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Exhibit 10.71

FIRST LOAN MODIFICATION AGREEMENT—EXIM

        This First Loan Modification Agreement (this "Loan Modification
Agreement') is entered into as of September    , 2004, by and among (i) 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") and (ii) ASPEN TECHNOLOGY, INC., a Delaware corporation with offices at
Ten Canal Park, Cambridge, Massachusetts 02141 and ASPENTECH, INC., a Texas
corporation with offices at Ten Canal Park, Cambridge, Massachusetts 02141
(jointly and severally, individually and collectively, "Borrower")

1.DESCRIPTION OF EXISTING INDEBTEDNESS AND OBLIGATIONS. Among other indebtedness
and obligations which may be owing by Borrower to Bank, Borrower is indebted to
Bank pursuant to a loan arrangement dated as of January 30, 2003, evidenced by,
among other documents, a certain Export-Import Bank Loan and Security Agreement
dated as of January 30, 2003 between Borrower and Bank (the "Loan Agreement").
Capitalized terms used but not otherwise defined herein shall have the same
meaning as in the Loan Agreement.

2.DESCRIPTION OF COLLATERAL. Repayment of the Obligations is secured by the
Collateral as described in the Loan Agreement (together with any other
collateral security granted to Bank, the "Security Documents").

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

3.DESCRIPTION OF CHANGE IN TERMS.

Modifications to Loan Agreement.

(i)The Loan Agreement shall be amended by deleting the following text appearing
in Section 2.5 of the Loan Agreement:

"2.5 L/C—FX Sublimit. Notwithstanding anything to the contrary contained herein,
the face amount of outstanding Letters of Credit (including drawn but
unreimbursed Letters of Credit and any Letter of Credit Reserve) issued under
this Exim Agreement plus the amount of the FX Reserve may not exceed $7,000,000
in the aggregate (the "L/C—FX Sublimit"). In addition, the aggregate amount of
FX Reserve hereunder and the FX Reserve (as defined in the Domestic Agreement)
under the Domestic Agreement shall not exceed $2,000,000."

and inserting in lieu thereof the following:

"2.5 L/C—FX Sublimit. Notwithstanding anything to the contrary contained herein,
the face amount of outstanding Letters of Credit (including drawn but
unreimbursed Letters of Credit and any Letter of Credit Reserve) issued under
this Exim Agreement plus the amount of the FX Reserve may not exceed $10,000,000
in the aggregate (the "L/C—FX Sublimit")."

4.FEES. Borrower shall reimburse Bank for all legal fees and expenses incurred
in connection with this amendment to the Existing Loan Documents.

5.RATIFICATION OF NEGATIVE PLEDGE. Borrower hereby ratifies, confirms and
reaffirms, all and singular, the terms and conditions of a certain Negative
Pledge Agreements each dated as of January 30, 2003 between Borrower and Bank,
and acknowledges, confirms and agrees that said Negative Pledge Agreement shall
remain in full force and effect.

6.RATIFICATION OF PERFECTION CERTIFICATE Borrower hereby ratifies, confirms and
reaffirms, all and singular, the terms and disclosures contained in certain
Perfection Certificates each dated as of January 30, 2003 and acknowledges,
confirms and agrees the disclosures and

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information therein has not changed, as of the date hereof except as set forth
on Schedule 1 annexed hereto.

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

8.RATIFICATION OF LOAN DOCUMENTS. Borrower hereby ratifies, confirms, and
reaffirms all terms and conditions of all security or other collateral granted
to the Bank, and confirms that the indebtedness secured thereby includes,
without limitation, the Obligations.

9.NO DEFENSES OF BORROWER. Borrower hereby acknowledges and agrees that Borrower
has no offsets, defenses, claims, or counterclaims against Bank with respect to
the Obligations, or otherwise, and that if Borrower now has, or ever did have,
any offsets, defenses, claims, or counterclaims against Bank, whether known or
unknown, at law or in equity, all of them are hereby expressly WAIVED and
Borrower hereby RELEASES Bank from any liability thereunder.

10.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 of Existing Loan Documents,
unless the party is expressly released by Bank in writing.

11.COUNTERSIGNATURE. This Loan Modification Agreement shall become effective
only when it shall have been executed by Borrower and Bank.

[Remainder of page intentionally left blank.]

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        This Loan Modification Agreement is executed as a sealed instrument
under the laws of the Commonwealth of Massachusetts as of the date first written
above.

 

BORROWER:
 
ASPEN TECHNOLOGY, INC.
 
By:          
Name:                      
Title:            
 
ASPENTECH, INC.
 
By:          
Name:                      
Title:            
 
BANK:
 
SILICON VALLEY BANK, d/b/a
SILICON VALLEY EAST
 
By:          
Name:                      
Title:            

        The undersigned, ASPENTECH SECURITIES CORP., a Massachusetts
corporation, ratifies, confirms and reaffirms, all and singular, the terms and
conditions of a certain Unlimited Guaranty dated January 30, 2003 (the
"Guaranty") and a certain Security Agreement dated as of January 30, 2003 (the
"Security Agreement") and acknowledges, confirms and agrees that the Guaranty
and Security Agreement shall remain in full force and effect and shall in no way
be limited by the execution of this Loan Modification Agreement, or any other
documents, instruments and/or agreements executed and/or delivered in connection
herewith.

ASPENTECH SECURITIES CORP
  By:          
Name:                      
Title:              

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Exhibit 10.71