Supplemental Master Mortgage Indenture No. 46, dated and effective as of December 19, 2023, between TriState Generation and Transmission Association, Inc. and U.S. Bank Trust Company, National Association as (successor) trustee

THIS SUPPLEMENTAL MASTER MORTGAGE INDENTURE NO. 46, dated and effective as of December 19, 2023 (this “Forty-sixth Supplemental Indenture”), is between U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION (as successor trustee to U.S. Bank National Association), a national banking association having a corporate trust office in Denver, Colorado (the “Trustee”), and TRI-STATE GENERATION AND TRANSMISSION ASSOCIATION, INC., a cooperative corporation organized and existing under the laws of the State of Colorado (the “Company”).

WHEREAS, the Company entered into the Master First Mortgage Indenture, Deed of Trust and Security Agreement, between the Company and the Trustee, amended, restated, and effective as of December 15, 1999 as previously amended and supplemented by forty-four supplemental indentures (collectively, the “Original Indenture”), for the purpose of providing for the issuance and securing of its senior secured debt thereunder; and

WHEREAS, pursuant to Sections 4.02 and 9.01(c) of the Original Indenture and the Loan Agreement, dated as of December 19, 2023 (the “2023 CFC Agreement”), between the Company and the National Rural Utilities Cooperative Finance Corporation (“CFC”), the Company has issued one (1) promissory note, CFC Note 9083 (as more particularly described in Exhibit E-36 and Attachment 1, the “Series 2023B Note”), which is issued to provide liquidity, as a committed take out of Long-Term Debt, and for other general corporate purposes, to be known as the Tri-State Generation and Transmission Association, Inc. Electric System Secured Obligation Series 2023B (the “Series 2023B Secured Obligation”) and to further supplement the Original Indenture by this Forty-sixth Supplemental Indenture in order to authorize the Series 2023B Secured Obligation; and

WHEREAS, as permitted by Sections 2.02 and 2.12 of the Original Indenture, the Company has requested the Trustee to authenticate the Series 2023B Note as the Series 2023B Secured Obligation and deliver it to CFC, and such Series 2023B Secured Obligation shall be entitled to the lien of the Indenture on a parity with all other Secured Obligations Outstanding under the Indenture; and

WHEREAS, pursuant to Section 9.01 of the Original Indenture, the Company, without the consent of the Holders, is authorized to make certain amendments to the Original Indenture; and

WHEREAS, the Original Indenture has been filed of record in the official public records as described more particularly on Exhibit H-40 hereto; and

WHEREAS, in addition to the property described in the Original Indenture, the Company has acquired certain other property rights and interests in property; and

WHEREAS, all acts and things necessary to make this Forty-sixth Supplemental Indenture the valid, legal, and binding obligation of the Company and to constitute these presents, together with the Original Indenture, a valid indenture and agreement according to its terms, having been done and performed, and the execution of this Forty-sixth Supplemental Indenture having in all respects been duly authorized, the Original Indenture as amended by this Forty-sixth Supplemental Indenture (as so amended, the “Indenture”) shall be amended and supplemented as follows:

Section 1.01 Confirmation of Granting Clause.

The Company hereby confirms and ratifies each of the Granting Clauses contained in the Original Indenture in order to secure the payment of the principal of, premium, if any, and interest and any other amounts due on the Series 2023B Secured Obligation.

Section 1.02 Supplemental Grant.

Pursuant to GRANTING CLAUSE THIRD of the Original Indenture and in order to secure the payment of the principal of, premium, if any, and interest and any other amounts due on the Series 2023B Secured Obligation, and the performance of the covenants therein and in the Indenture contained, and to declare the terms and conditions

on which the Series 2023B Secured Obligation is secured, and in consideration of the premises and of the acceptance of the Series 2023B Secured Obligation, by the Holders thereof, the Company by these presents does grant, bargain, sell, convey, assign, transfer, mortgage, hypothecate, pledge, set over and confirm to the Trustee, to be held in trust, together with the Trust Estate described in the Original Indenture, all property, rights, privileges and franchises of the Company of every kind and description, real, personal or mixed, tangible or intangible, whether now owned or hereafter acquired by the Company, wherever located, and grants a security interest therein for the purposes herein expressed, except any Excluded Property and any Excepted Property (each as defined in the Indenture) hereinafter expressly excepted from the lien hereof, or any property which has been released or disposed of pursuant to the terms of the Indenture, and including, without limitation, all and singular the following:

All right, title and interest of the Company in and to the real property more particularly described in Exhibit A-39 attached hereto, which identifies the real property acquired by the Company and not previously described in the Original Indenture.

A security interest in the Equipment, Contract Rights, General Intangibles and Proceeds (each as defined in the Original Indenture) of the personal property acquired by the Company since the recording of the Forty-fifth Supplemental Indenture; and in any funds, rights, rents, revenues and accounts receivable and general intangibles (including choses in action and judgments) arising under any contract subject to the lien of the Indenture all as described in GRANTING CLAUSE SECOND of the Indenture, acquired by the Company since the recording of the Forty-fifth Supplemental Indenture.

Section 2.01 Definitions of Words and Terms.

Words and terms used in this Forty-sixth Supplemental Indenture and not otherwise defined herein shall, except as otherwise stated, have the meanings assigned to them in the Original Indenture.

The following definitions shall be added to Section 1.01 of the Indenture in alphabetical order:

“Forty-sixth Supplemental Indenture” shall mean the Supplemental Master Mortgage Indenture No. 46, between the Company and the Trustee, dated effective as of December 19, 2023.

“Series 2023B Secured Obligation” shall mean the Tri-State Generation and Transmission Association, Inc. Electric System Secured Obligation, Series 2023B, designated on Exhibit E-36, authorized by the Original Indenture as amended and supplemented by the Forty-sixth Supplemental Indenture.

Section 2.02 Conflicts with Supplemental Indentures.

Supplemental Indentures may contain covenants which are different than the covenants of the Company contained in this Forty-sixth Supplemental Indenture provided that such covenants shall not conflict with the Original Indenture (except as permitted under Article IX of the Original Indenture). Such covenants are intended to be supplemental hereto and the Company shall be obligated to comply with all covenants concerning any matter whether contained in a Supplemental Indenture or this Forty-sixth Supplemental Indenture so long as such Supplemental Indenture is in effect.

a.The Company hereby authorizes the authentication of one (1) promissory note, dated effective as of December 19, 2023, issued by the Company to CFC in the principal amount of $100,000,000.00. Such note shall constitute the Tri-State Generation and Transmission Association, Inc. Electric System Secured Obligation, Series 2023B. The Holder of the Series 2023B Secured Obligation is CFC, and the Trustee shall execute a certificate of authentication to such note which shall indicate that such note is a Secured Obligation hereunder.

The Trustee's certificate of authentication for the Series 2023B Secured Obligation shall be as set forth below:

Certificate of Authentication for the Series 2023B Secured Obligation

(d) Pursuant to Section 2.02(b) of the Original Indenture, attached hereto as Attachment 1 is a summary of the terms of the note for the Series 2023B Secured Obligation. Also attached hereto is Exhibit E-36, a description of the principal amount, maturity date, interest rate, and other terms of the note constituting the Series 2023B Secured Obligation.

Section 3.02 Persons Deemed Holder.

Subject to the terms of Section 1.02(h) of the Original Indenture, the Trustee shall look to the Secured Obligation Register to conclusively determine the owner or Holder of such Series 2023B Secured Obligation for all purposes of the Indenture.

Section 3.03 Additional Secured Obligations to be Equally Secured.

Any series of Secured Obligations which may be authorized and issued pursuant to Article II of the Original Indenture shall be entitled to be secured under this Indenture equally and ratably with Secured Obligations theretofore issued and then Outstanding with no priority of any series of Secured Obligations over any other series of Secured Obligations (subject to subparagraph (b)(xi) of Section 2.02 of the Original Indenture).

Section 3.04 Registration, Transfer and Exchange.

The Series 2023B Secured Obligation shall be registered, exchanged, and replaced pursuant to Sections 2.05 and 2.06 of the Original Indenture.

Section 3.05 Payments on the Series 2023B Secured Obligation.

Payment on the Series 2023B Secured Obligation shall be made in the manner and in accordance with the 2023 CFC Agreement and the Series 2023B Secured Obligation. The Company shall serve as the Paying Agent for the Series 2023B Secured Obligation, and the Place of Payment of the Series 2023B Secured Obligation shall be the corporate offices of the Company set forth in Section 1.03 of the Original Indenture.

Section 3.06 Redemption and Prepayment.

The Series 2023B Secured Obligation shall be redeemable or prepayable, including the payment of a make-whole amount and prepayment administrative fee, if applicable, in accordance with the terms of the instruments evidencing and relating to such Series 2023B Secured Obligation and the 2023 CFC Agreement.

Section 4.01 Supplements to Exhibits to Original Indenture.

Exhibits A and E attached to the Original Indenture, as previously supplemented, are hereby supplemented by Exhibit A-39 and Exhibit E-36 attached hereto. Exhibit B to the Original Indenture is hereby amended and restated in its entirety to read as set forth in Exhibit B attached hereto. Exhibit H-40 is hereby incorporated into the Indenture as attached hereto. All Exhibits and Attachments are incorporated herein by reference.

Section 5.01 Representations and Warranties.

The Company represents and warrants that (a) it is duly authorized under the laws of the State of Colorado and all other applicable provisions of law to execute this Forty-sixth Supplemental Indenture and to issue the Series 2023B Secured Obligation, (b) all corporate action on the part of the Company required by its organizational documents and the Original Indenture to establish this Forty-sixth Supplemental Indenture and the Series 2023B Secured Obligation as a binding and enforceable obligation of the Company has been duly and effectively taken, and (c) all requirements of the Original Indenture, including but not limited to the requirements of Sections 2.02, 2.12, and 4.02, for the issuance and authentication of the Series 2023B Secured Obligation have been satisfied.

Section 5.02 Covenants under the Original Indenture.

The Company confirms, covenants and agrees that so long as the Series 2023B Secured Obligation remains Outstanding, it will deliver to the Trustee all reports, opinions and other documents required by the Original Indenture to be submitted to the Trustee at the time said reports, opinions or other documents are required to be submitted to the Trustee, and that it will faithfully perform or cause to be performed at all times any and all covenants, agreements and undertakings required on the part of the Company contained in the Indenture and the Series 2023B Secured Obligation. The Company further confirms its covenants and agrees with its undertakings in the Original Indenture.

Section 6.01 Ratification of Indenture.

The Original Indenture as amended and supplemented by this Forty-sixth Supplemental Indenture is in all respects ratified and confirmed, except as to any liens created by the Original Indenture which have been heretofore released of record, and the Original Indenture as so amended and supplemented shall be read, taken and construed as one and the same instrument. Except as herein otherwise expressly provided, all the provisions, definitions, terms and conditions of the Original Indenture shall be deemed to be incorporated in, and made a part of, this Forty-sixth Supplemental Indenture. All references to “this Indenture” or to “the Indenture” or to "hereunder" in the Indenture shall be to the Original Indenture, as amended and supplemented by this Forty-sixth Supplemental Indenture, and as otherwise amended and supplemented from time to time. Except as amended and supplemented by this Forty-sixth Supplemental Indenture, and except as to any liens created by the Original Indenture which have heretofore been released of record, the Original Indenture remains in full force and effect and is hereby ratified in full by the parties hereto.

Section 6.02 Benefits of Indenture.

Nothing in this Forty-sixth Supplemental Indenture is intended to give any Person, other than the parties hereto and the Holders of Outstanding Secured Obligations and any Credit Provider to the extent provided herein, any benefit or any legal or equitable right, remedy or claim under this Forty-sixth Supplemental Indenture.

Section 6.03 Provisions of the Indenture to Control.

The provisions of Article VII of the Indenture shall control the terms under which the Trustee shall serve under this Forty-sixth Supplemental Indenture.

Section 6.04 Binding Effect.

All the covenants, stipulations, promises and agreements in this Forty-sixth Supplemental Indenture by or on behalf of the Company shall inure to the benefit of the parties hereto and the Holders, and shall bind their respective successors and assigns, whether so expressed or not.

Section 6.05 Severability Clause.

In case any provision in this Forty-sixth Supplemental Indenture or in any Secured Obligations shall be invalid, illegal or unenforceable, the validity, legality and enforceability of the remaining provisions shall not in any way be affected or impaired thereby.

Section 6.06 Execution in Counterparts.

This Forty-sixth Supplemental Indenture may be executed in any number of counterparts, each of which shall be an original; and all of which shall together constitute but one and the same instrument.

Section 6.07 Governing Law.

This Forty-sixth Supplemental Indenture shall be construed and the rights and obligations of the parties hereunder enforced in accordance with and governed by the laws of the State of Colorado and applicable federal law, except (a) to the extent that the law of any other jurisdiction shall be mandatorily applicable; (b) to the extent that perfection, priority and enforcement and the effect of perfection, priority and enforcement of the lien of this Forty-sixth Supplemental Indenture, notice and enforcement of remedies may be governed by the laws of any state other than the State of Colorado as provided by law (including but not limited to the applicable laws of the States); or (c) that the rights, duties, obligations, privileges and immunities of the Trustee shall be governed by the laws of the jurisdiction in which the corporate trust office of the Trustee is located.

The Article and Section headings herein and in the Table of Contents are for convenience only and shall not affect the construction hereof.

Section 6.09 Successors and Assigns.

All covenants and agreements in this Forty-sixth Supplemental Indenture by the Company shall bind its successors and assigns, whether so expressed or not.

Section 6.10 Entire Agreement.

This Forty-sixth Supplemental Indenture embodies the entire agreement among the parties hereto with respect to the subject matters hereof.

Section 6.11 Acceptance of Trust.

The Trustee hereby acknowledges and accepts the trusts granted hereby.

TRANSMISSION ASSOCIATION, INC.,

			By: /s/ Patrick L. Bridges
[SEAL]			Patrick L. Bridges
			Senior Vice President and Chief Financial Officer
			Tri-State Generation and Transmission Association, Inc.
			1100 W. 116th Avenue
			Westminster, Colorado 80234

    

ATTEST:

By: /s/ Julie Kilty

Julie Kilty

Secretary

STATE OF COLORADO        )

)    ss.

COUNTY OF ADAMS        )

The foregoing instrument was acknowledged before me this 18th day of December 2023, by Patrick L. Bridges, Senior Vice President and Chief Financial Officer of Tri-State Generation and Transmission Association, Inc.

Witness my hand and official seal.

Notary Public

(Notary Seal)

By:    /s/ Michael McGuire

Michael McGuire

Vice President

U.S. Bank Trust Company, National Association

950 17th Street, 5th Floor

Denver, CO 80202

STATE OF COLORADO        )

)    ss.

COUNTY OF DENVER        )

The foregoing instrument was acknowledged before me this 14th day of December 2023, by Michael McGuire, Vice President of U.S. Bank Trust Company, National Association.

Witness my hand and official seal.

Notary Public

(Notary Seal)

A full copy of the Forty-sixth Supplemental Indenture with the full Exhibit A-39 relevant to each individual state is being filed of record with the Secretary of State of each of the States of Arizona, Colorado, Nebraska, New Mexico and Wyoming. Counterparts of this Forty-sixth Supplemental Indenture that are being filed in counties in Arizona, Colorado, Nebraska and Wyoming contain an Exhibit A-39 which identifies the fee owned property acquired by the Company and not previously described in the Original Indenture in that particular county and those easements acquired by the Company and not previously described in the Original Indenture in that particular county. In New Mexico, a notice of the recordings filed in the public utility filings of the New Mexico Secretary of State is filed in each appropriate New Mexico county.