Exhibit k.18

EXECUTION VERSION

AMENDMENT NO. 4

TO CREDIT AGREEMENT

AMENDMENT NO. 4 (this “Amendment”), dated as of June 22, 2018, to the Credit Agreement, dated as of June 23, 2014, among TORTOISE ENERGY INFRASTRUCTURE CORPORATION (the “Borrower”), each Lender from time to time party thereto, and THE BANK OF NOVA SCOTIA, as Administrative Agent (the “Administrative Agent”), as amended by Amendment No. 1, dated as of July 10, 2014, and Amendment No. 2, dated as of June 23, 2016, and Amendment No. 3, dated as of November 14, 2017 (as hereafter further amended, supplemented or otherwise modified, the “Credit Agreement”).

RECITALS

I. Each term that is defined in the Credit Agreement and not herein defined has the meaning ascribed thereto by the Credit Agreement when used herein.

II. The Borrower desires an amendment to the Credit Agreement upon the terms and conditions herein contained, and all Lenders have agreed thereto upon the terms and conditions herein contained.

AGREEMENTS

Accordingly, in consideration of the Recitals and the covenants, conditions and agreements hereinafter set forth, and for other good and valuable consideration, the receipt and adequacy of which are hereby acknowledged, the parties hereto agree as follows:

1. The definition of the term “Maturity Date” contained in Section 1.01 of the Credit Agreement is hereby amended by replacing the date “June 22, 2018” contained therein with the date “June 22, 2020.

2. Article X of the Credit Agreement is hereby amended by inserting a new Section 10.23 thereto as follows:

Section 10.23 Certain ERISA Matters

(a) Each Lender (x) represents and warrants, as of the date such Person became a Lender party hereto, and (y) covenants, from the date such Person became a Lender party hereto to the date such Person ceases being a Lender party hereto, for the benefit of, the Administrative Agent and its Affiliates, and not, for the avoidance of doubt, to or for the benefit of the Borrower, that at least one of the following is and will be true:

(i) such Lender is not using “plan assets” (within the meaning of 29 CFR § 2510.3-101, as modified by Section 3(42) of ERISA) of one or more Benefit Plans in connection with the Loans or the Commitments,

(ii) the transaction exemption set forth in one or more PTEs, such as PTE 84-14 (a class exemption for certain transactions determined by independent qualified professional asset managers), PTE 95-60 (a class exemption for certain transactions involving insurance company general accounts), PTE 90-1 (a class exemption for certain transactions involving insurance company pooled separate accounts), PTE 91-38 (a class exemption for certain transactions involving bank collective investment funds) or PTE 96-23 (a class exemption for certain transactions determined by in-house asset managers), is applicable with respect to such Lender’s entrance into, participation in, administration of and performance of the Loans, the Commitments and this Credit Agreement,

(iii) (A) such Lender is an investment fund managed by a “Qualified Professional Asset Manager” (within the meaning of Part VI of PTE 84-14), (B) such Qualified Professional Asset Manager made the investment decision on behalf of such Lender to enter into, participate in, administer and perform the Loans, the Commitments and this Credit Agreement, (C) the entrance into, participation in, administration of and performance of the Loans, the Commitments and this Credit Agreement satisfies the requirements of sub- sections (b) through (g) of Part I of PTE 84-14 and (D) to the best knowledge of such Lender, the requirements of subsection (a) of Part I of PTE 84-14 are satisfied with respect to such Lender’s entrance into, participation in, administration of and performance of the Loans, the Commitments and this Credit Agreement, or

(iv) such other representation, warranty and covenant as may be agreed in writing between the Administrative Agent, in its sole discretion, and such Lender.

(b) In addition, unless sub-clause (i) in the immediately preceding clause (a) is true with respect to a Lender or such Lender has not provided another representation, warranty and covenant as provided in sub-clause (iv) in the immediately preceding clause (a), such Lender further (x) represents and warrants, as of the date such Person became a Lender party hereto, to, and (y) covenants, from the date such Person became a Lender party hereto to the date such Person ceases being a Lender party hereto, for the benefit of, the Administrative Agent and its Affiliates, and not, for the avoidance of doubt, to or for the benefit of the Borrower, that

(i) none of the Administrative Agent or any of its Affiliates is a fiduciary with respect to the assets of such Lender (including in connection with the reservation or exercise of any rights by the Administrative Agent under this Credit Agreement, any Loan Document or any documents related to hereto or thereto),

(ii) the Person making the investment decision on behalf of such Lender with respect to the entrance into, participation in, administration of and performance of the Loans, the Commitments and this Credit Agreement is independent (within the meaning of 29 CFR § 2510.3-21) and is a bank, an insurance carrier, an investment adviser, a broker-dealer or other person that holds, or has under management or control, total assets of at least $50 million, in each case as described in 29 CFR § 2510.3-21(c)(1)(i)(A)-(E),

(iii) the Person making the investment decision on behalf of such Lender with respect to the entrance into, participation in, administration of and performance of the Loans, the Commitments and this Credit Agreement is capable of evaluating investment risks independently, both in general and with regard to particular transactions and investment strategies (including in respect of the Obligations),

(iv) the Person making the investment decision on behalf of such Lender with respect to the entrance into, participation in, administration of and performance of the Loans, the Commitments and this Credit Agreement is a fiduciary under ERISA or the Code, or both, with respect to the Loans, the Commitments and this Credit Agreement and is responsible for exercising independent judgment in evaluating the transactions hereunder, and

(v) no fee or other compensation is being paid directly to the Administrative Agent or any of its Affiliates for investment advice (as opposed to other services) in connection with the Loans, the Commitments or this Credit Agreement.

(c) The Administrative Agent hereby informs the Lenders that each such Person is not undertaking to provide impartial investment advice, or to give advice in a fiduciary capacity, in connection with the transactions contemplated hereby, and that such Person has a financial interest in the transactions contemplated hereby in that such Person or an Affiliate thereof (i) may receive interest or other payments with respect to the Loans, the Commitments and this Credit Agreement, (ii) may recognize a gain if it extended the Loans or the Commitments for an amount less than the amount being paid for an interest in the Loans or the Commitments by such Lender or (iii) may receive fees or other payments in connection with the transactions contemplated hereby, the Loan Documents or otherwise, including structuring fees, commitment fees, arrangement fees, facility fees, upfront fees, underwriting fees, ticking fees, agency fees, administrative agent or collateral agent fees, utilization fees, minimum usage fees, letter of credit fees, fronting fees, deal-away or alternate transaction fees, amendment fees, processing fees, term out premiums, banker’s acceptance fees, breakage or other early termination fees or fees similar to the foregoing.

(d) For purposes of this Section 10.23, the following defined terms when used herein have the following meanings:

“Benefit Plan” means any of (a) an “employee benefit plan” (as defined in ERISA) that is subject to Title I of ERISA, (b) a “plan” as defined in Section 4975 of the Internal Revenue Code or (c) any Person whose assets include (for purposes of ERISA Section 3(42) or otherwise for purposes of Title I of ERISA or Section 4975 of the Internal Revenue Code) the assets of any such “employee benefit plan” or “plan”.

“PTE” means a prohibited transaction class exemption issued by the U.S. Department of Labor, as any such exemption may be amended from time to time.

3. Paragraphs 1 and 2 hereof shall not be effective until each of the following conditions is satisfied (the date, if any, on which such conditions shall have first been satisfied being referred to herein as the “Amendment Effective Date”):

(a) the Administrative Agent shall have received from the Borrower and from each Lender either (i) a counterpart of this Amendment executed on behalf of the Borrower and each of the Lenders or (ii) written evidence satisfactory to the Administrative Agent (which may include facsimile or electronic mail transmission (in printable format)) that the Borrower and each of the Lenders have executed a counterpart of this Amendment;

(b) the Administrative Agent shall have received a certificate from the Secretary of the Borrower, in all respects satisfactory to the Administrative Agent,

(i) certifying as to the incumbency of authorized persons of the Borrower executing this Amendment, (ii) attaching a true, complete and correct copy of the resolutions of the board of directors of the Borrower approving the Credit Agreement and this Amendment, and certifying that such resolutions have not been rescinded or otherwise modified and remain in full force and effect on the date hereof, and (iii) certifying that the Borrower’s Organizational Documents have not been amended, supplemented or otherwise modified since November 14, 2017 or, if Borrower’s Organizational Documents have been amended, supplemented or otherwise modified since November 14, 2017, attaching true, complete and correct copies of each such amendment, supplement or modification; and

(c) all fees of the Administrative Agent (including the reasonable fees and expenses of counsel to the Administrative Agent) due and payable on or prior to the Amendment Effective Date shall have been paid.

4. The Borrower (a) reaffirms and admits the validity and enforceability of each Loan Document and all of its obligations thereunder, (b) agrees and admits that it has no defense to or offset against any such obligation, (c) represents and warrants that, as of the date of the execution and delivery hereof by the Borrower (and after giving effect hereto), no Default exists or would occur as a result therefrom, and (d) represents and warrants that all of the representations and warranties made by it in the Loan Documents to which it is a party are true and correct in all material respects, both immediately before and after giving effect to this Amendment (except to the extent such representations and warranties specifically relate to an earlier date, in which case such representations and warranties shall have been true and correct in all material respects on and as of such earlier date).

5. In all other respects, the Loan Documents shall remain in full force and effect, and no amendment in respect of any term or condition of any Loan Document shall be deemed to be an amendment in respect of any other term or condition contained in any Loan Document.

6. This Amendment may be executed in any number of counterparts, each of which shall constitute an original, but all of which when taken together shall constitute a single contract. It shall not be necessary in making proof of this Amendment to produce or account for more than one counterpart signed by the party to be charged.

7. THIS AMENDMENT SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAW OF THE STATE OF KANSAS, WITHOUT REGARD TO CONFLICT OF LAWS PRINCIPLES THAT WOULD REQUIRE THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION.

8. This statement is provided pursuant to K.S.A. §16-118: “THIS AMENDMENT TO CREDIT AGREEMENT IS A FINAL EXPRESSION OF THE AMENDMENT TO CREDIT AGREEMENT BETWEEN THE CREDITORS AND THE DEBTOR AND SUCH WRITTEN AMENDMENT TO CREDIT AGREEMENT MAY NOT BE CONTRADICTED BY EVIDENCE OF ANY PRIOR ORAL AMENDMENT TO CREDIT AGREEMENT OR OF A CONTEMPORANEOUS ORAL AMENDMENT TO CREDIT AGREEMENT BETWEEN THE CREDITORS AND DEBTOR.” THE FOLLOWING SPACE CONTAINS ANY NON- STANDARD TERMS, INCLUDING THE REDUCTION TO WRITING OF ANY PREVIOUS ORAL AMENDMENT TO CREDIT AGREEMENT:

NONE.

The creditors and debtor, by their respective initials or signatures below, confirm that no unwritten amendment to credit agreement exists between the parties:

Creditor:


Debtor:

[the remainder of this page has been intentionally left blank]

CONFLICT OF LAWS PRINCIPLES THAT WOULD REQUIRE THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION.

8. This statement is provided pursuant to K.S.A. §16-118: "THIS AMENDMENT TO CREDIT AGREEMENT IS A FINAL EXPRESSION OF THE AMENDMENT TO CREDIT AGREEMENT BETWEEN THE CREDITORS AND THE DEBTOR AND SUCH WRITTEN AMENDMENT TO CREDIT AGREEMENT MAY NOT BE CONTRADICTED BY EVIDENCE OF ANY PRIOR ORAL AMENDMENT TO CREDIT AGREEMENT OR OF A CONTEMPORANEOUS ORAL AMENDMENT TO CREDIT AGREEMENT BETWEEN THE CREDITORS AND DEBTOR." THE FOLLOWING SPACE CONTAINS ANY NON- STANDARD TERMS, INCLUDING THE REDUCTION TO WRITING OF ANY PREVIOUS ORAL AMENDMENT TO CREDIT AGREEMENT:

NONE.

The creditors and debtor, by their respective initials or signatures below, confirm that no unwritten amendment to credit agreement exists between the parties:

Creditor:


Debtor:

[the remainder of this page has been intentionally left blank]

CONFLICT OF LAWS PRINCIPLES THAT WOULD REQUIRE THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION.

NONE.

The creditors and debtor, by their respective initials or signatures below, confirm that no unwritten amendment to credit agreement exists between the parties:

Creditor:


Debtor:

[the remainder of this page has been intentionally left blank]

IN WITNESS WHEREOF, each party hereto has caused this Amendment No. 4 to the Credit Agreement to be executed by its duly authorized representative as of the day and year first above written.

TORTOISE ENERGY INFRASTRUCTURE

CORPORATION


	By:	/s/ P. Bradley Adams

	Name:	P. Bradley Adams
	Title:	Chief Executive Officer, Principal
		Financial Officer and Treasurer

	THE BANK OF NOVA SCOTIA, individually and as Administrative Agent


	By:	/s/ Kevin Chan

	Name:	Kevin Chan
	Title:	Director

Tortoise Energy Infrastructure Corporation – Amendment No. 4 to Credit Agreement

IN WITNESS WHEREOF, each party hereto has caused this Amendment No. 4 to the Credit Agreement to be executed by its duly authorized representative as of the day and year first above written.

TORTOISE ENERGY INFRASTRUCTURE

CORPORATION


	By:

	Name:	P. Bradley Adams
	Title:	Chief Executive Officer, Principal
		Financial Officer and Treasurer

	THE BANK OF NOVA SCOTIA, individually and as Administrative Agent


	By:

	Name:	Kevin Chan
	Title:	Director, FI Execution

Tortoise Energy Infrastructure Corporation – Amendment No. 4 to Credit Agreement