ONEOK (OKE) 424B5 Prospectus supplement for primary offering

Filed Pursuant to Rule 424(b)(5)

Registration Statement No. 333-239348

CALCULATION OF REGISTRATION FEE

Title of Each Class of Securities Offered	Proposed Maximum Offering Price	Amount of Registration Fee (1)
Common Stock, par value $0.01 per share	$1,000,000,000	$129,800

(1) Calculated in accordance with Rule 457(r) of the Securities Act of 1933, as amended.

PROSPECTUS SUPPLEMENT

(To Prospectus dated June 22, 2020)

Common Stock

Having an Aggregate Offering Price of Up to

$1,000,000,000

This prospectus supplement and the accompanying base prospectus relate to the offer and sale from time to time of shares of our common stock, par value $0.01 per share, in an amount having an aggregate offering price of up to $1,000,000,000 through the managers named in this prospectus supplement acting as sales agents or principals, or, if applicable, as Forward Sellers (as defined below) acting as agents or principals of the Forward Purchasers. These sales, if any, will be made pursuant to the terms of an equity distribution agreement among us and the managers, and, as applicable, the relevant Forward Purchasers, which was filed with the Securities and Exchange Commission on July 23, 2020 as an exhibit to a Current Report on Form 8-K (the “Equity Distribution Agreement”).

Under the terms of the Equity Distribution Agreement, we also may sell our common stock to any manager as principal for its own account at a price agreed upon at the time of the sale. If we sell our common stock to any such manager as principal, we will enter into a separate terms agreement with that manager and we will describe that agreement in a separate prospectus supplement or pricing supplement.

The Equity Distribution Agreement contemplates that, in addition to the issuance and sale by us of shares of our common stock to or through the managers as our sales agents, we may enter into separate forward sale agreements (each, together with any related pricing supplement, a “forward sale agreement” and, collectively, the “forward sale agreements”), with certain of the managers, or one of their respective affiliates (in such capacity, each, a “Forward Purchaser” and, collectively, the “Forward Purchasers”). If we enter into a forward sale agreement with any Forward Purchaser, we expect that such Forward Purchaser, acting in accordance with the mutually accepted instructions related to such forward sale agreement, will attempt to borrow and sell, through the relevant manager, acting as agent for such Forward Purchaser, shares of our common stock to hedge such Forward Purchaser’s exposure under such forward sale agreement. We refer to a manager, when acting as agent or principal for the relevant Forward Purchaser, as, individually, a “Forward Seller” and, collectively, the “Forward Sellers.” Each Forward Purchaser will be either one of the managers named in this prospectus supplement or an affiliate of one of those managers and, unless otherwise expressly stated or the context otherwise requires, references herein to the “related” or “relevant” Forward Purchaser mean, with respect to any manager, the affiliate of such manager that is acting as Forward Purchaser or, if applicable, such manager acting in its capacity as Forward Purchaser. We will not initially receive any proceeds from any sale of shares of our common stock borrowed by a Forward Purchaser and sold through a Forward Seller.

We currently expect to fully physically settle each forward sale agreement, if any, with the relevant Forward Purchaser on one or more dates specified by us on or prior to the maturity date of such forward sale agreement. However, subject to certain exceptions, we may also elect, in our sole discretion, to cash settle or net share settle all or any portion of our obligations under any forward sale agreement, in which case we may not receive any proceeds (in the case of cash settlement) or will not receive any proceeds (in the case of net share settlement), and we may owe cash (in the case of cash settlement) or shares of our common stock (in the case of net share settlement) to the relevant Forward Purchaser. See “Plan of Distribution.”

Our common stock is listed on the New York Stock Exchange (the “NYSE”), under the symbol “OKE.” The last reported sale price of our common stock on July 21, 2020 was $29.98 per share.

Sales of our common stock under this prospectus supplement, if any, will be made from time to time by means of ordinary brokers’ transactions through the facilities of the NYSE at market prices, in block transactions, or as otherwise agreed among us and the managers, as our sales agents or as Forward Sellers, by means of any other existing trading market for our common stock or to or through a market maker other than on an exchange. We or any of the managers may suspend the offering of common stock at any time and from time to time by notifying the other party. The offering of the shares is subject to receipt and acceptance and subject to the managers’ right to reject any order in whole or in part.

Investing in our common stock involves a high degree of risk. Before buying any common stock, you should read the discussion of material risks of investing in our common stock in “Risk Factors” beginning on page S-5 of this prospectus supplement, on page 7 of the accompanying base prospectus and the other risks identified in the documents incorporated by reference herein before making a decision to purchase our common stock in this offering.

The compensation to each manager for sales of common stock under this prospectus supplement shall be up to, but shall not exceed, 2.0% of the gross sale price of common stock sold by such manager. The compensation to each manager acting as a Forward Seller will be a mutually agreed commission in the form of a reduction to the initial forward price under the related forward sale agreement that shall be up to, but shall not exceed 2.0% of the gross sales price of the borrowed shares of our common stock sold through such manager, acting as Forward Seller, during the applicable forward hedge selling period for such shares (which gross sales price will be adjusted for daily accruals based on a floating interest rate, less a spread, and specified amounts related to expected dividends on shares of our common stock if an “ex-dividend” date occurs during such forward hedge selling period). Please read “Plan of Distribution” in this prospectus supplement. The net proceeds we receive from any sales under this prospectus supplement will be used as described under “Use of Proceeds” in this prospectus supplement. The common stock to which this prospectus supplement relates will be sold through only one manager, as our sales agent or as a Forward Seller, on any given day.

Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying base prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

Credit Suisse	BofA Securities	Goldman Sachs & Co. LLC	Mizuho Securities
Morgan Stanley	RBC Capital Markets	Scotiabank	SMBC Nikko
SunTrust Robinson Humphrey		TD Securities

Prospectus Supplement dated July 23, 2020.

IMPORTANT NOTICE ABOUT INFORMATION IN THIS

PROSPECTUS SUPPLEMENT AND THE ACCOMPANYING BASE PROSPECTUS

This document is in two parts. The first part is this prospectus supplement, which describes the terms of the offer and sale from time to time of our common stock pursuant to the Equity Distribution Agreement. The second part is the accompanying base prospectus, which gives more general information, some of which may not apply to the offer and sale from time to time of our common stock pursuant to the Equity Distribution Agreement. Generally, when we refer only to the “prospectus,” we are referring to both parts combined. If information varies between this prospectus supplement and the accompanying base prospectus, you should rely on the information in this prospectus supplement.

Any statement made in this prospectus supplement, the accompanying base prospectus or in a document incorporated or deemed to be incorporated by reference into this prospectus supplement or the accompanying base prospectus will be deemed to be modified or superseded for purposes of this prospectus supplement to the extent that a statement contained in this prospectus supplement, the accompanying base prospectus or in any other subsequently filed document that is also incorporated by reference into this prospectus supplement modifies or supersedes that statement. Any statement so modified or superseded will not be deemed, except as so modified or superseded, to constitute a part of this prospectus supplement or the accompanying base prospectus. Please read “Where You Can Find More Information” and “Incorporation by Reference” in this prospectus supplement and the accompanying base prospectus.

We have not, and the managers, the Forward Sellers and the Forward Purchasers have not, authorized any dealer or other person to give any information or to make any representation other than those contained or incorporated by reference in this prospectus supplement and the accompanying base prospectus or in any free writing prospectus prepared by or on behalf of us or to which we have referred you. This prospectus supplement and the accompanying base prospectus do not constitute an offer to sell or the solicitation of an offer to buy any securities other than the registered securities to which they relate, nor does this prospectus supplement or the accompanying base prospectus constitute an offer to sell or the solicitation of an offer to buy securities in any jurisdiction to any person to whom it is unlawful to make such offer or solicitation in such jurisdiction. You should not assume that the information contained in this prospectus supplement or the accompanying base prospectus or in any free writing prospectus is accurate on any date other than the respective date of such document.

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TABLE OF CONTENTS

PROSPECTUS SUPPLEMENT

PROSPECTUS SUPPLEMENT SUMMARY	S-1
RISK FACTORS	S-5
USE OF PROCEEDS	S-8
MATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCES TO NON-U.S. HOLDERS	S-9
PLAN OF DISTRIBUTION	S-13
LEGAL MATTERS	S-20
EXPERTS	S-21
WHERE YOU CAN FIND MORE INFORMATION	S-22
INCORPORATION BY REFERENCE	S-23
PROSPECTUS
ABOUT THIS PROSPECTUS	1
WHERE YOU CAN FIND MORE INFORMATION	1
INCORPORATION BY REFERENCE	2
CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS	3
ABOUT ONEOK	6
RISK FACTORS	7
USE OF PROCEEDS	8
DESCRIPTION OF DEBT SECURITIES	9
DESCRIPTION OF GUARANTEE OF DEBT SECURITIES	21
DESCRIPTION OF CAPITAL STOCK	22
DESCRIPTION OF STOCK PURCHASE CONTRACTS AND STOCK PURCHASE CONTRACT UNITS	28
DESCRIPTION OF DEPOSITARY SHARES	29
DESCRIPTION OF WARRANTS	31
PLAN OF DISTRIBUTION	32
LEGAL MATTERS	34
EXPERTS	34

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PROSPECTUS SUPPLEMENT SUMMARY

This summary highlights certain information about ONEOK. It is not complete and does not contain all the information that you should consider before investing in our common stock. You should carefully read this entire prospectus supplement, the accompanying base prospectus and the other documents incorporated by reference herein and therein to understand fully ONEOK and other considerations that are important in making your investment decision. Please read “Risk Factors” and the other cautionary statements in this prospectus supplement, the accompanying base prospectus, our Annual Report on Form 10-K for the year ended December 31, 2019 and our Quarterly Report on Form 10-Q for the quarter ended March 31, 2020, each of which is incorporated by reference herein, before making a decision to purchase our common stock in this offering.

Unless we otherwise indicate or unless the context requires otherwise, all references in this prospectus supplement to “we,” “our,” “us,” the “Company,” “ONEOK” or similar references mean ONEOK, Inc. and its consolidated subsidiaries and predecessors.

ONEOK, Inc.

ONEOK is a corporation incorporated under the laws of the state of Oklahoma, and our common stock is listed on the NYSE under the trading symbol “OKE.” We are a leading midstream service provider and own one of the nation’s premier natural gas liquids (“NGLs”) systems, connecting NGL supply in the Rocky Mountain, Permian and Mid-Continent regions with key market centers and an extensive network of natural gas gathering, processing, storage and transportation assets. We apply our core capabilities of gathering, processing, fractionating, transporting, storing and marketing natural gas and NGLs through vertical integration across the midstream value chain to provide our customers with premium services while seeking to generate consistent and sustainable earnings growth.

Recent Developments

COVID-19

The global and regional economic disruption caused by the COVID-19 pandemic has led to a volatile commodity price environment and, in some cases, a curtailment of crude production by our customers, which meaningfully reduced volumes on our system during the quarter ended June 30, 2020. While we are monitoring the situation, given the current industry and economic environment, at this time it remains impractical for us to provide any additional financial or volume guidance for the full year ending December 31, 2020 or beyond due to the number of potential variations of outcomes for price forecasts, curtailment quantities as well as the duration, pace and scale of economic recovery on a worldwide basis in the aftermath of this pandemic, among other factors.

For a further discussion of the impact of the COVID-19 pandemic on our business, operations and financial condition, including the risks associated with COVID-19, please see our Quarterly Report on Form 10-Q for the quarter ended March 31, 2020, which is incorporated by reference herein.

Debt Offering

In May 2020, we issued $600 million of 5.850% Notes due 2026, $600 million of 6.350% Notes due 2031 and $300 million of 7.150% Notes due 2051 (the “May Notes Offering”). A portion of the proceeds from the May Notes Offering were used to repay the outstanding borrowings under our $1.5 billion term loan agreement. The remainder was used for general corporate purposes.

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Equity Offering

In June 2020, we issued 29.9 million shares of our common stock in an underwritten public offering at $32.00 per share (the “Equity Offering”). We expect to use the net proceeds from the Equity Offering for general corporate purposes, which could include the repayment of our existing indebtedness and the funding of capital expenditures.

Our Principal Executive Offices

Our principal executive offices are located at 100 West Fifth Street, Tulsa, Oklahoma, 74103-4298, and our telephone number at that address is (918) 588-7000. The information above concerning us is only a summary and does not purport to be comprehensive. We maintain a website at www.oneok.com that provides information about our business and operations. Information contained on this website, however, is not incorporated into or otherwise a part of this prospectus supplement or the accompanying base prospectus.

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The Offering

Shares of Common Stock Offered Shares of our common stock, par value $0.01 per share, in an amount having an aggregate offering price of up to $1,000,000,000. The shares of common stock offered pursuant to this prospectus supplement and the accompanying prospectus include newly issued shares that may be offered and sold by us to or through the managers, acting as our sales agents or as principal, and borrowed shares of common stock that may be offered and sold by the Forward Purchasers through their respective Forward Sellers.

Manner of Offering Sales of our common stock under this prospectus supplement, if any, will be made from time to time by means of ordinary brokers’ transactions through the facilities of the NYSE at market prices, in block transactions, or as otherwise agreed among us and the managers, as our sales agents or as Forward Sellers, by means of any other existing trading market for our common stock or to or through a market maker other than on an exchange. In addition, borrowed common stock of the Company may be offered and sold by the Forward Sellers pursuant to this prospectus supplement and the accompanying base prospectus. See “Plan of Distribution” in this prospectus supplement.

We also may sell our common stock to any manager as principal for its own account at a price agreed upon at the time of the sale. If we sell our common stock to any such manager as principal, we will enter into a separate terms agreement with that manager and we will describe that agreement in a separate prospectus supplement or pricing supplement.

Use of Proceeds We intend to use the net proceeds from any sales of shares of our common stock to or through the sales agents and the net cash proceeds from the settlement of any forward sales agreements, after deducting managers’ (or, if applicable, the Forward Purchasers’) commissions and our offering expenses, for general corporate purposes, which may include repaying or refinancing a portion of our outstanding indebtedness and funding working capital, capital expenditures or acquisitions. Please read “Use of Proceeds.”

We will not initially receive any proceeds from any sale of borrowed shares of our common stock by a Forward Purchaser in connection with any forward sale agreement as a hedge of such forward sale agreement. For additional information, see “Plan of Distribution.”

Affiliates of certain of the managers are lenders under our revolving credit facility. To the extent we use proceeds from this offering to repay indebtedness under our revolving credit facility, such affiliates may receive proceeds from this offering. Additionally, affiliates of certain of the managers are dealers under our commercial paper program. To the extent we use proceeds from this offering to repay notes issued under our commercial paper program and such affiliates hold such notes, such affiliates may receive proceeds from this offering. Please read “Plan of Distribution.”

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Exchange Listing Our common stock is listed on the NYSE under the symbol “OKE.”

Risk Factors There are risks associated with this offering and our business. See “Risk Factors” in this prospectus supplement, the accompanying base prospectus and the documents incorporated by reference into this prospectus supplement and the accompanying base prospectus for a discussion of factors you should carefully consider before making a decision to purchase our common stock in this offering.

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RISK FACTORS

An investment in our common stock involves risk. You should carefully read the risk factors set forth in our most recent Annual Report on Form 10-K, subsequent Quarterly Reports on Form 10-Q and those that are included in this prospectus supplement, in the accompanying base prospectus or that may be included in any applicable prospectus supplement, together with all of the other information included in, or incorporated by reference into, this prospectus supplement and the accompanying base prospectus, when evaluating an investment in our common stock.

Risks Related to any Forward Sale Agreements

Settlement provisions contained in any forward sale agreement subject us to certain risks.

Each Forward Purchaser will have the right to accelerate its forward sale agreement (with respect to all or any portion of the transaction under such forward sale agreement that the relevant Forward Purchaser determines is affected by an event described below) and require us to physically settle or, if we so elect and the Forward Purchaser permits our election, cash settle or net share settle on a date specified by such Forward Purchaser if:

• in such Forward Purchaser’s commercially reasonable judgment, it or its affiliate (x) is unable to hedge in a commercially reasonable manner its exposure under such forward sale agreement because insufficient shares of our common stock have been made available for borrowing by securities lenders or (y) would incur a stock loan cost in excess of a specified threshold to hedge in a commercially reasonable manner its exposure under such forward sale agreement;

• we declare any dividend, issue or distribution on shares of our common stock (a) with a cash value in excess of a specified amount per calendar quarter or with an ex-dividend date prior to the anticipated ex-dividend date for such cash dividend, (b) of share capital or securities granting the right to payment of dividends and/or the proceeds of liquidation of us equally or proportionately with such payments to holders of such common stock, for payment (cash or other consideration) at less than the prevailing market price as determined by the calculation agent under the particular forward sale agreement, (c) of share capital or other securities of another issuer acquired or owned (directly or indirectly) by us as a result of a spin-off or other similar transaction, for payment (cash or other consideration) at less than the prevailing market price as determined by the calculation agent under the particular forward sale agreement or (d) of any other type of securities, rights or warrants or other assets, for payment (cash or other consideration) at less than the prevailing market price as determined by the calculation agent under the particular forward sale agreement;

• certain ownership thresholds applicable to such Forward Purchaser, its affiliates and all other persons who may form a beneficial share ownership group or whose ownership positions would be aggregated with such Forward Purchaser are exceeded;

• an event is announced that if consummated would result in a specified extraordinary event (including certain mergers or tender offers, as well as certain events involving our nationalization, our insolvency or a delisting of our common stock) or the occurrence of a change in law or disruption in the Forward Purchaser’s ability to hedge its exposure under the forward sale agreement; or

• certain other events of default or termination events occur, including, among others, any material misrepresentation made in connection with such forward sale agreement or our insolvency (each as more fully described in each forward sale agreement).

A Forward Purchaser’s decision to exercise its right to accelerate the settlement of any forward sale agreement will be made irrespective of our interests, including our need for capital. In such cases, we could be required to issue and deliver shares of our common stock under the physical settlement provisions of the applicable forward sale agreement irrespective of our capital needs, which would result in dilution to our diluted earnings per share.

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We expect that any forward sale agreement will be physically settled by delivery of shares of our common stock, unless we elect to cash settle or net share settle the forward sale agreement, subject to the satisfaction of certain conditions. Upon physical settlement or, if we so elect, net share settlement of any forward sale agreement, delivery of shares of our common stock in connection with such physical settlement or, to the extent we are obligated to deliver shares of our common stock, net share settlement will result in dilution to our earnings per share and dividends per share.

If we elect cash settlement or net share settlement with respect to all or a portion of the shares of our common stock underlying a forward sale agreement, we expect the applicable Forward Purchaser (or an affiliate thereof) to purchase a number of shares of our common stock in secondary market transactions over an unwind period to:

• return shares of our common stock to securities lenders in order to unwind such Forward Purchaser’s hedge (after taking into consideration any shares of our common stock to be delivered by us to such Forward Purchaser, in the case of net share settlement); and

• if applicable, in the case of net share settlement, deliver shares of our common stock to us to the extent required in settlement of such forward sale agreement.

In addition, the purchase of shares of our common stock in connection with a Forward Purchaser or its affiliate unwinding its hedge positions could cause the price of shares of our common stock to increase over such time (or prevent a decrease over such time), thereby increasing the amount of cash we would owe to such Forward Purchaser (or decreasing the amount of cash that the Forward Purchaser would owe us) upon a cash settlement of the relevant forward sale agreement or increasing the number of shares of our common stock we would deliver to such Forward Purchaser (or decreasing the number of shares of our common stock that such Forward Purchaser would deliver to us) upon net share settlement of the relevant forward sale agreement.

The forward sale price we expect to receive upon physical settlement of any forward sale agreement will be subject to adjustment on a daily basis based on a floating interest rate factor equal to a specified daily rate less a spread to be mutually agreed by us and the applicable Forward Purchaser, and will be decreased on certain dates based on amounts related to expected dividends on shares of our common stock during the term of such forward sale agreement. If the specified daily rate is less than the spread under such forward sale agreement on any day, the interest factor will result in a daily reduction of the forward sale price. If the volume weighted average price at which a Forward Purchaser (or its affiliate) is able to purchase shares during the applicable unwind period under a forward sale agreement is above the relevant forward sale price, in the case of cash settlement, we would pay the applicable Forward Purchaser under such forward sale agreement an amount in cash equal to the difference or, in the case of net share settlement, we would deliver to such Forward Purchaser a number of shares of our common stock having a value equal to the difference. Thus, we could be responsible for a potentially substantial cash payment in the case of cash settlement. If the volume weighted average price at which a Forward Purchaser (or its affiliate) is able to purchase shares during the applicable unwind period under a forward sale agreement is below the relevant forward sale price, in the case of cash settlement, we would be paid the difference in cash by the relevant Forward Purchaser under such forward sale agreement or, in the case of net share settlement, we would receive from such Forward Purchaser a number of shares of our common stock having a value equal to the difference. See “Plan of Distribution” for information on the forward sale agreements.

In case of our bankruptcy or insolvency, the forward sale agreements would automatically terminate, and we would not receive the expected proceeds from the sale of shares of our common stock.

If we or a regulatory authority with jurisdiction over us institutes, or we consent to, a proceeding seeking a judgment in bankruptcy or insolvency or any other relief under any bankruptcy or insolvency law or other similar law affecting creditors’ rights, or we or a regulatory authority with jurisdiction over us presents a petition for our winding-up or liquidation, or we consent to such a petition, the forward sale agreements will automatically terminate. If a forward sale agreement so terminates, we would not be obligated to deliver to the applicable Forward Purchaser any shares of our common stock not previously delivered, and such Forward Purchaser would

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be discharged from its obligation to pay the relevant forward sale price per share in respect of any shares of our common stock not previously settled. Therefore, to the extent that there are any shares of our common stock with respect to which such forward sale agreement has not been settled at the time of the commencement of any such bankruptcy or insolvency proceedings, we would not receive the relevant forward sale price per share in respect of those shares of our common stock.

This offering and future issuances of our common stock could be dilutive to our earnings per share.

The issuance and sale by us of any shares of our common stock in this offering or upon settlement of any forward sale agreements we may enter into with any of the Forward Purchasers, the receipt of the net proceeds therefrom and the use of those net proceeds could have a dilutive effect on our earnings per share. Additional issuances of our common stock, including in connection with development activity and acquisitions, if any, could also be dilutive to our earnings per share. The issuance or sale by us of our common stock, including the sale by us of shares in this offering or pursuant to any forward sale agreements, in connection with acquisitions, if any, or in the secondary market (including upon the issuance of shares of common stock under our stock option and other equity incentive plans or pursuant to options or other awards granted under those plans), or the perception that such additional issuances or sales could occur, could also adversely affect the trading price of our common stock and our ability to raise capital through future offerings of equity or equity-related securities. In addition, if we are unable to apply any net proceeds we may receive from this offering or from settlement under any forward sale agreements we may enter into to make investments that generate sufficient revenues to offset the dilutive impact of the issuance by us of shares of our common stock in this offering or pursuant to those forward sale agreements, there will be further dilution of our earnings per.

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USE OF PROCEEDS

We intend to use the net proceeds of any sales of shares of our common stock to or through the sales agents and the net cash proceeds from the settlement of any forward sales agreements, after deducting managers’ (or, if applicable, the Forward Purchasers’) commissions and our offering expenses, for general corporate purposes, which may include repaying or refinancing a portion of our outstanding indebtedness and funding working capital, capital expenditures or acquisitions.

We will not initially receive any proceeds from any sale of borrowed shares of our common stock by a Forward Purchaser in connection with a forward sale agreement as a hedge of such forward sale agreement. In the event of full physical settlement of a forward sale agreement, which we expect to occur on or prior to the maturity date of the forward sale agreement, we expect to receive aggregate cash proceeds equal to the product of the forward sale price under the forward sale agreement and the number of shares of our common stock underlying the forward sale agreement, subject to the price adjustment and other provisions of the forward sale agreement. If, however, we elect to cash settle or net share settle any forward sale agreement, we would expect to receive an amount of proceeds that is significantly lower than the product set forth in the preceding sentence (in the case of any cash settlement) or will not receive any proceeds (in the case of any net share settlement), and we may owe cash (in the case of any cash settlement) or shares of our common stock (in the case of any net share settlement) to the relevant Forward Purchaser. See “Plan of Distribution.”

If we enter into a forward sale agreement with any Forward Purchaser, we expect that such Forward Purchaser or its affiliate will attempt to borrow from third parties and sell, through the relevant manager, acting as Forward Seller, shares of our common stock to hedge such Forward Purchaser’s exposure under such forward sale agreement. All of the net proceeds from the sale of any such borrowed shares will be paid to the applicable Forward Purchaser (or one or more of its affiliates). Each Forward Purchaser will be either a manager or an affiliate of a manager. As a result, a manager or its affiliate will receive the net proceeds from any sale of borrowed shares of our common stock made in connection with any forward sale agreements.

Affiliates of certain of the managers are lenders under our revolving credit facility. To the extent we use proceeds from this offering to repay indebtedness under our revolving credit facility, such affiliates may receive proceeds from this offering. Additionally, affiliates of certain of the managers are dealers under our commercial paper program. To the extent we use proceeds from this offering to repay notes issued under our commercial paper program and such affiliates hold such notes, such affiliates may receive proceeds from this offering. Please read “Plan of Distribution.”

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MATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCES TO NON-U.S. HOLDERS

The following discussion is a summary of the material U.S. federal income tax consequences to Non-U.S. Holders (as defined below) of the purchase, ownership and disposition of our common stock issued pursuant to this offering, but does not purport to be a complete analysis of all potential tax effects. The effects of other U.S. federal tax laws, such as estate and gift tax laws, and any applicable state, local or non-U.S. tax laws are not discussed. This discussion is based on the U.S. Internal Revenue Code of 1986, as amended (the “Code”), Treasury Regulations promulgated thereunder, judicial decisions, and published rulings and administrative pronouncements of the U.S. Internal Revenue Service (the “IRS”), in each case in effect as of the date hereof. These authorities may change or be subject to differing interpretations. Any such change or differing interpretation may be applied retroactively in a manner that could adversely affect a Non-U.S. Holder of our common stock. We have not sought and will not seek any rulings from the IRS regarding the matters discussed below. There can be no assurance the IRS or a court will not take a contrary position to that discussed below regarding the tax consequences of the purchase, ownership and disposition of our common stock.

This discussion is limited to Non-U.S. Holders that hold our common stock as a “capital asset” within the meaning of Section 1221 of the Code (generally, property held for investment). This discussion does not address all U.S. federal income tax consequences relevant to a Non-U.S. Holder’s particular circumstances, including the impact of the Medicare contribution tax on net investment income. In addition, it does not address consequences relevant to Non-U.S. Holders subject to special rules, including, without limitation:

• U.S. expatriates and former citizens or long-term residents of the United States;

• persons subject to the alternative minimum tax;

• persons holding our common stock as part of a hedge, straddle or other risk reduction strategy or as part of a conversion transaction or other integrated investment;

• banks, insurance companies, and other financial institutions;

• brokers, dealers or traders in securities;

• “controlled foreign corporations,” “passive foreign investment companies,” and corporations that accumulate earnings to avoid U.S. federal income tax;

• partnerships or other entities or arrangements treated as partnerships for U.S. federal income tax purposes (and investors therein);

• tax-exempt organizations or governmental organizations;

• persons deemed to sell our common stock under the constructive sale provisions of the Code;

• persons who hold or receive our common stock pursuant to the exercise of any employee stock option or otherwise as compensation;

• tax-qualified retirement plans;

• “qualified foreign pension funds” as defined in Section 897(l)(2) of the Code and entities all of the interests of which are held by qualified foreign pension funds; and

• persons subject to special tax accounting rules as a result of any item of gross income with respect to the stock being taken into account in an “applicable financial statement.”

If an entity or arrangement treated as a partnership for U.S. federal income tax purposes holds our common stock, the tax treatment of a partner in the partnership will depend on the status of the partner, the activities of the partnership and certain determinations made at the partner level. Accordingly, partnerships holding our common stock and the partners in such partnerships should consult their tax advisors regarding the U.S. federal income tax consequences to them.

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THIS DISCUSSION IS FOR INFORMATIONAL PURPOSES ONLY AND IS NOT TAX ADVICE. INVESTORS SHOULD CONSULT THEIR TAX ADVISORS WITH RESPECT TO THE APPLICATION OF THE U.S. FEDERAL INCOME TAX LAWS TO THEIR PARTICULAR SITUATIONS AS WELL AS ANY TAX CONSEQUENCES OF THE PURCHASE, OWNERSHIP AND DISPOSITION OF OUR COMMON STOCK ARISING UNDER THE U.S. FEDERAL ESTATE OR GIFT TAX LAWS OR UNDER THE LAWS OF ANY STATE, LOCAL OR NON-U.S. TAXING JURISDICTION OR UNDER ANY APPLICABLE TAX TREATY.

Definition of a Non-U.S. Holder

For purposes of this discussion, a “Non-U.S. Holder” is any beneficial owner of our common stock that is neither a “U.S. person” nor an entity or arrangement treated as a partnership for U.S. federal income tax purposes. A U.S. person is any person that, for U.S. federal income tax purposes, is or is treated as any of the following:

• an individual who is a citizen or resident of the United States;

• a corporation created or organized under the laws of the United States, any state thereof, or the District of Columbia;

• an estate, the income of which is subject to U.S. federal income tax regardless of its source; or

• a trust that (1) is subject to the primary supervision of a U.S. court and the control of one or more “United States persons” (within the meaning of Section 7701(a)(30) of the Code), or (2) has a valid election in effect to be treated as a United States person for U.S. federal income tax purposes.

Distributions

Distributions of cash or property on our common stock will constitute dividends for U.S. federal income tax purposes to the extent paid from our current or accumulated earnings and profits, as determined under U.S. federal income tax principles. Amounts not treated as dividends for U.S. federal income tax purposes will constitute a return of capital and first be applied against and reduce a Non-U.S. Holder’s adjusted tax basis in its common stock, but not below zero. Any excess will be treated as capital gain and will be treated as described below under “—Sale or Other Taxable Disposition.”

Except as described in the discussion below on effectively connected income and subject to the discussions of backup withholding and FATCA, dividends paid to a Non-U.S. Holder of our common stock will be subject to U.S. federal withholding tax at a rate of 30% of the gross amount of the dividends (or such lower rate specified by an applicable income tax treaty, provided the Non-U.S. Holder furnishes a valid IRS Form W-8BEN or W-8BEN-E (or other applicable documentation) certifying qualification for the lower treaty rate). A Non-U.S. Holder that does not timely furnish the required documentation, but that qualifies for a reduced treaty rate, may obtain a refund of any excess amounts withheld by timely filing an appropriate claim for refund with the IRS. Non-U.S. Holders should consult their tax advisors regarding their entitlement to benefits under any applicable income tax treaty.

If dividends paid to a Non-U.S. Holder are effectively connected with the Non-U.S. Holder’s conduct of a trade or business within the United States (and, if required by an applicable income tax treaty, the Non-U.S. Holder maintains a permanent establishment in the United States to which such dividends are attributable), the Non-U.S. Holder will be exempt from the U.S. federal withholding tax described above. To claim the exemption, the Non-U.S. Holder must furnish to the applicable withholding agent a valid IRS Form W-8ECI, certifying that the dividends are effectively connected with the Non-U.S. Holder’s conduct of a trade or business within the United States.

Any such effectively connected dividends will be subject to U.S. federal income tax on a net income basis at the regular graduated rates applicable to U.S. persons. A Non-U.S. Holder that is a corporation also may be

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subject to a branch profits tax at a rate of 30% (or such lower rate specified by an applicable income tax treaty) on such effectively connected dividends, as adjusted for certain items. Non-U.S. Holders should consult their tax advisors regarding any applicable tax treaties that may provide for different rules.

Sale or Other Taxable Disposition

A Non-U.S. Holder will not be subject to U.S. federal income tax on any gain realized upon the sale or other taxable disposition of our common stock unless:

• the gain is effectively connected with the Non-U.S. Holder’s conduct of a trade or business within the United States (and, if required by an applicable income tax treaty, the Non-U.S. Holder maintains a permanent establishment in the United States to which such gain is attributable);

• the Non-U.S. Holder is a nonresident alien individual present in the United States for 183 days or more during the taxable year of the disposition and certain other requirements are met; or

• our common stock constitutes a U.S. real property interest (“USRPI”) by reason of our status as a U.S. real property holding corporation (“USRPHC”) for U.S. federal income tax purposes.

Gain described in the first bullet point above generally will be subject to U.S. federal income tax on a net income basis at the regular graduated rates applicable to U.S. persons. A Non-U.S. Holder that is a corporation also may be subject to a branch profits tax at a rate of 30% (or such lower rate specified by an applicable income tax treaty) on such effectively connected gain, as adjusted for certain items.

Gain described in the second bullet point above will be subject to U.S. federal income tax at a rate of 30% (or such lower rate specified by an applicable income tax treaty), which may be offset by U.S. source capital losses of the Non-U.S. Holder (even though the individual is not considered a resident of the United States), provided the Non-U.S. Holder has timely filed U.S. federal income tax returns with respect to such losses.

With respect to the third bullet point above, we believe that we currently are, and expect to remain for the foreseeable future, a USRPHC for U.S. federal income tax purposes. However, a Non-U.S. Holder of our common stock generally will not be subject to U.S. net federal income tax as a result of our being a USRPHC if our common stock is “regularly traded,” as defined by applicable Treasury Regulations, on an established securities market, and such Non-U.S. Holder owned, actually or constructively, 5% or less of our common stock throughout the shorter of the five-year period ending on the date of the sale or other taxable disposition or the Non-U.S. Holder’s holding period (such period, the “applicable period”). If our common stock is not considered to be so traded or the Non-U.S. Holder owned 5% or more of our common stock at any time during the applicable period, a Non-U.S. Holder generally would be subject to net U.S. federal income tax on the gain realized on a disposition of our common stock as a result of our being a USRPHC and generally would be required to file a U.S. federal income tax return. Additionally, if our common stock is not considered to be regularly traded, a 15% withholding tax would apply to the gross proceeds from a disposition.

Non-U.S. Holders should consult their tax advisors regarding potentially applicable income tax treaties that may provide for different rules.

Information Reporting and Backup Withholding

Payments of dividends on our common stock will not be subject to backup withholding, provided the applicable withholding agent does not have actual knowledge or reason to know the holder is a United States person and the holder either certifies its non-U.S. status, such as by furnishing a valid IRS Form W-8BEN, W-8BEN-E or W-8ECI, or otherwise establishes an exemption. However, information returns are required to be filed with the IRS in connection with any distributions on our common stock paid to the Non-U.S. Holder, regardless of whether such distributions constitute dividends or whether any tax was actually withheld. In

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addition, proceeds of the sale or other taxable disposition of our common stock within the United States or conducted through certain U.S.-related brokers generally will not be subject to backup withholding or information reporting, if the applicable withholding agent receives the certification described above and does not have actual knowledge or reason to know that such holder is a United States person, or the holder otherwise establishes an exemption. Proceeds of a disposition of our common stock conducted through a non-U.S. office of a non-U.S. broker generally will not be subject to backup withholding or information reporting.

Copies of information returns that are filed with the IRS may also be made available under the provisions of an applicable treaty or agreement to the tax authorities of the country in which the Non-U.S. Holder resides or is established.

Backup withholding is not an additional tax. Any amounts withheld under the backup withholding rules may be allowed as a refund or a credit against a Non-U.S. Holder’s U.S. federal income tax liability, provided the required information is timely furnished to the IRS.

Additional Withholding Tax on Payments Made to Foreign Accounts

Withholding taxes may be imposed under Sections 1471 to 1474 of the Code (such Sections commonly referred to as the Foreign Account Tax Compliance Act, or “FATCA”) on certain types of payments made to non-U.S. financial institutions and certain other non-U.S. entities. Specifically, a 30% withholding tax may be imposed on dividends on, or (subject to the proposed Treasury Regulations discussed below) gross proceeds from the sale or other disposition of, our common stock paid to a “foreign financial institution” or a “non-financial foreign entity” (each as defined in the Code), unless (1) the foreign financial institution undertakes certain diligence and reporting obligations, (2) the non-financial foreign entity either certifies it does not have any “substantial United States owners” (as defined in the Code) or furnishes identifying information regarding each substantial United States owner, or (3) the foreign financial institution or non-financial foreign entity otherwise qualifies for an exemption from these rules. If the payee is a foreign financial institution and is subject to the diligence and reporting requirements in (1) above, it must enter into an agreement with the U.S. Department of the Treasury requiring, among other things, that it undertake to identify accounts held by certain “specified United States persons” or “United States owned foreign entities” (each as defined in the Code), annually report certain information about such accounts, and withhold 30% on certain payments to non-compliant foreign financial institutions and certain other account holders. Foreign financial institutions located in jurisdictions that have an intergovernmental agreement with the United States governing FATCA may be subject to different rules.

Under the applicable Treasury Regulations and administrative guidance, withholding under FATCA generally applies currently to payments of dividends on our common stock. While withholding under FATCA would have applied also to payments of gross proceeds from the sale or other disposition of stock on or after January 1, 2019, recently proposed Treasury Regulations eliminate FATCA withholding on payments of gross proceeds entirely. Taxpayers generally may rely on these proposed Treasury Regulations until final Treasury Regulations are issued.

Prospective investors should consult their tax advisors regarding the potential application of withholding under FATCA to their investment in our common stock.

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PLAN OF DISTRIBUTION

On July 23, 2020, we entered into an Equity Distribution Agreement with Credit Suisse Securities (USA) LLC, BofA Securities, Inc., Goldman Sachs & Co. LLC, Mizuho Securities USA LLC, Morgan Stanley & Co. LLC, RBC Capital Markets, LLC, Scotia Capital (USA) Inc., SMBC Nikko Securities America, Inc., SunTrust Robinson Humphrey, Inc. and TD Securities (USA) LLC, as managers, and, as applicable, the relevant Forward Purchasers (as defined below), under which we are permitted to offer and sell from time to time shares of our common stock having an aggregate offering price of up to $1,000,000,000 through the managers, acting as sales agents, or, if applicable, as Forward Sellers in connection with any forward sale agreements. On July 23, 2020, we filed the Equity Distribution Agreement with the Securities and Exchange Commission (“SEC”) as an exhibit to a Current Report on Form 8-K, which is incorporated by reference into this prospectus supplement. The sales, if any, of common stock made under the Equity Distribution Agreement will be made through the managers, as our sales agents or as Forward Sellers, by means of ordinary brokers’ transactions on the NYSE at market prices, in block transactions, or as otherwise agreed upon by the managers and us, by means of any other existing trading market for our common stock or to or through a market maker other than on an exchange. The managers will not engage in any transactions that stabilize the price of our common stock.

The Equity Distribution Agreement contemplates that, in addition to the issuance and sale by us of shares of our common stock to or through the managers as our sales agents, we may enter into separate forward sale agreements (each, together with any related pricing supplement, a “forward sale agreement” and, collectively, the “forward sale agreements”), with certain of the managers, or one of their respective affiliates (in such capacity, each, a “Forward Purchaser” and, collectively, the “Forward Purchasers”). If we enter into a forward sale agreement with any Forward Purchaser, we expect that such Forward Purchaser, acting in accordance with the mutually accepted instructions related to such forward sale agreement, will attempt to borrow and sell, through the relevant manager, acting as agent for such Forward Purchaser, shares of our common stock to hedge such Forward Purchaser’s exposure under such forward sale agreement. We refer to a manager, when acting as agent or principal for the relevant Forward Purchaser, as, individually, a “Forward Seller” and, collectively, the “Forward Sellers”. Each Forward Purchaser will be either one of the managers named in this prospectus supplement or an affiliate of one of those managers and, unless otherwise expressly stated or the context otherwise requires, references herein to the “related” or “relevant” Forward Purchaser mean, with respect to any manager, the affiliate of such manager that is acting as Forward Purchaser or, if applicable, such manager acting in its capacity as Forward Purchaser. We will not initially receive any proceeds from any sale of shares of our common stock borrowed by a Forward Purchaser and sold through a Forward Seller.

We will report at least quarterly the number of shares of common stock sold through the managers (including as Forward Sellers) under the Equity Distribution Agreement, the net proceeds to us (after deduction of the compensation to the managers, or, if applicable, the Forward Purchasers, and any regulatory transaction fees, if any, but before other expenses) and the compensation paid by us to the managers in connection with the sales of shares of our common stock.

The offering of common stock pursuant to the Equity Distribution Agreement will terminate upon the earlier of (1) the sale of all common stock subject to the Equity Distribution Agreement or (2) the termination of the Equity Distribution Agreement by us or by each of the managers.

In connection with the sale of the shares of common stock on our behalf, each of the managers may be deemed to be an “underwriter” within the meaning of the Securities Act of 1933, as amended (the “Securities Act”), and the compensation paid to the managers may be deemed to be underwriting commissions or discounts. We have agreed to provide indemnification and contribution to the managers (whether acting as our sales agent, principal or Forward Seller) and Forward Purchasers against certain liabilities, including civil liabilities under the Securities Act.

The managers and their respective affiliates are full service financial institutions engaged in various activities, which may include securities trading, commercial and investment banking, financial advisory,

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investment management, principal investment, hedging, financing and brokerage activities. The managers and their respective affiliates have provided in the past and may provide from time to time in the future certain commercial banking, financial advisory, investment banking and other services for us for which they will receive customary fees. Affiliates of certain of the managers are dealers under our commercial paper program and, to the extent that they or their affiliates hold such commercial paper, will receive their respective share of any repayment by us of amounts outstanding thereunder. Affiliates of certain of the managers are also lenders under our revolving credit agreement. Affiliates of certain of the managers hold our common stock.

Sales Through Managers as our Sales Agent or to Managers as Principal

In connection with any offers of shares of our common stock through a manager, acting as our sales agent, we will designate the maximum number of shares of common stock to be sold on a daily basis or otherwise through one of the managers as we and that manager agree and the minimum sale price per share of common stock. Subject to the terms and conditions of the Equity Distribution Agreement, the managers will use their reasonable efforts to sell on our behalf all of the designated shares of common stock. We may instruct the managers not to sell any shares of common stock if the sales cannot be effected at or above the price designated by us in any such instruction.

We or any of the managers may suspend the offering of common stock at any time and from time to time by notifying the other party. The offering of the shares is subject to receipt and acceptance and subject to the managers’ right to reject any order in whole or in part.

Each manager will provide to us written confirmation following the close of trading on the NYSE each day in which shares of common stock are sold by it as our agent under the Equity Distribution Agreement. Each confirmation provided by one of the managers will include the number of shares of common stock sold on that day, the aggregate gross sales proceeds, the net proceeds to us (after deduction of the compensation to such manager and any regulatory transaction fees, if any, but before other expenses) and the compensation payable by us to such manager with respect to such manager’s sales.

We will pay each manager a commission of up to, but not exceeding, 2.0% of the gross sale price of the shares of common stock sold by such manager pursuant to the Equity Distribution Agreement. We have agreed to reimburse the managers for certain of their expenses.

Under the terms of the Equity Distribution Agreement, we also may sell common stock to one or more of the managers as principal for its own account at a price agreed upon at the time of sale. If we sell common stock to one or more of the managers as principal, we will enter into a separate agreement with such manager and we will describe such agreement in a separate prospectus supplement or pricing supplement.

Settlement for sales of common stock by managers will generally occur on the second business day following the date on which any sales were made (or such earlier day as is industry practice for regular-way trading), or on some other date that is agreed upon by us and the manager in connection with a particular transaction, in return for payment of the net proceeds to us. There is no arrangement for funds to be received in an escrow, trust or similar arrangement.

If we or any of the managers have reason to believe that our common stock is no longer an “actively-traded security” as defined under Rule 101(c)(l) of Regulation M under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), that party will promptly notify the other parties and sales of common stock pursuant to the Equity Distribution Agreement or any terms agreement will be suspended until Rule 101(c)(1) or another exemptive provision has been satisfied in the judgment of each party.

Sales Through Forward Sellers

If we enter into a forward sale agreement with any Forward Purchaser, we expect that such Forward Purchaser or its affiliate will attempt to borrow from third parties and sell, through the relevant manager, acting

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as sales agent for such Forward Purchaser, shares of our common stock to hedge such Forward Purchaser’s exposure under such forward sale agreement.

In connection with any forward sale agreement, we will deliver instructions to the relevant manager directing such manager, as Forward Seller, to offer and sell the applicable borrowed shares of our common stock on behalf of the relevant Forward Purchaser. Such instructions shall specify the maximum number of shares to be sold and the minimum price per share at which such shares may be sold. Subject to, among others, the terms and conditions in the Equity Distribution Agreement and the acceptance of such instructions from us by the applicable manager, such manager has agreed to use its commercially reasonable efforts, consistent with its normal trading and sales practices and applicable laws and regulations, to sell, as Forward Seller for the applicable Forward Purchaser, all of the shares so designated for sale by us in accordance with such instructions, on the terms and subject to the conditions set forth in the Equity Distribution Agreement. We or the applicable manager may at any time immediately suspend the offering of shares of our common stock through such manager, as Forward Seller, upon notice to the other party.

The applicable manager will provide written confirmation to us following the close of trading on the NYSE on each day on which shares of our common stock are sold through such manager, as Forward Seller, under the Equity Distribution Agreement. Each confirmation will include the number of shares of our common stock sold on that day, the gross offering proceeds received from such sale, the net proceeds and the compensation payable by us to such manager in connection with such sales of our common stock.

In connection with each forward sale agreement, we will pay the applicable manager, acting as Forward Seller in connection with such forward sale agreement, a commission, in the form of a reduction to the initial forward price under the related forward sale agreement, at a rate that shall be up to, but shall not exceed 2.0% of the gross sales price of the borrowed shares of our common stock sold through such manager, acting as Forward Seller, during the applicable forward selling period for such shares (subject to certain possible adjustments to such gross sales price for daily accruals and any dividends having an “ex-dividend” date during such forward selling period). We may also agree with certain of the managers, acting as Forward Seller, to sell shares of our common stock other than through ordinary brokers’ transactions using sales efforts and methods that may constitute “distributions” within the meaning of Rule 100 of Regulation M under the Exchange Act, and for which we may agree to pay such manager a commission, in the form of a reduction to the initial forward price under the related forward sale agreement, that may exceed 2.0% of the gross sales price of our common stock sold through such manager. We sometimes refer to this commission as the “forward seller commission.”

We expect that settlement between a Forward Purchaser and the relevant manager, as Forward Seller, for sales of borrowed shares of our common stock, as well as settlement between such manager and buyers of such shares in the market, will occur on the second business day (or on such other date as may be agreed upon by the relevant parties) following the respective dates on which any such sales are made in return for the payment of the net proceeds therefor. There is no arrangement for funds to be received in an escrow, trust or similar arrangement. The obligations of a Forward Purchaser and the related manager, acting as Forward Seller, under the Equity Distribution Agreement are subject to a number of conditions, which such Forward Purchaser and manager, respectively, may waive in their sole and absolute discretion.

Pursuant to each forward sale agreement, if any, we will have the right to issue and deliver to the Forward Purchaser party thereto a specified number of shares of our common stock on the terms and subject to the conditions set forth therein, or, alternatively, to elect cash settlement or net share settlement, as described below, for all or any portion of such shares. The initial forward price per share under each forward sale agreement will equal the product of (1) an amount equal to one minus the applicable forward selling commission and (2) the volume weighted average price per share at which the borrowed shares of our common stock were sold pursuant to the Equity Distribution Agreement by the relevant manager, acting as Forward Seller, during the applicable forward selling period for such shares to hedge the relevant Forward Purchaser’s exposure under such forward

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sale agreement (subject to certain possible adjustments for daily accruals and any dividends having an “ex-dividend” date during such forward selling period). Thereafter, the forward price will be subject to the price adjustment provisions of the applicable forward sale agreement, as described in the next paragraph. We will not initially receive any proceeds from any sale of shares of our common stock borrowed by a Forward Purchaser or its affiliate and sold through a Forward Seller, and all of such net proceeds will be paid to the relevant Forward Purchaser (or one or more of its affiliates).

We currently expect to fully physically settle each forward sale agreement, if any, with the relevant Forward Purchaser on one or more dates specified by us on or prior to the maturity date of such forward sale agreement, although, as discussed below, we will generally have the right, subject to certain exceptions and conditions, to elect cash settlement or net share settlement instead of physical settlement for any of the shares we have agreed to sell under such forward sale agreement. If we elect or are deemed to have elected to physically settle any forward sale agreement by delivering shares of our common stock, we will receive an amount of cash from the relevant Forward Purchaser equal to the product of (1) the forward price per share at such time under such forward sale agreement and (2) the number of shares of our common stock as to which we have elected or are deemed to have elected physical settlement, subject to the price adjustment and other provisions under such forward sale agreement. Each forward sale agreement will provide that the forward price will be subject to adjustment on a daily basis based on a specified floating interest rate factor less a spread. In addition, the forward price will be subject to decrease on certain dates specified in the relevant forward sale agreement by the amount per share of dividends we expect to declare on our common stock during the term of such forward sale agreement. If the specified floating interest rate factor is less than the applicable spread on any day, the interest rate factor will result in a daily reduction of the forward price.

We expect that, before any issuance of shares of our common stock upon physical settlement or net share settlement of any forward sale agreement, the shares issuable upon settlement of such forward sale agreement will be reflected in our diluted earnings per share calculations using the treasury stock method. Under this method, the number of shares of our common stock used in calculating diluted earnings per share and dividends per share will be deemed to be increased by the excess, if any, of the number of shares that would be issued upon physical settlement of such forward sale agreement over the number of shares that could be purchased by us in the market (based on the average market price during the relevant forward selling period specified in such forward sale agreement) using the proceeds receivable upon settlement (based on the adjusted forward price at the end of the relevant reporting period). Consequently, prior to physical or net share settlement of the forward sale agreement and subject to the occurrence of certain events, we anticipate there will be no dilutive effect on our earnings per share as a result of such forward sale agreement except during periods when the average market price of our common stock is above the per share adjusted forward price of such forward sale agreement, subject to increase or decrease based on the specified floating interest rate factor less a spread, and subject to decrease by amounts related to expected dividends on our common stock during the term of that particular forward sale agreement. However, if we decide to physically or net share settle any forward sale agreement, delivery of shares of our common stock by us will result in dilution to our earnings per share.

Except under the circumstances described below and subject to certain conditions in each forward sale agreement, we will generally have the right, in lieu of physical settlement of any forward sale agreement, to elect cash or net share settlement in respect of any or all of the shares of common stock subject to such forward sale agreement. If we elect to cash or net share settle all or any part of any forward sale agreement, we would expect the relevant Forward Purchaser or one of its affiliates to purchase shares of our common stock in secondary market transactions over an unwind period to:

• return shares of our common stock to securities lenders in order to unwind such Forward Purchaser’s hedge (after taking into consideration any shares of our common stock to be delivered by us to such Forward Purchaser, in the case of net share settlement); and

• if applicable, in the case of net share settlement, deliver shares of our common stock to us to the extent required upon settlement of such forward sale agreement.

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If the price of our common stock at which these purchases by such Forward Purchaser (or its affiliate) are made is below the relevant forward price, such Forward Purchaser will pay us such difference in cash (if we elect to cash settle) or deliver to us shares of our common stock having a market value equal to such difference (if we elect to net share settle). If the price of our common stock at which these purchases are made by such Forward Purchaser (or its affiliate) exceeds the applicable forward price, we will pay such Forward Purchaser an amount in cash equal to such difference (if we elect to cash settle) or we will deliver to such Forward Purchaser a number of shares of our common stock having a market value equal to such difference (if we elect to net share settle). Any such difference could be significant and could result in our receipt of a significant amount of cash or number of shares of our common stock from such Forward Purchaser or require us to pay a significant amount of cash or deliver a significant number of shares of our common stock to such Forward Purchaser.

In addition, the purchase of our common stock by a Forward Purchaser or its affiliate to unwind the Forward Purchaser’s hedge position could cause the price of our common stock to increase above the price that would have prevailed in the absence of those purchases (or prevent a decrease in such price), thereby increasing the amount of cash (in the case of cash settlement) or the number of shares (in the case of net share settlement) that we may owe such Forward Purchaser upon settlement of the applicable forward sale agreement or decrease the amount of cash (in the case of cash settlement) or the number of shares (in the case of net share settlement) that such Forward Purchaser may owe us upon settlement of the applicable forward sale agreement.

Each Forward Purchaser will have the right to accelerate its forward sale agreement (with respect to all or any portion of the transaction under such forward sale agreement that the relevant Forward Purchaser determines is affected by an event described below) and require us to physically settle or, if we so elect and the Forward Purchaser permits our election, cash settle or net share settle on a date specified by such Forward Purchaser if:

• in such Forward Purchaser’s commercially reasonable judgment, it or its affiliate (x) is unable to hedge in a commercially reasonable manner its exposure under such forward sale agreement because insufficient shares of our common stock have been made available for borrowing by securities lenders or (y) would incur a stock loan cost in excess of a specified threshold to hedge in a commercially reasonable manner its exposure under such forward sale agreement;

• we declare any dividend, issue or distribution on shares of our common stock (a) with a cash value in excess of a specified amount per calendar quarter or with an ex-dividend date prior to the anticipated ex-dividend date for such cash dividend, (b) of share capital or securities granting the right to payment of dividends and/or the proceeds of liquidation of us equally or proportionately with such payments to holders of such common stock, for payment (cash or other consideration) at less than the prevailing market price as determined by the calculation agent under the particular forward sale agreement, (c) of share capital or other securities of another issuer acquired or owned (directly or indirectly) by us as a result of a spin-off or other similar transaction, for payment (cash or other consideration) at less than the prevailing market price as determined by the calculation agent under the particular forward sale agreement or (d) of any other type of securities, rights or warrants or other assets, for payment (cash or other consideration) at less than the prevailing market price as determined by the calculation agent under the particular forward sale agreement;

• certain ownership thresholds applicable to such Forward Purchaser, its affiliates and all other persons who may form a beneficial share ownership group or whose ownership positions would be aggregated with such Forward Purchaser are exceeded;

• an event is announced that if consummated would result in a specified extraordinary event (including certain mergers or tender offers, as well as certain events involving our nationalization, our insolvency or a delisting of our common stock) or the occurrence of a change in law or disruption in the Forward Purchaser’s ability to hedge its exposure under the forward sale agreement; or

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• certain other events of default or termination events occur, including, among others, any material misrepresentation made in connection with such forward sale agreement or our insolvency (each as more fully described in each forward sale agreement).

A Forward Purchaser’s decision to exercise its right to accelerate all or a portion of the settlement of any forward sale agreement and to require us to physically settle the relevant shares will be made irrespective of our interests, including our need for capital. In such cases, we could be required to issue and deliver shares of our common stock under the terms of the physical settlement provisions of the applicable forward sale agreement irrespective of our capital needs, which would result in dilution to our earnings per share and dividends per share.

In addition, upon certain events of bankruptcy or insolvency relating to us, the forward sale agreements will terminate without further liability of the parties thereto. Following any such termination, we would not issue any shares of our common stock pursuant to such forward sale agreements, and we would not receive any proceeds pursuant to the forward sale agreements. For further information, see “Risk Factors.”

The descriptions of certain provisions of the forward sale agreements appearing above and the descriptions of certain provisions of the forward sale agreements that we expect to enter into in connection with this offering appearing elsewhere in this prospectus supplement are not complete and are subject to, and qualified in their entirety by reference to, the terms and provisions of such forward sale agreements. A form of the forward sale agreement is included as an exhibit to the Equity Distribution Agreement. On July 23, 2020, we filed the Equity Distribution Agreement with the SEC as an exhibit to a Current Report on Form 8-K, which is incorporated by reference into this prospectus supplement.

Relationships/FINRA Conduct Rules

From time to time, the managers and their affiliates have provided, directly or indirectly, investment and commercial banking or financial advisory services to us and our affiliates, for which they have received customary fees and commissions, and they expect to provide these services to us and our affiliates in the future, for which they expect to receive customary fees and commissions.

Affiliates of certain of the managers are lenders under our revolving credit facility and, to the extent we use proceeds from this offering to repay indebtedness under our revolving credit, will receive their respective shares of any repayment of amounts outstanding under such facility with the proceeds of this offering. Additionally, affiliates of certain of the managers are dealers under our commercial paper program. To the extent we use proceeds from this offering to repay notes issued under our commercial paper program and such affiliates hold such notes, such affiliates may receive proceeds from this offering.

In the ordinary course of their various business activities, the managers and their respective affiliates, officers, directors and employees may purchase, sell or hold a broad array of investments and actively traded securities, derivatives, loans, commodities, currencies, credit default swaps and other financial instruments for their own account and for the accounts of their customers, and such investment and trading activities may involve or relate to our assets, securities and/or instruments (directly, as collateral securing other obligations or otherwise) and/or persons and entities with relationships with us. The managers and their respective affiliates may also communicate independent investment recommendations, market color or trading ideas and/or publish or express independent research views in respect of such assets, securities or instruments and may at any time hold, or recommend to clients that they should acquire, long and/or short positions in such assets, securities and instruments.

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If we enter into a forward sale agreement with any Forward Purchaser, we expect that such Forward Purchaser or its affiliate will attempt to borrow from third parties and sell, through the relevant manager, acting as Forward Seller, shares of our common stock to hedge such Forward Purchaser’s exposure under such forward sale agreement. All of the net proceeds from the sale of any such borrowed shares will be paid to the applicable Forward Purchaser (or one or more of its affiliates). Each Forward Purchaser will be either a manager or an affiliate of a manager. As a result, a manager or its affiliate will receive the net proceeds from any sale of borrowed shares of our common stock made in connection with any forward sale agreements.

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LEGAL MATTERS

The validity of the common stock being offered hereunder is being passed upon for us by GableGotwals, Tulsa, Oklahoma. Certain other legal matters for us will be passed upon for us by Latham & Watkins LLP, Houston, Texas. The managers and the Forward Purchasers will be represented by Shearman & Sterling LLP, New York, New York.

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EXPERTS

The financial statements and management’s assessment of the effectiveness of internal control over financial reporting (which is included in Management’s Report on Internal Control over Financial Reporting) incorporated in this prospectus supplement by reference to the Annual Report on Form 10-K for the year ended December 31, 2019 have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

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WHERE YOU CAN FIND MORE INFORMATION

We file annual, quarterly and other reports and other information with the SEC under the Exchange Act. The SEC maintains a website (www.sec.gov) that contains reports, proxy and information statements and other information regarding issuers that file electronically with the SEC. Our SEC filings are available on the SEC’s website. You also can obtain information about us at the offices of the NYSE, located at 11 Wall Street, New York, New York 10005.

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INCORPORATION BY REFERENCE

The SEC allows us to “incorporate by reference” information into this prospectus supplement. This means that we can disclose important information to you by referring you to another document filed separately with the SEC. The information incorporated by reference is considered to be part of this prospectus supplement, and information that we file later with the SEC will automatically update and supersede the previously filed information. We incorporate by reference the documents listed below and any future filings made by us with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act, other than any portions of the respective filings that were furnished, pursuant to Item 2.02 or Item 7.01 of Current Reports on Form 8-K (including exhibits related thereto) or other applicable SEC rules, rather than filed, prior to the consummation of the offering under this prospectus supplement:

• Annual Report on Form 10-K (File No. 001-13643) for the year ended December 31, 2019, filed on February 25, 2020;

• Quarterly Report on Form 10-Q (File No. 001-13643) for the quarter ended March 31, 2020, filed on April 29, 2020;

• Current Reports on Form 8-K (File No. 001-13643) filed on January  16, 2020, February  27, 2020, March  10, 2020, April  17, 2020, May  7, 2020, May  22, 2020, June  16, 2020 (with respect to Item 1.01), June  30, 2020 (with respect to Item 1.01) and July 23, 2020;

• our Definitive Proxy Statement on Schedule 14A (File No. 001-13643) filed on April  3, 2020 (solely to the extent incorporated by reference into our Annual Report on Form 10-K for the year ended December 31, 2019); and

• the description of our common stock contained in our Form 8-A registration statement filed with the SEC on November 21, 1997, including any amendment or report filed for the purpose of updating that description.

If information in incorporated documents conflicts with information in this prospectus supplement, you should rely on the most recent information. If information in an incorporated document conflicts with information in another incorporated document, you should rely on the most recent incorporated document.

Documents incorporated by reference are available from us without charge, excluding any exhibits to those documents unless the exhibit is specifically incorporated by reference as an exhibit in this document. You can obtain documents incorporated by reference in this document by requesting them in writing or by telephone at the following address and phone number:

ONEOK, Inc.

100 West Fifth Street

Tulsa, Oklahoma 74103

Attention: Corporate Secretary

Telephone: (918) 588-7000

We have not authorized anyone to provide you with information other than the information contained or incorporated by reference in this prospectus supplement or the accompanying base prospectus. We are not making an offer to sell, or soliciting an offer to buy, securities in any jurisdiction where the offer and sale is not permitted. You should assume that the information appearing or incorporated by reference in this prospectus supplement, the accompanying base prospectus or any applicable pricing supplement is accurate only as of the date of the documents containing the information, regardless of the time of its delivery or of any sale of our securities. Our business, financial condition, results of operations and prospects may have changed since those dates.

S-23

Debt Securities, Common Stock, Stock Purchase Contracts,

Stock Purchase Contract Units, Preferred Stock, Depositary Shares, and Warrants

Guarantee of Debt Securities of ONEOK, Inc. by ONEOK Partners, L.P. and by ONEOK Partners Intermediate Limited Partnership

We may offer and sell, from time to time in one or more issuances, (1) one or more series of debt securities, which may be senior or subordinated notes or debentures, or other senior or subordinated evidences of indebtedness, which may be fully and unconditionally guaranteed by ONEOK Partners, L.P. and by ONEOK Partners Intermediate Limited Partnership and which may include terms permitting or requiring holders to convert or exchange their debt securities for common stock, preferred stock or other securities, (2) shares of our common stock, (3) stock purchase contracts, (4) stock purchase contract units that consist of (a) a stock purchase contract and (b) senior or subordinated debt securities, or preferred stock, U.S. Treasury securities or other debt obligations of third parties, that may be used to secure the holders’ obligations under a purchase contract, (5) shares of our preferred stock, which may include terms permitting or requiring holders to convert or exchange their preferred stock for common stock or other securities, (6) depositary shares, or (7) warrants.

We will provide you with the specific terms of the particular securities being offered in supplements to this prospectus. Any prospectus supplement may also add, update, or change information contained in this prospectus. You should read this prospectus and each related prospectus supplement carefully before you make an investment decision. This prospectus may not be used to sell securities unless accompanied by a prospectus supplement.

Our common stock, par value $0.01 per share, is listed on the New York Stock Exchange under the symbol “OKE.”

Investing in these securities involves certain risks. Please read “Risk Factors” on page 7 of this prospectus.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

The date of this Prospectus is June 22, 2020.

TABLE OF CONTENTS

	Page
ABOUT THIS PROSPECTUS		1
WHERE YOU CAN FIND MORE INFORMATION		1
INCORPORATION BY REFERENCE		2
CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS		3
ABOUT ONEOK		6
RISK FACTORS		7
USE OF PROCEEDS		8
DESCRIPTION OF DEBT SECURITIES		9
DESCRIPTION OF GUARANTEE OF DEBT SECURITIES		21
DESCRIPTION OF CAPITAL STOCK		22
DESCRIPTION OF STOCK PURCHASE CONTRACTS AND STOCK PURCHASE CONTRACT UNITS		28
DESCRIPTION OF DEPOSITARY SHARES		29
DESCRIPTION OF WARRANTS		31
PLAN OF DISTRIBUTION		32
LEGAL MATTERS		34
EXPERTS		34

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ABOUT THIS PROSPECTUS

The information contained in this prospectus is not complete and may be changed. We have not authorized anyone else to provide you with information other than the information provided in or incorporated by reference in this prospectus, any prospectus supplement, or documents to which we otherwise refer you. We are not making an offer of any securities in any jurisdiction where the offer is not permitted. You should not assume that the information in this prospectus, any prospectus supplement or any document incorporated by reference is accurate as of any date other than the date of the document in which such information is contained or such other date referred to in such document, regardless of the time of any sale or issuance of a security.

This prospectus is part of a registration statement that we have filed with the Securities and Exchange Commission, or the SEC, utilizing a “shelf” registration process. Under this shelf registration process, we may sell different types of securities described in this prospectus in one or more offerings. This prospectus provides you with a general description of the securities we may offer. Each time we sell securities, we will provide a prospectus supplement that will contain specific information about the terms of that offering and the securities offered by us in that offering. The prospectus supplement may also add, update or change information in this prospectus. You should read both this prospectus and any prospectus supplement together with additional information described under the headings “Where You Can Find More Information” and “Incorporation by Reference.”

This prospectus contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by reference to the actual documents. Copies of some of the documents referred to herein have been filed or will be filed or incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described below in the section entitled “Where You Can Find More Information.”

Unless we otherwise indicate or unless the context requires, all references in this prospectus to:

• “ONEOK,” “we,” “our,” “us” or similar references mean ONEOK, Inc. and its subsidiaries, predecessors and acquired businesses;

• “common stock” mean our common stock, par value $0.01 per share;

• “preferred stock” means our preferred stock, par value $0.01 per share; and

• “securities” mean the debt securities, common stock, stock purchase contracts, stock purchase contract units, preferred stock, depositary shares and warrants described in this prospectus.

WHERE YOU CAN FIND MORE INFORMATION

We have filed a registration statement on Form S-3 with the SEC under the Securities Act of 1933, as amended, or the Securities Act, that registers the securities offered by this prospectus. The registration statement, including the attached exhibits, contains additional relevant information about us. The rules and regulations of the SEC allow us to omit some information included in the registration statement from this prospectus.

We file annual, quarterly and current reports, proxy statements and other information with the SEC. The SEC maintains a website that contains information we file electronically, which you can access over the Internet at www.sec.gov. Our common stock is listed on the New York Stock Exchange (NYSE: OKE), and you can obtain information about us at the offices of the New York Stock Exchange, 11 Wall Street, New York, New York 10005. General information about us, including our Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K, and amendments to those reports, is available free of charge through our website at www.oneok.com as soon as reasonably practicable after we electronically file them with, or furnish them to, the SEC. Information on, or accessible through, our website is not incorporated into this prospectus or our other securities filings and is not a part of these filings.

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INCORPORATION BY REFERENCE

The SEC allows us to “incorporate by reference” the information we have filed with the SEC. This means that we can disclose important information to you by referring you to another document filed separately with the SEC. The information incorporated by reference is considered to be part of this prospectus, and information that we file later with the SEC will automatically update and supersede the previously filed information.

The documents listed below and any future filings made by us with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended, other than any portions of the respective filings that were furnished, pursuant to Item 2.02 or Item 7.01 of Current Reports on Form 8-K (including exhibits related thereto) or other applicable SEC rules, rather than filed, prior to the termination of the offerings under this prospectus are incorporated by reference in this prospectus:

• Annual Report on Form 10-K (File No. 001-13643) for the year ended December 31, 2019, filed on February 25, 2020;

• Quarterly Report on Form 10-Q for the period ended March  31, 2020, filed on April 29, 2020;

• Current Reports on Form 8-K (File No. 001-13643) filed on January 16, 2020 (Item 8.01), February  27, 2020 (Item 8.01), March  10, 2020 (Items 1.01, 2.03 and 9.01 (other than Exhibit 99.1)), April  17, 2020 (Item 8.01), May  7, 2020 (Items 1.01, 2.03 and 9.01 (other than Exhibit 99.1)), May 22, 2020 (Item 5.07), and June 16, 2020 (Items 1.01 and 9.01 (other than Exhibit 99.1)); and

• the description of our common stock contained in our Form 8-A registration statement filed with the SEC on November 21, 1997, including any amendment or report filed for the purpose of updating that description.

You may request a copy of these filings (other than an exhibit to the filings unless we have specifically incorporated that exhibit by reference into the filing), at no cost, by writing or telephoning us at the following address:

ONEOK, Inc.

100 West Fifth Street

Tulsa, Oklahoma 74103

Attention: Corporate Secretary

Telephone: (918) 588-7000

We have not authorized anyone to provide you with information other than the information contained or incorporated by reference in this prospectus or in any prospectus supplement. If anyone provides you with different or inconsistent information, you should not rely on it. We are not making an offer to sell, or soliciting an offer to buy, securities in any jurisdiction where the offer and sale is not permitted. You should assume that the information appearing or incorporated by reference in this prospectus, the applicable prospectus supplement or any applicable pricing supplement is accurate only as of the date of the documents containing the information, regardless of the time of its delivery or of any sale of our securities. Our business, financial condition, results of operations and prospects may have changed since those dates.

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CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

Some of the statements contained in, or incorporated by reference into, this prospectus are forward-looking statements as defined under federal securities laws. The forward-looking statements relate to our anticipated financial performance (including projected operating income, net income, capital expenditures, cash flows and projected levels of dividends), liquidity, management’s plans and objectives for our future capital-growth projects and other future operations (including plans to construct additional natural gas and natural gas liquids (“NGLs”) pipelines, processing and fractionation facilities and related cost estimates), our business prospects, the outcome of regulatory and legal proceedings, market conditions and other matters. We make these forward-looking statements in reliance on the safe harbor protections provided under federal securities legislation and other applicable laws. The following discussion is intended to identify important factors that could cause future outcomes to differ materially from those set forth in the forward-looking statements.

Forward-looking statements include the items identified in the preceding paragraph, the information concerning possible or assumed future results of our operations and other statements contained in or incorporated by reference into this prospectus identified by words such as “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “forecast,” “goal,” “guidance,” “intend,” “may,” “might,” “outlook,” “plan,” “potential,” “project,” “scheduled,” “should,” “will,” “would,” and other words and terms of similar meaning.

One should not place undue reliance on forward-looking statements. Known and unknown risks, uncertainties and other factors may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by forward-looking statements. Those factors may affect our operations, markets, products, services and prices. In addition to any assumptions and other factors referred to specifically in connection with the forward-looking statements, factors that could cause our actual results to differ materially from those contemplated in any forward-looking statement include, among others, the following:

• the impact on drilling and production by factors beyond our control, including the demand for natural gas and crude oil; producers’ desire and ability to drill and obtain necessary permits; regulatory compliance; reserve performance; and capacity constraints on the pipelines that transport crude oil, natural gas and NGLs from producing areas and our facilities;

• the effects of weather and other natural phenomena, including climate change, on our operations, demand for our services and energy prices;

• the length and severity of a pandemic or other health crisis, such as the recent outbreak of COVID-19 and the measures that international, federal, state and local governments, agencies, law enforcement and/or health authorities implement to address it, which may (as with COVID-19) precipitate or exacerbate one or more of the factors herein, reduce the demand for natural gas, NGLs and crude oil and significantly disrupt or prevent us and our customers and counterparties from operating in the ordinary course for an extended period and increase the cost of operating our business;

• the timing and extent of changes in energy commodity prices, including changes due to production decisions by other countries, such as the failure of countries to abide by recent agreements to reduce production volumes;

• economic climate and growth in the geographic areas in which we do business;

• risks associated with adequate supply to our gathering, processing, fractionation and pipeline facilities, including production declines that outpace new drilling or extended periods of ethane rejection;

• competition from other United States and foreign energy suppliers and transporters, as well as alternative forms of energy, including, but not limited to, solar power, wind power, geothermal energy and biofuels such as ethanol and biodiesel;

• demand for our services and products in the proximity of our facilities;

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• the ability to market pipeline capacity on favorable terms, including the effects of:

• future demand for and prices of natural gas, NGLs and crude oil;

• competitive conditions in the overall energy market;

• availability of supplies of United States natural gas and crude oil; and

• availability of additional storage capacity;

• acts of nature, sabotage, terrorism or other similar acts that cause damage to our facilities or our suppliers’, customers’ or shippers’ facilities;

• the possibility of future terrorist attacks or the possibility or occurrence of an outbreak of, or changes in, hostilities or changes in the political conditions throughout the world;

• the timely receipt of approval by applicable governmental entities for construction and operation of our pipeline and other projects and required regulatory clearances;

• our ability to acquire all necessary permits, consents or other approvals in a timely manner, to promptly obtain all necessary materials and supplies required for construction, and to construct gathering, processing, storage, fractionation and transportation facilities without labor or contractor problems;

• the profitability of assets or businesses acquired or constructed by us;

• the risk of a slowdown in growth or decline in the United States or international economies, including liquidity risks in United States or foreign credit markets;

• risks of marketing, trading and hedging activities, including the risks of changes in energy prices or the financial condition of our counterparties;

• the uncertainty of estimates, including accruals and costs of environmental remediation;

• changes in demand for the use of natural gas, NGLs and crude oil because of market conditions caused by concerns about climate change;

• the impact of uncontracted capacity in our assets being greater or less than expected;

• the composition and quality of the natural gas and NGLs we gather and process in our plants and transport on our pipelines;

• the efficiency of our plants in processing natural gas and extracting and fractionating NGLs;

• our ability to control construction costs and completion schedules of our pipelines and other projects;

• the effects of changes in governmental policies and regulatory actions, including changes with respect to income and other taxes, pipeline safety, environmental compliance, climate change initiatives, production limits and authorized rates of recovery of natural gas and natural gas transportation costs;

• the ability to recover operating costs and amounts equivalent to income taxes, costs of property, plant and equipment and regulatory assets in our state and FERC-regulated rates;

• the results of administrative proceedings and litigation, regulatory actions, executive orders, rule changes and receipt of expected clearances involving any local, state or federal regulatory body, including the FERC, the National Transportation Safety Board, the PHMSA, the EPA and the CFTC;

• difficulties or delays experienced by trucks, railroads or pipelines in delivering products to or from our terminals or pipelines;

• the capital-intensive nature of our businesses;

• the mechanical integrity of facilities operated;

• risks associated with pending or possible acquisitions and dispositions, including our ability to finance or integrate any such acquisitions and any regulatory delay or conditions imposed by regulatory bodies in connection with any such acquisitions and dispositions;

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• the risk that material weaknesses or significant deficiencies in our internal controls over financial reporting could emerge or that minor problems could become significant;

• the impact of unforeseen changes in interest rates, debt and equity markets, inflation rates, economic recession and other external factors over which we have no control, including the effect on pension and postretirement expense and funding resulting from changes in equity and bond market returns;

• our indebtedness and guarantee obligations could make us vulnerable to general adverse economic and industry conditions, limit our ability to borrow additional funds and/or place us at competitive disadvantages compared with our competitors that have less debt or have other adverse consequences;

• actions by rating agencies concerning our credit;

• our ability to access capital at competitive rates or on terms acceptable to us;

• the impact and outcome of pending and future litigation;

• performance of contractual obligations by our customers, service providers, contractors and shippers;

• our ability to control operating costs and make cost-saving changes;

• the impact of recently issued and future accounting updates and other changes in accounting policies;

• the risk of increased costs for insurance premiums, security or other items as a consequence of terrorist attacks;

• the risk inherent in the use of information systems in our respective businesses and those of our counterparties and service providers, implementation of new software and hardware, and the impact on the timeliness of information for financial reporting;

• the impact of potential impairment charges; and

• the risk factors listed in the reports we have filed and may file with the SEC, which are incorporated by reference.

These factors are not necessarily all of the important factors that could cause actual results to differ materially from those expressed in any of our forward-looking statements. Other factors could also affect adversely on our future results. These and other risks are described in greater detail in Part 1, Item 1A, Risk Factors, in our Annual Report on Form 10-K for the year ended December 31, 2019, and Part II, Item 1A, Risk Factors, in our Quarterly Report on Form 10-Q for the period ended March 31, 2020 and in our other filings that we make with the SEC, which are available via the SEC’s website at www.sec.gov and our website at www.oneok.com. All forward-looking statements attributable to us or persons acting on our behalf are expressly qualified in their entirety by these factors. Any such forward-looking statement speaks only as of the date on which such statement is made, and other than as required under securities laws, we undertake no obligation to update publicly any forward-looking statement whether as a result of new information, subsequent events or change in circumstances, expectations or otherwise.

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ABOUT ONEOK

We are a corporation incorporated under the laws of the state of Oklahoma, and our common stock is listed on the New York Stock Exchange under the trading symbol “OKE.” We are a leading midstream service provider and own one of the nation’s premier NGL systems, connecting NGL supply in the Mid-Continent, Permian and Rocky Mountain regions with key market centers and an extensive network of natural gas gathering, processing, storage and transportation assets. We apply our core capabilities of gathering, processing, fractionating, transporting, storing and marketing natural gas and NGLs through vertical integration across the midstream value chain to provide our customers with premium services while seeking to generate consistent and sustainable earnings growth.

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RISK FACTORS

Before you invest in our securities, you should carefully consider those risk factors included in our most recent Annual Report on Form 10-K, our Quarterly Reports on Form 10-Q and our other filings with the SEC that are incorporated herein by reference and any prospectus supplement or free writing prospectus used in connection with an offering of our securities, as well as the information relating to us identified above under “Cautionary Statement Regarding Forward-Looking Statements.”

If any of the risks discussed in the foregoing documents were actually to occur, our business, financial condition, results of operations, or cash flow could be materially adversely affected. In that case, our ability to pay dividends to our shareholders or pay interest on, or the principal of, any debt securities, may be reduced, the trading price of our securities could decline and you could lose all or part of your investment.

7

USE OF PROCEEDS

Unless we inform you otherwise in an applicable prospectus supplement, ONEOK will use the net proceeds from the sale of the offered securities for general corporate purposes. These purposes may include repayment and refinancing of debt, acquisitions, working capital, capital expenditures and repurchases and redemptions of securities. Pending any specific application, we may initially invest funds in marketable securities or apply them to the reduction of short-term indebtedness.

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DESCRIPTION OF DEBT SECURITIES

The following description states the general terms and provisions of our debt securities. The debt securities offered by this prospectus will be issued under one of two separate indentures among us, ONEOK Partners, L.P. and ONEOK Partners Intermediate Limited Partnership (together with ONEOK Partners, L.P., the “Guarantors”), and U.S. Bank National Association, as trustee. We have filed the forms of indenture as exhibits to the registration statement of which this prospectus is a part. The debt securities will be unsecured obligations of ONEOK and will be either senior or subordinated debt. Senior debt will be issued under a senior indenture and subordinated debt will be issued under a subordinated indenture. The senior indenture and the subordinated indenture are sometimes referred to in this prospectus individually as an “Indenture” and collectively as the “Indentures.” Each prospectus supplement that we provide when we offer debt securities will describe the specific terms of the debt securities offered through that prospectus supplement and any general terms outlined in this section that will not apply to those debt securities. Unless otherwise specified in this prospectus, the term “debt securities” includes senior debt securities and subordinated debt securities and the descriptions of the debt securities describe both the senior debt securities and the subordinated debt securities unless otherwise specified in this prospectus or any prospectus supplement.

We have summarized the material terms and provisions of the Indentures in this section. The summary is not complete. We have filed the forms of each of the Indentures as exhibits to the registration statement of which this prospectus forms a part. You should read the applicable form of Indenture for additional information before you buy any debt securities. Each of the Indentures is qualified under the Trust Indenture Act. You should refer to the Trust Indenture Act for provisions that apply to the debt securities. This summary also is subject to and qualified by reference to the description of the particular terms of the debt securities described in the applicable prospectus supplement or supplements and pricing supplement or supplements. Capitalized terms used but not defined in this summary have the meanings specified in the applicable Indenture. In this section, “we,” “us” and “our” refer only to ONEOK, Inc. and not to any of our subsidiaries.

Debt securities issued under either Indenture will be issued as part of a series that will be established pursuant to a supplemental indenture or other authorized corporate action designating the specific terms of the series of debt securities. A prospectus supplement will describe these terms and will include, among other things, the following:

• the title of the debt securities of the particular series and whether the debt securities will be senior debt securities or subordinated debt securities;

• the total principal amount of those debt securities and the percentage of their principal amount at which we will issue those debt securities;

• the date or dates on which the principal of those debt securities will be payable;

• the interest rate, the method for determining the interest rate (if the interest rate is variable), the date from which interest will accrue, interest payment dates and record dates for interest payments;

• the place or places where payments on those debt securities will be made, where holders may surrender their debt securities for transfer or exchange and where to serve notices or demands;

• any provisions for optional redemption or early repayment;

• any provisions that would obligate us to redeem, purchase or repay those debt securities;

• any provisions for conversion or exchange of the debt securities;

• whether payments on the debt securities of the particular series will be payable by reference to any index, formula or other method;

• any deletions from, changes of or additions to the events of default, covenants or other provisions described in this prospectus;

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• the portion of the principal amount of those debt securities that will be payable if the maturity is accelerated, if other than the entire principal amount;

• any additional means of defeasance of all or any portion of those debt securities, any additional conditions or limitations to defeasance of those debt securities or any changes to those conditions or limitations;

• any provisions granting special rights to holders of the debt securities of the particular series upon the occurrence of events identified in the prospectus supplement;

• if other than the trustee, the designation of any paying agent or security registrar for those debt securities and the designation of any transfer or other agents or depositories for those debt securities;

• whether we will issue the debt securities of the particular series in individual physical certificates to each holder or in the form of temporary or permanent global securities that a depository will hold on behalf of holders;

• the denominations in which we will issue the debt securities of the particular series or in which they may be owned, if other than $1,000 or any integral multiple of $1,000;

• whether the debt securities of such series will be guaranteed by the Guarantors pursuant to the guarantee provisions of the Indenture governing such series, any modifications to the terms of such provisions applicable to the debt securities of such series and the applicability of any other guarantees; and

• any other terms or conditions that are consistent with such Indenture, which may include the applicability of or change in the subordination provisions of such Indenture or providing collateral, security or assurance for a series of debt securities.

We may sell the debt securities at a discount (which may be substantial) below their stated principal amount. These discounted debt securities may bear no interest or interest at a rate that at the time of issuance is below market rates. We will describe in the prospectus supplement any material United States federal income tax consequences and other special considerations.

Certain Restrictive Covenants Under Our Senior Indenture

Under the senior indenture, we have agreed to two principal restrictions on our activities for the benefit of holders of the senior debt securities. The restrictive covenants summarized below will apply to a series of senior debt securities (unless waived or amended) as long as any of those senior debt securities are outstanding or, unless the prospectus supplement for the series states otherwise. We have used in this summary description capitalized terms that we have defined below under “—Glossary.” Our Restricted Subsidiaries are those that own or lease a Principal Property.

Other than the restrictions on Liens and Sale/Leaseback transactions under the senior indenture described below, the Indentures and the debt securities do not contain any covenants or other provisions designed to protect holders of any debt securities in the event we participate in a highly leveraged transaction. The Indentures and the debt securities also do not contain provisions that give holders of the debt securities the right to require us to repurchase their securities in the event of change-in-control, recapitalization or similar restructuring or otherwise or upon a decline in our credit rating.

For these purposes, “debt” means obligations for money borrowed, evidenced by notes, bonds, debentures or other similar evidences of indebtedness.

Limitation on Liens

We agree that we will not, and will not permit any Restricted Subsidiary to, create, incur, issue or assume any debt secured by any Lien on any Principal Property, or on shares of stock or debt of any Restricted Subsidiary, without making effective provision for the outstanding securities issued under the senior indenture

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(except as otherwise specified pursuant to an applicable supplemental indenture) to be secured by the Lien equally and ratably with (or prior to) any and all debt and obligations secured or to be secured thereby for so long as such debt is so secured, except that the foregoing restriction will not apply to:

• Any Lien existing on the date of the first issue of securities under the senior indenture.

• Any Lien on any Principal Property or Restricted Securities of any Person existing at the time such Person is merged or consolidated with or into us or a Restricted Subsidiary, or such Person becomes a Restricted Subsidiary.

• Any Lien on any Principal Property existing at the time of acquisition of such Principal Property by us or a Restricted Subsidiary, whether or not assumed by us or such Restricted Subsidiary, provided that no such Lien may extend to any other Principal Property of ours or of any Restricted Subsidiary.

• Any Lien on any Principal Property (including any improvements on an existing Principal Property) of ours or of any Restricted Subsidiary, and any Lien on the shares of stock of a Restricted Subsidiary that was formed or is held for the purpose of acquiring and holding such Principal Property, in each case to secure all or any part of the cost of acquisition, development, operation, construction, alteration, repair or improvement of all or any part of such Principal Property (or to secure Indebtedness incurred by us or a Restricted Subsidiary for the purpose of financing all or any part of such cost); provided that such Lien is created prior to, at the time of, or within 12 months after the latest of, the acquisition, completion of construction or improvement or commencement of commercial operation of such Principal Property and provided, further, that no such Lien may extend to any other Principal Property of us or any Restricted Subsidiary, other than any theretofore unimproved real property on which the Principal Property is so constructed or developed or the improvement is located.

• Any Lien on any Principal Property or Restricted Securities to secure debt owing to us or to another Restricted Subsidiary.

• Any Lien in favor of governmental bodies to secure advances or other payments pursuant to any contract or statute or to secure debt incurred to finance the purchase price or cost of constructing or improving the property subject to such Lien.

• Any Lien created in connection with a project financed with, and created to secure, non-recourse indebtedness.

• Carriers’, warehousemen’s, mechanics’, landlords’, materialmen’s, repairmen’s or other similar Liens arising in the ordinary course of business which are not delinquent or remain payable without penalty or which are being contested in good faith and by appropriate proceedings.

• Liens (other than Liens imposed by Employee Retirement Income Security Act of 1974) on the property of ours or any of our Restricted Subsidiaries incurred, or pledges or deposits required, in connection with workmen’s compensation, unemployment insurance and other social security legislation.

• Liens securing taxes that remain payable without penalty or which are being contested in good faith by appropriate proceedings where collection thereof is stayed; provided that we have or any Restricted Subsidiary has set aside on its books reserves with respect to such taxes (segregated to the extent required by GAAP) deemed by it to be adequate.

• Any right which any municipal or governmental body or agency may have by virtue of any franchise, license or contract to purchase or designate a purchaser of, or order the sale of, any property of ours upon payment of reasonable compensation therefor or to terminate any franchise, license or other rights or to regulate our property and business.

• Any Liens, neither assumed by us or any Restricted Subsidiary or on which we or any Restricted Subsidiary customarily pays interest, existing upon real estate or rights in or relating to real estate

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acquired by us or any Restricted Subsidiary for sub-station, measuring station, regulating station, gas purification station, compressor station, transmission line, distribution line or right-of-way purposes.

• Easements or reservations in any property of ours or of any Restricted Subsidiary for the purpose of roads, pipe lines, gas transmission and distribution lines, electric light and power transmission and distribution lines, water mains and other like purposes, and zoning ordinances, regulations and restrictions which do not impair the use of such property in the operation of the business of ours or of any Restricted Subsidiary.

• Any extension, renewal, substitution or replacement (or successive extensions, renewals, substitutions or replacements), in whole or in part, of any Lien referred to in above, provided that the debt secured thereby may not exceed the principal amount of debt so secured at the time of such renewal or refunding, and that such renewal or refunding Lien must be limited to all or any part of the same property and improvements thereon, shares of stock or debt that secured the Lien renewed or refunded.

• Any Lien not permitted above securing debt that, together with the aggregate outstanding principal amount of other secured debt that would otherwise be subject to the foregoing restrictions (excluding debt secured by Liens permitted under the foregoing exceptions) and the Attributable Debt in respect of all Sale and Leaseback Transactions (not including Attributable Debt in respect of any such Sale and Leaseback Transactions described in the third and fourth “bullet points” in “Limitations on Sale and Leaseback Transactions”) would not then exceed 15% of Consolidated Net Tangible Assets.

Limitation on Sale/Leaseback Transactions

We agree that we will not, and will not permit any Restricted Subsidiary to, enter into any Sale and Leaseback Transaction unless:

• we or a Restricted Subsidiary would be entitled, without securing the outstanding securities under the senior indenture, to incur debt secured by a Lien on the Principal Property that is the subject of such Sale and Leaseback Transaction;

• the Attributable Debt associated therewith would be in an amount permitted under the “basket” described above under “Limitation on Liens”;

• the proceeds received in respect of the Principal Property so sold and leased back at the time of entering into such Sale and Leaseback Transaction are used for the business and operations of us or any subsidiary; or

• within 12 months after the sale or transfer, an amount equal to the proceeds received in respect of the Principal Property so sold and leased back at the time of entering into such Sale and Leaseback Transaction is applied to the prepayment (other than mandatory prepayment) of any outstanding securities issued under the senior indenture or Funded Indebtedness of ours or of a Restricted Subsidiary (other than Funded Indebtedness that is held by us or any Restricted Subsidiary or Funded Indebtedness of ours that is subordinate in right of payment to any outstanding securities issued under the senior indenture).

Glossary

“Attributable Debt” means, as to any particular Sale and Leaseback Transaction under which any Person is at the time liable, at any date as of which the amount thereof is to be determined, the total net amount of rent required to be paid by that Person under the lease during the remaining term thereof (excluding amounts required to be paid on account of maintenance and repairs, services, insurance, taxes, assessments, water rates and similar charges and contingent rents), discounted from the respective due dates thereof at the weighted average of the rates of interest (or yield to maturity, in the case of senior debt securities originally sold at a discount) borne by the debt securities then outstanding under the senior indenture, compounded annually.

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“Consolidated Net Tangible Assets” means the total amount of assets (less applicable reserves and other properly deductible items) that under generally accepted accounting principles, or GAAP, would be included on a consolidated balance sheet of ours and our subsidiaries after deducting therefrom (A) all current liabilities, provided, however, that there will not be deducted billings recorded as revenues deferred pending the outcome of rate proceedings (less applicable income taxes thereon), if and to the extent the obligation to refund the same has not been finally determined, (B) appropriate allowance for minority interests in common stocks of subsidiaries and (C) all goodwill, trade names, trademarks, patents, unamortized debt discount and expense and other like intangibles, which in each case under GAAP would be included on the consolidated balance sheet.

“Funded Indebtedness” as applied to any Person, means all debt of that Person maturing after, or renewable or extendable at that Person’s option beyond, 12 months from the date of determination.

“Lien” means any lien, mortgage, pledge, encumbrance, charge or security interest securing debt; provided, however, that the following types of transactions will not be considered for purposes of this definition to result in a Lien: (1) any acquisition by us or any of our Restricted Subsidiaries of any property or assets subject to any reservation or exception under the terms of which any vendor, lessor or assignor creates, reserves or excepts or has created, reserved or excepted an interest in oil, gas or any other mineral in place or the proceeds thereof, (2) any conveyance or assignment whereby we or any Restricted Subsidiary convey or assign to any Person or Persons an interest in oil, gas or any other mineral in place or the proceeds thereof, (3) any Lien upon any property or assets either owned or leased by us or any Restricted Subsidiary or in which we or any Restricted Subsidiary own an interest that secures for the benefit of the Person or Persons paying the expenses of developing or conducting operations for the recovery, storage, transportation or sale of the mineral resources of the property or assets (or property or assets with which it is unitized) the payment to that Person or Persons of our or a Restricted Subsidiary’s proportionate part of such development or operating expenses or (4) any hedging arrangements entered into in the ordinary course of business, including any obligation to deliver any mineral, commodity or asset in connection therewith.

“Person” means any individual, corporation, partnership, limited liability company, joint venture, association, joint-stock company, trust, unincorporated organization or government or any agency or political subdivision thereof.

“Principal Property” means any property located in the United States, except any property that in the opinion of our board of directors is not of material importance to the total business conducted by us and our consolidated subsidiaries.

“Restricted Securities” means shares of stock or debt of any Restricted Subsidiary.

“Restricted Subsidiary” means any subsidiary that owns or leases Principal Property.

“Sale/Leaseback Transaction” means any arrangement with any Person pursuant to which we or any Restricted Subsidiary lease any Principal Property that has been or is to be sold or transferred by us to that Person, other than (1) a lease for a term, including renewals at the option of the lessee, of not more than three years or classified as an operating lease under GAAP, (2) leases between us and a Restricted Subsidiary or between Restricted Subsidiaries, (3) leases of a Principal Property executed by the time of, or within 12 months after the latest of, the acquisition, the completion of construction or improvement, or the commencement of commercial operation, of the Principal Property and (4) the ground lease for ONEOK Plaza, 100 West Fifth Street, Tulsa, Oklahoma 74103.

Consolidation, Merger and Sale of Assets

The Indentures generally permit a consolidation or merger between us and another entity. They also permit the sale by us of all or substantially all of our assets. We have agreed, unless we inform you otherwise in the

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prospectus supplement, however, that we will consolidate with or merge into any entity or transfer or dispose of all or substantially all of our assets to any entity only if:

• immediately after giving effect to the transaction, no default or event of default under either of the Indentures would have occurred and be continuing or would result from the transaction;

• we are the continuing corporation or, if we are not the continuing corporation, the resulting entity is organized and existing under the laws of any United States jurisdiction and assumes the due and punctual payments on the debt securities and the performance of our covenants and obligations under the Indenture and those debt securities; and

• we provide the trustee with a certificate and a legal opinion, each stating that the applicable Indenture permits the transaction.

Under the senior indenture, if we engage in any of these transactions that result in any Principal Property or shares of stock or debt of any Restricted Subsidiary becoming subject to any Lien and unless we are otherwise able to create that Lien, the senior debt securities (so long as those senior debt securities are entitled to the protection of the “Limitation on Liens” covenant) will be secured to at least the same extent as the debt that would become secured by the Lien as a result of the transaction.

Events of Default

Unless we inform you otherwise in the prospectus supplement, the following are events of default for a series of debt securities:

• our failure to pay interest on that series of debt securities for 30 days after it becomes due and payable;

• our failure to pay principal of or any premium on that series of debt securities when due;

• our failure to comply with any of our covenants or agreements for that series of debt securities or in the applicable Indenture (other than an agreement or covenant that we have included in such Indenture solely for the benefit of less than all series of debt securities) for 60 days after the trustee or the holders of at least 25% in principal amount of all outstanding debt securities affected by that failure provide written notice to us;

• the default under any agreement under which we have or any Restricted Subsidiary has at the time outstanding debt in excess of $100,000,000 and, if that debt has not already matured, it has been accelerated and the acceleration is not rescinded within 30 days after we receive notice from the trustee or the holders of at least 25% in principal amount of all outstanding debt securities of a series so long as, prior to the entry of judgment in favor of the trustee for payment of the debt securities of that series, we do not cure the default, or the default under the agreement has not been waived;

• various events involving our bankruptcy, insolvency or reorganization; or

• any other event of default provided for that series of debt securities.

A default under one series of debt securities will not necessarily be a default under another series. The trustee may withhold notice to the holders of a series of debt securities of any default or event of default (except in any payment on that series of debt securities) if the trustee considers it in the interest of the holders of that series of debt securities to do so.

If an event of default for any series of debt securities occurs and is continuing, the trustee or the holders of at least 25% in principal amount of the outstanding debt securities of the series affected by the default (or, in some cases, 25% in principal amount of all debt securities affected, voting as one class) may require us to pay on an accelerated basis the principal of and all accrued and unpaid interest on those debt securities. The holders of a majority in principal amount of the outstanding debt securities of the series affected by the default (or of all debt securities affected, voting as one class) may in some cases rescind this accelerated payment requirement.

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If an event of default occurs and is continuing, the trustee must use the degree of care and skill of a prudent man in the conduct of his own affairs. The trustee will become obligated to exercise any of its powers under the applicable Indenture at the request of any of the holders of any debt securities only after those holders have offered the trustee indemnity reasonably satisfactory to it.

The holders of a majority in principal amount of debt securities of any series have the right to waive past defaults under the applicable Indenture that relate to that series except for a default in the payment on the debt securities or a provision that can only, under the applicable Indenture, be modified or amended if all holders that are affected consent.

In most cases, holders of a majority in principal amount of the outstanding debt securities of a series (or of all debt securities affected, voting as one class) may direct the time, method and place of:

• conducting any proceeding for any remedy available to the trustee; and

• exercising any trust or power conferred on the trustee.

The Indentures require us to file each year with the trustee a written statement as to our compliance with the covenants contained in the Indentures.

Modification and Waiver

We and each guarantor (if any) may amend or supplement either of the Indentures if the holders of a majority in principal amount of the outstanding debt securities of all series that the amendment or supplement affects (acting as one class) consent to it. Without the consent of the holder of each debt security affected, however, no modification may:

• reduce the principal of the debt security or change its stated maturity;

• reduce the rate of or change the time for payment of interest on the debt security;

• reduce any premium payable on the redemption of the debt security or change the time at which the debt security may or must be redeemed;

• change any obligation to pay additional amounts on the debt security;

• impair the holder’s right to institute suit for the enforcement of any payment on the debt security;

• impair the holder’s right to convert or exchange any debt security;

• reduce the percentage of principal amount of debt securities whose holders must consent to an amendment to or supplement of the applicable Indenture;

• reduce the percentage of principal amount of debt securities necessary to waive compliance with some of the provisions of the applicable Indenture; or

• modify provisions relating to amendment or waiver, except to increase percentages or to provide that other provisions of the applicable Indenture cannot be amended or waived without the consent of each holder affected.

We and each guarantor (if any) may amend or supplement either of the Indentures or waive any provision of such Indenture without the consent of any holders of debt securities in various circumstances, including:

• to provide for the assumption of our obligations under the applicable Indenture and the debt securities by a successor;

• to add covenants that would benefit the holders of any debt securities or to surrender any of our rights or powers;

• to provide for the issuance of additional securities, including debt securities of a particular series, under the applicable Indenture;

• to add events of default;

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• to provide any security for or guarantees of any series of debt securities;

• to provide for the form or terms of any series of debt securities;

• to appoint a successor trustee or to provide for the administration of the trusts under the applicable Indenture by more than one trustee;

• to cure any ambiguity, omission, defect or inconsistency that does not adversely affect the interests of the holders of outstanding debt securities of any series;

• to make any change to the extent necessary to permit or facilitate defeasance or discharge of any series of debt securities that does not adversely affect the interests of the holders of outstanding debt securities of any series;

• to convey, transfer, assign, mortgage or pledge any property to or with the trustee;

• to permit the qualification of the applicable Indenture under the Trust Indenture Act;

• to change or eliminate any restriction on the payment of principal of, or premium, if any, on, any debt securities;

• to add to, change or eliminate any of the provisions of the applicable Indenture in respect of one or more series of debt securities; provided, however, that any such addition, change or elimination not otherwise permitted shall neither apply to any debt security of any series created prior to the execution of such supplemental indenture and entitled to the benefit of such provision nor modify the rights of the holder of any such debt security with respect to such provision or shall become effective only when there is no such debt security outstanding;

• reflect the release of any guarantor of its obligations under the guarantee, in the manner provided by the indenture; or

• to make any change that does not affect the rights of any holder.

The holders of a majority in principal amount of the outstanding debt securities under either Indenture may waive our obligations to comply with various covenants, including those relating to:

• our obligation to secure the debt securities in the event of mergers, consolidations and sales of assets;

• corporate existence;

• with respect to the senior debt securities, the restrictions on Liens and Sale/Leaseback Transactions; and

• defeasance.

When we use the term defeasance, we mean discharge from some or all of our obligations under either Indenture. If we deposit with the trustee funds or government securities the maturing principal and interest of which is sufficient to make payments on the debt securities of a series on the dates those payments are due and payable, then, at our option, either of the following will occur:

• “legal defeasance,” which means that we and each guarantor (if any) will be discharged from our obligations with respect to the debt securities of that series; or

• “covenant defeasance,” which means that we will no longer have any obligation to comply with the restrictive covenants under the applicable Indenture and any other restrictive covenants that apply to that series of the debt securities, and the related events of default will no longer apply to us.

If we defease a series of debt securities, the holders of the debt securities of the series affected will not be entitled to the benefits of the applicable Indenture, to provide temporary debt securities, to register the transfer or exchange of debt securities, to replace stolen, lost or mutilated debt securities or to maintain paying agencies and hold money for payment in trust. In the case of covenant defeasance, our obligation to pay principal, premium and interest on the debt securities will also survive.

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Unless we inform you otherwise in the prospectus supplement, we will be required to deliver to the trustee an opinion of counsel that the deposit and related defeasance would not cause the holders of the debt securities to recognize income, gain or loss for federal income tax purposes. If we elect legal defeasance, that opinion of counsel must be based upon a ruling from the Internal Revenue Service or a change in law to that effect.

Subordination Provisions for Subordinated Debt Securities

Any subordinated debt securities issued under the subordinated indenture will be subordinate and subject in right of payment to the prior payment in full of all of our Senior Indebtedness. The following provisions will apply to the subordinated debt securities unless otherwise specified in the prospectus supplement:

Subject to any collateral, security, assurance or guarantee provided for the benefit of any series of subordinated debt securities, if any, the payment of principal, any premium and interest on the subordinated debt securities will be subordinated in right of payment to the prior payment in full of all of our Senior Indebtedness. This means that in certain circumstances where we may not be making payments on all of our debt obligations as they become due, the holders of all of our Senior Indebtedness will be entitled to receive payment in full of all amounts that are due or will become due on the Senior Indebtedness before the holders of subordinated debt securities will be entitled to receive any payment or distribution (other than in the form of subordinated securities) on the subordinated debt securities. These circumstances include the following circumstances:

• we make a payment or distribute assets to creditors upon any liquidation, dissolution, winding up or reorganization of our company, or as part of an assignment or marshalling of our assets for the benefit of our creditors;

• we file for bankruptcy or certain other events in bankruptcy, insolvency or similar proceedings occur; and

• the maturity of the subordinated debt securities is accelerated. For example, the entire principal amount of a series of subordinated debt securities may be declared to be due and immediately payable or may be automatically accelerated due to an event of default as described under “—Events of Default.”

In addition, we are generally not permitted to make payments of principal, any premium or interest on the subordinated debt securities if we default on our obligation to make payments on our Senior Indebtedness and do not cure such default. We are also prohibited from making payments on subordinated debt securities if an event of default (other than a payment default) that permits the holders of senior indebtedness to accelerate the maturity of the Senior Indebtedness occurs and we and the trustee have received a notice of such event of default. However, unless the senior indebtedness has been accelerated because of that event of default, this payment blockage upon notice cannot last more than 179 days.

These subordination provisions mean that if we are insolvent a holder of Senior Indebtedness is likely to ultimately receive out of our assets more than a holder of the same amount of our subordinated debt securities, and a creditor of ours that is owed a specific amount but who owns neither our Senior Indebtedness nor our subordinated debt securities may ultimately receive less than a holder of the same amount of Senior Indebtedness and more than a holder of subordinated debt securities.

The subordinated indenture does not limit the amount of senior indebtedness we are permitted to have and we may in the future incur additional senior indebtedness.

“Senior Indebtedness” is defined in the subordinated indenture to mean, with respect to us,

(i) the principal, premium, if any, and interest (including interest, whether or not allowable, accruing after the filing of a petition initiating any proceeding under any state, federal or foreign bankruptcy law) in respect of (A) our indebtedness and obligations related thereto and (B) indebtedness evidenced by securities, debentures, notes, bonds or other similar instruments issued by us;

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(ii) all our finance lease, purchase money and similar obligations;

(iii) all our obligations issued or assumed as the deferred purchase price of property, all our conditional sale obligations and all our obligations under any title retention agreement;

(iv) all our obligations for the reimbursement of any letter of credit, any banker’s acceptance, any security purchase facility, any repurchase agreement or similar arrangement, any commercial paper, any interest rate swap, any other hedging arrangement, or any obligation under options or any similar credit or other transaction;

(v) all obligations for indemnification, contributions, earnouts, adjustments of purchase price or similar obligations;

(vi) all obligations in respect of workers compensation claims, self-insurance, indemnities, bid performance, warranty release, appeal, surety and similar bonds;

(vii) all obligations of the type referred to in clauses (i) through (vi) above of other Persons for the payment of which we are responsible or liable as obligor, guarantor or otherwise;

(viii) all obligations of the type referred to in clauses (i) through (vii) above of other Persons secured by any lien on any property or asset of ours (whether or not such obligation is assumed by us); and

(ix) all renewals, extensions, modifications and refunding of obligations of the type referred to in clauses (i) through (viii) above; whether incurred on or prior to the date of the subordinated indenture or thereafter incurred. Notwithstanding the foregoing, “Senior Indebtedness” shall not include (1) any Additional Junior Indebtedness, (2) debt securities issued pursuant to the subordinated indenture and guarantees in respect of such debt securities, (3) our trade accounts payable arising in the ordinary course of business (such trade accounts payable being pari passu in right of payment to debt securities issued pursuant to the subordinated indenture), or (4) obligations with respect to which in the instrument creating or evidencing the same or pursuant to which the same is outstanding, it is provided that such obligations are pari passu or junior in right of payment to debt securities issued pursuant to the subordinated indenture. Senior Indebtedness shall continue to be Senior Indebtedness and be entitled to the subordination provisions irrespective of any amendment, modification or waiver of any term of such Senior Indebtedness.

“Additional Junior Indebtedness” is defined in the subordinated indenture to mean, without duplication and other than the subordinated debt securities, any indebtedness, liabilities, guarantees or obligations of ours or any of our subsidiaries, under debt securities (or guarantees in respect of debt securities or preferred securities) initially issued after the date of the subordinated indenture to any trust, or a trustee of a trust, partnership or other entity affiliated with us that is, directly or indirectly, a finance subsidiary (as such term is defined in Rule 3a-5 under the Investment Company Act of 1940) or other financing vehicle of ours or any subsidiary of ours in connection with the issuance by that entity of preferred securities or other securities that are issued on a pari passu basis with the subordinated debt securities.

If this prospectus is being delivered in connection with a series of subordinated securities, the accompanying prospectus supplement or the information incorporated by reference will set forth the approximate amount of senior indebtedness outstanding as of a recent date.

Guarantee

To the extent provided in a prospectus supplement and either a supplemental indenture or a resolution of our board of directors, in each case, relating to a particular series of debt securities, each of our subsidiaries that becomes a guarantor of the debt securities of such series, and any of our subsidiaries that is a successor thereto, will fully, irrevocably, unconditionally and absolutely guarantee the due and punctual payment of the principal of, and premium, if any, and interest on such debt securities, and all other amounts due and payable under the

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applicable indenture and such debt securities by us to the trustee or the holders of such debt securities, however, such guarantors will not otherwise be subject to the covenants, obligations and duties provided for in the indenture solely in their capacity as guarantors.

Satisfaction and Discharge

The Indentures will cease to be of further effect and will be deemed to have been satisfied and discharged with respect to a particular series of debt securities, when the following conditions have been satisfied:

• all debt securities of that series have been delivered to the trustee for cancellation, or all debt securities of that series not previously delivered to the trustee for cancellation have become due and payable or will become due and payable at their stated maturity or on a redemption date within one year, and we:

• irrevocably deposit with the trustee, in trust, funds sufficient to pay and discharge the entire indebtedness on the senior debt securities of that series that had not been previously delivered for cancellation, for principal (and premium, if any) and interest, if any, to the date of the deposit (for debt securities that have become due and payable) or to the stated maturity or the redemption date, as the case may be;

• have paid or caused to be paid all other sums payable under the applicable Indenture or have made arrangements for any such payments satisfactory to the payee; and

• have delivered to the trustee an officer’s certificate and opinion of counsel, each stating that all these conditions precedent provided for satisfaction and discharge of the Indenture have been complied with.

Governing Law

New York law governs the Indentures and the debt securities.

Trustee

U.S. Bank National Association is trustee under the Indentures. The Indentures contain limitations on the right of the trustee, if it becomes one of our creditors, to obtain payment of claims or to realize payment on property received for those claims, as security or otherwise. The trustee is permitted to engage in other transactions with us in the ordinary course of business. If, however, it acquires any conflicting interest, it must eliminate that conflict or resign.

Form, Exchange, Registration and Transfer

We will issue the debt securities in registered form, without interest coupons. We will not charge a service charge for any registration of transfer or exchange of the debt securities. We may, however, require the payment of any tax or other governmental charge payable for that registration.

Holders may exchange debt securities of any series for other debt securities of the same series, the same total principal amount and the same terms but in different authorized denominations in accordance with the applicable Indenture. Holders may present debt securities for registration of transfer at the office of the security registrar or any transfer agent we designate. The security registrar or transfer agent will effect the transfer or exchange when it is satisfied with the documents of title and identity of the person making the request.

We have appointed the trustee as security registrar for the debt securities. If a prospectus supplement refers to any transfer agent initially designated by us, we may at any time rescind that designation or approve a change in the location through which any transfer agent acts. We are required to maintain an office or agency for transfers and exchanges in each place of payment. We may at any time designate additional transfer agents for any series of debt securities.

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In the case of any redemption, neither the security registrar nor the transfer agent will be required to register the transfer or exchange of any debt security either:

• during a period beginning 15 business days prior to the mailing of the relevant notice of redemption and ending on the close of business on the day of mailing of that notice; or

• if we have called the debt security for redemption in whole or in part, except the unredeemed portion of any debt security being redeemed in part.

Payment and Paying Agents

Unless we inform you otherwise in a prospectus supplement, payments on the debt securities will be made in U.S. dollars at the office of the trustee. At our option, however, we may make payments by check mailed to the holder’s registered address or, for global debt securities, by wire transfer. Unless we inform you otherwise in a prospectus supplement, we will make interest payments to the person in whose name the debt security is registered at the close of business on the record date for the interest payment.

Unless we inform you otherwise in a prospectus supplement, we have designated the trustee as our paying agent for payments on debt securities issued under the Indentures. We may at any time designate additional paying agents or rescind the designation of any paying agent or approve a change in the office through which any paying agent acts.

Subject to the requirements of any applicable abandoned property laws, the trustee and paying agent will pay to us upon written request any money they are holding for payments on the debt securities that remain unclaimed for two years after the date upon which that payment has become due. After payment to us, holders entitled to the money must look to us for payment. In that case, all liability of the trustee or paying agent with respect to that money will cease.

Book-Entry Debt Securities

We may issue the debt securities of a series in the form of one or more global debt securities that would be deposited with a depositary or its nominee identified in the prospectus supplement. We may issue global debt securities in either temporary or permanent form. We will describe in the prospectus supplement the terms of any depositary arrangement and the rights and limitations of owners of beneficial interests in any global debt security.

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DESCRIPTION OF GUARANTEE OF DEBT SECURITIES

To the extent provided in a prospectus supplement and either an indenture supplement or a resolution of our board of directors, in each case, relating to a particular series of debt securities, each of our subsidiaries that becomes a guarantor of the debt securities of such series, and any of our subsidiaries that is a successor thereto, will fully, irrevocably, unconditionally and absolutely guarantee the due and punctual payment of the principal of, and premium, if any, and interest on such debt securities, and all other amounts due and payable under the applicable indenture and such debt securities by us to the trustee or the holders of such debt securities, and any provisions permitting a release of such guarantee will be included in such prospectus supplement and indenture supplement or resolution, however, such guarantors will not otherwise be subject to the covenants, obligations and duties provided for in the indenture solely in their capacity as guarantors.

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DESCRIPTION OF CAPITAL STOCK

General

We are authorized to issue a total of 1,300,000,000 shares of all classes of capital stock. Of those authorized shares, 1,200,000,000 are shares of common stock, 444,011,317 shares of which were outstanding as of June 18, 2020, and 100,000,000 are shares of preferred stock. Of the authorized preferred stock, there are 20,000,000 shares designated as Convertible Preferred Stock, Series A (none of which was outstanding on June 18, 2020), 30,000,000 shares designated as Convertible Preferred Stock, Series B (none of which was outstanding on June 18, 2020), 1,000,000 shares designated as Series C Participating Preferred Stock (none of which was outstanding on June 18, 2020), and 20,000 shares designated as Series E Non-Voting Perpetual Preferred Stock (all of which were outstanding on June 18, 2020).

The additional shares of our authorized stock available for issuance might be issued at times and under circumstances so as to have a dilutive effect on earnings per share and on the equity ownership of the holders of our common stock. The ability of our board of directors to issue additional shares of stock could enhance the board’s ability to negotiate on behalf of the shareholders in a takeover situation but could also be used by the board to make a change-in-control more difficult, thereby denying shareholders the potential to sell their shares at a premium and entrenching current management.

The following description is a summary of the material provisions of our capital stock and various provisions of our certificate of incorporation and bylaws. This summary is not intended to be complete and is qualified by reference to the provisions of applicable law and our certificate of incorporation and bylaws included as exhibits to the registration statement of which this prospectus is a part.

Common Stock

As of June 18, 2020, there were 14,095 holders of record. The issued and outstanding shares of common stock are validly issued, fully paid and non-assessable. Subject to any preferential rights of any prior ranking class or series of capital stock, including the preferred stock, holders of our common stock are entitled to receive dividends on that stock, payable either in cash, property or shares out of assets legally available for distribution when, as and if authorized and declared by our board of directors and to share ratably in our assets legally available for distribution to our shareholders in the event of liquidation, dissolution or winding-up. Subject to various exceptions, we will not be able to pay any dividend or make any distribution of assets on shares of our common stock until we pay dividends on any shares of preferred stock then outstanding with dividend or distribution rights senior to our common stock.

Holders of our common stock are entitled to one vote per share on all matters voted on by our shareholders, including the election of directors. Our certificate of incorporation does not provide for cumulative voting for the election of directors, which means that holders of more than one-half of the outstanding shares of our voting securities will be able to elect all of the directors then standing for election and holders of the remaining shares will not be able to elect any director.

Our board of directors may make rules and regulations concerning the transfer of shares of our common stock from time to time, in accordance with our bylaws.

Holders of our common stock will have no conversion, sinking fund or redemption rights.

Some provisions of the Oklahoma General Corporation Act, our certificate of incorporation and our bylaws may discriminate against holders of a substantial amount of the shares of our common stock. See “—Oklahoma Law” and “—Certificate of Incorporation and Bylaws.” Similarly, some provisions of our certificate of incorporation and our bylaws may have the effect of delaying, deferring or preventing a change-in-control with

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respect to an extraordinary corporate transaction, such as a merger, reorganization, tender offer, sale or transfer of substantially all of our assets.

Preferred Stock

Our board of directors is authorized to issue shares of preferred stock, in one or more series or classes, and to fix for each series or class the preferences, conversion or other rights, voting powers, restrictions, limitations as to dividends, qualifications, or terms or redemption, as are permitted by Oklahoma law and as are stated in the resolution or resolutions adopted by the board providing for the issuance of shares of that series or class.

Our board has authorized series designated as Convertible Preferred Stock, Series A and Convertible Preferred Stock, Series B. Our board has also authorized a series designated as Series C Participating Preferred Stock, which relates to our Second Amended and Restated Rights Agreement. No shares of Series C Participating Preferred Stock were issued, and the Second Amended and Restated Rights Agreement expired February 4, 2013, and was not renewed. Our board has further authorized a series of preferred stock designated as Series E Non-Voting Perpetual Preferred Stock, which pays quarterly dividends on each share, when, as and if declared by our board, at a rate of 5.5% per year. In April 2017, through a wholly owned subsidiary, we issued and contributed 20,000 shares of Series E Preferred Stock to ONEOK Foundation, Inc. for use in future charitable and nonprofit causes. No other shares of Series E Non-Voting Perpetual Preferred Stock have been issued.

When we offer to sell a particular series of preferred stock, we will describe the specific terms of the securities in a supplement to this prospectus. The prospectus supplement will also indicate whether the terms and provisions described in this prospectus apply to the particular series of preferred stock. The preferred stock will be issued under a certificate of designations relating to each series of preferred stock. The issuance of our preferred stock is also subject to our certificate of incorporation.

Preemptive Rights

No holder of any shares of any class of our stock has any preemptive or preferential right to acquire or subscribe for any unissued shares of any class of stock or any unauthorized securities, convertible into or carrying any right, option or warrant to subscribe for or acquire shares of any class of stock.

Oklahoma Law

Oklahoma Takeover Statute

We are subject to Section 1090.3 of the Oklahoma General Corporation Act. In general, Section 1090.3 prevents an “interested shareholder” from engaging in a “business combination” with an Oklahoma corporation for three years following the date that person became an interested shareholder, unless:

• prior to the date that person became an interested shareholder, the corporation’s board of directors approved the business combination or the transaction in which the interested shareholder became an interested shareholder;

• upon consummation of the transaction that resulted in the interested shareholder becoming an interested shareholder, the interested shareholder owned at least 85% of the corporation’s voting stock outstanding at the time the transaction commenced, excluding stock held by directors who are also officers of the corporation and stock held by certain employee stock plans; or

• on or subsequent to the date of the transaction in which that person became an interested shareholder, the business combination was approved by the corporation’s board of directors and authorized at a meeting of shareholders by the affirmative vote of the holders of at least two-thirds of the outstanding voting stock of the corporation not owned by the interested shareholder.

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Section 1090.3 defines a “business combination” to include:

• any merger or consolidation involving the corporation and an interested shareholder;

• any sale, transfer, pledge or other disposition of 10% or more of the assets of the corporation involving an interested shareholder;

• subject to limited exceptions, any transaction that results in the issuance or transfer by the corporation of the stock of the corporation to an interested shareholder;

• any transaction involving the corporation that has the effect of increasing the proportionate share of the stock of any class or series of the corporation beneficially owned by the interested shareholder; or

• the receipt by an interested shareholder of any loans, guarantees, pledges or other financial benefits provided by or through the corporation.

For purposes of the description above and Section 1090.3, the term “corporation” also includes a corporation’s majority-owned subsidiaries. In addition, Section 1090.3, defines an “interested shareholder” as an entity or person beneficially owning 15% or more of a corporation’s outstanding voting stock and any entity or person affiliated with or controlling or controlled by that entity or person.

Oklahoma Control Share Provisions

Our certificate of incorporation provides that we are not subject to the control share provisions of the Oklahoma General Corporation Act. With exceptions, these provisions prevent holders of more than 20% of the voting power of the stock of an Oklahoma corporation from voting their shares. If we were to become subject to the control share provisions of the Oklahoma General Corporation Act in the future, this provision may delay the time it takes anyone to gain control of us.

Certificate of Incorporation and Bylaws

Exculpation

Our certificate of incorporation provides that our directors and officers will not be personally liable for monetary damages for any action taken, or any failure to take any action, unless:

• the director or officer has breached his or her duty of loyalty to ONEOK or its shareholders;

• the breach or failure to perform constitutes an act or omission not in good faith or which involves intentional misconduct or a knowing violation of law;

• the director served at the time of payment of an unlawful dividend or an unlawful stock purchase or redemption, unless the director was absent at the time the action was taken or dissented from the action; or

• the director or officer derived an improper personal benefit from the transaction.

Indemnification

We will generally indemnify any person who was, is, or is threatened to be made, a party to a proceeding by reason of the fact that he or she:

• is or was our director, officer, employee or agent; or

• is or was serving at our request as a director, officer, employee or agent of another corporation, partnership, limited liability company, joint venture, trust or other enterprise or as a member of any committee or similar body.

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Any indemnification of our directors, officers or others pursuant to the foregoing provisions for liabilities arising under the Securities Act are, in the opinion of the SEC, against public policy as expressed in the Securities Act and are unenforceable.

Shareholder Action; Special Meeting of Shareholders

Our certificate of incorporation eliminates the ability of our shareholders to act by written consent. Our bylaws provide that special meetings of our shareholders may be called only by a majority of the members of our board of directors.

Advance Notice Requirements for Shareholder Proposals

At any annual meeting of our shareholders, the only business that shall be brought before the meeting is that which is brought:

• pursuant to our notice of meeting;

• by or at the discretion of our board of directors; or

• by any of our shareholders of record at the time the notice is given, who are entitled to vote at the meeting and who comply with the notice procedures set forth in our bylaws as summarized below.

For business to be properly brought before an annual meeting by a shareholder pursuant to the immediately preceding clause, the shareholder must have given timely notice in writing to our secretary. To be timely as to an annual meeting of shareholders, a shareholder’s notice must be received at our principal executive offices not less than 120 calendar days or more than 150 calendar days before the date our proxy statement is released to shareholders in connection with the previous year’s annual meeting; provided however, that if the date of the meeting is changed by more than 30 days from the date of the previous year’s meeting, notice must be received no later than the close of business on the 10th day following the earlier of the day on which notice of the date of the meeting was mailed to shareholders or public disclosure of that date was made. The shareholder notice shall set forth as to each matter the shareholder proposes to bring before the meeting:

• a brief description of and the reasons for proposing the matter at the meeting;

• with respect to the shareholder giving notice and the beneficial owner, if any, on whose behalf the proposal is being made:

• the name and address of such person;

• the class or series and number of shares of ONEOK which are owned beneficially and of record by such person and any affiliates or associates of such person;

• the name of each nominee holder of shares of all stock of ONEOK owned beneficially but not of record by such person or any affiliates or associates of such person, and the number of such shares of stock of ONEOK held by each such nominee holder;

• whether and the extent to which any derivative instrument, swap, option, warrant, short interest, hedge or profit interest or other transaction has been entered into by or on behalf of such person, or any affiliates or associates of such person, with respect to stock of ONEOK; and

• whether and the extent to which any other transaction, agreement, arrangement or understanding (including any short position or any borrowing or lending of shares of stock of ONEOK) has been made by or on behalf of such person, or any affiliates or associates of such person, the effect or intent of any of the foregoing being to mitigate loss to, or to manage risk or benefit of stock price changes for, such person, or any affiliates or associates of such person, or to increase or decrease the voting power or pecuniary or economic interest of such person, or any affiliates or associates of such person, with respect to stock of ONEOK;

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• a representation that the shareholder giving notice intends to appear in person or by proxy at the annual meeting to bring such business before the meeting;

• any material interest of the shareholder of record, the beneficial owner, if any, on whose behalf the proposal is made, or any affiliate or associate of any of the foregoing, in the proposal;

• a description of all agreements, arrangements and understandings between the shareholder, the beneficial owner, if any, on whose behalf the proposal is made or any affiliate or associate of any of the foregoing, and any other person or persons (including their names) in connection with the proposal of the business by the shareholder; and

• all other information that would be required to be disclosed by such person as a participant in a solicitation of proxies for the election of directors in a contested election, or would be otherwise required to be disclosed in connection with such solicitation, in each case pursuant to Regulation 14A under the Securities Exchange Act of 1934, as amended.

These provisions may impede shareholders’ ability to bring matters before an annual meeting of shareholders.

Higher Vote for Some Business Combinations and Other Actions

Subject to various exceptions, including acquiring 85% of the outstanding shares less shares owned by related persons in a single transaction, a business combination (including, but not limited to, a merger or consolidation, the sale, lease, exchange, mortgage, pledge, transfer or other disposition of our assets in excess of $5,000,000, various issuances and reclassifications of securities and the adoption of a plan or proposal for liquidation or dissolution) with or upon a proposal by a related person, who is a person that is the direct or indirect beneficial owner of more than 10% of the outstanding voting shares of our stock (subject to various exceptions), and any affiliates of that person, shall require, in addition to any approvals required by law, the approval of the business combination by either:

• a majority vote of all of the independent directors; or

• the holders of at least 66-2/3% of the outstanding shares otherwise entitled to vote as a single class with the common stock to approve the business combination, excluding any shares owned by the related person.

In addition, our certificate of incorporation provides that our bylaws may only be adopted, amended or repealed by a majority of the board of directors or by 80% of our shareholders, voting as a class. Our certificate of incorporation also requires the affirmative vote of 80% of our shareholders to amend, repeal or adopt provisions in our certificate of incorporation relating to, among other things,

• the number of directors and the manner of electing those directors, including the election of directors to newly created directorships;

• provisions relating to changes in the bylaws;

• a director’s personal liability to us or our shareholders;

• shareholder ratification of various contracts, transactions and acts; and

• voting requirements for approval of business combinations.

Transactions with Interested Parties

Our certificate of incorporation provides that, in the absence of fraud, no contract or other transaction will be affected or invalidated by the fact that any of our directors are in any way interested in or connected with any other party to the contract or transaction or are themselves parties to the contract or transaction, provided that the

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interest is fully disclosed or otherwise known to our board of directors at the meeting of the board at which the contract or transaction is authorized or confirmed, and provided further that a quorum of disinterested directors is present at the meeting of our board of directors authorizing or confirming the contract or transaction and the contract or transaction is approved by a majority of the quorum, and no interested director votes on the contract or transaction. Any contract, transaction or act entered into or taken by us or our board or any committee thereof that is ratified by a majority of a quorum of the shareholders having voting power at any annual meeting, or any special meeting called for that purpose, will be valid and binding as though ratified by all of our shareholders. Any director may vote upon any contract or other transaction between us and any subsidiary corporation without regard to the fact that he is also a director of that subsidiary corporation. No contract or agreement between us and any other corporation or party that owns a majority of our capital stock or any subsidiary of that other corporation shall be made or entered into without the affirmative vote of a majority of the whole board of directors at a regular meeting of the board.

Transfer Agent and Registrar

The current transfer agent and registrar for our common stock is Equiniti Trust Company.

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DESCRIPTION OF STOCK PURCHASE CONTRACTS

AND STOCK PURCHASE CONTRACT UNITS

We may issue stock purchase contracts for the purchase of our securities or securities of an entity unaffiliated or affiliated with us, a basket of such securities or any combination of the above as specified in the applicable prospectus supplement. Each stock purchase contract will entitle the holder thereof to purchase, and obligate us to sell, on specified dates, such securities, at a specified purchase price, all as set forth in the applicable prospectus supplement. The applicable prospectus supplement will also specify the methods by which the holders may purchase such securities, any acceleration, cancellation or termination provisions or other provisions relating to the settlement of a stock purchase contract and, if applicable, the identity of any of our subsidiaries guaranteeing our obligations with respect to such stock purchase contracts. Stock purchase contracts may require holders to satisfy their obligations thereunder when the stock purchase contracts are issued. Our obligation to settle such prepaid stock purchase contracts on the relevant settlement date may constitute indebtedness. Accordingly, the prepaid stock purchase contracts will be issued under one of the Indentures. The stock purchase contracts may be issued separately or as part of a stock purchase contract unit that consists of (a) a stock purchase contract and (b) senior or subordinated debt securities, or preferred stock, U.S. Treasury securities or other debt obligations of third parties, that may be used to secure the holders’ obligations under a stock purchase contract. The stock purchase contracts may require us to make periodic payments to the holders of the stock purchase contract units, and such payments may be unsecured or prefunded on some basis. The stock purchase contracts may require holders to secure their obligations in a specified manner and, in certain circumstances, we may deliver newly issued prepaid stock purchase contracts upon release to a holder of any collateral securing such holder’s obligations under the original stock purchase contract.

The applicable prospectus supplement will describe the general terms of any stock purchase contracts or stock purchase contract units and, if applicable, prepaid stock purchase contracts. The description in the prospectus supplement will not purport to be complete and will be qualified in its entirety by reference to (a) the stock purchase contracts, (b) the collateral arrangements and depository arrangements, if applicable, relating to such stock purchase contracts or stock purchase contract units and (c) if applicable, the prepaid stock purchase contracts and the documents pursuant to which such prepaid stock purchase contracts will be issued. Some of the material United States federal income tax considerations applicable to the stock purchase contracts and the stock purchase contract units will also be discussed in the applicable prospectus supplement.

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DESCRIPTION OF DEPOSITARY SHARES

General

We may, at our option, elect to offer fractional shares of preferred stock, rather than full shares of preferred stock. If we exercise this option, we will issue to the public receipts for depositary shares, and each of these depositary shares will represent a fraction (to be set forth in the applicable prospectus supplement) of a share of a particular series of preferred stock.

The shares of any series of preferred stock underlying the depositary shares will be deposited under a deposit agreement between us and a bank or trust company selected by us. The depositary will have its principal office in the United States and a combined capital of at least $50,000,000. Subject to the terms of the deposit agreement, each owner of a depositary share will be entitled, in proportion, to the applicable fraction of a share of preferred stock underlying that depositary share, to all the rights and preferences of the preferred stock underlying that depositary share. Those rights (to be set forth in the applicable prospectus supplement) include dividend, voting, redemption and liquidation rights.

The depositary shares will be evidenced by depositary receipts issued pursuant to the deposit agreement. Depositary receipts will be distributed to those persons purchasing the fractional shares of preferred stock underlying the depositary shares, in accordance with the terms of the offering. Copies of the forms of deposit agreement and depositary receipt will be filed as exhibits to the registration statement. The following summary of the deposit agreement, the depositary shares and the depositary receipts is not complete. You should refer to the forms of the deposit agreement and depositary receipts that will be filed with the SEC in connection with the offering of the specific depositary shares.

Pending the preparation of definitive engraved depositary receipts, the depositary may, upon our written order, issue temporary depositary receipts substantially identical to the definitive depositary receipts but not in definitive form. These temporary depositary receipts entitle their holders to all the rights of definitive depositary receipts which are to be prepared without unreasonable delay. Temporary depositary receipts will then be exchangeable for definitive depositary receipts at our expense.

Dividends and Other Distributions

The depositary will distribute all cash dividends or other cash distributions received with respect to the preferred stock to the record holders of depositary shares relating to the preferred stock in proportion to the number of depositary shares owned by those holders.

If there is a distribution other than in cash, the depositary will distribute property received by it to the record holders of depositary shares that are entitled to receive the distribution, unless the depositary determines that it is not feasible to make the distribution. If this occurs, the depositary may, with our approval, sell the property and distribute the net proceeds from the sale to the applicable holders.

Redemption of Depositary Shares

If a series of preferred stock represented by depositary shares is subject to redemption, the depositary shares will be redeemed from the proceeds received by the depositary resulting from the redemption, in whole or in part, of that series of preferred stock held by the depositary. The redemption price per depositary share will be equal to the applicable redemption fraction of the redemption price per share payable with respect to that series of the preferred stock. Whenever we redeem shares of preferred stock that are held by the depositary, the depositary will redeem, as of the same redemption date, the number of depositary shares representing the shares of preferred stock so redeemed. If fewer than all the depositary shares are to be redeemed, the depositary shares to be redeemed will be selected by lot or pro rata as may be determined by the depositary.

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Voting the Preferred Stock

Upon receipt of notice of any meeting at which the holders of the preferred stock are entitled to vote, the depositary will mail the information contained in such notice to the record holders of the depositary shares underlying the preferred stock. Each record holder of the depositary shares on the record date, which will be the same date as the record date for the preferred stock, will be entitled to instruct the depositary as to the exercise of the voting rights pertaining to the amount of the preferred stock represented by the holder’s depositary shares. The depositary will then try, as far as practicable, to vote the number of shares of preferred stock underlying those depositary shares in accordance with such instructions. We will agree to take all actions which may be deemed necessary by the depositary to enable the depositary to do so. The depositary will not vote the shares of preferred stock to the extent it does not receive specific instructions from the holders of depositary shares underlying the preferred stock.

Amendment and Termination of the Depositary Agreement

The form of depositary receipt evidencing the depositary shares and any provision of the deposit agreement may at any time be amended by agreement between us and the depositary. However, any amendment which materially and adversely alters the rights of the holders of depositary shares will not be effective unless the amendment has been approved by the holders of at least a majority of the depositary shares then outstanding. The deposit agreement may be terminated by us or by the depositary only if (a) all outstanding depositary shares have been redeemed or (b) there has been a final distribution of the underlying preferred stock in connection with our liquidation, dissolution or winding up and the preferred stock has been distributed to the holders of depositary receipts.

Charges of Depositary

We will pay all transfer and other taxes and governmental charges arising solely from the existence of the depositary arrangements. We will also pay charges of the depositary in connection with the initial deposit of the preferred stock and any redemption of the preferred stock. Holders of depositary receipts will pay other transfer and other taxes and governmental charges and those other charges, including a fee for the withdrawal of shares of preferred stock upon surrender of depositary receipts, as are expressly provided in the deposit agreement to be for their accounts.

Miscellaneous

The depositary will forward to holders of depositary receipts all reports and communications from us that we deliver to the depositary and that we are required to furnish to the holders of the preferred stock.

Neither we nor the depositary will be liable if either of us is prevented or delayed by law or any circumstance beyond our control in performing our respective obligations under the deposit agreement. Our obligations and those of the depositary will be limited to performance in good faith of our respective duties under the deposit agreement. Neither we nor the depositary will be obligated to prosecute or defend any legal proceeding in respect of any depositary shares or preferred stock unless satisfactory indemnity is furnished. We and the depositary may rely upon written advice of counsel or accountants, or upon information provided by persons presenting preferred stock for deposit, holders of depositary receipts or other persons believed to be competent and on documents believed to be genuine.

Resignation and Removal of Depositary

The depositary may resign at any time by delivering notice to us of its election to resign. We may remove the depositary at any time. Any resignation or removal will take effect upon the appointment of a successor depositary and its acceptance of the appointment. The successor depositary must be appointed within 60 days after delivery of the notice of resignation or removal and must be a bank or trust company having its principal office in the United States and having a combined capital and surplus of at least $50,000,000.

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DESCRIPTION OF WARRANTS

We may issue warrants for the purchase of debt securities, preferred stock, common stock, or units of two or more of these types of securities. Each series of warrants will be issued under a separate warrant agreement to be entered into between us and a bank or trust company, as warrant agent. The warrant agent will act solely as our agent in connection with the warrants and will not assume any obligation or relationship of agency or trust for or with any registered holders of warrants or beneficial owners of warrants.

We will distribute a prospectus supplement with regard to each issue of warrants. Each prospectus supplement will describe:

• in the case of warrants to purchase debt securities, the designation, aggregate principal amount, currencies, denominations and terms of the series of debt securities purchasable upon exercise of the warrants and the price at which you may purchase the debt securities upon exercise;

• in the case of warrants to purchase preferred stock, the designation, number of shares, stated value and terms, such as liquidation, dividend, conversion and voting rights, of the series of preferred stock purchasable upon exercise of the warrants and the price at which you may purchase such number of shares of preferred stock of such series upon such exercise;

• in the case of warrants to purchase common stock, the number of shares of common stock purchasable upon the exercise of the warrants and the price at which you may purchase such number of shares of common stock upon such exercise;

• the period during which you may exercise the warrants;

• any provision adjusting the securities that may be purchased on exercise of the warrants, and the exercise price of the warrants, to prevent dilution or otherwise;

• the place or places where warrants can be presented for exercise or for registration of transfer or exchange; and

• any other material terms of the warrants.

Warrants for the purchase of preferred stock and common stock will be offered and exercisable for U.S. dollars only. Warrants will be issued in registered form only. The exercise price for warrants will be subject to adjustment as described in the applicable prospectus supplement.

Prior to the exercise of any warrants to purchase debt securities, preferred stock or common stock, holders of the warrants will not have any of the rights of holders of the debt securities, preferred stock or common stock purchasable upon exercise, including:

• in the case of warrants for the purchase of debt securities, the right to receive payments of principal of, any premium or interest on the debt securities purchasable upon exercise or to enforce covenants in the applicable indenture; or

• in the case of warrants for the purchase of preferred stock or common stock, the right to vote or to receive any payments of dividends on the preferred stock or common stock purchasable upon exercise.

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PLAN OF DISTRIBUTION

We may sell our securities through agents, underwriters or dealers, or directly to purchasers.

We may designate agents to solicit offers to purchase our securities.

• We will name any agent involved in offering or selling our securities, and any commissions that we will pay to the agent, in our prospectus supplement.

• Unless we indicate otherwise in our prospectus supplement, our agents will act on a best-efforts basis for the period of their appointment.

• Our agents may be deemed to be underwriters under the Securities Act of any of our securities that they offer or sell.

We may use one or more underwriters in the offer or sale of our securities.

• If we use an underwriter, we will execute an underwriting agreement with the underwriter(s) at the time that we reach an agreement for the sale of our securities.

• We will include the names of the managing underwriter(s), as well as any other underwriters, and the terms of the transaction, including the compensation the underwriters and dealers will receive, in our prospectus supplement.

• The underwriter(s) will use our prospectus supplement to sell our securities.

We may use a dealer to sell our securities.

• If we use a dealer, we, as principal, will sell our securities to the dealer.

• The dealer will then sell our securities to the public at varying prices that the dealer will determine at the time it sells our securities.

• We will include the name of the dealer and the terms of our transactions with the dealer in our prospectus supplement.

We may directly solicit offers to purchase our securities, and we may directly sell our securities to institutional or other investors. We will describe the terms of our direct sales in our prospectus supplement.

We may indemnify agents, underwriters and dealers against certain liabilities, including liabilities under the Securities Act.

We may authorize our agents and underwriters to solicit offers by certain institutions to purchase our securities at the public offering price under delayed delivery contracts.

• If we use delayed delivery contracts, we will disclose that we are using them in the prospectus supplement and will tell you when we will demand payment and delivery of the securities under the delayed delivery contracts.

• These delayed delivery contracts will be subject only to the conditions that we set forth in the prospectus supplement.

• We will indicate in our prospectus supplement the commission that underwriters and agents soliciting purchases of our securities under delayed delivery contracts will be entitled to receive.

Underwriters, dealers and agents and their affiliates may engage in transactions with, or perform services for, or be customers of ONEOK and its affiliates in the ordinary course of business.

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Other than our common stock, all securities offered by this prospectus will be a new issue of securities with no established trading market. Any underwriter to whom securities are sold by us for public offering and sale may make a market in such securities, but such underwriters will not be obligated to do so and may discontinue any market making at any time without notice. The securities may or may not be listed on a national securities exchange or a foreign securities exchange, except for the common stock which is currently listed and traded on the New York Stock Exchange. Any common stock sold by this prospectus will be listed for trading on the New York Stock Exchange subject to official notice of issuance. We cannot give you any assurance as to the liquidity of the trading markets for any securities.

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LEGAL MATTERS

The validity of the securities being offered hereby will be passed upon for us by GableGotwals, Tulsa, Oklahoma, except that Latham & Watkins LLP, Houston, Texas, will pass upon such matters to the extent governed by New York law.

EXPERTS

The financial statements and management’s assessment of the effectiveness of internal control over financial reporting (which is included in Management’s Report on Internal Control over Financial Reporting) incorporated in this Prospectus by reference to ONEOK, Inc.’s Annual Report on Form 10-K for the year ended December 31, 2019 have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

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Common Stock

Having an Aggregate Offering Price of Up to

$1,000,000,000

PROSPECTUS SUPPLEMENT

Credit Suisse

BofA Securities

Goldman Sachs & Co. LLC

Mizuho Securities

Morgan Stanley

RBC Capital Markets

Scotiabank

SMBC Nikko

SunTrust Robinson Humphrey

TD Securities

July 23, 2020