Officers Certificate, dated October 7, 2021, pursuant to Sections 102, 201, 301 and 303 of the Indenture dated March 1, 2011, as amended and supplemented, among Kilroy Realty, L.P., as issuer, Kilroy Realty Corporation, as guarantor, and U.S. Bank National Association, as trustee, establishing a series of securities entitled 2.650% Senior Notes due 2033, including the form of 2.650% Senior Note due 2033 and the form of related guarantee

Exhibit 4.3

Officers’ Certificate

Pursuant to Sections 102, 201, 301 and 303 of the Indenture

Dated: October 7, 2021

The undersigned, Merryl E. Werber, Senior Vice President, Chief Accounting Officer and Controller, and Michelle Ngo, Senior Vice President, Chief Financial Officer and Treasurer, of Kilroy Realty Corporation, a Maryland corporation (“KRC”), the guarantor (the “Guarantor”) of the Securities referred to below and the sole general partner (the “General Partner”) of Kilroy Realty, L.P., a Delaware limited partnership (the “Company”), hereby certify as follows:

The undersigned, having read the appropriate provisions of the Indenture, dated as of March 1, 2011 (the “Base Indenture”), among the Company, the Guarantor and U.S. Bank National Association, as trustee (the “Trustee”), as amended and supplemented by the Supplemental Indenture, dated as of July 5, 2011 (the “Supplemental Indenture”), among the Company, the Guarantor and the Trustee (the Base Indenture, as so amended and supplemented, is called the “Indenture”), including Sections 102, 201, 301 and 303 thereof and the definitions in such Indenture relating thereto, an executed copy of the Company Order (as defined in the Indenture) of even date herewith delivered pursuant to Sections 203 and 303 of the Indenture in connection with the issuance of the Securities referred to below, and certain other corporate and partnership documents and records, and having made such examination and investigation as, in the opinion of the undersigned, each considers necessary to enable the undersigned to express an informed opinion as to whether (a) the conditions set forth in the Indenture relating to the establishment of the title and terms of the Company’s 2.650% Senior Notes due 2033 (the “Securities”), the form of certificate evidencing the Securities and the form and terms of the guarantees (the “Guarantees”) of the Guarantor to be endorsed on the certificates evidencing the Securities, have been satisfied, and (b) the conditions in the Indenture relating to the issuance, authentication and delivery of the Securities have been satisfied, each hereby certify that:

This certificate shall constitute an Officers’ Certificate (as defined in the Indenture) of the Company and the Guarantor and is being executed by the undersigned in their capacity as officers of the Guarantor and officers of the General Partner of the Company.

(SIGNATURE PAGE FOLLOWS)

IN WITNESS WHEREOF, we have hereunto set our hands as of the date first written above.

(Officers’ Certificate Pursuant to Sections 102, 201, 301 and 303 of the Indenture)

ANNEX I

Capitalized terms used in this Annex I and not otherwise defined herein have the same definitions as in the Indenture referred to in the Officers’ Certificate of which this Annex I constitutes a part.

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The Securities of such series are redeemable at the option of the Company, at any time or from time to time prior to August 15, 2033 (the “Par Call Date”), either in whole or in part, at a Redemption Price equal to the greater of (i) 100% of the principal amount of the Securities of such series to be redeemed and (ii) the sum of the present values of the remaining scheduled payments of principal of and Interest (exclusive of Interest accrued to the applicable Redemption Date) on the Securities of such series to be redeemed assuming that such Securities matured, and that Interest on such Securities was payable, on the Par Call Date discounted to such Redemption Date on a semiannual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate plus 20 basis points, plus in each case accrued and unpaid Interest on the principal amount of the Securities of such series being redeemed to such Redemption Date.

On and after the Par Call Date, the Securities of such series are redeemable at the option of the Company, at any time or from time to time, either in whole or in part, at a Redemption Price equal to 100% of the principal amount of the Securities of such series to be redeemed, plus accrued and unpaid Interest on the principal amount of the Securities of such series being redeemed to the applicable Redemption Date.

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Notwithstanding the foregoing, installments of Interest that are due and payable on any Interest Payment Date falling on or prior to a Redemption Date with respect to the Securities of such series will be payable to the Persons who were the Holders of the Securities of such series (or one or more Predecessor Securities), registered as such at the close of business on the relevant Regular Record Dates according to their terms and the provisions of the Indenture. Written notice of redemption must be given to Holders of the Securities of such series (or portions thereof) to be redeemed not less than 15 nor more than 60 days prior to the applicable Redemption Date.

If less than all of the Securities of such series are to be redeemed, the particular Securities of such series to be redeemed shall be selected in the manner provided in Section 1103 of the Indenture in minimum principal amounts of $2,000 and integral multiples of $1,000 in principal amount in excess thereof; provided that, in the case of any Security of such series redeemed in part, the unredeemed portion thereof shall be in a principal amount of $2,000 or an integral multiple of $1,000 in excess thereof.

Notwithstanding the foregoing, the Company shall not redeem the Securities of such series on any date if the principal amount of the Securities of such series has been accelerated, and such acceleration has not been rescinded or cured on or prior to the applicable Redemption Date as provided in the Indenture.

The redemption of the Securities of such series shall otherwise be made as provided in the Indenture, including Article Eleven thereof.

Certain Definitions

“Statistical Release” means the statistical release designated “H.15” or any successor publication which is published weekly by the Federal Reserve System and which establishes yields on actively traded United States government securities adjusted to constant maturities or, if such statistical release is not published at the time of any determination of the Treasury Rate, then such other reasonably comparable index as the Company shall designate.

“Treasury Rate” means, with respect to any Redemption Date, the arithmetic mean of the yields for the five most recent days published in the Statistical Release under the caption “Treasury Constant Maturities” for the maturity (rounded to the nearest month) corresponding to the remaining term (the “Remaining Life”) of the Securities of such series to be redeemed (assuming for this purpose that such Securities matured on the Par Call Date). If no maturity exactly corresponds to such Remaining Life, yields for the two published maturities most closely corresponding to such Remaining Life shall be calculated pursuant to the immediately preceding sentence, and the Treasury Rate shall be interpolated or extrapolated from such yields on a straight-line basis, rounding in each of such relevant periods to the nearest month. The Treasury Rate shall be determined by the Company on the third business day preceding the date on which the Company mails or otherwise transmits notice of redemption to the Holders of the applicable Securities of such series. For purposes of determining the Treasury Rate, the most recent Statistical Release published prior to the applicable date of determination of the Treasury Rate shall be used. As used in the second preceding sentence, the term “business day” means any day (other than a Saturday or Sunday) that is not a day on which banking institutions in The City of New York are authorized or required by law, regulation or executive order to close.

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Additional Covenants

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Additional Definitions

“Acquired Debt” means Debt of a Person:

Acquired Debt shall be deemed to be incurred on the date the acquired Person is merged or consolidated with or into the Company or any of its Subsidiaries or becomes a Subsidiary of the Company or the date of the related acquisition, as the case may be.

“Annual Debt Service Charge” means, for any period, the interest expense of the Company and its Subsidiaries for such period, determined on a consolidated basis in accordance with United States generally accepted accounting principles, including, without duplication:

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“Consolidated Income Available for Debt Service” for any period means Consolidated Net Income of the Company and its Subsidiaries for such period, plus amounts which have been deducted and minus amounts which have been added for, without duplication:

all determined on a consolidated basis in accordance with United States generally accepted accounting principles.

“Consolidated Net Income” for any period means the amount of net income (or loss) of the Company and its Subsidiaries for such period, excluding, without duplication:

all determined on a consolidated basis in accordance with United States generally accepted accounting principles.

“Debt” means, with respect to any Person, any indebtedness of such Person, whether or not contingent, in respect of:

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and also includes, to the extent not otherwise included, any obligation of such Person to be liable for, or to pay, as obligor, guarantor or otherwise (other than for purposes of collection in the ordinary course of business), Debt of the types referred to above of another Person (it being understood that Debt shall be deemed to be incurred by such Person whenever such Person shall create, assume, guarantee or otherwise become liable in respect thereof). In the case of clause (d) above, the term “Debt” shall not include any lease of property by such Person as lessee which is required to be reflected on such Person’s balance sheet as an operating lease in accordance with United States generally accepted accounting principles.

“Original Issue Date” shall have the meaning set forth in Section (2) of this Annex I.

“Total Assets” means the sum of, without duplication:

all determined on a consolidated basis in accordance with United States generally accepted accounting principles.

“Total Unencumbered Assets” means the sum of, without duplication:

all determined on a consolidated basis in accordance with United States generally accepted accounting principles; provided, however, that, in determining Total Unencumbered Assets as a percentage of outstanding Unsecured Debt for purposes of the Additional Covenant entitled “Maintenance of Total Unencumbered Assets” as set forth in Section (16)(d) of this Annex I, all investments in unconsolidated limited partnerships, unconsolidated limited liability companies and other unconsolidated entities shall be excluded from Total Unencumbered Assets.

“Undepreciated Real Estate Assets” means, as of any date, the cost (original cost plus capital improvements) of real estate assets, right-of-use assets associated with leases of property required to be reflected as finance leases on the balance sheet of the Company and its Subsidiaries in accordance with United States generally accepted accounting principles and related intangibles of the Company and its Subsidiaries on such date, before depreciation and amortization, all determined on a consolidated basis in accordance with United States generally accepted accounting principles; provided, however, that “Undepreciated Real Estate Assets” shall not include right-of-use assets associated with leases of property required to be reflected as operating leases on the balance sheet of the Company and its Subsidiaries in accordance with United States generally accepted accounting principles.

“Unsecured Debt” means Debt of the Company or any of its Subsidiaries which is not secured by a Lien on any property or assets of the Company or any of its Subsidiaries.

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“SECTION 116.    ELECTRONIC SIGNATURES; CORPORATE SEAL

“The words “execution,” “signed,” “signature,” and words of like import in this Indenture shall include images of manually executed signatures transmitted by facsimile, email or other electronic format (including, without limitation, “pdf,” “tif” or “jpg”) and other electronic signatures (including without limitation, DocuSign and AdobeSign). The use of electronically transmitted images of manual signatures, other electronic signatures and electronic records (including, without limitation, any contract or other record created, generated, sent, communicated, received, or stored by electronic means) shall be of the same legal effect, validity and enforceability as a manually executed signature or use of a paper-based record-keeping system to the fullest extent permitted by applicable law, including the Federal Electronic Signatures in Global and National Commerce Act, the New York State Electronic Signatures and Records Act and any other applicable law, including, without limitation, any state law based on the Uniform Electronic Transactions Act or the Uniform Commercial Code. Without limitation to the foregoing, and anything in this Indenture to the contrary notwithstanding, (a) any Officers’ Certificate, Company Order, Company Request, Opinion of Counsel, Security, Guarantee endorsed on any Security, opinion of counsel, instrument, agreement or other document delivered pursuant to this Indenture may be executed, attested and transmitted by any of the foregoing electronic means and formats, (b) all references in Section 303 or elsewhere in this Indenture to the execution, attestation or authentication of any Security, any Guarantee endorsed on any Security, or any certificate of authentication appearing on or attached to any Security by means of a manual or facsimile signature shall be deemed to include signatures that are made or transmitted by any of the foregoing electronic means or formats, and (c) any requirement in the Indenture that any signature be made under a corporate seal (or facsimile thereof) shall not be applicable to the Securities or any Guarantees endorsed on any Securities. The Company agrees to assume all risks arising out of the use of using digital signatures, including without limitation the risk of the Trustee acting on unauthorized instructions.”

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ANNEX II

Form of 2.650% Senior Note due 2033

and Form of Guarantee Endorsed Thereon

[Include only for Global Securities - UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY (55 WATER STREET, NEW YORK, NEW YORK) (THE “DEPOSITARY,” WHICH TERM INCLUDES ANY SUCCESSOR DEPOSITARY FOR THIS SECURITY) TO THE COMPANY OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITARY (AND ANY PAYMENT HEREON IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITARY), ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.]

CUSIP: 49427R AR3

ISIN: US49427RAR30

No. R -

KILROY REALTY, L.P.

2.650% SENIOR NOTES DUE 2033

Kilroy Realty, L.P., a Delaware limited partnership (herein called the “Company,” which term includes any successor under the Indenture referred to on the reverse hereof), for value received hereby promises to pay to        , or its registered assigns, the principal sum of        DOLLARS ($        ) on November 15, 2033 at the office or agency of the Company maintained for that purpose in accordance with the terms of the Indenture, in such coin or currency of the United States of America as at the time of payment shall be legal tender for the payment of public and private debts, and to pay Interest, semi-annually in arrears on May 15 and November 15 of each year, commencing May 15, 2022, on said principal sum at said office or agency, in like coin or currency, at the rate per annum of 2.650%, from the May 15 or November 15, as the case may be, next preceding the date of this Note (as defined on the reverse hereof) to which Interest has been paid or duly provided for, unless no Interest has been paid or duly provided for on the Notes, in which case from October 7, 2021, until payment of said principal sum has been made or duly provided for. Except as otherwise provided in or permitted pursuant to Section 307 of the Indenture (as defined on the reverse hereof), the principal of and premium, if any, and Interest on the Notes shall be paid at the office or agency designated by the Company for such purpose.

The Company promises to pay Interest on overdue principal and (to the extent that payment of such Interest is permitted by applicable law) overdue premium, if any, and Interest at the rate of 2.650% per annum.

Reference is made to the further provisions of this Note set forth on the reverse hereof. Such further provisions shall for all purposes have the same effect as though fully set forth at this place.

This Note shall not be valid or become obligatory for any purpose until the certificate of authentication hereon shall have been signed manually by the Trustee (as defined on the reverse hereof) or a duly authorized Authenticating Agent under the Indenture.

(Signature Page Follows)

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IN WITNESS WHEREOF, the Company has caused this Note to be duly executed.

TRUSTEE’S CERTIFICATE OF AUTHENTICATION

This is one of the 2.650% Senior Notes due 2033 referred to in the within-mentioned Indenture.

[FORM OF REVERSE SIDE OF NOTE]

KILROY REALTY, L.P.

2.650% SENIOR NOTES DUE 2033

This Note is one of a duly authorized series of Securities of the Company, designated as its 2.650% Senior Notes due 2033 (herein called the “Notes”), issued under and pursuant to an Indenture, dated as of March 1, 2011 (the “Base Indenture”), among the Company, Kilroy Realty Corporation, a Maryland corporation (the “Guarantor”, which term includes any successor under the Indenture hereinafter referred to), and U.S. Bank National Association, as trustee (herein called the “Trustee,” which term includes any successor thereto under the Indenture), as supplemented by the Supplemental Indenture, dated as of July 5, 2011 (the “First Supplemental Indenture”; the Base Indenture, as amended and supplemented by the First Supplemental Indenture and as the same may be further amended and supplemented from time to time, is hereinafter called the “Indenture”), among the Company, the Guarantor and the Trustee and the Officers’ Certificate of the Company and the Guarantor dated October 7, 2021, delivered pursuant to Sections 102, 201, 301 and 303 of the Indenture (the “Officers’ Certificate”), to which reference is hereby made for a description of the rights, limitations of rights, obligations, duties and immunities thereunder of the Trustee, the Company, the Guarantor and the Holders of the Notes. Terms (whether or not capitalized) that are defined in the Indenture and used but not otherwise defined in this Note shall have the respective meanings ascribed thereto in the Indenture.

If an Event of Default with respect to the Notes occurs and is continuing, then the principal of and accrued and unpaid Interest on all of the Notes may be declared or, in the case of certain Events of Default, shall automatically become immediately due and payable in the manner and with the effect provided in the Indenture.

The Indenture contains provisions permitting the Company, the Guarantor and the Trustee, with the consent of the Holders of not less than a majority in aggregate principal amount of all Outstanding Securities of each series affected by such supplemental indenture, to execute supplemental indentures adding any provisions to or changing in any manner or eliminating any of the provisions of the Indenture or of any supplemental indenture or the Securities of such series or modifying in any manner the rights of the Holders of the Securities of such Series, subject to exceptions set forth in Section 902 of the Indenture. The Indenture also contains provisions permitting the Holders of specified percentages in aggregate principal amount of the Notes then Outstanding, on behalf of the Holders of all of the Notes, to waive compliance by the Company or the Guarantor with certain provisions of the Indenture and certain past defaults or Events of Default with respect to the Notes and their consequences.

No reference herein to the Indenture and no provision of this Note, the Guarantee endorsed on this Note or the Indenture shall alter or impair, as among the Company and the Holder of this Note, the obligation of the Company, which is absolute and unconditional, to pay the principal of and premium, if any, and Interest on this Note at the place, at the respective times, at the rate, in the respective amounts and in the coin or currency herein and in the Indenture prescribed.

Interest on the Notes shall be computed on the basis of a 360-day year of twelve 30-day months.

The Notes are issuable in fully registered form, without coupons, in minimum denominations of $2,000 principal amount and in integral multiples of $1,000 principal amount in excess thereof. As provided in the Indenture and subject to certain limitations set forth therein, the Notes may be surrendered for registration of transfer or for exchange for a like aggregate principal amount of Notes of authorized denominations as requested by the Holders surrendering the same. No service charge shall be made for any registration of transfer or exchange of Notes, but the Company may require payment of a sum sufficient to

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cover any tax or other governmental charge that may be imposed in connection therewith, subject to exceptions set forth in the Indenture.

The Company shall have the right to redeem the Notes, in whole at any time and from time to time in part, at the Redemption Price and on the terms and conditions set forth in the Indenture and the Officers’ Certificate.

Written notice of redemption must be given to Holders of the Notes (or portions thereof) to be redeemed not less than 15 nor more than 60 days prior to the applicable Redemption Date.

The Notes are not subject to redemption through the operation of any sinking fund.

No recourse under or upon any obligation, covenant or agreement contained in the Indenture or the Notes, or because of any indebtedness evidenced thereby, shall be had against any past, present or future stockholder, employee, officer or director, as such, of the Company, the General Partner, the Guarantor or of any successor, either directly or through the Company, the General Partner, the Guarantor or any successor, under any rule of law, statute or constitutional provision or by the enforcement of any assessment or by any legal or equitable proceeding or otherwise, all such liability being expressly waived and released by the acceptance of the Notes by the Holders and as part of the consideration for the issue of the Notes.

This Note shall be governed by, and construed in accordance with, the laws of the State of New York.

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ABBREVIATIONS

The following abbreviations, when used in the inscription of the face of this Note, shall be construed as though they were written out in full according to applicable laws or regulations.

Additional abbreviations may also be used though not in the above list.

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GUARANTEE

Kilroy Realty Corporation, a Maryland corporation (hereinafter referred to as the “Guarantor,” which term includes any successor under the Indenture referred to below), hereby irrevocably and unconditionally guarantees on a senior basis on the terms set forth in the Indenture, the Guarantee Obligations, which include (i) the due and punctual payment of the principal of and premium, if any, and Interest (including the Redemption Price upon redemption pursuant to Article Eleven of the Indenture) on the 2.650% Senior Notes due 2033 (the “Notes”) of Kilroy Realty, L.P., a Delaware limited partnership (the “Company,” which term includes any successor thereto under the Indenture), whether at Stated Maturity, upon acceleration, upon redemption or otherwise, the due and punctual payment of Interest on any overdue principal and (to the extent permitted by law) any overdue premium, if any, and Interest on the Notes, and the due and punctual performance of all other obligations of the Company to the Holders of the Notes or the Trustee all in accordance with the terms set forth in Article Sixteen of the Indenture, and (ii) in case of any extension of time of payment or renewal of any Notes or any such other obligations, that the same shall be promptly paid in full when due or performed in accordance with the terms of the extension or renewal, whether at Stated Maturity, by acceleration, call for redemption or otherwise.

This Guarantee has been issued under and pursuant to an Indenture, dated as of March 1, 2011 (the “Base Indenture”), among the Company, the Guarantor and U.S. Bank National Association, as trustee (herein called the “Trustee,” which term includes any successor thereto under the Indenture), as supplemented by the Supplemental Indenture, dated as of July 5, 2011 (the “First Supplemental Indenture”; the Base Indenture, as amended and supplemented by the First Supplemental Indenture and as the same may be further amended and supplemented from time to time, is hereinafter called the “Indenture”), among the Company, the Guarantor and the Trustee and the Officers’ Certificate of the Company and the Guarantor dated October 7, 2021, delivered pursuant to Sections 102, 201, 301 and 303 of the Indenture (the “Officers’ Certificate”). Terms (whether or not capitalized) that are defined in the Indenture and used but not otherwise defined in this Guarantee shall have the respective meanings ascribed thereto in the Indenture.

The obligations of the Guarantor to the Holders of the Notes and to the Trustee pursuant to this Guarantee and the Indenture are expressly set forth in Article Sixteen of the Indenture and reference is hereby made to such Indenture for the precise terms of this Guarantee.

Without limitation to the provisions of Article Sixteen of the Indenture, the Guarantor hereby waives diligence, presentment, demand of payment, filing of claims with a court in the event of merger or bankruptcy of the Company, any right to require a proceeding first against the Company, the benefit of discussion, protest or notice with respect to the Notes and all demands whatsoever.

No recourse under or upon any obligation, covenant or agreement contained in the Indenture or the Notes, or because of any indebtedness evidenced thereby, shall be had against any past, present or future stockholder, employee, officer or director, as such, of the Company, the General Partner or the Guarantor or of any successor, either directly or through the Company, the General Partner or the Guarantor or any successor, under any rule of law, statute or constitutional provision or by the enforcement of any assessment or by any legal or equitable proceeding or otherwise, all such liability being expressly waived and released by the acceptance of the Notes by the Holders and as part of the consideration for the issue of the Notes.

This is a continuing Guarantee and shall remain in full force and effect and shall be binding upon the Guarantor and its successors until full and final payment of all of the Company’s obligations under the Notes and Indenture or until legally discharged in accordance with the Indenture and shall inure to the benefit of the successors and assigns of the Trustee and the Holders of the Notes, and, in the event of any transfer or assignment of rights by any Holder of the Notes or the Trustee, the rights and privileges herein conferred upon that party shall automatically extend to and be vested in such transferee or assignee, all

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subject to the terms and conditions hereof. This is a Guarantee of payment and performance and not of collection.

This Guarantee shall not be valid or become obligatory for any purpose until the certificate of authentication on the Note upon which this Guarantee is endorsed shall have been signed manually by the Trustee or a duly authorized Authenticating Agent under the Indenture.

The obligations of the Guarantor under this Guarantee shall be limited as provided in Article Sixteen of the Indenture to the extent necessary so that it does not constitute a fraudulent conveyance or fraudulent transfer.

THE TERMS OF ARTICLE SIXTEEN OF THE INDENTURE ARE INCORPORATED HEREIN BY REFERENCE.

This Guarantee shall be governed by, and construed in accordance with, the laws of the State of New York.

(Signature Page Follows)

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IN WITNESS WHEREOF, the Guarantor has caused this instrument to be duly executed.

ASSIGNMENT

For value received                     hereby sell(s) assign(s) and transfer(s) unto                     (Please insert social security or other Taxpayer Identification Number of assignee) the within Note, and hereby irrevocably constitutes and appoints                    attorney to transfer said Note on the books of the Company, with full power of substitution in the premises.

NOTICE: The signature on this Assignment must correspond with the name as written upon the face of the Note in every particular without alteration or enlargement or any change whatever.

ANNEX III

Resolutions