MainStay MacKay DefinedTerm Municipal Opportunities Fund (MMD) SC TO-I Issuer tender offer statement

Ex-(a)(1)(v)

NOTICE OF GUARANTEED DELIVERY

FOR TENDER OF COMMON SHARES OF BENEFICIAL INTEREST OF

NYLI MACKAY DEFINEDTERM MUNI OPPORTUNITIES FUND

This form, or one substantially equivalent hereto, must be used to accept the Offer (as defined below) if time will not permit the Letter of Transmittal and other required documents to be delivered to the Depositary on or before 5:00 p.m., New York City time, on November 14, 2024, or such later date to which the Offer is extended (the “Expiration Date”). Such form may be transmitted by email transmission or mailed to the Depositary, and must be received by the Depositary on or before 5:00 p.m. New York City time on the Expiration Date. See Section 2, “Procedures for Tendering Shares,” of the Offer to Purchase.

The Depositary for the Offer is:

Computershare Trust Company, N.A.

By Email Transmission:

(For Eligible Institutions Only)

CANOTICEOFGUARANTEE@computershare.com

THE ABOVE EMAIL ADDRESS CAN ONLY BE USED FOR DELIVERY OF THIS NOTICE OF GUARANTEED DELIVERY. ANY TRANSMISSION OF OTHER MATERIALS WILL NOT BE ACCEPTED AND WILL NOT BE CONSIDERED A VALID SUBMISSION FOR THE TENDER.

By Mail:   Computershare Trust Company, N.A. c/o Voluntary Corporate Actions P.O. Box 43011 Providence, RI 02940-3011 By Registered, Certified or Express Mail or Overnight Courier:   Computershare Trust Company, N.A. c/o Voluntary Corporate Actions 150 Royall Street, Suite V Canton, MA 02021

DELIVERY OF THIS INSTRUMENT TO AN ADDRESS OTHER THAN AS SET FORTH

ABOVE OR TRANSMISSION VIA AN EMAIL ADDRESS OTHER THAN ONE LISTED

ABOVE DOES NOT CONSTITUTE A VALID DELIVERY. THE ABOVE EMAIL ADDRESS CAN ONLY BE USED FOR DELIVERY OF THIS NOTICE OF GUARANTEED DELIVERY.

This Notice of Guaranteed Delivery is not to be used to guarantee signatures. If a signature on the Letter of Transmittal is required to be guaranteed by an eligible institution under the instructions thereto, such signature guarantee must appear in the applicable space provided on the Letter of Transmittal.

If you have any questions regarding these materials, you should contact Georgeson LLC, the Information Agent, at (866) 735-3249.

VOLUNTARY CORPORATE ACTIONS: MMD

Ladies and Gentlemen;

The undersigned hereby tenders to NYLI MacKay DefinedTerm Muni Opportunities Fund (the “Fund”), upon the terms and subject to the conditions set forth in its Offer to Purchase, dated October 17, 2024 and the related Letter of Transmittal (which, together with any amendments or supplements to these documents, collectively constitute the “Offer”), receipt of which is hereby acknowledged, the number of Shares set forth below pursuant to the guaranteed delivery procedures set forth in Section 2, “Procedures for Tendering Shares,” of the Offer to Purchase.

Number of Shares Tendered:

The Depository Trust Company

Account Number:

Name(s) of Record Holder(s):

Address:

Area Code and Telephone Number:

Social Security Number/Taxpayer Identification Number:

Dated:    , 20
	Signature(s)

To be effective, this form must be properly completed, signed and delivered, together with your properly completed Letter of Transmittal, to the Depositary at one of the addresses listed on the first page of this Notice of Guaranteed Delivery by the Expiration Date. Do not send your tender materials to New York Life Investment Management LLC, its counsel or the Information Agent.

VOLUNTARY CORPORATE ACTIONS: MMD

GUARANTEE

(Not To Be Used For Signature Guarantee)

The undersigned, a participant in the Security Transfer Agents Medallion Program, the New York Stock Exchange Medallion Signature Guarantee Program, the Stock Exchange Medallion Program or an “Eligible Guarantor Institution” as such term is defined in Rule 17Ad-15 under the Securities Exchange Act of 1934, as amended, hereby (a) represents that the above named person(s) “own(s)” the Shares tendered hereby within the meaning of Rule 14e-4 under the Securities Exchange Act of 1934, as amended (“Rule 14e-4”), (b) represents that such tender of Shares complies with Rule l4e-4 and (c) guarantees to deliver to the Depositary confirmation of Book-Entry Transfer of such Shares into the Depositary’s accounts at The Depository Trust Company, in each case with delivery of a properly completed and duly executed Letter of Transmittal, with any required signature guarantees, or an Agent’s Message (as defined in the Offer to Purchase), and any other required documents, within two New York Stock Exchange trading days after the date hereof.

Name of Firm:
				(Authorized Signature)
Address:			Name:
				(Please Print)
	City     State      Zip Code
			Title:

Area Code and Tel. No.:		Dated:	,
			20

VOLUNTARY CORPORATE ACTIONS: MMD