Document:

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                                                                Exhibit 10.43

                           LOAN MODIFICATION AGREEMENT

       This Loan Modification Agreement is entered into as of June 26, 2002, by
and between Moldflow Corporation (the "Borrower") and Silicon Valley Bank, a
California-chartered bank doing business in Massachusetts under the name
"Silicon Valley East" ("Bank").

1. DESCRIPTION OF EXISTING OBLIGATIONS: Among other Obligations which may be
owing by Borrower to Bank, Borrower is indebted to Bank pursuant to, among other
documents, a Loan Agreement, dated November 13, 2001, as may be amended from
time to time, (the "Loan Agreement"). The Loan Agreement provides for, among
other things, a Committed Line in the original principal amount of Five Million
Dollars ($5,000,000). Defined terms used but not otherwise defined herein shall
have the same meanings as set forth in the Loan Agreement.

Hereinafter, all indebtedness owing by Borrower to Bank shall be referred to as
the "Obligations."

2. Hereinafter, all other documents evidencing or securing the Obligations shall
be referred to as the "Existing Loan Documents".

3. DESCRIPTION OF CHANGE IN TERMS.

       A. MODIFICATION(S) TO LOAN AGREEMENT.

            1.   The defined term of "Profitability" under Section 5.7 entitled
                 "Financial Covenants" is hereby amended in part to read as
                 follows:

                   Borrower will have a minimum net profit of $1 for each fiscal
                   quarter except Borrower may suffer losses not to exceed
                   $500,000 for the quarters ending June 30, 2002 and September
                   30, 2002. For calculation purposes, Profitability shall be
                   defined as Borrower's net income after taxes, but prior to
                   depreciation, amortization and non-cash restructuring
                   expenses. For purposes of this covenant, restructuring
                   expenses shall be deducted from net profit when cash payments
                   are made in respect of such expenses.

4. CONSISTENT CHANGES. The Existing Loan Documents are hereby amended wherever
necessary to reflect the changes described above.

5. NO DEFENSES OF BORROWER. Borrower agrees that, as of this date, it has no
defenses against paying the Obligations.

6. CONTINUING VALIDITY. Borrower understands and agrees that in modifying the
existing Obligations, Bank is relying upon Borrower's representations,
warranties, and agreements, as set forth in the Existing Loan Documents. Except
as expressly modified pursuant to this Loan Modification Agreement, the terms of
the Existing Loan Documents remain unchanged and in full force and effect.
Bank's agreement to modifications to the existing Obligations pursuant to this
Loan Modification Agreement in no way shall obligate Bank to make any future
modifications to the Obligations. Nothing in this Loan Modification Agreement
shall constitute a satisfaction of the Obligations. It is the intention of Bank
and Borrower to retain as liable parties all makers and endorsers of Existing
Loan Documents, unless the party is expressly released by Bank in writing.
Unless expressly released herein, no maker, endorser, or guarantor will be
released by virtue of this Loan Modification Agreement. The terms of this
Paragraph apply not only to this Loan Modification Agreement, but also to all
subsequent loan modification agreements.

7. JURISDICTION/VENUE. 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 Loan Modification Agreement; provided, however, that if for any
reason Bank cannot avail itself of the courts of the Commonwealth of
Massachusetts, then venue shall lie in Santa Clara County, California.

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8. COUNTERSIGNATURE. This Loan Modification Agreement shall become effective
only when it shall have been executed by Borrower and Bank (provided, however,
in no event shall this Loan Modification Agreement become effective until signed
by an officer of Bank in California).

       This Loan Modification Agreement is executed as of the date first written
above.

BORROWER:                                BANK:

MOLDFLOW CORPORATION                     SILICON VALLEY BANK, doing business
                                         as SILICON VALLEY EAST

By: /s/ Suzanne E. Rogers                By: /s/ Mark Gallagher
  -------------------------------           -------------------------------
Name: Suzanne E. Rogers                  Name: Mark Gallagher
     ----------------------------             -----------------------------
Title: Vice President                    Title: Vice President
      ---------------------------              ----------------------------

                                         SILICON VALLEY BANK

                                         By: /s/ Maggie Garcia
                                            ---------------------------------
                                         Name: Maggie Garcia
                                              -------------------------------
                                         Title: Assistant Vice Preseident
                                               ------------------------------
                                              (Signed at Santa Clara County, CA)

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                                                                    Exhibit 4.4

                                ESCROW AGREEMENT

This Escrow Agreement (the "Agreement") is dated as of the date set forth below,
by and between, Illinois River Energy, LLC (the "Company"), U.S. Bancorp Piper
Jaffray, Inc. (the "Underwriter") and First Midwest Bank (the "Escrow Agent").
(The "Escrow Agent," the "Underwriter" and the "Company" may also be hereinafter
referred to as the "Parties").

                                    RECITALS

         A. The Company desires to establish an escrow account with the Escrow
Agent into which certain monies and documents will be deposited and held in
escrow until a minimum of $25,000,000 has been raised in connection with the
Company's public offering (the "Offering") of its Class A and Class B Units (the
"Units").

         B. The Company will retain the services of the Underwriter to assist
with the sale of the Units on a best efforts basis.

         C. The Company and the Underwriter have agreed to provide for the
impoundment of the proceeds to be received from the sale of the Units.

         D. First Midwest Bank hereby agrees to act as Escrow Agent, and the
Company and the Underwriter desire to retain First Midwest Bank as Escrow Agent
on the terms and conditions set forth in this Agreement.

         NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the Parties hereby agree as
follows:

1.   DEPOSITS: The Company shall deliver to the Escrow Agent all checks, drafts
     and money orders ("Subscription Payments") and all Subscription Agreements
     and other related documents ("Subscription Documents") received by the
     Company from Subscribers in connection with the Offering. All Subscription
     Payments shall be made payable to "FIRST MIDWEST BANK AS ESCROW AGENT FOR -
     ILLINOIS RIVER ENERGY, LLC ESCROW."

     ALL FUNDS DEPOSITED WITH THE ESCROW AGENT SHALL REMAIN THE PROPERTY OF THE
     SUBSCRIBERS ACCORDING TO THEIR RESPECTIVE INTERESTS AND SHALL NOT BE
     SUBJECT TO ANY LIEN OR CHARGE BY THE ESCROW AGENT OR THE UNDERWRITER OR BY
     JUDGMENT OR CREDITORS' CLAIMS AGAINST THE COMPANY, THE ESCROW AGENT OR THE
     UNDERWRITER UNTIL RELEASED TO THE COMPANY IN ACCORDANCE WITH SECTION 3
     HEREOF.

2.   INVESTMENT OF FUNDS: All Subscription Payments shall be cleared and
     deposited by the Escrow Agent into an institutional Money Market Account
     ("Escrow Account"); provided that the Escrow Account must accrue interest
     on a daily basis and allow for the immediate withdrawal of funds without
     premium or penalty.

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3.       DISBURSEMENT OF FUNDS:

          a.   TERMINATION OF THE OFFERING: If the Escrow Agent has not
               received, on or before December 15, 2002, subject to extension by
               the Company to March 31, 2003 ("Termination Date"), Subscription
               Payments in the aggregate amount of at least $25,000,000, then
               the Escrow Agent shall refund to Subscribers without interest,
               all Subscription Payments held in the Escrow Account per written
               instruction from the Company. Unless instructed otherwise, the
               Escrow Agent shall release all Subscription Payments held in the
               Escrow Account, and the corresponding Subscription Documents, to
               each Subscriber respectively, at the address given by such
               Subscriber in the Subscription Agreement. All disbursements by
               the Escrow Agent pursuant to this Section shall be made by the
               Escrow Agent's usual escrow checks and shall be mailed by first
               class United States Postal Services mail, postage pre-paid, as
               soon as practicable but not later than the third business day
               after the Termination Date. All interest on funds held in the
               Escrow Account shall be for the account of the Company and shall
               be paid to the Company.

          b.   DISBURSEMENT OF 10% OF ESCROW FUNDS: If the Escrow Agent
               receives, on or before the Termination Date, Subscription
               Payments in an aggregate amount of not less than $25,000,000 and
               written acceptance of each Subscriber's subscription by the
               Company, then the Escrow Agent shall disburse, upon written
               instruction from the Company, substantially in the form attached
               hereto as Exhibit A, 10% of the Subscription Payments held in the
               Escrow Account to the Company ("Initial Disbursement"). If the
               Escrow Agent receives additional Subscription Payments after the
               Initial Disbursement, the Escrow Agent shall deposit the
               Subscription Payments into the Escrow Account and upon receiving
               written instruction from the Company, substantially in the form
               attached hereto as Exhibit A, shall disburse to the Company 10%
               of all Subscription Payments received after the Initial
               Disbursement. The Escrow Agent shall retain the remaining 90% of
               all Subscription Payments in the Escrow Account to be disbursed
               as set forth in Section 3(c) below.

          c.   DISBURSEMENT OF REMAINING 90% OF SUBSCRIPTION PAYMENTS: Upon
               receipt by the Escrow Agent of written confirmation from the
               Company that the Company has received an executed commitment
               letter from a lender for the amount of debt financing that the
               Company determines necessary ("Commitment Letter Notice"), the
               Escrow Agent shall disburse to the Company, pursuant to written
               instruction from the Company, substantially in the form attached
               hereto as Exhibit A, the remaining 90% of the Subscription
               Payments remaining in the Escrow Account in immediately available
               funds ("90% Disbursement"). If the Escrow Agent receives
               additional Subscription Payments after the 90% Disbursement, then
               the Escrow Agent shall disburse the Subscription Payments to the
               Company upon written instruction from the Company, substantially
               in the Form attached hereto as Exhibit A. If the Escrow Agent
               does not receive the Commitment Letter Notice from the Company by
               the Termination Date, then the Escrow Agent shall refund to
               Subscribers without interest, the remaining 90% of each
               Subscriber's Subscription

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               Payment per written instruction from the Company. The Escrow
               Agent shall also disburse to the Company all interest on funds
               held in the Escrow Account.

          d.   REJECTION OF SUBSCRIPTION OR TERMINATION OF OFFERING: No later
               than 10 days after receipt by Escrow Agent of written notice (i)
               from the Company that the Company intends to reject a
               Subscriber's subscription, or (ii) from the Company that it is
               terminating the Offering, Escrow Agent shall pay to the
               Subscribers the amount of Subscription Payment held in the Escrow
               Account for each subscriber without interest or deduction. All
               interest on funds held in the Escrow Account shall be for the
               account of the Company and shall be paid to the Company.

4.   COLLECTED FUNDS: No Subscription Payment shall be disbursed pursuant to
     Section 3 until such Subscription Payment has been received by the Escrow
     Agent in immediately available funds.

5.   LIABILITY OF ESCROW AGENT: In performing its duties under the Agreement,
     the Escrow Agent shall not be liable to the Company, any Subscriber, or any
     Party for damages, losses, or expenses, except for gross negligence or
     willful misconduct on the part of the Escrow Agent. The Escrow Agent shall
     not incur any such liability for (I) any act or failure to act made or
     omitted in good faith, or (II) any action taken or omitted in reliance upon
     any instrument, including any written statement or affidavit provided for
     in this Agreement that the Escrow Agent shall in good faith believe to be
     genuine, nor will the Escrow Agent be liable or responsible for forgeries,
     fraud, impersonations, or determining or verifying the scope of any
     person's authority acting or purporting to act on behalf of any party to
     this Agreement. In addition, the Escrow Agent may consult with legal
     counsel in connection with the Escrow Agent's duties under this Agreement
     and shall be fully protected in any action taken, suffered, or permitted by
     it in good faith in accordance with the advice of counsel.

6.   FEES AND EXPENSES: It is understood that the fees and usual charges set
     forth on Schedule I attached to this Agreement for services of the Escrow
     Agent shall be considered compensation for ordinary services as
     contemplated by this Agreement. In the event that the conditions of this
     Agreement are not promptly fulfilled, or if the Escrow Agent renders any
     service not provided for in this Agreement, or if the Company requests a
     substantial modification of its terms, or if any controversy arises, or if
     the Escrow Agent is made a party to, or intervenes in, any litigation
     pertaining to this escrow or its subject matter, the Escrow Agent shall be
     reasonably compensated for such extraordinary services and reimbursed for
     all costs, attorney's fees, including allocated costs of in-house counsel,
     and expenses occasioned by such default, delay, controversy or litigation,
     and the Escrow Agent shall have the right to retain all documents and/or
     things of value at any time held by the Escrow Agent in this escrow until
     such compensation, fees, costs and expenses are paid. The Company promises
     to pay these sums upon demand. Unless otherwise provided, the Company will
     pay

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     all of the Escrow Agent's usual charges and the Escrow Agent may deduct
     such sums from the funds deposited in the Escrow Account if the funds are
     to be disbursed to the Company.

7.   CONTROVERSIES: If any controversy arises between the Parties to this
     Agreement, or with any other party, concerning the subject matter of this
     Agreement, its terms or conditions, the Escrow Agent will not be required
     to determine the controversy or to take any action regarding it. The Escrow
     Agent may hold all documents and funds and may wait for settlement of any
     such controversy by final appropriate legal proceedings or other means, as
     the Escrow Agent, in its discretion may deem appropriate, despite what may
     be set forth elsewhere in this Agreement. In such event, the Escrow Agent
     will not be liable for interest or damage. Furthermore, the Escrow Agent
     may, at its option, file an action of interpleader requiring the parties to
     answer and litigate any claims and rights among themselves. The Escrow
     Agent is authorized to deposit with the clerk of the court all documents
     and funds held in escrow, less any interest on funds held in the Escrow
     Account to be applied against all costs, expenses, charges and reasonable
     attorney fees incurred by the Escrow Agent due to the interpleader action
     and which the Company agrees to pay. Upon initiating such action, the
     Escrow Agent shall be fully released, and discharged of and from, all
     obligations and liability imposed by the terms of this Agreement.

8.   INDEMNIFICATION OF ESCROW AGENT: The Company and its successors and assigns
     agree jointly and severally to indemnify and hold the Escrow Agent harmless
     against any and all losses, claims, damages, liabilities, and expenses,
     including reasonable costs of investigation, counsel fees, including
     allocated costs of in-house counsel and disbursements that may be imposed
     on the Escrow Agent or incurred by the Escrow Agent in connection with the
     performance of its duties under this Agreement, including but not limited
     to any litigation arising from this Agreement or involving its subject
     matter, except to the extent such action, loss, claim, damage, liability,
     or expense results from or is caused by the willful misconduct or gross
     negligence of the Escrow Agent.

9.   RESIGNATION OF ESCROW AGENT: The Escrow Agent may resign at any time upon
     giving at least thirty (30) days written notice to the Company, provided,
     however, that no such resignation shall become effective until the
     appointment of a successor escrow agent, which shall be accomplished as
     follows: The Company shall use its best efforts to obtain a successor
     escrow agent within thirty (30) days after receiving such notice. If the
     Company fails to agree upon a successor escrow agent within such time, the
     Escrow Agent shall have the right to appoint a successor escrow agent. The
     successor escrow agent shall execute and deliver an instrument accepting
     such appointment and it shall, without further acts, be vested with all the
     estates, properties, rights, powers, and duties of the predecessor escrow
     agent as if originally named as escrow agent. The Escrow Agent shall
     thereupon be discharged from any further duties and liability under this
     Agreement.

10.  AUTOMATIC SUCCESSION: Upon the Company's and the Underwriter's consent, any
     company into which the Escrow Agent may be merged or with which it may be
     consolidated,

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     or any company to whom the Escrow Agent may transfer a substantial amount
     of its global escrow business, shall be the Successor to the Escrow Agent
     without the execution or filing of any paper or any further act on the part
     of any of the Parties, anything herein to the contrary notwithstanding. The
     Successor Escrow Agent shall be vested with all the estates, properties,
     rights, powers, and duties of the Escrow Agent as if originally named as
     escrow agent.

11.  TERMINATION: The offering period for this escrow shall terminate on the
     Termination Date. Upon termination of the offering period, the Escrow Agent
     shall disburse the funds in the Escrow Account in the manner and upon the
     terms directed in paragraph 3 hereof. The Company may, in its sole
     discretion, terminate the Offering and abandon the sale of the Units at any
     time prior to the Termination Date.

12.  MISCELLANEOUS:

          a.   GOVERNING LAWS: This Agreement is to be construed and interpreted
               according to Illinois law.

          b.   TRUST POWERS: The Escrow Agent hereby represents to the Company
               that the Escrow Agent has all necessary trust powers and
               authority to act as escrow agent as set forth in this Agreement.

          c.   COUNTERPART: This Agreement may be executed in two or more
               counterparts, each of which shall be deemed an original, but all
               of which together shall constitute on and the same instrument.

          d.   NOTICES: All instructions, notices and demands herein provided
               for shall be in writing and shall be mailed postage prepaid,
               first class mail, delivered by courier, or telecopied as follows:

         If to the Company:                       If to the Escrow Agent:

         Illinois River Energy, LLC               First Midwest Bank
         1201 South Seventh Street, Suite 110     2801 W. Jefferson Street
         Rochelle, IL 61068                       Joliet, IL 60435

         Telephone No:(815) 561-0650              Telephone No: (815) 773-2604
         Telecopier No: (815) 561-0720            Telecopier No: (815) 773-2696

         If to the Underwriter:

         U.S. Bancorp Piper Jaffray Inc.
         2780 Skypark Drive, Suite 400
         Torrance, CA 90505

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         Telephone No: (310) 325-3825
         Telecopier No: (310) 325-5785

          e.   AMENDMENTS: This Agreement may be amended by written notice
               signed by the Company, except that Section 6 through Section 12
               may be amended only with the consent of the Escrow Agent.

          f.   BINDING AGREEMENT AND SUBSTITUTION OF ESCROW AGENT: The terms and
               conditions of this Escrow Agreement shall be binding on the
               heirs, executors and assigns, creditors or transferees, or
               successors in interest, whether by operation of law or otherwise,
               of the Parties hereto. If, for any reason, the Escrow Agent named
               herein is unable or unwilling to continue to act, then the
               Company, at its sole discretion, may substitute another escrow
               agent.

                [The rest of this page left blank intentionally]

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The Company represents and agrees that it has not made, nor will it make in the
future, any representation that states or implies that the Escrow Agent has
endorsed, recommended or guaranteed the purchase, value, or repayment of the
Securities offered for sale by the Company. The Company further agrees that it
will insert in any prospectus, offering circular, advertisement, subscription
agreement or other document made available to prospective purchasers of the
Securities, the following statement in bold face type: "First Midwest Bank is
acting only as an escrow agent in connection with the Offering described herein,
and has not endorsed, recommended or guaranteed the purchase or value of any of
the units subscribed," and will furnish to the Escrow Agent a copy of each such
prospectus, offering circular, advertisement, subscription agreement or other
document at least 5 business days prior to its distribution to prospective
Subscribers.

THE UNDERSIGNED ACKNOWLEDGE THAT FIRST MIDWEST BANK IS ACTING ONLY AS AN ESCROW
AGENT IN CONNECTION WITH THE OFFERING OF THE SECURITIES DESCRIBED HEREIN, AND
HAS NOT ENDORSED, RECOMMENDED OR GUARANTEED THE PURCHASE OR VALUE OF SUCH
SECURITIES.

                [The rest of this page left blank intentionally]

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     The Parties have executed this Agreement as of the last date set forth
below.

ILLINOIS RIVER ENERGY, LLC:                     FIRST MIDWEST BANK:

By: /s/ Floyd Schultz                           By: /s/ Robert Diedrich
    ---------------------------                    ----------------------------

Print Name: Floyd Schultz                       Print Name: Robert Diedrich
           --------------------                            --------------------

Date: 9-11-02                                   Date: 9-17-02
     --------------------------                      --------------------------

U.S. BANCORP PIPER JAFFRAY INC.:

By:   /s/ Mark E. Fisler
   ---------------------------

Print Name:  Mark E. Fisler
           -------------------

Date: 9-11-02
     --------------

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                                   SCHEDULE I

                                FEES AND CHARGES

     No fees will be charged by First Midwest for ordinary escrow services.

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                                                                       EXHIBIT A

                         FUND DISBURSEMENT INSTRUCTIONS

     The undersigned certifies that he, she or it is duly authorized to
execute and deliver this Escrow Notice on behalf of Illinois River Energy,
LLC (the "Company"). Pursuant to the Escrow Agreement dated ____________, 2002
(the "Escrow Agreement") by and among the Company, the Underwriter and
First Midwest Bank (the "Escrow Agent"), the Company hereby request that the
Escrow Agent remit, in immediately available funds, $_____________ from the
Escrow Account to the following parties as follows:

         PARTY                                              AMOUNT
         -----                                              ------
                                                            $

                                                            $

         TOTAL                                              $

         IN WITNESS WHEREOF, the undersigned have executed this Fund
Disbursement Instruction as of the date set forth below.

                                                     ILLINOIS RIVER ENERGY, LLC

Dated:                                      By:
      -------------                            --------------------------------
                                                  Its:
                                                      -------------------------

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