Exhibit 5.1

[Letterhead of Wachtell, Lipton, Rosen & Katz]

April 30, 2024

Nasdaq, Inc.

151 W. 42nd Street

New York, New York 10036

Re: Registration Statement on Form S-3

Ladies and Gentlemen:

We have acted as special outside counsel to Nasdaq, Inc., a Delaware corporation (the “Company”), in connection with the Registration Statement on Form S-3 (the “Registration Statement”) to be filed on the date hereof with the U.S. Securities and Exchange Commission (the “SEC”) in connection with the registration, pursuant to the Securities Act of 1933, as amended (including the rules and regulations thereunder, the “Act”), which is automatically effective under the Act pursuant to Rule 462(e) promulgated thereunder, of an indeterminate amount of the Company’s (a) shares of common stock, par value $0.01 per share (“Common Stock”); (b) shares of preferred stock, par value $0.01 per share (“Preferred Stock”), which may be issued in one or more series; (c) depositary receipts (the “Receipts”) representing fractional shares of Preferred Stock, which are called depositary shares (the “Depositary Shares”) and which may be issued pursuant to one or more depositary agreements (each, a “Depositary Agreement”) proposed to be entered into between the Company and one or more bank or trust companies to be named in the applicable Depositary Agreement (each, a “Bank Depositary”); (d) debt securities (“Debt Securities”), which may be issued in one or more series under the indenture, dated as of June 7, 2013 (the “Indenture”), between the Company and Wells Fargo Bank, National Association, as trustee, which is incorporated by reference as an exhibit to the Registration Statement; (e) warrants to purchase shares of Common Stock, shares of Preferred Stock or Debt Securities (“Warrants”), which may be issued pursuant to one or more warrant agreements (each, a “Warrant Agreement”) proposed to be entered into by the Company and one or more warrant agents to be named therein; (f) subscription rights to purchase shares of Common Stock, shares of Preferred Stock or Debt Securities (“Subscription Rights”), which may be issued under one or more subscription rights certificates (each, a “Subscription Rights Certificate”) and/or pursuant to one or more subscription rights agreements (each, a “Subscription Rights Agreement”) proposed to be entered into by the Company and one or more subscription agents to be named therein; (g) purchase contracts (“Purchase Contracts”) obligating the holders thereof to purchase from the Company, and the Company to sell to such holders, shares of Common Stock, shares of Preferred Stock or Debt Securities at a future date or dates, which may be issued pursuant to one or more purchase contract agreements (each, a “Purchase Contract Agreement”) proposed to be entered into by the Company and one or more purchase contract agents to be named therein; (h) purchase units of the Company (“Purchase Units”), each consisting of a Purchase Contract and debt securities, preferred securities or debt obligations of third parties, including U.S. treasury securities, or any combination of the foregoing, which may be issued pursuant to one or more agreements (each, a “Purchase Unit Agreement”) proposed to be entered into by the Company and one or more purchase unit agents to be named therein; and (i) such indeterminate number of shares of Common Stock, Preferred Stock or Depositary Shares and indeterminate amount of Debt Securities as may be issued upon conversion, exchange or exercise, as applicable, of any Preferred Stock, Depositary Shares, Debt Securities, Warrants or Subscription Rights or settlement of any Purchase Contracts or Purchase Units, including such shares of Common Stock or Preferred Stock as may be issued pursuant to anti-dilution adjustments determined at the time of offering (collectively, “Indeterminate Securities”). The Common Stock, Preferred Stock, Depositary Shares, Debt Securities, Warrants, Subscription Rights, Purchase Contracts, Purchase Units and Indeterminate Securities offered pursuant to the Registration Statement are collectively referred to herein as the “Securities.”

April 30, 2024

Page 2

The prospectus that is part of the Registration Statement as supplemented in the future by various supplements to the prospectus (each, a “Prospectus Supplement”) will provide for the issuance and sale by the Company of the Securities, which may be offered pursuant to Rule 415 under the Act.

As used herein, “Transaction Documents” means the Depositary Agreements, the Indenture and the supplemental indentures and officer’s certificates establishing the terms of the Debt Securities pursuant thereto, the Warrant Agreements, the Subscription Rights Agreements, the Purchase Contract Agreements, the Purchase Unit Agreements and any applicable underwriting or purchase agreement.

We have examined and relied on originals or copies certified or otherwise identified to our satisfaction of such documents, corporate records, certificates of the Company or public officials and other instruments as we have deemed necessary or appropriate for the purposes of this opinion letter. We have also conducted such investigations of fact and law as we have deemed necessary or advisable for purposes of this letter. In such examination, we have assumed (a) the authenticity of original documents and the genuineness of all signatures; (b) each natural person signing any document reviewed by us had the legal capacity to do so; (c) each person signing in a representative capacity any document reviewed by us had authority to sign in such capacity; (d) the conformity to the originals of all documents submitted to us as copies; and (e) the truth, accuracy and completeness of the information, representations and warranties contained in the agreements, records, documents, instruments and certificates we have reviewed.

The opinions stated in paragraphs 1 through 8 below further presume that all of the following (collectively, the “general conditions”) shall have occurred prior to the issuance of the Securities referred to therein: (a) the Registration Statement, and any amendments thereto (including post-effective amendments), will have become effective under the Act; (b) an appropriate Prospectus Supplement or term sheet with respect to such Securities will have been prepared, delivered and filed in compliance with the Act; (c) all Securities will be issued and sold in compliance with applicable federal and state securities laws and in the manner stated in the Registration Statement and the applicable Prospectus Supplement(s); (d) the applicable Transaction Documents will have been duly authorized, executed and delivered by the Company and the other parties thereto, including, if such Securities are to be sold or otherwise distributed pursuant to a firm commitment underwritten offering, the underwriting agreement or purchase agreement with respect thereto; (e) the Board of Directors of the Company, including any duly authorized committee thereof, will have taken all necessary corporate action to approve the issuance and sale of such Securities and related matters and appropriate officers of the Company will have taken all related action as directed by or under the direction of the Board of Directors of the Company; and (f) the terms of the applicable Transaction Documents and the issuance and sale of such Securities will have been duly established in conformity with the certificate of incorporation of the Company so as not to breach, violate, conflict with or constitute a default under (1) the organizational documents of any party or any agreement or instrument to which any party thereto is subject, (2) any law, rule or regulation to which any party thereto is subject (excepting the laws of the State of New York and the General Corporation Law of the State of Delaware (the “DGCL”) as such laws apply to the Company and the transaction pursuant to which the Securities are offered), (3) any judicial or regulatory order or decree of any governmental authority or (4) any consent, approval, license, authorization or validation of, or filing, recording or registration with any governmental authority.

April 30, 2024

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We also assume that at the time of issuance of the Securities, the Company is and will remain duly organized, validly existing and in good standing under the laws of the State of Delaware and that the Company will have duly authorized the issuance of the Securities and related matters. Except to the extent expressly stated in the opinions contained herein, we have assumed that each of the Transaction Documents constitutes the valid and binding obligation of each party to such Transaction Document, enforceable against such party in accordance with its terms. As to any facts material to the opinions expressed herein that we did not independently establish or verify, we have relied and will rely upon statements and representations of officers and other representatives of the Company and others.

We are members of the Bar of the State of New York, and we have not considered, and we express no opinion as to, the laws of any jurisdiction other than the laws of the State of New York and the DGCL, in each case as in effect on the date hereof.

Based upon the foregoing, and subject to the qualifications set forth in this letter, we advise you that, in our opinion:

1.   With respect to any shares of Common Stock offered by the Company pursuant to the Registration Statement, including any Indeterminate Securities constituting Common Stock (the “Offered Common Stock”), when (a) the general conditions shall have been satisfied, (b) if the Offered Common Stock is to be certificated, certificates in the form required under the DGCL representing the shares of Offered Common Stock are duly executed and countersigned and (c) the shares of Offered Common Stock are registered in the Company’s share registry and delivered upon payment of the agreed-upon consideration therefor, the shares of Offered Common Stock, when issued and sold or otherwise distributed in accordance with the provisions of the applicable Transaction Documents, will be validly issued, fully paid and nonassessable, provided that the consideration therefor is not less than $0.01 per share of Common Stock.

2.   With respect to the shares of any series of Preferred Stock offered by the Company pursuant to the Registration Statement, including any Indeterminate Securities constituting Preferred Stock of such series (the “Offered Preferred Stock”), when (a) the general conditions shall have been satisfied, (b) the Board of Directors of the Company, or a duly authorized committee thereof, has duly adopted a Certificate of Designations for the Offered Preferred Stock in accordance with the DGCL (the “Certificate”), (c) the filing of the Certificate with the Secretary of State of the State of Delaware has duly occurred, (d) if the Offered Preferred Stock is to be certificated, certificates in the form required under the DGCL representing the shares of Offered Preferred Stock are duly executed and countersigned and (e) the shares of Offered Preferred Stock are registered in the Company’s share registry and delivered upon payment of the agreed-upon consideration therefor, the shares of Offered Preferred Stock, when issued and sold or otherwise distributed in accordance with the provisions of the applicable Transaction Documents, will be validly issued, fully paid and nonassessable, provided that the consideration therefor is not less than $0.01 per share of Preferred Stock.

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3.   With respect to any Depositary Shares offered by the Company pursuant to the Registration Statement, including any Indeterminate Securities constituting Depositary Shares (the “Offered Depositary Shares”), when (a) the general conditions shall have been satisfied, (b) the applicable Depositary Agreement has been duly authorized, executed and delivered by the parties thereto, (c) the terms of the Receipts have been established in conformity with the applicable Depositary Agreement, (d) the Preferred Stock represented by the Offered Depositary Shares has been duly authorized and validly issued and the certificates therefor have been duly delivered to the Bank Depositary, (e) the Receipts are duly issued against deposit of such Preferred Stock in accordance with the applicable Depositary Agreement and (f) the Receipts have been duly completed, executed, authenticated, delivered and countersigned, and are issued and sold, in accordance with the applicable Depositary Agreement,, the Receipts will be validly issued and will entitle the holders thereof to the rights specified therein and in the applicable Depositary Agreement.

4.   With respect to any series of Debt Securities offered by the Company pursuant to the Registration Statement, including any Indeterminate Securities constituting Debt Securities of such series (the “Offered Debt Securities”), when (a) the general conditions shall have been satisfied, (b) the issuance, sale and terms of the Offered Debt Securities and related matters have been approved and established in conformity with the applicable Transaction Documents and (c) the certificates evidencing the Offered Debt Securities have been issued in a form that complies with the provisions of the applicable Transaction Documents and have been duly executed and authenticated in accordance with the provisions of the Offered Debt Securities and any other applicable Transaction Documents and issued and sold or otherwise distributed in accordance with the provisions of the applicable Transaction Document upon payment of the agreed-upon consideration therefor, the Offered Debt Securities will constitute valid and binding obligations of the Company, enforceable against the Company in accordance with their respective terms under the laws of the State of New York.

5.   With respect to any Warrants offered by the Company pursuant to the Registration Statement (the “Offered Warrants”), when (a) the general conditions shall have been satisfied, (b) the Common Stock, Preferred Stock and/or Debt Securities for which the Offered Warrants are exercisable have been duly authorized for issuance by the Company and (c) certificates evidencing the Offered Warrants have been duly executed, delivered and countersigned in accordance with the provisions of the applicable Warrant Agreement, the Offered Warrants, when issued and sold or otherwise distributed in accordance with the provisions of the applicable Transaction Documents upon payment of the agreed-upon consideration therefor, will constitute valid and binding obligations of the Company, enforceable against the Company in accordance with their respective terms under the laws of the State of New York.

6.   With respect to any Subscription Rights offered by the Company pursuant to the Registration Statement (the “Offered Subscription Rights”), when (a) the general conditions shall have been satisfied, (b) the Common Stock, Preferred Stock and/or Debt Securities relating to such Offered Subscription Rights have been duly authorized for issuance by the Company and (c) the Subscription Rights Certificates have been duly executed, delivered and countersigned in accordance with the provisions of the applicable Subscription Rights Agreement, the Offered Subscription Rights, when issued and sold or otherwise distributed in accordance with the provisions of the applicable Transaction Documents upon payment of the agreed-upon consideration therefor, will constitute valid and binding obligations of the Company, enforceable against the Company in accordance with their respective terms under the laws of the State of New York.

7.   With respect to any Purchase Contracts offered by the Company pursuant to the Registration Statement (the “Offered Purchase Contracts”), when (a) the general conditions shall have been satisfied, (b) the Common Stock, Preferred Stock and/or Debt Securities relating to such Offered Purchase Contracts have been duly authorized for issuance by the Company and (c) the Offered Purchase Contracts have been duly executed, delivered and countersigned in accordance with the provisions of the applicable Purchase Contract Agreement, the Offered Purchase Contracts, when issued and sold or otherwise distributed in accordance with the provisions of the applicable Transaction Documents upon payment of the agreed-upon consideration therefor, will constitute valid and binding obligations of the Company, enforceable against the Company in accordance with their respective terms under the laws of the State of New York.

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8.   With respect to any Purchase Units offered by the Company pursuant to the Registration Statement (the “Offered Purchase Units”), when (a) the general conditions shall have been satisfied, (b) the Purchase Contract and debt securities, preferred securities or debt obligations of third parties, including U.S. treasury securities, or any combination of the foregoing, included in such Offered Purchase Units have been duly authorized for issuance or sale by the Company or by third parties, as applicable, and (c) certificates evidencing the Offered Purchase Units have been duly executed, delivered and countersigned in accordance with the provisions of the applicable Purchase Unit Agreement, the Offered Purchase Units, when issued and sold or otherwise distributed in accordance with the provisions of the applicable Transaction Documents upon payment of the agreed-upon consideration therefor, will constitute valid and binding obligations of the Company, enforceable against the Company in accordance with their respective terms under the laws of the State of New York.

The opinions set forth above are subject to the effects of (a) bankruptcy, insolvency, fraudulent conveyance, reorganization, moratorium and other similar laws relating to or affecting the enforcement of creditors’ rights generally; (b) general equitable principles (whether considered in a proceeding in equity or at law); (c) an implied covenant of good faith and fair dealing; (d) provisions of law that require that a judgment for money damages rendered by a court in the United States be expressed only in United States dollars; (e) limitations by any governmental authority that limit, delay or prohibit the making of payments outside the United States; and (f) generally applicable laws that (1) provide for the enforcement of oral waivers or modifications where a material change of position in reliance thereon has occurred or provide that a course of performance may operate as a waiver, (2) limit the availability of a remedy under certain circumstances where another remedy has been elected, (3) limit the enforceability of provisions releasing, exculpating or exempting a party from, or requiring indemnification of a party for, liability for its own action or inaction, to the extent the action or inaction involves negligence, gross negligence, recklessness, willful misconduct or unlawful conduct, (4) may, where less than all of a contract may be unenforceable, limit the enforceability of the balance of the contract to circumstances in which the unenforceable portion is not an essential part of the agreed-upon exchange, (5) may limit the enforceability of provisions providing for compounded interest, imposing increased interest rates or late payment charges upon delinquency in payment or default or providing for liquidated damages or for premiums or penalties upon acceleration, or (6) limit the waiver of rights under usury laws. Furthermore, the manner in which any particular issue relating to the opinions would be treated in any actual court case would depend in part on facts and circumstances particular to the case and would also depend on how the court involved chose to exercise the wide discretionary authority generally available to it. We express no opinion as to the effect of Section 210(p) of the Dodd-Frank Wall Street Reform and Consumer Protection Act.

We express no opinion as to whether, or the extent to which, the laws of any particular jurisdiction apply to the subject matter hereof, including, without limitation, the enforceability of the governing law provision contained in any Securities and their governing documents. We do not express any opinion with respect to any law, rule or regulation that is applicable to any party to any of the Transaction Documents or the transactions contemplated thereby solely because such law, rule or regulation is part of a regulatory regime applicable to any such party or any of its affiliates as a result of the specific assets or business operations of such party or such affiliates.

This letter speaks only as of its date and is delivered in accordance with the requirements of Item 601(b)(5) of Regulation S-K under the Act. We disclaim any undertaking to advise you of any subsequent changes in the facts stated or assumed herein or of any subsequent changes in applicable laws. We hereby consent to the filing of copies of this opinion letter as an exhibit to the Registration Statement and to the use of our name in the prospectus forming a part of the Registration Statement under the caption “Legal Matters.” In giving this consent, we do not thereby admit that we are within the category of persons whose consent is required under Section 7 of the Act.

Very truly yours,

/s/ Wachtell, Lipton, Rosen & Katz