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                            FOURTH AMENDMENT TO LEASE

LESSOR:                     ATHENAEUM PROPERTY LLC

LESSEE:                     BITSTREAM, INC.

DATE OF LEASE:              MARCH 17, 1992;
                            (First Amendment September 7, 1993; Second
                            Amendment July 14, 1994; Third Amendment June
                            15, 1996)

PREMISES:                   ATHENAEUM HOUSE, 215 FIRST STREET, CAMBRIDGE,
                            MASSACHUSETTS

     FOR GOOD AND VALUABLE CONSIDERATION, the receipt and sufficiency of which
are hereby acknowledged, the lease between Athenaeum Property LLC as Lessor and
Bitstream Inc., a Delaware corporation, as Lessee and March 17, 1992, and
amended on September 7, 1993 and by letter agreement on July 14, 1994 and
amended on June 15, 1996), is hereby amended for the forth time effective March
1, 1997, as follows:

     1.   Expand Leased Premises. Effective June 1, 1997 (the "Effective Date"),
          the Leased Premises shall be expanded to include approximately 4,700
          rentable square feet ("Expanded Leased Premises"), more or less, on
          the ground floor of the Building as shown on Exhibit A 
          hereto. Lessee agrees it is leasing the Expanded Leased Premises in
          its "as is" condition, except that the Expanded Leased Premises shall
          be delivered in vacuumed clean condition, free of debris and personal
          effects, and all systems to be maintained by Landlord under the lease
          shall be in good working order.

     2.   Increased Rent. The Base Rent for the Leased Premises shall be
          increased as of the Effective Date by $70,500.00 per year, calculated
          as 4,700 square feet at $15.00 per rentable square feet.

     3.   Increased Rent Adjustment. As of the Effective Date, the Rent
          Adjustment percentage in Paragraph 5 shall be increased from 7.01
          percent to 8.66 percent.

     4.   Term; Option to Extend. The term of the Lease shall remain unchanged.
          In the event Lessee exercises its option to extend the lease, the Base
          Rent on the Extended Leased Premises shall be at Fair Market Value as
          reasonably determined by Lessor but in no event less that the Base
          Rent in Paragraph 2 above.

     5.   Right to Terminate. If, on or before April 1, 1997, the Lessee decides
          it does not wish to occupy the Expanded Leased Premises, it shall give
          Lessor written notice on or before April 1, 1997 and the expansion
          contemplated herein shall be null and void. As


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          consideration for this right, Lessee shall, in the event it terminates
          this expansion, pay Lessor one month's rent (at the time of its notice
          to terminate). Lessor agrees that if the Expanded Leased premises are
          then released with less than one month's vacancy, the amount paid by
          Lessee will be abated on a pro rata basis for the days the space is
          occupied by a new tenant for business.

     6.   Broker. The Lessor and Lessee each represent and warrant to the other
          that each has had no dealings with any Brokers concerning this lease
          other than Robert A. Jones & Co., and each party agrees to indemnify
          and hold the other harmless for any damages occasioned to the other by
          reason of breach of this representation and warranty.

     7.   Construction; Interpretation. To the extent this lease amendment
          conflicts with the existing lease, this amendment shall control. Both
          parties acknowledge the lease remains in full force and effect. Other
          than stated in this amendment, all other terms and conditions remain
          the same.

EXECUTED as sealed instrument this 3rd day of March 1997.

ATHENAEUM PROPERTY LLC



By:
   -------------------------------------             --------------------------
   President                                         Witness
   Athenaeum F.A. Inc.
   Managing Member


BITSTREAM INC.



By:
   -------------------------------------             --------------------------
   Vice President, Treasurer                         Witness
   and Chief Financial
   Officer Duly Authorized


Assuming the lessee does not terminate this expansion, lessee will retain the
right until the effective date (6-1-97), to require the lessor to terminate
lessee's lease obligation on the 2800 square feet on the ground floor referenced
in the Third Amendment.

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