Exhibit 10.22(d)

THIRD LOAN MODIFICATION AGREEMENT

This Third Loan Modification Agreement (this “Loan Modification Agreement”) is entered into as of January 28, 2005, 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 QBLIGATIONS.  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 Loan and Security Agreement dated as of January 30, 2003 between Borrower and Bank, as amended by a certain letter agreement dated February 14, 2003, a certain First Loan Modification Agreement dated June 27, 2003, and a certain Second Loan Modification Agreement dated September     , 2004 (as amended, 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 4 of the Schedule to the Loan Agreement:

“MATURITY DATE

(Section 6.1):   January 29, 2005”

and inserting in lieu thereof the following:

“MATURITY DATE

(Section 6.1):   April 1, 2005”

(ii)                                 The Loan Agreement shall be amended by deleting Section 5(a)(i) and (ii) of the Schedule thereto in their entirety and inserting in lieu thereof the

following:

“a.  Minimum Tangible Net Worth:

Borrower shall maintain, as of the last day of each month, to be tested monthly, a Tangible Net Worth of not less than the sum of (i) plus (ii) below:

(i)

(a)                                 from August 1, 2004 through and including August 31, 2004 - $116,000,000

(b)                                 from September 1, 2004 through and including September 30, 2004 - $140,000,000

(c)                                  from October 1, 2004 through and including October 31, 2004 - $128,000,000

(d)                                 from November 1, 2004 through and including November 30, 2004 - $116,000,000

(e)                                  from December 1, 2004 through and including December 31, 2004 - $140,000,000

(f)                                   from January 1, 2005 through and including January 31, 2005 - $110,000,000

(g)                                  from February 1, 2005 through and including February 28, 2005 - $100,000,000

(h)                                 from March 1, 2005 and thereafter - $120,000,000.

(ii)                                  75% of all consideration received after August 1, 2004 from proceeds from the issuance of any equity securities of the Borrower (other than (i) the issuance of stock options, restricted stock or other stock-based awards under the Borrower’s director or employee stock incentive plans, or (ii) stock purchases under the Borrower’s employee stock purchase plan) and/or subordinated debt incurred by the Borrower (net of refinanced amounts of existing subordinated debt).”

4.                                      FEES.  Borrower shall pay to Bank a modification fee equal to Twenty-Five Thousand Dollars ($25,000.00), which fee shall be due on the date hereof and shall be deemed fully earned as of the date hereof.  The Borrower shall also reimburse Bank for all legal fees and expenses incurred in connection with this amendment to the Existing Loan Documents.

5.                                      WAIVER.  Bank hereby waives Borrower’s failure to comply with the Minimum Tangible Net Worth requirement set forth in Section 5(a) of the Schedule to the Loan Agreement as of December 31, 2004.  The Bank’s waiver of Borrower’s compliance with said foregoing affirmative covenant shall apply only to the foregoing specific period.

6.                                      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.

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

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

9.                                      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.

10.                               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.

11.                               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.

12.                               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.]

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.

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.

PROMISSORY NOTE
(Exim)

FOR VALUE RECEIVED, the undersigned (jointly and severally, individually and collectively, the “Borrower”), jointly and severally promises to pay to the order of Silicon Valley Bank (“Bank”), at such place as the holder hereof may designate, in lawful money of the United States of America, the aggregate unpaid principal amount of all advances (“Advances”) made by Bank to Borrower, up to a maximum principal amount of Ten Million Dollars ($10,000,000.00), plus interest on the aggregate unpaid principal amount of such Advances, at the rates and in accordance with the terms of the Export-Import Bank Loan and Security Agreement between Borrower and Bank dated as of January 30, 2003, as amended from time to time (the “Loan Agreement”) on the first calendar day of each month after an Advance has been made. The entire principal amount and all accrued interest shall be due and payable on April 1, 2005, or on such earlier date, as provided for in the Loan Agreement.

Borrower irrevocably waives the right to direct the application of any and all payments at any time hereafter received by Bank from or on behalf of Borrower, and Borrower irrevocably agrees that Bank shall have the continuing exclusive right to apply any and all such payments against the then due and owing obligations of Borrower as Bank may deem advisable. In the absence of a specific determination by Bank with respect thereto, all payments shall be applied in the following order: (a) then due and payable fees and expenses; (b) then due and payable interest payments and mandatory prepayments; and (c) then due and payable principal payments and optional prepayments.

Bank is hereby authorized by Borrower to endorse on Bank’s books and records each Advance made by Bank under this Note and the amount of each payment or prepayment of principal of each such Advance received by Bank; it being understood, however, that failure to make any such endorsement (or any errors in notation) shall not affect the obligations of Borrower with respect to Advances made hereunder, and payments of principal by Borrower shall be credited to Borrower notwithstanding the failure to make a notation (or any errors in notation) thereof on such books and records.

Borrower promises to pay Bank all reasonable costs and reasonable expenses including all reasonable attorneys’ fees, incurred in such collection or in any suit or action to collect this Note or in any appeal thereof, unless a final court of competent jurisdiction finds that the Bank acted with gross negligence or willful misconduct. Borrower waives presentment, demand, protest, notice of protest, notice of dishonor, notice of nonpayment, and any and all other notices and demands in connection with the delivery, acceptance, performance, default or enforcement of this Note, as well as any applicable statute of limitations. No delay by Bank in exercising any power or right hereunder shall operate as a waiver of any power or right. Time is of the essence as to all obligations hereunder.

This Note is issued pursuant to the Loan Agreement, which shall govern the rights and obligations of Borrower with respect to all obligations hereunder.

The law of the Commonwealth of Massachusetts shall apply to this Agreement. BORROWER AND BANK EACH 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 NOTE OR THE LOAN 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.

BORROWER WAIVES ITS RIGHT TO A JURY TRIAL OF ANY CLAIM OR CAUSE OF ACTION BASED UPON OR ARISING OUT OF ANY OF THE EXIM LOAN DOCUMENTS OR ANY OF THE TRANSACTIONS CONTEMPLATED THEREIN, INCLUDING CONTRACT CLAIMS, TORT CLAIMS, BREACH OF DUTY CLAIMS, AND ALL OTHER COMMON LAW OR STATUTORY CLAIMS. BORROWER RECOGNIZES AND AGREES THAT THE FOREGOING WAIVER CONSTITUTES A MATERIAL INDUCEMENT FOR IT TO ENTER INTO THIS AGREEMENT. BORROWER REPRESENTS AND WARRANTS THAT IT HAS REVIEWED THIS WAIVER WITH ITS LEGAL COUNSEL AND THAT IT KNOWINGLY AND VOLUNTARILY WAIVES ITS JURY TRIAL RIGHTS FOLLOWING CONSULTATION WITH LEGAL COUNSEL.