocation of the
Termination Payment, if at the time of the allocation, the Main Street Landlord
or the Moody Street Landlord, as applicable, has (i) not charged Tenant for
additional rent, then

<PAGE>
Confidential Materials omitted and filed separately with the Securities and
Exchange Commission. Asterisks denote omissions.




the calculation of Tenant's Main Street Rent Share or Tenant's Moody Street Rent
Share, as applicable shall not include any estimated payments of additional
rent; or (ii) charged Tenant for additional rent, then the calculation of
Tenant's Main Street Rent Share or Tenant's Moody Street Rent Share, as
applicable, shall include an estimate of additional rent payments over the
remaining term of the Existing Lease, such estimate to be based on the then
current charges for additional rent under the Existing Lease. All sublease
payments under any EL Sublease shall be paid,, directly to Landlord, and shall
be applied first to reduce Landlord's Main Street Rent Share and Landlord's
Moody Street Rent Share, as applicable, and the balance will be applied to
reduce Tenant's Main Street Rent Share and Tenant's Moody Street Rent Share, as
applicable. For example, if an EL Sublease for the Moody Street Lease results in
sublease payments made to Landlord of $ * , Landlord would first apply the
$ * against Landlord's Moody Street Rent Share of $ * , and the
remaining $ * would be applied to reduce Tenant's Moody Street Rent Share.

      6. ESTOPPEL/INDEMNIFICATION.

      Section 6.1. Estoppel. On or before the Rent Commencement Date, Tenant
shall deliver to Landlord the Estoppel Certificates. If an Existing Landlord
refuses to sign an Estoppel Certificate, Landlord agrees to accept in lieu
thereof an Estoppel Certificate signed by Tenant.

      Section 6.2. Indemnification. Except for Landlord's obligation to pay
Landlord's Rent Contribution in accordance with Section 1 above, (i) Landlord
shall have no obligations or liability under the Existing Leases, and nothing
herein shall be deemed to constitute an assumption by Landlord of any of
Tenant's obligations under the Existing Leases; and (ii) Tenant shall remain
liable for all of its obligations under the Existing Leases. Tenant shall
indemnify, defend with counsel acceptable to Landlord, and hold Landlord
harmless from and against any and all claims, liabilities, causes of action,
suits, investigations, losses, damages, and obligations whatsoever, whether
direct or indirect, foreseen or unforeseen, arising under, pursuant to, or in
connection with the Existing Leases.

      7. LANDLORD DEFAULT. If Landlord defaults in its agreement to pay any
payment of Landlord's Rent Contribution or, any Termination Payment that
Landlord is obligated to pay hereunder, and such default continues for ten
business days after Landlord's receipt of notice from Tenant setting forth such
default, then Tenant may, after the expiration of the ten business day period,
pay to the applicable Existing Landlord the overdue payment of Landlord's Rent
Contribution or the Termination Payment, as the case may be, and then set-off
against its next payment of Basic Rent due under this Lease, the amount that
Tenant has so paid to the Existing Landlord (the "Set-off Amount"). Any Set-off
Amount shall then constitute a Landlord's Rent Contribution or Termination
Payment, as the case may be, and shall be characterized in the same manner set
forth in paragraphs 2 and 5 above.

<PAGE>

                                   SCHEDULE A
                           SCHEDULE OF EXISTING RENTS

<PAGE>
Confidential Materials omitted and filed separately with the Securities and
Exchange Commission. Asterisks denote omissions.




                           THE ARSENAL ON THE CHARLES
 PROJECTED ATHENAHEALTH - WALTHAM RENT BUYOUT and RENT FROM LANDLORD - 10/7/04

<TABLE>
<CAPTION>
                               MAR. 05     APR. 05      MAY 05  JUNE 05    JULY 05      AUG. 05
                              ---------   ---------   --------- -------    -------     ---------
<S>                           <C>         <C>         <C>       <C>        <C>         <C>
716 MAIN STREET
Rent Commencing 3/1/05 and
 Ending 11/30/05
Basic Rent with early
 termination
 as of 11/30/05                      *           *           *       *          *             *

ONE MOODY STREET
Rent Commencing 3/1/05
 and Ending 11/30/05
Basic Rent                           *           *           *       *          *             *

TOTAL BASIC RENT OBLIGATION          *           *           *       *          *             *

PAYMENT SCHEDULE
$ *  Buyout

716 MAIN STREET
Basic Rent                           *           *           *       *

ONE MOODY STREET
Basic Rent                           *           *           *       *          *             *

LANDLORD RENT SHARE TO A
TOTAL OF $ *                         *           *           *       *          *             *

REMAINING RENT PAYMENTS
 AFTER $ *  RENT
 SHARE OBLIGATION:
Payout                               *           *           *       *          *             *

CUMULATIVE LOAN PAYOUT
 TO 12/31/05                         *           *           *       *          *             *

NO. OF PERIODS REMAINING
 IN LEASE TERM                       *           *           *       *          *             *

MONTHLY AMORTIZATION TO
 END OF WALTHAM LEASE                                                *          *             *

8% INTEREST ON PRIOR MONTHS
 LOAN BALANCE THROUGH
 6/30/07 (ACCRUED AND
 ADDED TO LOAN UP TO
 12/31/05                                                            *          *             *

TOTAL MONTHLY AMORTIZATION
 AND INTEREST PAYMENTS
 DUE FROM TENANT
 COMMENCING 1/1/05


BALANCE OF LOAN AFTER
 PRIOR MOS. AMORTIZATION
 PLUS ADDITIONAL LANDLORD
 RENT SHARE AND PLUS
 ACCRUED INTEREST TO
 12/31/05                                                            *          *             *

ESTIMATED MONTHLY LOAN
 AMORTIZATION 7/1/07-
 6/1/15 (P&I)

ESTIMATED INTEREST ON
 FIXED LOAN COMMENCING
 7/1/07

TOTAL ESTIMATED COST TO
TENANT

<CAPTION>
                                SEPT. 05     OCT. 05     NOV. 05     DEC. 05    JAN. 06
                               ---------   ---------   ---------   ---------   --------
<S>                            <C>         <C>         <C>         <C>         <C>
716 MAIN STREET
Rent Commencing 3/1/05 and
 Ending 11/30/05
Basic Rent with early
 termination
 as of 11/30/05                       *           *           *           *          *

ONE MOODY STREET
Rent Commencing 3/1/05
 and Ending 11/30/05
Basic Rent                            *           *           *           *          *

TOTAL BASIC RENT OBLIGATION           *           *           *           *          *

PAYMENT SCHEDULE
$ *  Buyout

716 MAIN STREET
Basic Rent

ONE MOODY STREET
Basic Rent                            *           *           *           *          *

LANDLORD RENT SHARE TO A
TOTAL OF $ *                          *           *           *           *          *

REMAINING RENT PAYMENTS
 AFTER $ *  RENT
 SHARE OBLIGATION:
Payout                                *           *           *           *          *

CUMULATIVE LOAN PAYOUT
 TO 12/31/05                          *           *           *           *          *

NO. OF PERIODS REMAINING
 IN LEASE TERM                        *           *           *           *          *

MONTHLY AMORTIZATION TO
 END OF WALTHAM LEASE                 *           *           *           *          *

8% INTEREST ON PRIOR MONTHS
 LOAN BALANCE THROUGH
 6/30/07 (ACCRUED AND
 ADDED TO LOAN UP TO
 12/31/05                              *           *           *           *           *

TOTAL MONTHLY AMORTIZATION
 AND INTEREST PAYMENTS
 DUE FROM TENANT
 COMMENCING 1/1/05                     *           *           *           *           *

BALANCE OF LOAN AFTER
 PRIOR MOS. AMORTIZATION
 PLUS ADDITIONAL LANDLORD
 RENT SHARE AND PLUS
 ACCRUED INTEREST TO
 12/31/05                              *           *           *           *           *

ESTIMATED MONTHLY LOAN
 AMORTIZATION 7/1/07-
 6/1/15 (P&I)

ESTIMATED INTEREST ON
 FIXED LOAN COMMENCING
 7/1/07

TOTAL ESTIMATED COST TO
 TENANT
</TABLE>

                                     1 of 3

<PAGE>
          Confidential Material omitted and filed separately with the
        Securities and Exchange Commission. Asterisks denote omissions.

                           THE ARSENAL ON THE CHARLES
  PROJECTED ATHENAHEALTH - WALTHAM RENT BUYOUT and RENT FROM LANDLORD - 10/7/04

<TABLE>
<CAPTION>
                                                                           Feb. 06     Mar. 06     Apr. 06     May 06      June 06
<S>                                                                      <C>          <C>        <C>         <C>         <C>
716 MAIN STREET
Rent Commencing 3/1/05 and Ending 11/30/05                                     *          *           *          *            *
Basic Rent with early termination as of 11/30/05

ONE MOODY STREET
Rent Commencing 3/1/05 and Ending 11/30/05
Basic Rent                                                                     *          *           *          *            *

TOTAL BASIC RENT OBLIGATION                                                    *          *           *          *            *

PAYMENT SCHEDULE
$* Buyout

716 MAIN STREET
Basic Rent

ONE MOODY STREET
Basic Rent                                                                     *          *           *

LANDLORD RENT SHARE TO A TOTAL OF $*                                           *          *           *          *            *

REMAINING RENT PAYMENTS AFTER $* RENT SHARE
OBLIGATION:
Payout                                                                         *          *           *          *            *

CUMULATIVE LOAN PAYOUT TO 12/31/05                                             *          *           *

NO. OF PERIODS REMAINING IN LEASE TERM                                         *          *           *          *            *

MONTHLY AMORTIZATION TO END OF WALTHAM LEASE                                   *          *           *          *            *

8% INTEREST ON PRIOR MONTHS LOAN BALANCE THROUGH 6/30/07
(ACCRUED AND ADDED TO LOAN UP TO 12/31/05                                      *          *           *          *            *

TOTAL MONTHLY AMORTIZATION AND INTEREST PAYMENTS DUE FROM
TENANT COMMENCING 1/1/05                                                       *          *           *          *            *

BALANCE OF LOAN AFTER PRIOR MOS. AMORTIZATION PLUS
ADDITIONAL LANDLORD RENT SHARE AND PLUS ACCRUED INTEREST TO
12/31/05                                                                       *          *           *          *            *

ESTIMATED MONTHLY LOAN AMORTIZATION 7/1/07-6/1/15 (P&I)

ESTIMATED INTEREST ON FIXED LOAN COMMENCING 7/1/07

TOTAL ESTIMATED COST TO TENANT
</TABLE>

<TABLE>
<CAPTION>
                                                                           July 06     Aug 06     Sept. 06     Oct. 06     Nov. 06
<S>                                                                      <C>         <C>         <C>         <C>         <C>
716 MAIN STREET
Rent Commencing 3/1/05 and Ending 11/30/05                                *          *           *          *            *
Basic Rent with early termination as of 11/30/05

ONE MOODY STREET
Rent Commencing 3/1/05 and Ending 11/30/05
Basic Rent                                                                *          *           *          *            *

TOTAL BASIC RENT OBLIGATION                                               *          *           *          *            *

PAYMENT SCHEDULE
$* Buyout

716 MAIN STREET
Basic Rent

ONE MOODY STREET
Basic Rent

LANDLORD RENT SHARE TO A TOTAL OF $*                                      *          *           *          *            *

REMAINING RENT PAYMENTS AFTER $* RENT SHARE
OBLIGATION:
Payout                                                                    *          *           *          *            *

CUMULATIVE LOAN PAYOUT TO 12/31/05

NO. OF PERIODS REMAINING IN LEASE TERM                                    *          *           *          *            *

MONTHLY AMORTIZATION TO END OF WALTHAM LEASE                              *          *           *          *            *

8% INTEREST ON PRIOR MONTHS LOAN BALANCE THROUGH 6/30/07
(ACCRUED AND ADDED TO LOAN UP TO 12/31/05                                 *          *           *          *            *

TOTAL MONTHLY AMORTIZATION AND INTEREST PAYMENTS DUE FROM
TENANT COMMENCING 1/1/05                                                  *          *           *          *            *

BALANCE OF LOAN AFTER PRIOR MOS. AMORTIZATION PLUS
ADDITIONAL LANDLORD RENT SHARE AND PLUS ACCRUED INTEREST TO
12/31/05                                                                  *          *           *          *            *

ESTIMATED MONTHLY LOAN AMORTIZATION 7/1/07-6/1/15 (P&I)

ESTIMATED INTEREST ON FIXED LOAN COMMENCING 7/1/07

TOTAL ESTIMATED COST TO TENANT
</TABLE>


<PAGE>

          Confidential Material omitted and filed separately with the
        Securities and Exchange Commission. Asterisks denote omissions.

                           THE ARSENAL ON THE CHARLES
  PROJECTED ATHENAHEALTH - WALTHAM RENT BUYOUT and RENT FROM LANDLORD - 10/7/04

<TABLE>
<CAPTION>


                                                              DEC. 06     JAN. 06     FEB. 07     MAR. 07      APR. 07
<S>                                                           <C>         <C>         <C>         <C>         <C>
716 MAIN STREET
Rent Commencing 3/1/05 and Ending 11/30/05                       *          *            *           *        *
Basic Rent with early termination as of 11/30/05

ONE MOODY STREET
Rent Commencing 3/1/05 and Ending 11/30/05
Basic Rent                                                       *          *            *           *        *

TOTAL BASIC RENT OBLIGATION                                      *          *            *           *        *

PAYMENT SCHEDULE
$* Buyout

716 MAIN STREET
Basic Rent

ONE MOODY STREET
Basic Rent

LANDLORD RENT SHARE TO A TOTAL OF $*                             *          *            *           *        *

REMAINING RENT PAYMENTS AFTER $* RENT SHARE
OBLIGATION:
Payout                                                           *          *            *           *        *

CUMULATIVE LOAN PAYOUT TO 12/31/05

NO. OF PERIODS REMAINING IN LEASE TERM                           *          *            *           *        *

MONTHLY AMORTIZATION TO END OF WALTHAM LEASE                     *          *            *           *        *

8% INTEREST ON PRIOR MONTHS LOAN BALANCE THROUGH 6/30/07
(ACCRUED AND ADDED TO LOAN UP TO 12/31/05                        *          *            *           *        *

TOTAL MONTHLY AMORTIZATION AND INTEREST PAYMENTS DUE FROM
TENANT COMMENCING 1/1/05                                         *          *            *           *        *

BALANCE OF LOAN AFTER PRIOR MOS. AMORTIZATION PLUS
ADDITIONAL LANDLORD RENT SHARE AND PLUS ACCRUED INTEREST
TO 12/31/05                                                      *          *            *           *        *

ESTIMATED MONTHLY LOAN AMORTIZATION 7/1/07-6/1/15 (P&I)

ESTIMATED INTEREST ON FIXED LOAN COMMENCING 7/1/07

TOTAL ESTIMATED COST TO TENANT
</TABLE>

<TABLE>
<CAPTION>
                                                                                                                        ESTIMATED
                                                                                                                       TOTAL COST
                                                                 MAY 07      JUNE 07       JULY 07         TOTAL        TO TENANT
<S>                                                          <C>         <C>           <C>           <C>              <C>
716 MAIN STREET
Rent Commencing 3/1/05 and Ending 11/30/05                       *          *            *           *
Basic Rent with early termination as of 11/30/05

ONE MOODY STREET
Rent Commencing 3/1/05 and Ending 11/30/05
Basic Rent                                                       *          *            *           *

TOTAL BASIC RENT OBLIGATION                                      *          *            *           *

PAYMENT SCHEDULE
$* Buyout

716 MAIN STREET
Basic Rent                                                                                           *

ONE MOODY STREET
Basic Rent                                                                                           *

LANDLORD RENT SHARE TO A TOTAL OF $*                             *          *            *           *

REMAINING RENT PAYMENTS AFTER $* RENT SHARE
OBLIGATION:
Payout                                                           *          *            *           *        *

CUMULATIVE LOAN PAYOUT TO 12/31/05

NO. OF PERIODS REMAINING IN LEASE TERM                           *          *            *

MONTHLY AMORTIZATION TO END OF WALTHAM LEASE                     *          *                        *

8% INTEREST ON PRIOR MONTHS LOAN BALANCE THROUGH 6/30/07
(ACCRUED AND ADDED TO LOAN UP TO 12/31/05                        *          *                        *        *

TOTAL MONTHLY AMORTIZATION AND INTEREST PAYMENTS DUE FROM
TENANT COMMENCING 1/1/05                                         *          *

BALANCE OF LOAN AFTER PRIOR MOS. AMORTIZATION PLUS
ADDITIONAL LANDLORD RENT SHARE AND PLUS ACCRUED INTEREST
TO 12/31/05                                                      *          *            *

ESTIMATED MONTHLY LOAN AMORTIZATION 7/1/07-6/1/15 (P&I)                                  *

ESTIMATED INTEREST ON FIXED LOAN COMMENCING 7/1/07                                                            *

TOTAL ESTIMATED COST TO TENANT                                                                                *
</TABLE>

<PAGE>

                                   SCHEDULE B
                              ESTOPPEL CERTIFICATES

1.   Tenant--Main Street Lease and Moody Street Lease

2.   Main Street Landlord

3.   Moody Street Landlord
<PAGE>

                           LEASE ESTOPPEL CERTIFICATE

      Pursuant to

      (A) that certain Sublease dated as of April 9, 2003, as affected by that
certain letter agreement dated April 9, 2003, as further affected by that
certain Assignment of Sublease dated as of March 16, 2004, and as further
amended by that certain Amendment and Assumption of Sublease effective as of May
1, 2004 (collectively, the "Main Street Lease"), athenahealth, Inc., having a
place of business at One Moody Street, Waltham, Massachusetts 02450 (the
"Tenant") is leasing certain property as identified in the Main Street Lease
which is a portion of the building located at 716 Main Street, Waltham,
Massachusetts 02450 (the "Main Street Building") from Skorz/Waltham, LLC, with a
place of business at c/o Karger Realty, Inc., 407 Squire Road, Revere,
Massachusetts 02151 (the "Main Street Landlord"), and

      (B) that certain Amendment and Restatement of Lease dated as of February
1, 2000, as further amended by that certain First Amendment to Lease dated as of
October 31, 2000, and as further amended by that certain Second Amendment to
Lease dated as of February 22, 2002 (as so amended, the "Moody Street Lease"),
Tenant is leasing certain property as identified in the Moody Street Lease which
is a portion of the property located at One Moody Street, Waltham, Massachusetts
(the "Moody Street Building") from One Moody Realty, LLC with a place of
business at c/o Karger Realty, Inc., 407 Squire Road, Revere, MA 02151 (the
"Moody Street Landlord").

      Capitalized terms used herein and not otherwise defined herein shall have
the meaning assigned thereto in the Main Street Lease and the Moody Street
Lease.

      This Lease Estoppel Certificate is executed in connection therewith and is
being delivered to the President and Fellows of Harvard College, a Massachusetts
educational and charitable corporation, with a place of business at c/o Harvard
Real Estate Services, Holyoke Center, Suite 800, Cambridge, Massachusetts 02138
("Harvard") in connection with that certain lease by and between Harvard and
Tenant for certain property located at 300 North Beacon Street (known as
Building 97), and at 311 Arsenal Street (known as Building 311), the Arsenal on
the Charles, Watertown, Massachusetts 02472, dated as of October __, 2004,

      Based on the understanding of the foregoing, Tenant hereby represents and
warrants to Harvard as follows:

      1.    The premises leased under the Main Street Lease consist of
            approximately 3,000 rentable square feet in the basement of the Main
            Street Building, 10,800 rentable square feet on the second floor of
            the Main Street Building, and 8,500 rentable square feet on the
            third floor of the Main Street Building, for a total of
            approximately 22,300 rentable square feet (the "Main Street
            Premises").

      2.    The premises leased under the Moody Street Lease consist of
            approximately 11,188 rentable square feet on the second floor of the
            Moody Street Building, 5,466 rentable square feet on the third floor
            of the Moody Street Building, 11,850 rentable square feet on the
            fourth floor of the Moody Street Building, and 6,250

<PAGE>
Confidential Materials omitted and filed separately with the Securities and
Exchange Commission. Asterisks denote omissions.




            rentable square feet on the fifth floor of the Moody Street
            Building, for a total of approximately 34,754 rentable square feet.

      3.    The current Base Rent for the Main Street Premises is $ *  per
            month, plus any Additional Rent as specified in the Main Street
            Lease to be payable equal to $_________ per month.

      4.    The current Annual Fixed Rent for the Moody Street Premises is
            $ * , payable in equal monthly installments of $ * , plus any common
            area charges, taxes and other stipulated charges as specified in the
            Moody Street Lease to be payable, which are currently $__________
            per month.

      5.    Tenant presently occupies the Main Street Premises and the Moody
            Street Premises and is conducting its business therein, which
            business is the use permitted under the respective Leases.

      6.    No rent or other payments have been paid by the Tenant in advance of
            its due date under either the Main Street Lease or the Moody Street
            Lease.

      7.    Neither the Main Street Landlord nor the Moody Street Landlord is
            holding any security deposit in connection with their respective
            leases except the amounts set forth as follows:

<TABLE>
<S>                                         <C>                       <C>
Main Street Landlord:                       $ *                       (Letter of Credit)
Moody Street Landlord:                      $ *                       (Letter of Credit)
</TABLE>

      8.    The Main Street Lease is the complete statement of the lease
            agreement between the Main Street Landlord and Tenant with respect
            to the Main Street Premises and is presently in full force and
            effect according to its terms.

      9.    The Moody Street Lease is the complete statement of the lease
            agreement between the Moody Street Landlord and Tenant with respect
            to the Moody Street Premises and is presently in full force and
            effect according to its terms.

      10.   Neither the Main Street Lease nor the Moody Street Lease has been
            assigned, modified, supplemented or amended.

      11.   There are presently no subleases in effect with respect to all or
            any portion of the Main Street Premises or the Moody Street
            Premises, and no party other than the Tenant is occupying all or any
            portion of the Main Street Premises or Moody Street Premises.

      12.   Tenant is aware of no default or event of default under either the
            Main Street Lease or the Moody Street Lease, and is aware of no
            event that has occurred which with the passage of time or the giving
            of notice would constitute a default thereunder as of the date
            hereof. Furthermore, all conditions under the Main Street Lease and
            the Moody Street Lease to be performed by the respective

                                        2

<PAGE>

            Landlords and Tenant have been performed satisfactorily and in
            accordance with the respective leases. On this date, there are no
            existing defenses or offsets which the Main Street Landlord, the
            Moody Street Landlord or Tenant has against the enforcement of
            either the Main Street Lease or the Moody Street Lease.

      13.   Tenant represents and warrants that the current term of the Main
            Street Lease will expire on June 30, 2007 and that the Main Street
            Lease contains no options to extend, except as follows:

            None.

      14.   Tenant represents and warrants that the current term of the Moody
            Street Lease will expire on June 30, 2007 and that the Moody Street
            Lease contains no options to extend, except as follows:

            A one time option to extend the term of the Moody Street Lease for
            five years, provided Tenant gives written notice to Moody Street
            Landlord at least twelve months prior to June 30, 2007.

      15.   Tenant represents and warrants that Tenant shall have the right to
            terminate the Main Street Lease as to any or all of the Main Street
            Premises without penalty with three months written notice after
            September 1, 2005.

                                        3

<PAGE>

            EXECUTED as an instrument under seal as of the ____ day of October,
            2004.

                                     TENANT
                                     athenahealth, Inc.

                                     By: ________________________________
                                         duly authorized
                                     Name: ______________________________
                                     Title: _____________________________

                                        4

<PAGE>
Confidential Materials omitted and filed separately with the Securities and
Exchange Commission. Asterisks denote omissions.



                           LEASE ESTOPPEL CERTIFICATE

         Pursuant to that certain Sublease dated as of April 9, 2003, as
affected by that certain letter agreement dated April 9, 2003, as further
amended by that certain Assignment of Sublease dated as of March 16, 2004, and
as further amended by that certain Amendment and Assumption of Sublease
effective as of May 1, 2004 (as so amended, the "Main Street Lease"),
athenahealth, Inc., having a place of business at One Moody Street, Waltham,
Massachusetts 02450 (the "Tenant") is leasing certain property as identified in
the Main Street Lease which is a portion of the building located at 716 Main
Street, Waltham, Massachusetts 02450 (the "Main Street Building") from
Skorz/Waltham, LLC, with a place of business at c/o Karger Realty, Inc., 407
Squire Road, Revere, Massachusetts 02151 (the "Main Street Landlord").
Capitalized terms used herein and not otherwise defined herein shall have the
meaning assigned thereto in the Main Street Lease.

         Main Street Landlord hereby represents and warrants as follows:

         1.       The premises leased under the Main Street Lease consist of
                  approximately 3,000 rentable square feet in the basement of
                  the Main Street Building, 10,800 rentable square feet on the
                  second floor of the Main Street Building, and 8,500 rentable
                  square feet on the third floor of the Main Street Building,
                  for a total of approximately 22,300 rentable square feet (the
                  "Main Street Premises").

         2.       Tenant presently occupies the Main Street Premises and is
                  conducting its business therein, which business is the use
                  permitted under the Main Street Lease.

         3.       The current Base Rent for the Main Street Premises is
                  $ *  per month, plus any Additional Rent as specified in
                  the Main Street Lease to be payable equal to $______ per
                  month.

         4.       No rent or other payments have been paid by the Tenant in
                  advance of its due date under the Main Street Lease.

         5.       The Main Street Landlord is not holding any security deposit
                  in connection with the Main Street Lease except the amount set
                  forth as follows:

                  $ *  (Letter of Credit)

         6.       The Main Street Lease is the complete statement of the lease
                  agreement between the Main Street Landlord and Tenant with
                  respect to the Main Street Premises and is presently in full
                  force and effect according to its terms.

         7.       The Main Street Lease has not been assigned, modified,
                  supplemented or amended.

         8.       There are presently no subleases in effect with respect to all
                  or any portion of the Main Street Premises, and no party other
                  than the Tenant is occupying all or any portion of the Main
                  Street Premises.

<PAGE>

         9.       Tenant is aware of no default or event of default under the
                  Main Street Lease, and is aware of no event that has occurred
                  which with the passage of time or the giving of notice would
                  constitute a default thereunder as of the date hereof.
                  Furthermore, all conditions under the Main Street Lease to be
                  performed by the Main Street Landlord and Tenant have been
                  performed satisfactorily and in accordance with the Main
                  Street Lease. On this date, there are no existing defenses or
                  offsets which the Main Street Landlord or Tenant has against
                  the enforcement of the Main Street Lease.

         10.      Main Street Landlord represents and warrants that the current
                  term of the Main Street Lease will expire on June 30, 2007 and
                  that the Main Street tease contains no options to extend,
                  except as follows:

                  None.

         11.      Main Street Landlord represents and warrants that Tenant shall
                  have the right to terminate the Main Street Lease as to any or
                  all of the Main Street Premises without penalty with three
                  months written notice after September 1, 2005.

                                        2

<PAGE>

      EXECUTED as an instrument under seal as of the ____ day of October, 2004.

                                       MAIN STREET LANDLORD
                                       SKORZ/WALTHAM, LLC

                                       By: ________________________________
                                           duly authorized
                                       Name: ______________________________
                                       Title: _____________________________

                                        3

<PAGE>
Confidential Materials omitted and filed separately with the Securities and
Exchange Commission. Asterisks denote omissions.



                           LEASE ESTOPPEL CERTIFICATE

         Pursuant to that certain Amendment and Restatement of Lease dated as of
February 1, 2000, as further amended by that certain First Amendment to Lease
dated as of October 31, 2000, and as further amended by that certain Second
Amendment to Lease dated as of February 22, 2002 (as so amended, the "Moody
Street Lease"), athenahealth, Inc., having a place of business at One Moody
Street, Waltham, Massachusetts 02450 (the "Tenant") is leasing certain property
as identified in the Moody Street Lease which is a portion of the building
located at One Moody Street, Waltham, Massachusetts 02450 (the "Moody Street
Building") from One Moody Realty, LLC with a place of business at do Karger
Realty, Inc. 407 Squire Road, Revere, MA 02151 (the "Moody Street Landlord").
Capitalized terms used herein and not otherwise defined herein shall have the
meaning assigned thereto in the Moody Street Lease.

         Moody Street Landlord hereby represents and warrants as follows:

         1.       The premises leased under the Moody Street Lease consist of
                  approximately 11,188 rentable square feet on the second floor
                  of the Moody Street Building, 5,466 rentable square feet on
                  the third floor of the Moody Street Building, 11,850 rentable
                  square feet on the fourth floor of the Moody Street Building,
                  and 6,250 rentable square feet on the fifth floor of the Moody
                  Street Building, for a total of approximately 34,754 rentable
                  square feet.

         2.       Tenant presently occupies the Moody Street Premises and is
                  conducting its business therein, which business is the use
                  permitted under the Moody Street Lease.

         3.       The current Annual Fixed Rent for the Moody Street Premises is
                  $ * , payable in equal monthly installments of
                  $ * , plus any common area charges, taxes and other
                  stipulated charges as specified in the Moody Street Lease to
                  be payable, which are currently $______ per month.

         4.       No rent or other payments have been paid by the Tenant in
                  advance of its due date under the Moody Street Lease.

         5.       The Moody Street Landlord is not holding any security deposit
                  in connection with the Moody Street Lease except the amount
                  set forth as follows:

                  $ *  (Letter of Credit)

         6.       The Moody Street Lease is the complete statement of the lease
                  agreement between the Moody Street Landlord and Tenant with
                  respect to the Moody Street Premises and is presently in full
                  force and effect according to its terms.

         7.       The Moody Street Lease has not been assigned, modified,
                  supplemented or amended.

<PAGE>

         8.       There are presently no subleases in effect with respect to all
                  or any portion of the Moody Street Premises, and no party
                  other than the Tenant is occupying all or any portion of the
                  Moody Street Premises.

         9.       Tenant is aware of no default or event of default under the
                  Moody Street Lease, and is aware of no event that has occurred
                  which with the passage of time or the giving of notice would
                  constitute a default thereunder as of the date hereof.
                  Furthermore, all conditions under the Moody Street Lease to be
                  performed by the Moody Street Landlord and Tenant have been
                  performed satisfactorily and in accordance with the Moody
                  Street Lease. On this date, there are no existing defenses or
                  offsets which the Moody Street Landlord or Tenant has against
                  the enforcement of the Moody Street Lease.

         10.      Moody Street Landlord represents and warrants that the current
                  term of the Moody Street Lease will expire on June 30, 2007
                  and that the Moody Street Lease contains no options to extend,
                  except as follows:

                  A one time option to extend the term of the Moody Street Lease
                  for five years, provided Tenant gives written notice to Moody
                  Street Landlord at least twelve months prior to June 30, 2007.

                                        2

<PAGE>

      EXECUTED as an instrument under seal as of the _______ day of October,
      2004.

                                     MOODY STREET LANDLORD
                                     One Moody Realty, LLC

                                     By: _________________________________
                                         duly authorized
                                     Name: _______________________________
                                     Title:_______________________________

                                        3

<PAGE>

                             EXHIBIT K - LEASE RIDER

      The following provisions are hereby incorporated into this Lease.

                        A. Tenant's Right of First Offer.

1.    Right of First Offer/Conditions

      a.    Tenant shall have a right of first offer (the "Right of First
            Offer") after initial lease-up, on the First Offer Space, as defined
            below, upon the terms and conditions set forth in this Section A.
            This Right of First Offer shall apply only to athenahealth, Inc.,
            and no assignee, subtenant or successor of athenahealth, Inc. shall
            have any rights under this Right of First Offer.

      b.    The space that is subject to the rights in this Section A is limited
            to the tenantable space in Building 311 located on the second, third
            and fourth floors, and that Landlord intends to lease for general
            office use (the "First Offer Space").

      c.    Tenant shall not be permitted to exercise this Right of First Offer,
            and Landlord shall have no obligation to deliver an Offering Notice,
            as defined below, unless Landlord determines that the following
            conditions precedent (collectively, the "First Offer Conditions")
            have been satisfied at the time that any First Offer Space becomes
            available:

            (i)   this Lease is in full force and effect and athenahealth, Inc.
                  is the Tenant,

            (ii)  Tenant is in compliance with the terms of the Lease and no
                  Breach or Event of Default of Tenant shall have occurred and
                  be continuing;

            (iii) Landlord determines, based on the then current Tenant's
                  Financial Statement, that Tenant is sufficiently capable of
                  meeting the additional financial obligations for the First
                  Offer Space;

            (iv)  athenahealth, Inc. is occupying at least 80% of the Building
                  311 Premises;

            (v)   The First Offer Space is intended for the exclusive use of
                  athenahealth, Inc. or its Affiliates; and

            (vi)  The existing tenant in any First Offer Space has not extended
                  or renewed its Lease for such First Offer Space or entered
                  into a new lease for such First Offer space.

2.    Landlord's Offering Notice. At any time after Landlord has determined that
      an existing tenant in any First Offer Space will not extend or renew its
      lease or enter into a new lease for such space, but prior to leasing any
      such First Offer Space to a party other than the existing tenant of such
      space, and provided that Landlord has determined that the First Offer
      Conditions have been satisfied, Landlord agrees to provide Tenant written
      notice

<PAGE>

      (the "Offering Notice") of the availability of such First Offer Space. The
      Offering Notice will (i) identify the First Offer Space that Landlord
      intends to lease, (ii) set forth the date that Landlord expects to be able
      to deliver such space for lease and the lease term that Landlord is
      offering such First Offer Space (the "First Offer Space Term"); and (iii)
      indicate the Basic Rent that Landlord is offering such First Offer Space
      (the "First Offer Space Basic Rent").

3.    Availability of First Offer Space. The First Offer Space shall not be
      deemed to be available if Landlord or any affiliate of Harvard intends to
      occupy such First Offer Space.

4.    Tenant's Election. Within ten Business Days after Landlord's delivery of
      an Offering Notice to Tenant, Tenant shall either (i) give Landlord
      written notice that Tenant elects to lease such First Offer Space (the
      "Acceptance Notice"), or (ii) give Landlord written notice that Tenant
      elects not to lease the First Offer Space (the "Refusal Notice"). If
      Tenant timely gives an Acceptance Notice, Landlord and Tenant shall enter
      into a written amendment to this Lease incorporating such First Offer
      space into the Premises demised hereunder. Landlord ` and Tenant shall
      enter into such written amendment within thirty days following Landlord's
      delivery to Tenant of such written amendment. Such amendment shall
      provide:

      a.    such First Offer Space shall be demised to Tenant upon delivery of
            the same by Landlord to Tenant ("First Offer Space Commencement
            Date") for the First Offer Space Term, and shall be considered part
            of the Premises, provided that all of the terms stated in the
            Offering Notice shall govern Tenant's leasing of the First Offer
            Space, including that the Basic Rent for such First Offer Space
            shall be the First Offer. Space Basic Rent, and appropriate
            adjustments shall be made to Tenant's Share of Parking Spaces,
            Tenant's Share of Operating Costs and Tenant's Share of Taxes during
            the First Offer Space Term to reflect the addition of the First
            Offer Space to the Premises; and

      b.    such First Offer Space shall be leased by Tenant in its "As-Is"
            condition subject to Landlord's obligation to deliver the services
            set forth in Article 9 of this Lease, and the Work Letter shall not
            apply to the First Offer Space.

5.    Waiver.

      a.    In the event that (i) Tenant gives a Refusal Notice, (ii) Tenant
            fails to give Landlord notice of Tenant's election within the ten
            Business Day period described in Section A.4. above, or (iii) Tenant
            fails to enter into a written amendment to this Lease with respect
            to such First Offer Space within the thirty day period described in
            Section A.4. above, then, with respect to the First Offer Space
            identified in such Offering Notice: (1) Tenant shall be deemed to
            have waived its Right of First Offer, (2) Landlord shall be deemed
            to have satisfied its obligations with respect to Tenant's Right of
            First Offer, Tenant's Right of First Offer shall thereafter be
            terminated, and Tenant shall have no further rights with respect to
            such First Offer Space for the balance of the Lease Term, and (3)
            Landlord may

                                        2

<PAGE>

            then enter into a lease for all or any portion of such First Offer
            Space upon such terms and conditions as Landlord may elect in
            Landlord's sole discretion.

      b.    Tenant shall execute for the benefit of Landlord a written statement
            evidencing the waiver, or deemed waiver, of Tenant's Right of First
            Offer following any of the circumstances described in Section
            A.5(a); and if Tenant fails to execute such statement within five
            days after a written request from Landlord, Landlord may execute
            such statement on Tenant's behalf.

      c.    Tenant shall have no claim against Landlord under this Section A if
            Landlord fails (either inadvertently or negligently) to .offer any
            First Offer Space to Tenant, and Tenant hereby waives any and all
            such claims related to this Section A. If Landlord though knowingly
            and intentionally breaches its obligation to deliver to Tenant an
            Offering Notice that Landlord was, under the terms of this Section
            A, obligated to deliver, Tenant may seek in a judicial proceeding,
            recovery of any reasonable actual damages incurred by Tenant as a
            result of Landlord's failure to deliver such Offering Notice, but in
            no event shall any Tenant's recovery exceed $10.00 per rentable
            square foot multiplied by the square footage of such First Offer
            Space.

                              B. Rooftop Equipment.

      Tenant may place certain equipment on the roof of the Buildings subject to
the following additional requirements and restrictions:

      a.    Subject to the provisions of this Section B, the roof of the
            Buildings may used for housing and operating certain equipment,
            including, but not limited to a back-up generator, to be purchased
            and installed by Tenant as part of Tenant's Work (defined in Exhibit
            D, all as specifically approved in writing by Landlord (any
            equipment installed within the roof of the Buildings, as the same
            may be modified, altered or replaced during the term hereof, is
            collectively referred to herein as "Tenant's Rooftop Equipment").
            Landlord's approval shall not be unreasonably withheld provided
            Tenant demonstrates to Landlord's satisfaction that the proposed
            equipment (x) does not interfere with any Building Systems on the
            roof; (y) will not affect the structural integrity of the Buildings
            or impact the roof or the roof membrane in any manner, and (z) shall
            be adequately sound-proofed to meet all requirements of Legal
            Requirements and Landlord's specified maximum decibel levels for
            equipment operations.

      b.    Tenant shall not install or operate Tenant's Rooftop Equipment until
            Tenant has obtained and submitted to Landlord copies of all required
            governmental permits, licenses, and authorizations necessary for the
            installation and operation thereof. In addition, Tenant shall comply
            with all reasonable construction rules and regulations promulgated
            by Landlord in the installation, maintenance and operation of
            Tenant's Rooftop Equipment. Tenant's contractor shall be subject to
            prior written approval by Landlord, and shall be an approved
            contractor under the terms of the roof warranty. In the event that
            Tenant, after commercially

                                        3

<PAGE>

            reasonable efforts, shall be unable to obtain all of the required
            governmental permits, licenses, and authorizations necessary for the
            installation and operation of a back-up generator on the roof of
            Building 311, Tenant may pursue all required governmental permits,
            licenses, and authorizations necessary for the installation and
            operation of a back-up generator to be placed adjacent to Building
            311 or Building 97, in a location designated by Landlord, in its
            sole discretion.

      c.    Landlord shall have no obligation to provide any services including,
            without limitation, electric current, or gas service to the roof or
            to Tenant's Rooftop Equipment.

      d.    Tenant shall be responsible for the cost of repairing and
            maintaining Tenant's Rooftop Equipment and the cost of repairing any
            damage to the Buildings, or the cost of any necessary improvements
            to the Buildings, caused by or as a result of the installation,
            replacement and/or removal of Tenant's Rooftop Equipment. At the end
            of the Lease Term, Tenant shall remove all Tenant's Rooftop
            Equipment and repair any damage caused by such removal as required
            by Section 5.1.4 of this Lease or the provisions of Exhibit F.

      e.    Landlord makes no warranties or representations to Tenant as to the
            suitability of the roof for the installation and operation of
            Tenant's Rooftop Equipment.

      f.    If any of Tenant's Work on the roof of the Buildings, including
            without limitation the installation and maintenance of Tenant's
            Rooftop Equipment, damages the roof or invalidates or adversely
            affects any warranty provided by Landlord to Tenant, Tenant shall be
            fully responsible for the cost of repairs (and any subsequent
            repairs to the roof to the extent that any warranty is invalidated
            or adversely affected).

                                        4

<PAGE>

                        EXHIBIT L: SHUTTLE BUS SCHEDULE

<TABLE>
<S>                             <C>                          <C>                          <C>
100 Talcott Avenue              7:15 AM                      7:25 AM                      7:35 AM
200 Talcott Avenue              7:16 AM                      7:26 AM                      7:36 AM
311 Arsenal St.                 7:17 AM                      7:27 AM                      7:37 AM
300 N. Beacon                   7:18 AM                      7:28 AM                      7:38 AM

100 Talcott Avenue              7:55 AM                      8:05 AM                      8:15 AM
200 Talcott Avenue              7:56 AM                      8:06 AM                      8:16 AM
311 Arsenal St.                 7:57 AM                      8:07 AM                      8:17 AM
300 N. Beacon                   7:58 AM                      8:08 AM                      8:18 AM

100 Talcott Avenue              8:35 AM                      8:45 AM                      8:55 AM
200 Talcott Avenue              8:36 AM                      8:46 AM                      8:56 AM
311 Arsenal St.                 8:37 AM                      8:47 AM                      8:57 AM
300 N. Beacon                   8:38 AM                      8:48 AM                      8:58 AM

100 Talcott Avenue              9:15 AM                      9:30 AM
200 Talcott Avenue              9:16 AM                      9:31 AM
311 Arsenal St.                 9:17 AM                      9:32 AM
300 N. Beacon                   9:18 AM                      9:33 AM

100 Talcott Avenue              9:39 AM                      10:06 AM
200 Talcott Avenue              9:40 AM                      10:07 AM
311 Arsenal St.                 9:41 AM                      10:08 AM
300 N. Beacon                   9:42 AM                      10:09 AM

100 Talcott Avenue              10:15 AM                     10:42 AM
200 Talcott Avenue              10:16 AM                     10:43 AM
311 Arsenal St.                 10:17 AM                     10:44 AM
300 N. Beacon                   10:18 AM                     10:45 AM

100 Talcott Avenue              10:51 AM                     11:18 AM
200 Talcott Avenue              10:52 AM                     11:19 AM
311 Arsenal St.                 10:53 AM                     11:20 AM
300 N. Beacon                   10:54 AM                     11:21 AM

100 Talcott Avenue              11:27 AM                     11:54 AM
200 Talcott Avenue              11:28 AM                     11:55 AM
311 Arsenal St.                 11:29 AM                     11:56 AM
300 N. Beacon                   11:30 AM                     11:57 AM
</TABLE>

<PAGE>

<TABLE>
<S>                             <C>                          <C>                          <C>
100 Talcott Avenue              12:03 PM                     12:30 PM
200 Talcott Avenue              12:04 PM                     12:31 PM
311 Arsenal St.                 12:05 PM                     12:32 PM
300 N. Beacon                   12:06 PM                     12:33 PM

100 Talcott Avenue              12:39 PM                     1:06 PM
200 Talcott Avenue              12:40 PM                     1:07 PM
311 Arsenal St.                 12:41 PM                     1:08 PM
300 N. Beacon                   12:42 PM                     1:09 PM

100 Talcott Avenue              1:15 PM                      1:42 PM
200 Talcott Avenue              1:16 PM                      1:43 PM
311 Arsenal St.                 1:17 PM                      1:44 PM
300 N. Beacon                   1:18 PM                      1:45 PM

100 Talcott Avenue              1:51 PM                      2:18 PM
200 Talcott Avenue              1:52 PM                      2:19 PM
311 Arsenal St.                 1:53 PM                      2:20 PM
300 N. Beacon                   1:54 PM                      2:21 PM

100 Talcott Avenue              2:27 PM                      2:54 PM
200 Talcott Avenue              2:28 PM                      2:55 PM
311 Arsenal St.                 2:29 PM                      2:56 PM
300 N. Beacon                   2:30 PM                      2:57 PM

100 Talcott Avenue              3:03 PM                      3:30 PM
200 Talcott Avenue              3:04 PM                      3:31 PM
311 Arsenal St.                 3:05 PM                      3:32 PM
300 N. Beacon                   3:06 PM                      3:33 PM

100 Talcott Avenue              3:30 PM                      4:06 PM
200 Talcott Avenue              3:40 PM                      4:07 PM
311 Arsenal St.                 3:41 PM                      4:08 PM
300 N. Beacon                   3:42 PM                      4:09 PM

100 Talcott Avenue              4:15 PM                      4:42 PM
200 Talcott Avenue              4:16 PM                      4:43 PM
311 Arsenal St.                 4:17 PM                      4:44 PM
300 N. Beacon                   4:18 PM                      4:45 PM

100 Talcott Avenue              4:51 PM                      5:18 PM
200 Talcott Avenue              4:52 PM                      5:19 PM
311 Arsenal St.                 4:53 PM                      5:20 PM
300 N. Beacon                   4:54 PM                      5:21 PM
</TABLE>

                                        2

<PAGE>

<TABLE>
<S>                             <C>                          <C>                          <C>
100 Talcott Avenue              5:27 PM                      5:54 PM
200 Talcott Avenue              5:28 PM                      5:55 PM
311 Arsenal St.                 5:29 PM                      5:56 PM
300 N. Beacon                   5:30 PM                      5:57 PM

100 Talcott Avenue              6:03 PM                      6:30 PM
200 Talcott Avenue              6:04 PM                      6:31 PM
311 Arsenal St.                 6:05 PM                      6:32 PM
300 N. Beacon                   6:06 PM                      6:33 PM
</TABLE>

                                        3
<PAGE>
                     EXHIBIT L-1: 4TH SHUTTLE BUS SCHEDULE

<TABLE>
<CAPTION>
<S>                         <C>            <C>            <C>          <C>
100 Talcott Avenue          7:15 AM        7:25 AM        7:35 AM      7:45 AM
200 Talcott Avenue          7:16 AM        7:26 AM        7:36 AM      7:46 AM
311 Arsenal St.             7:17 AM        7:27 AM        7:37 AM      7:47 AM
300 N. Beacon               7:18 AM        7:28 AM        7:38 AM      7:48 AM

100 Talcott Avenue          7:55 AM        8:05 AM        8:15 AM      8:25 AM
200 Talcott Avenue          7:56 AM        8:06 AM        8:16 AM      8:26 AM
311 Arsenal St.             7:57 AM        8:07 AM        8:17 AM      8:27 AM
300 N. Beacon               7:58 AM        8:08 AM        8:18 AM      8:28 AM

100 Talcott Avenue          8:35 AM        8:45 AM        8:55 AM      9:05 AM
200 Talcott Avenue          8:36 AM        8:46 AM        8:56 AM      9:06 AM
311 Arsenal St.             8:37 AM        8:47 AM        8:57 AM      9:07 AM
300 N. Beacon               8:38 AM        8:48 AM        8:58 AM      9:08 AM

100 Talcott Avenue          9:15 AM        9:30 AM
200 Talcott Avenue          9:16 AM        9:31 AM
311 Arsenal St.             9:17 AM        9:32 AM
300 N. Beacon               9:18 AM        9:33 AM

100 Talcott Avenue          9:39 AM        10:06 AM
200 Talcott Avenue          9:40 AM        10:07 AM
311 Arsenal St.             9:41 AM        10:08 AM
300 N. Beacon               9:42 AM        10:09 AM

100 Talcott Avenue          10:15 AM       10:42 AM
200 Talcott Avenue          10:16 AM       10:43 AM
311 Arsenal St.             10:17 AM       10:44 AM
300 N. Beacon               10:18 AM       10:45 AM

100 Talcott Avenue          10:51 AM       11:18 AM
200 Talcott Avenue          10:52 AM       11:19 AM
311 Arsenal St.             10:53 AM       11:20 AM
300 N. Beacon               10:54 AM       11:21 AM

100 Talcott Avenue          11:27 AM       11:54 AM
200 Talcott Avenue          11:28 AM       11:55 AM
311 Arsenal St.             11:29 AM       11:56 AM
300 N. Beacon               11:30 AM       11:57 AM
</TABLE>


<PAGE>

<TABLE>
<CAPTION>

<S>                         <C>            <C>
100 Talcott Avenue          12:03 PM       12:30 PM
200 Talcott Avenue          12:04 PM       12:31 PM
311 Arsenal St.             12:05 PM       12:32 PM
300 N. Beacon               12:06 PM       12:33 PM

100 Talcott Avenue          12:39 PM       1:06 PM
200 Talcott Avenue          12:40 PM       1:07 PM
311 Arsenal St.             12:41 PM       1:08 PM
300 N. Beacon               12:42 PM       1:09 PM

100 Talcott Avenue          1:15 PM        1:42 PM
200 Talcott Avenue          1:16 PM        1:43 PM
311 Arsenal St.             1:17 PM        1:44 PM
300 N. Beacon               1:18 PM        1:45 PM

100 Talcott Avenue          1:51 PM        2:18 PM
200 Talcott Avenue          1:52 PM        2:19 PM
311 Arsenal St.             1:53 PM        2:20 PM
300 N. Beacon               1:54 PM        2:21 PM

100 Talcott Avenue          2:27 PM        2:54 PM
200 Talcott Avenue          2:28 PM        2:55 PM
311 Arsenal St.             2:29 PM        2:56 PM
300 N. Beacon               2:30 PM        2:57 PM

100 Talcott Avenue          3:03 PM        3:30 PM
200 Talcott Avenue          3:04 PM        3:31 PM
311 Arsenal St.             3:05 PM        3:32 PM
300 N. Beacon               3:06 PM        3:33 PM

100 Talcott Avenue          3:30 PM        4:06 PM
200 Talcott Avenue          3:40 PM        4:07 PM
311 Arsenal St.             3:41 PM        4:08 PM
300 N. Beacon               3:42 PM        4:09 PM

100 Talcott Avenue          4:15 PM        4:42 PM
200 Talcott Avenue          4:16 PM        4:43 PM
311 Arsenal St.             4:17 PM        4:44 PM
300 N. Beacon               4:18 PM        4:45 PM

100 Talcott Avenue          4:51 PM        5:18 PM
200 Talcott Avenue          4:52 PM        5:19 PM
311 Arsenal St.             4:53 PM        5:20 PM
300 N. Beacon               4:54 PM        5:21 PM
</TABLE>


                                       2

<PAGE>

<TABLE>
<CAPTION>

<S>                         <C>            <C>
100 Talcott Avenue          5:27 PM        5:54 PM
200 Talcott Avenue          5:28 PM        5:55 PM
311 Arsenal St.             5:29 PM        5:56 PM
300 N. Beacon               5:30 PM        5:57 PM

100 Talcott Avenue          6:03 PM        6:30 PM
200 Talcott Avenue          6:04 PM        6:31 PM
311 Arsenal St.             6:05 PM        6:32 PM
300 N. Beacon               6:06 PM        6:33 PM
</TABLE>


                                       3