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                                                                   EXHIBIT 10.12

                            NEGATIVE PLEDGE AGREEMENT

      This Negative Pledge Agreement is made as of June 12, 2003, by and between
EGENERA, INC., a Delaware corporation with offices at 165 Forest Street,
Marlborough, Massachusetts 01752 ("Borrower") and SILICON VALLEY BANK, a
California-chartered bank, with its principal place of business at 3003 Tasman
Drive, Santa Clara, California 95054 and with a loan production office located
at One Newton Executive Park, Suite 200,2221 Washington Street, Newton,
Massachusetts 02462, doing business under the name "Silicon Valley East"
("Bank").

In connection with, among other documents, the Loan and Security Agreement (the
"Loan Documents") being concurrently executed herewith between Borrower and
Bank, Borrower agrees as follows:

      1.    Except for the granting of non-exclusive licenses or sublicenses by
            Borrower in the ordinary course of business, Borrower has not, and
            shall not, sell, transfer, assign, mortgage, pledge, lease, grant a
            security interest in, or encumber any of Borrower's Intellectual
            Property (as defined below).

      2.    Borrower has not, and shall not, enter into a negative pledge
            agreement, or similar agreement, affecting the rights of the
            Intellectual Property with any other party.

      3.    It shall be an event of default under the Loan Documents between
            Borrower and Bank if there is a breach of any term of this Negative
            Pledge Agreement.

      4.    As used herein,

            a.    "Intellectual Property" means:

                  (i)   Any and all Copyrights;

                  (ii)  Any and all trade secrets, and any and all intellectual
                        property rights in computer software and computer
                        software products now or hereafter existing, created,
                        acquired or held;

                  (iii) Any and all design rights which may be available to
                        Borrower now or hereafter existing, created, acquired or
                        held;

                  (iv)  All Mask Works or similar rights available for the
                        protection of semiconductor chips;

                  (v)   All Patents;

                  (vi)  Any Trademarks;

                  (vii) Any and all claims for damages by way of past, present
                        and future infringements of any of the rights included
                        above, with the right, but not the obligation, to sue
                        for and collect such damages for said use or
                        infringement of the intellectual property rights
                        identified above;

                  (viii) All licenses or other rights to use any of the
                        Copyrights, Patents, Trademarks, or Mask Works and all
                        license fees and royalties arising from such use to the
                        extent permitted by such license or rights; and

                  (ix)  All amendments, extensions, renewals and extensions of
                        any of the Copyrights, Trademarks, Patents, or Mask
                        Works; and

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                  (x)   All proceeds and products of the foregoing, including
                        without limitation all payments under insurance or any
                        indemnity or warranty payable in respect of any of the
                        foregoing.

            b.    "Copyrights" means any and all copyright rights, copyright
                  applications, copyright registrations and like protections in
                  each work of authorship and derivative work thereof, whether
                  published or unpublished and whether or not the same also
                  constitutes a trade secret, now or hereafter existing,
                  created, acquired or held.

            c.    "Mask Works" means all mask work or similar rights available
                  for the protection of semiconductor chips, now owned or
                  hereafter acquired;

            d.    "Patents" means all patents, patent applications and like
                  protections including without limitation improvements,
                  divisions, continuations, renewals, reissues, extensions and
                  continuations-in-part of the same.

            e.    "Trademarks" means any trademark and servicemark rights,
                  whether registered or not, applications to register and
                  registrations of the same and like protections, and the entire
                  goodwill of the business of Borrower connected with and
                  symbolized by such trademarks.

      5.    Capitalized terms used but not otherwise defined herein shall have
            the same meaning as in the Loan Documents.

      6.    The laws of the Commonwealth of Massachusetts shall apply to this
            Agreement. BORROWER ACCEPTS FOR ITSELF AND IN CONNECTION WITH ITS
            PROPERTIES, UNCONDITIONALLY, THE NON-EXCLUSIVE JURISDICTION OF ANY
            STATE OR FEDERAL COURT OF COMPETENT JURISDICTION IN THE COMMONWEALTH
            OF MASSACHUSETTS IN ANY ACTION, SUIT, OR PROCEEDING OF ANY KIND,
            AGAINST IT WHICH ARISES OUT OF OR BY REASON OF THIS AGREEMENT;
            PROVIDED, HOWEVER, THAT IF FOR ANY REASON BANK CANNOT AVAIL ITSELF
            OF THE COURTS OF THE COMMONWEALTH OF MASSACHUSETTS, BORROWER
            ACCEPTS JURISDICTION OF THE COURTS AND VENUE IN SANTA CLARA COUNTY,
            CALIFORNIA. NOTWITHSTANDING THE FOREGOING, THE BANK SHALL HAVE THE
            RIGHT TO BRING ANY ACTION OR PROCEEDING AGAINST THE BORROWER OR ITS
            PROPERTY IN THE COURTS OF ANY OTHER JURISDICTION WHICH THE BANK
            DEEMS NECESSARY OR APPROPRIATE IN ORDER TO REALIZE ON THE COLLATERAL
            OR TO OTHERWISE ENFORCE THE BANK'S RIGHTS AGAINST THE BORROWER OR
            ITS PROPERTY.

      7.    This Agreement shall become effective only when it shall have been
            executed by Borrower and Bank.

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      EXECUTED as a sealed instrument under the laws of the Commonwealth of
Massachusetts as of the date first written above.

                                        BORROWER:

                                        EGENERA, INC.

                                        By: /s/ Thomas F. Sheehon
                                            -----------------------------------
                                        Name: Thomas F. Sheehon
                                        Title: CFO

                                        BANK:

                                        SILICON VALLEY BANK

                                        By: /s/ D. Reich
                                            -----------------------------------
                                        Name: D. Reich

                                        Title: SVP

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