Supplemental Prospectus (SEC Filing - 424B5)

Filed Pursuant to Rule 424(b)(5)
Registration No. 333-251074

CALCULATION OF REGISTRATION FEE

PROSPECTUS SUPPLEMENT

(To Prospectus dated December 2, 2020)

Up to $500,000,000

Common Stock

We have entered into a sales agency agreement with BNY Mellon Capital Markets, LLC ('BNYMCM') and J.P. Morgan Securities LLC ('JPM') relating to shares of our common stock, par value $1.00 per share, offered by this prospectus supplement and the accompanying prospectus pursuant to an 'at-the-market' equity offering program. In accordance with the terms of the sales agency agreement, we may offer and sell up to $500,000,000 in shares of our common stock from time to time through BNYMCM and JPM (the 'Agents') as our agents for the offer and sale of the shares. Sales of the shares will be made at market prices prevailing at the time of sale.

Our common stock is listed on the New York Stock Exchange under the symbol 'SWX'. On April 7, 2021, the last reported sales price of our common stock on the New York Stock Exchange was $69.54 per share.

Sales of our common stock, if any, under this prospectus supplement and the accompanying prospectus may be made in sales deemed to be 'at-the-market' equity offerings as defined in Rule 415 promulgated under the Securities Act of 1933, as amended, or the Securities Act, the Agents will use commercially reasonable efforts to sell on our behalf all of the shares of common stock requested to be sold by us, consistent with its normal trading and sales practices, on mutually agreed terms between the Agents and us. There is no arrangement for funds to be received in any escrow, trust or similar arrangement. Please see 'Plan of Distribution' beginning on page S-6.

The Agents will receive from us a commission equal to 1% of the sales price of all shares sold through them as agents under the sales agency agreement. In connection with the sale of our common stock on our behalf, the Agents may be deemed to be 'underwriters' within the meaning of the Securities Act and the compensation of the Agents may be deemed to be underwriting commissions or discounts. Please see 'Plan of Distribution' beginning on page S-6.

Investing in our common stock involves risks. See 'Risk Factors' beginning on page S-3 of this prospectus supplement and Item 1A 'Risk Factors' beginning on page 8 of our Annual Report on Form 10-K for the year ended December 31, 2020, as well as additional risks that may be described in future reports or information that we file with the Securities and Exchange Commission, or the SEC, including our Quarterly Reports on Form 10-Q, for a discussion of certain risks that you should consider in connection with an investment in our common stock.

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

The date of this prospectus supplement is April 8, 2021.

TABLE OF CONTENTS

You should read this prospectus supplement and the accompanying prospectus together with the additional information described under the heading 'Where You Can Find More Information and Incorporation by Reference' in this prospectus supplement. Neither we nor the Agents have authorized anyone to provide you with any information other than that contained in this prospectus supplement, the accompanying prospectus, the documents incorporated by reference, any amendment or supplement to this prospectus supplement or the accompanying prospectus or in any free writing prospectus prepared by or on behalf of us or to which we have referred you. We will not make an offer to sell these securities in any jurisdiction where the offer or sale is not permitted. You should assume that the information appearing in this prospectus supplement and the accompanying prospectus is accurate as of the dates on their covers. Our business, financial condition, results of operations and prospects may have changed since those dates. Any information contained on or accessible through our Internet site is not incorporated herein and does not constitute part of this prospectus supplement.

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ABOUT THIS PROSPECTUS SUPPLEMENT

This document is in two parts. The first part is this prospectus supplement, which describes the specific terms of this offering and also adds to and updates information contained in the accompanying prospectus and the documents incorporated by reference. The second part, the accompanying prospectus, provides more general information, some of which may not apply to this offering.

To the extent the information contained in this prospectus supplement differs or varies from the information contained in the accompanying prospectus or documents incorporated by reference, the information in this prospectus supplement supersedes such information. In addition, any statement in a filing we make with the SEC under the Securities Exchange Act of 1934, as amended, or the Exchange Act, prior to the termination of this offering that adds to, updates or changes information contained in an earlier filing we made with the SEC shall be deemed to modify and supersede such information in the earlier filing.

Before purchasing any securities, you should carefully read both this prospectus supplement and the accompanying prospectus, together with the additional information described under the heading 'Where You Can Find More Information'. You should also read and consider the information set forth in the section entitled 'Risk Factors' in each of this prospectus supplement, the accompanying prospectus and the documents incorporated by reference in this prospectus supplement and the accompanying prospectus before you make an investment decision.

We are not making any representation to any purchaser of the common stock regarding the legality of an investment in the common stock by such purchaser. You should not consider any information in this prospectus supplement to be legal, business or tax advice. You should consult your own attorney, business advisor and tax advisor for legal, business and tax advice regarding an investment in the common stock.

The common stock is being offered only for sale in jurisdictions where it is lawful to make such offer. The distribution of this prospectus supplement and the offering of the common stock in other jurisdictions may also be restricted by law. Persons who receive this prospectus supplement should inform themselves about and observe any such restrictions. This prospectus supplement does not constitute, and may not be used in connection with, an offer or solicitation by anyone in any jurisdiction in which such offer or solicitation is not authorized or in which the person making such offer or solicitation is not authorized or qualified to do so or to any person to whom it is unlawful to make such offer or solicitation. See 'Plan of Distribution' beginning on page S-6 of this prospectus supplement.

When we use the terms the 'Company,' 'we,' 'our,' or 'us,' we are referring to Southwest Gas Holdings, Inc., a Delaware corporation, together with our subsidiaries, except where the context otherwise requires or where otherwise indicated. The term 'Southwest Gas Holdings' refers to Southwest Gas Holdings, Inc. without its consolidated subsidiaries. The term 'Southwest' refers to our subsidiary, Southwest Gas Corporation.

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RISK FACTORS

Investing in our common stock involves risks. You should carefully consider the risk factors set forth below, as well as the additional risk factors described in 'Item 1A-Risk Factors' in our Annual Report on Form 10-K for the year ended December 31, 2020, which is incorporated by reference in this prospectus supplement and the accompanying prospectus, as well as those risks discussed from time to time in our subsequently filed reports, before deciding to invest in the common stock. You should also consider the other information contained or incorporated by reference in this prospectus supplement before deciding to invest in our common stock.

We may use the net proceeds of this offering in ways that have a negative impact on our stock price.

We intend to use the net proceeds of this offering for general corporate purposes, which may include the acquisition of property for the construction, completion, extension or improvement of pipeline systems and facilities located in and around the communities Southwest serves. Our management will have broad discretion in the application of the net proceeds from this offering and could spend the proceeds in ways that do not improve our results of operations or enhance the value of our common stock. Accordingly, you will be relying on the judgment of our management with regard to the use of net proceeds, and you will not have the opportunity, as part of your investment decision, to assess whether the proceeds are being used appropriately. Our failure to apply these funds effectively could have a material adverse effect on our business and cause the price of our common stock to decline.

You may experience future dilution as a result of future equity offerings or other equity issuances.

In order to raise additional capital, we may in the future offer and issue additional shares of our common stock or other securities convertible into or exchangeable for our common stock. We cannot assure you that we will be able to sell shares or other securities in any other offering at a price per share that is equal to or greater than the price per share paid by you, and investors purchasing shares or other securities in the future could have rights superior to existing stockholders. The price per share at which we sell additional shares of our common stock or other securities convertible into or exchangeable for our common stock in future transactions may be higher or lower than the price per share in this offering paid by you.

Our common stock price may be volatile or may decline.

The market price for our common stock may fluctuate significantly from time to time as a result of many factors, including:

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CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING INFORMATION

This prospectus supplement, the accompanying prospectus and the documents we incorporate by reference herein and therein contain forward-looking statements within the meaning of Section 27A of the Securities Act and Section 21E of the Securities Exchange Act of 1934, as amended (the 'Exchange Act'). All statements other than statements of historical fact included or incorporated by reference in this prospectus supplement and the accompanying prospectus are forward-looking statements, including, without limitation, statements regarding the Company's plans, objectives, goals, intentions, projections, strategies, future events or performance, negotiations, and underlying assumptions. The words 'may,' 'if,' 'will,' 'should,' 'could,' 'expect,' 'plan,' 'anticipate,' 'believe,' 'estimate,' 'predict,' 'project,' 'continue,' 'forecast,' 'intend,' 'endeavor,' 'promote,' 'seek,' and similar words and expressions are generally used and intended to identify forward-looking statements. For example, statements regarding operating margin patterns, customer growth, the composition of our customer base, price volatility, including that experienced related to gas prices in early 2021, seasonal patterns, payment of debt, the Company's company-owned life insurance strategy, replacement market and new construction market, impacts from the novel Coronavirus (COVID-19), including on our employees, customers, supply chain, transportation network, our financial position, revenue, earnings, cash flows, debt covenants, operations, regulatory recovery, work deployment or resumption and related uncertainties stemming from this pandemic, expected impacts of valuation adjustments associated with the redeemable noncontrolling interest in Linetec Services, LLC, the impacts of U.S. tax reform including disposition in regulatory proceedings, including future proceedings, and bonus depreciation tax deductions, the impact of recent Pipeline and Hazardous Materials Safety Administration rulemaking, the amounts and timing for completion of estimated future construction expenditures, plans to pursue infrastructure programs or programs under SB151 legislation, forecasted operating cash flows and results of operations, net earnings impacts or recovery costs from gas infrastructure replacement and Customer Owned Yard Line programs (COYL) and surcharges, funding sources of cash requirements, amounts generally expected to be reflected in 2021 or future period revenues from regulatory rate proceedings including amounts requested or preliminarily settled from any general rate cases, the outcome of judicial review of a previous Nevada rate case, rates and surcharges, purchase gas adjustment ('PGA'), and other rate adjustments, sufficiency of working capital and current credit facilities, bank lending practices, the Company's views regarding its liquidity position, ability to raise funds and receive external financing capacity and the intent and ability to issue various financing instruments and stock under at-the-market offerings or otherwise, future dividend increases and the Company's board of directors' current target dividend payout ratio, pension and postretirement benefits, certain impacts of tax acts, the effect of any rate changes or regulatory proceedings, contract or construction change order negotiations, impacts of accounting standard updates, statements regarding future gas prices, gas purchase contracts and derivative financial instruments, recoverability of regulatory assets, the impact of certain legal proceedings, and the timing and results of future rate hearings, including any general rate cases and the final resolution for recovery of the Customer Data Modernization Initiative in all jurisdictions, and statements regarding pending procedures or approvals are forward-looking statements.

A number of important factors affecting the business and financial results of the Company could cause actual results to differ materially from those stated in the forward-looking statements. These factors include, but are not limited to, customer growth rates, conditions in the housing market, the impacts of COVID-19 including that which may result from a sustained restriction on commerce by government officials or otherwise, including impacts on employment in our territories, the health impacts to our customers and employees due to the persistence of the virus, the ability to collect on customer accounts due to the current or an extended moratorium on late fees or service disconnection, the ability to obtain regulatory recovery of all costs and financial impacts resulting from this pandemic, the ability of infrastructure services business to resume work with all customers and the impact of a delay or termination of work as a result thereof, the impacts of future restrictions placed on our business by government regulation or otherwise (such as self-imposed restrictions for the safety of employees and customers), including related to personal distancing, investment in personal protective equipment and other protocols, the impact of a resurgence of the virus following the full resumption of commerce in our territories, and decisions of customers of Centuri as to whether to pursue capital projects due to economic

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impacts resulting from the pandemic or otherwise, the ability to recover costs through the PGA mechanisms or other regulatory assets, the effects of regulation/deregulation, governmental or regulatory policy regarding pipeline safety, natural gas or alternative energy, the regulatory support for ongoing infrastructure programs, the timing and amount of rate relief, the timing and methods determined by regulators to refund amounts to customers resulting from U.S. tax reform, changes in rate design, variability in volume of gas or transportation service sold to customers, changes in gas procurement practices, changes in capital requirements and funding, the impact of credit rating actions and conditions in the capital markets on financing costs, the impact of variable rate indebtedness associated with a discontinuance of the London Interbank Offered Rate including in relation to amounts of indebtedness then outstanding, changes in construction expenditures and financing, changes in operations and maintenance expenses, effects of pension expense forecasts, accounting changes and regulatory treatment related thereto, currently unresolved and future liability claims, changes in pipeline capacity for the transportation of gas and related costs, results of Centuri bid work, the impact of weather on Centuri's operations, future acquisition-related costs, impacts of changes in value of the redeemable noncontrolling interest if at other than fair value, Centuri utility infrastructure expenses, differences between actual and originally expected outcomes of Centuri bid or other fixed-price construction agreements, outcomes from contract and change order negotiations, ability to successfully procure new work, impacts from work awarded or failing to be awarded from significant customers, the mix of work awarded, the amount of work awarded to Centuri following the lifting of work stoppages or reduction, the result of productivity inefficiencies from regulatory requirements or otherwise, delays in commissioning individual projects, acquisitions, and management's plans related thereto, competition, our ability to raise capital in external financings, our ability to continue to remain within the ratios and other limits subject to our debt covenants, and ongoing evaluations in regard to goodwill and other intangible assets. In addition, the Company can provide no assurance that its discussions regarding certain trends relating to its financing and operating expenses will continue or cease to continue in future periods. Additional factors that could cause actual results to differ and that you should consider prior to investing in our securities are discussed under the heading 'Risk Factors' and in other sections of this prospectus supplement and the accompanying prospectus and our current and periodic reports, and other filings, filed from time to time with the SEC that are incorporated by reference into this prospectus supplement and the accompanying prospectus. See 'Incorporation by Reference' and 'Where You Can Find More Information' below for information about how to obtain copies of those documents. All forward-looking statements in this prospectus and the documents incorporated by reference herein are made only as of the date of the document in which they are contained, based on information available to us as of the date of that document, and we caution you not to place undue reliance on forward-looking statements in light of the risks and uncertainties associated with them. We assume no obligation to update or revise any forward-looking statements, even if experience or future changes show that the indicated results or events will not be realized.

You should consider these risks and those set forth in, or incorporated into, the 'Risk Factors' section of this prospectus supplement and in our most recent Annual Report on Form 10-K prior to investing in our common stock.

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USE OF PROCEEDS

We expect to use net proceeds from the sale of shares of common stock under the sales agency agreement for general corporate purposes, including the acquisition of property for the construction, completion, extension or improvement of pipeline systems and facilities located in and around the communities Southwest serves, as well as for the repayment or repurchase of indebtedness (including amounts outstanding from time to time under our lines of credit, senior notes, term loan or future credit facilities), and to provide for working capital. Certain Agents or affiliates of agents are lenders (and in certain cases agents) under our lines of credit, senior notes, and term loan and may receive a portion of the net proceeds from any sales of our common shares pursuant to this prospectus supplement. See 'Plan of Distribution - Conflicts of Interest.'

PLAN OF DISTRIBUTION

We have entered into a sales agency agreement, dated as of April 8, 2021 with the Agents under which we may issue and sell shares of our common stock with an aggregate sales price of up to $500,000,000 from time to time through the Agents as our agents for the offer and sale of the shares. The sales, if any, of the shares of common stock under the sales agency agreement will be made in 'at the market' offerings as defined in Rule 415 of the Securities Act.

From time to time during the term of the sales agency agreement, and subject to the terms and conditions set forth therein, we may deliver an issuance notice to the Agents specifying the length of the selling period (not to exceed 20 trading days), the amount of common stock to be sold and the minimum price below which sales may not be made. Upon receipt of an issuance notice from us, and subject to the terms and conditions of the sales agency agreement, the Agents have agreed to use their commercially reasonable efforts consistent with their normal trading and sales practices to sell such shares on such terms. We or the Agents may suspend the offering of shares of common stock at any time upon proper notice to the others, upon which the selling period will immediately terminate. Settlement between us and the Agents for sales of common stock will occur on the second business day following the date on which any sales are made, or on some other date that is agreed to between us and the Agents in connection with a particular transaction. The obligation of the Agents under the sales agency agreement to settle such purchases with us pursuant to any issuance notice is subject to a number of conditions, which the Agents reserve the right to waive in their sole discretion. In addition, the shares may be offered and sold by such other methods, including privately negotiated transactions, as we and the Agents agree to in writing.

We will pay the Agents a commission equal to 1% of the sales price of all shares sold through them as agents under the sales agency agreement. We have also agreed to reimburse the Agents for their reasonable documented out-of-pocket expenses, including fees and expenses of counsel, in connection with the sales agency agreement. We estimate that the expenses of this offering payable by us, excluding compensation payable to the Agents under the terms of the sales agency agreement, will be approximately $500,000.

We will deliver to the New York Stock Exchange copies of this prospectus supplement and the accompanying prospectus pursuant to the rules of the exchange. We will report at least quarterly the number of shares of common stock sold through the Agents in at-the-market offerings, the net proceeds to us and the compensation paid by us to the Agents in connection with such sales of common stock.

If either Agent or we have reason to believe that the exemptive provisions set forth in Rule 101(c)(1) of Regulation M under the Exchange Act are not satisfied, that party will promptly notify the other and sales of our common stock under the sales agency agreement will be suspended until that or other exemptive provisions have been satisfied in the judgment of such Agent and us.

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In connection with the sale of the common stock hereunder, the Agents may be deemed to be 'underwriters' within the meaning of the Securities Act of 1933, and the compensation paid to the Agents may be deemed to be underwriting commissions or discounts. We have agreed to indemnify the Agents against certain civil liabilities, including liabilities under the Securities Act of 1933.

The offering of common stock pursuant to the sales agency agreement will terminate upon the earlier of (1) the sale of all shares of common stock subject to the sales agency agreement and (2) termination of the sales agency agreement by either the Agents or us, in each case upon written notice

We have agreed not to directly or indirectly sell, offer to sell, contract to sell, grant any option to sell or otherwise dispose of, shares of our common stock or securities convertible into or exchangeable for shares of our common stock, warrants or any rights to purchase or acquire our common stock for a period beginning on the first trading day prior to the delivery of any issuance notice to the Agents and ending on the first trading day following the settlement date for the applicable issuance notice, without the prior written consent of the Agents. This consent may be given at any time without public notice. The restriction described in this paragraph does not apply to sales of:

Conflicts of Interest

Affiliates of the Agents are, and, in the future, one or more affiliates of the Agents may be, lenders or agents under our credit facilities, term loan facilities or other borrowing facilities, including the Term Loan Agreement, dated as of March 23, 2021, by and among us, The Bank of New York Mellon, as Administrative Agent, JPMorgan Chase Bank, N.A., as Joint Lead Arranger and Joint Bookrunner, and the other lenders party, book runners and syndication agents thereto (the 'Term Loan Agreement'), the Amended and Restated Revolving Credit Agreement, dated as of April 10, 2020, by and among us, The Bank of New York Mellon, as Administrative Agent, Joint Lead Arranger and Joint Bookrunner, JPMorgan Chase Bank, N.A., as Co- Syndication Agent, Joint Lead Arranger and Joint Bookrunner and the other lenders party, book runners, syndication agents and joint lead arrangers (the 'Revolving Credit Agreement') and the Amended and Restated Revolving Credit Agreement, dated as of April 10, 2020, by and among Southwest, The Bank of New York Mellon, as Administrative Agent, Joint Lead Arranger and Joint Bookrunner, JPMorgan Chase Bank, N.A., as Co-Syndication Agent, Joint Lead Arranger and Joint Bookrunner and the other lenders party, book runners, syndication agents, joint lead arrangers and documentation agents thereto (the 'Southwest Revolving Credit Agreement'). To the extent that we use the net proceeds from this offering to repay amounts we have borrowed, may borrow or re-borrow in the future under those facilities, including the Term Loan Agreement, the Revolving Credit Agreement and the Southwest Revolving Credit Agreement, those lenders may receive their pro rata portion of any of the proceeds from this offering that we use to repay any such amounts. See 'Use of Proceeds.'

Other Relationships

The Agents and their respective affiliates are full service financial institutions engaged in various activities, which may include sales and trading, commercial and investment banking, advisory, investment management, investment research, principal investment, hedging, market making, brokerage and other financial and non-financial activities and services. Certain of the Agents and their respective affiliates have provided, and may

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in the future provide, a variety of these services to us and to persons and entities with relationships with us, for which they received or will receive customary fees and expenses.

In the ordinary course of their various business activities, the Agents and their respective affiliates, officers, directors and employees may purchase, sell or hold a broad array of investments and actively trade 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 assets, securities and/or instruments of the issuer (directly, as collateral securing other obligations or otherwise) and/or persons and entities with relationships with us. The Agents 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.

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, 2020 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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LEGAL MATTERS

The validity of the shares of common stock offered by this prospectus supplement and the accompanying prospectus will be passed upon for us by Morrison & Foerster LLP. Certain legal matters will be passed upon for the Agents by Ballard Spahr LLP.

WHERE YOU CAN FIND MORE INFORMATION

Available Information

We are required to file annual, quarterly and current reports, proxy statements and other information with the SEC. Our filings with the SEC are available to the public through the SEC's Internet site at http://www.sec.gov and through the New York Stock Exchange, 11 Wall Street, New York, New York 10005, on which our common stock is listed.

We have filed with the SEC an automatic registration statement on Form S-3 relating to the common stock covered by this prospectus supplement. This prospectus supplement is a part of the registration statement and does not contain all the information in the registration statement. Whenever a reference is made in this prospectus supplement to a contract or other document of the Company, the reference is only a summary and you should refer to the exhibits that are a part of the registration statement for a copy of the contract or other document. You may review a copy of the registration statement through the SEC's Internet site.

Incorporation by Reference

The SEC allows us to 'incorporate by reference' into this prospectus supplement and the accompanying prospectus the information in other documents that we file with it, which means that we can disclose important information to you by referring you to those documents. The information that we incorporate by reference is considered to be a part of this prospectus supplement and the accompanying prospectus.

Any reports that we file with the SEC on or after the date of this prospectus supplement and before the date that the offering of the shares is terminated will automatically update and, where applicable, supersede any information contained in this prospectus supplement and the accompanying prospectus or incorporated by reference into this prospectus supplement and the accompanying prospectus. This means that you must look at all of the SEC filings that we incorporate by reference to determine if any of the statements in this prospectus supplement and the accompanying prospectus or in any documents previously incorporated by reference into this prospectus supplement and the accompanying prospectus have been modified or superseded. We specifically incorporate by reference into this prospectus supplement and the accompanying prospectus the following documents filed with the SEC (other than, in each case, documents or information deemed furnished and not filed in accordance with SEC rules, including pursuant to Item 2.02 or Item 7.01 of Form 8-K, and no such information shall be deemed specifically incorporated by reference hereby):

You may obtain a copy of any or all of the documents referred to above which have been or may be incorporated by reference into this prospectus supplement and the accompanying prospectus (excluding certain

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exhibits unless they are specifically incorporated by reference in any such documents) at no cost to you by writing or telephoning us at the following:

Southwest Gas Holdings, Inc.

8360 S. Durango Dr.

P.O. Box 98510

Las Vegas, Nevada 89193-8510

Attention: Corporate Secretary

Telephone: (702) 876-7237

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PROSPECTUS

Southwest Gas Holdings, Inc.

Southwest Gas Corporation

Common Stock

Preferred Stock

Debt Securities

Guarantees of Debt Securities

Depositary Shares

Warrants

Units

Rights

Southwest Gas Holdings, Inc. may offer and sell any combination of the following securities from time to time in amounts, at prices and on terms that will be determined at the time of any such offering:

Southwest Gas Corporation may offer and sell any combination of the following securities from time to time in amounts, at prices and on terms that will be determined at the time of any such offering:

This prospectus describes some of the general terms that may apply to these securities. We will provide the specific terms of these securities, including their offering prices, in prospectus supplements to this prospectus. Any prospectus supplements may also add, update or change information contained in this prospectus. You should carefully read both this prospectus and any prospectus supplement before you invest.

Southwest Gas Holdings, Inc.'s common stock is listed on the New York Stock Exchange under the symbol 'SWX.' On December 1, 2020, the reported last sale price on the New York Stock Exchange for our common stock was $65.28 per share.

These securities may be offered and sold to or through one or more underwriters, dealers and agents or directly to purchasers or through a combination of these methods, on a continuous or delayed basis. You can find additional information about our plan of distribution for the securities under the heading 'Plan of Distribution' beginning on page 22 of this prospectus. We will also describe the plan of distribution for any particular offering of these securities in the prospectus supplement. This prospectus may not be used to sell our securities unless it is accompanied by a prospectus supplement.

Investing in our securities involves risks. You should consider the risk factors described in any accompanying prospectus supplement or any documents we incorporate by reference.

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

The date of this prospectus is December 2, 2020

TABLE OF CONTENTS

You should rely only on the information contained or incorporated by reference in this prospectus, in any accompanying prospectus supplement or in any free writing prospectus filed by us with the Securities and Exchange Commission (the 'SEC'). We have not authorized any other person to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. You should assume that the information appearing in this prospectus and any prospectus supplement or in any such free writing prospectus is accurate as of the dates on their covers. Our business, financial condition, results of operations and prospects may have changed since those dates. Any information contained on or accessible through our Internet site is not incorporated herein and does not constitute part of this prospectus.

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ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we filed with the SEC under the Securities Act of 1933, as amended (the 'Securities Act'), utilizing a 'shelf' registration process. Under this shelf registration process, we may, from time to time, sell in one or more offerings any of our securities described in this prospectus.

This prospectus provides you with a general description of the securities that 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, including the specific amounts, prices and terms of the securities offered. The prospectus supplement may also add, update or change information contained in this prospectus. If there is any inconsistency between the information in this prospectus and a prospectus supplement, you should rely on the information in that prospectus supplement.

You should carefully read both this prospectus and any prospectus supplement, together with additional information described under the heading 'Where You Can Find More Information' and 'Incorporation by Reference.'

In this prospectus, unless the context indicates otherwise, the words and terms 'Southwest Gas Holdings,' 'the Company,' 'we,' 'our,' 'ours' and 'us' refer to Southwest Gas Holdings, Inc. and its consolidated subsidiaries, including Southwest Gas Corporation.

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CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING INFORMATION

This prospectus and the documents we incorporate by reference herein and therein contain forward-looking statements within the meaning of Section 27A of the Securities Act and Section 21E of the Securities Exchange Act of 1934, as amended (the 'Exchange Act'). All statements other than statements of historical fact included or incorporated by reference in this prospectus are forward-looking statements, including, without limitation, statements regarding the Company's plans, objectives, goals, intentions, projections, strategies, future events or performance, negotiations, and underlying assumptions. The words 'may,' 'if,' 'will,' 'should,' 'could,' 'expect,' 'plan,' 'anticipate,' 'believe,' 'estimate,' 'predict,' 'project,' 'continue,' 'forecast,' 'intend,' 'endeavor,' 'promote,' 'seek,' and similar words and expressions are generally used and intended to identify forward-looking statements. For example, statements regarding operating margin patterns, customer growth, the composition of our customer base, price volatility, seasonal patterns, payment of debt, the Company's company-owned life insurance strategy, replacement market and new construction market, impacts from the novel Coronavirus (COVID-19), including on our employees, customers, supply chain, transportation network, our financial position, revenue, earnings, cash flows, debt covenants, operations, regulatory recovery, work deployment or resumption and related uncertainties stemming from this pandemic, expected impacts of valuation adjustments associated with any redeemable noncontrolling interest, the impacts of U.S. tax reform including disposition in regulatory proceedings and bonus depreciation tax deductions, the impact of recent Pipeline and Hazardous Materials Safety Administration rulemaking, the amounts and timing for completion of estimated future construction expenditures, plans to pursue infrastructure programs or programs under SB151 legislation, forecasted operating cash flows and results of operations, net earnings impacts from gas infrastructure replacement surcharges, funding sources of cash requirements, amounts generally expected to be reflected in 2020 or future period revenues from regulatory rate proceedings including amounts requested or settled from recent and ongoing general rate cases, the outcome of judicial review of the previous Nevada rate case, rates and surcharges, purchase gas adjustment ('PGA'), and other rate adjustments, sufficiency of working capital and current credit facilities, bank lending practices, the Company's views regarding its liquidity position, ability to raise funds and receive external financing capacity and the intent and ability to issue various financing instruments and stock under at-the-market offerings or otherwise, future dividend increases and the Company's board of directors' current target dividend payout ratio, pension and postretirement benefits, certain impacts of tax acts, the effect of any other rate changes or regulatory proceedings, contract or construction change order negotiations, impacts of accounting standard updates, infrastructure replacement mechanisms and Customer-Owned Yard Line programs, statements regarding future gas prices, gas purchase contracts and derivative financial instruments, recoverability of regulatory assets, the impact of certain legal proceedings, and the timing and results of future rate hearings, including the ongoing general rate cases and the final resolution for recovery of the Customer Data Modernization Initiative in all jurisdictions, and statements regarding pending approvals are forward-looking statements.

A number of important factors affecting the business and financial results of the Company could cause actual results to differ materially from those stated in the forward-looking statements. These factors include, but are not limited to, customer growth rates, conditions in the housing market, the impacts of COVID-19 including that which may result from a sustained restriction on commerce by government officials or otherwise, including impacts on employment in our territories, the health impacts to our customers and employees due to the persistence of the virus, the ability to collect on customer accounts due to the current or an extended moratorium on late fees or service disconnection, the ability to obtain regulatory recovery of all costs and financial impacts resulting from this pandemic, the ability of infrastructure services business to resume work with all customers and the impact of a delay or termination of work as a result thereof, the impacts of future restrictions placed on our business by government regulation or otherwise (such as self-imposed restrictions for the safety of employees and customers), including related to personal distancing, investment in personal protective equipment and other protocols, the impact of a resurgence of the virus following the resumption of commerce in our territories, and decisions of customers of Centuri Group, Inc. ('Centuri,' or the 'utility infrastructure services' segment) as to whether to pursue capital projects due to economic impacts resulting from the pandemic or otherwise, the ability to recover costs through the PGA mechanisms or other regulatory assets, the effects of

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regulation/deregulation, governmental or regulatory policy regarding pipeline safety, natural gas or alternative energy, the regulatory support for ongoing infrastructure programs, the timing and amount of rate relief, the timing and methods determined by regulators to refund amounts to customers resulting from U.S. tax reform, changes in rate design, variability in volume of gas or transportation service sold to customers, changes in gas procurement practices, changes in capital requirements and funding, the impact of conditions in the capital markets on financing costs, the impact of variable rate indebtedness associated with a discontinuance of the London Interbank Offered Rate, including in relation to amounts of indebtedness then outstanding, changes in construction expenditures and financing, changes in operations and maintenance expenses, effects of pension expense forecasts, accounting changes and regulatory treatment related thereto, currently unresolved and future liability claims, changes in pipeline capacity for the transportation of gas and related costs, results of Centuri bid work, the impact of weather on Centuri's operations, future acquisition-related costs, impacts of changes in value of any redeemable noncontrolling interest if at other than fair value, Centuri utility infrastructure expenses, differences between actual and originally expected outcomes of Centuri bid or other fixed-price construction agreements, outcomes from contract and change order negotiations, ability to successfully procure new work, impacts from work awarded or failing to be awarded from significant customers, the mix of work awarded, the amount of work awarded to Centuri following the lifting of work stoppages or reduction, the result of productivity inefficiencies from regulatory requirements or otherwise, delays in commissioning individual projects, acquisitions, and management's plans related thereto, competition, our ability to raise capital in external financings, our ability to continue to remain within the ratios and other limits subject to our debt covenants, and ongoing evaluations in regard to goodwill and other intangible assets. In addition, the Company can provide no assurance that its discussions regarding certain trends relating to its financing and operating expenses will continue or cease to continue in future periods. Additional factors that could cause actual results to differ and that you should consider prior to investing in our securities are discussed under the heading 'Risk Factors' and in other sections of this prospectus and our current and periodic reports, and other filings, filed from time to time with the SEC that are incorporated by reference into this prospectus. See 'Incorporation by Reference' and 'Where You Can Find More Information' below for information about how to obtain copies of those documents. All forward-looking statements in this prospectus and the documents incorporated by reference herein are made only as of the date of the document in which they are contained, based on information available to us as of the date of that document, and we caution you not to place undue reliance on forward-looking statements in light of the risks and uncertainties associated with them. We assume no obligation to update or revise any forward-looking statements, even if experience or future changes show that the indicated results or events will not be realized.

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OUR COMPANY

Southwest Gas Holdings, Inc., a Delaware corporation, is a holding company headquartered in Las Vegas, Nevada. Through its wholly owned subsidiaries, Southwest Gas Corporation ('Southwest') and Centuri, the Company operates in two business segments: natural gas operations and utility infrastructure services. At the annual meeting of stockholders of Southwest Gas Holdings, Inc., held on May 2, 2019, stockholders voted to approve changing the state of incorporation of Southwest Gas Holdings, Inc. from California to Delaware. The reincorporation was effective as of September 20, 2019. Southwest continues to be incorporated in the state of California.

Southwest was incorporated in March 1931 under the laws of the state of California. Southwest is engaged in the business of purchasing, distributing, and transporting natural gas for customers in portions of Arizona, Nevada, and California. Southwest is the largest distributor of natural gas in Arizona, selling and transporting natural gas in most of central and southern Arizona, including the Phoenix and Tucson metropolitan areas. Southwest is also the largest distributor of natural gas in Nevada, serving the Las Vegas metropolitan area and portions of northern Nevada. In addition, Southwest distributes and transports natural gas for customers in portions of California, including the Lake Tahoe area and the high desert and mountain areas in San Bernardino County.

Centuri is a comprehensive utility infrastructure services enterprise dedicated to delivering a diverse array of solutions to North America's gas and electric providers. Centuri derives revenue primarily from installation, replacement, repair and maintenance of energy distribution systems. Centuri operations are generally conducted under the business names of NPL Construction Co., NPL Canada Ltd., New England Utility Constructors, Inc., and Linetec Services, LLC.

Southwest is subject to regulation by the Arizona Corporation Commission, the Public Utilities Commission of Nevada, and the California Public Utilities Commission (the 'CPUC'). The CPUC regulates the issuance of all securities by Southwest, with the exception of short-term borrowings. Certain of the Company's and Southwest's accounting practices, transmission facilities and rates are subject to regulation by the Federal Energy Regulatory Commission (the 'FERC'). Centuri is not regulated by the state utilities commissions or by the FERC in any of its operating areas.

Our administrative offices are located at 8360 S. Durango Drive, Las Vegas, Nevada 89113, telephone number (702) 876-7237.

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RISK FACTORS

Our business is subject to certain risks and uncertainties. You should carefully consider and evaluate all of the information included and incorporated by reference in this prospectus and any applicable prospectus supplement, including the risk factors incorporated by reference to our Annual Report on Form 10-K for the year ended December 31, 2019, as well as any risk factors we may describe in any subsequent periodic reports or information we file with the SEC. It is possible that our business, financial condition, liquidity or results of operations could be materially adversely affected by any of these risks.

USE OF PROCEEDS

Unless otherwise indicated in the applicable prospectus supplement or other offering material, we intend to use the net proceeds from the sale of securities for general corporate purposes, which may include the following: refunding, repurchasing, retiring upon maturity or redeeming existing debt; funding for working capital; capital expenditures; repurchases of our capital stock; and strategic investments and acquisitions.

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DESCRIPTION OF CAPITAL STOCK

General

The authorized capital stock of Southwest Gas Holdings consists of (1) 120,000,000 shares of Southwest Gas Holdings common stock, with a $1.00 par value, (2) 5,000,000 shares of preferred stock, without par value, and (3) 2,000,000 shares of preference stock, with a $20.00 par value. As of November 30, 2020, there were issued and outstanding 56,830,353 shares of Southwest Gas Holdings common stock and no shares of Southwest Gas Holdings preferred stock or preference stock. No other classes of capital stock are authorized under our articles of incorporation.

The following description of Southwest Gas Holdings' capital stock is only a summary and is qualified in its entirety by reference to our articles of incorporation and bylaws. Therefore, you should read carefully the more detailed provisions of our articles of incorporation and bylaws, copies of which are incorporated by reference as exhibits to the registration statement of which this prospectus is a part.

Common Stock

We have one class of common stock. All holders of our common stock are entitled to the same rights and privileges, as described below.

Voting Rights. Except as otherwise provided by law, each holder of common stock is entitled to one vote per share on each matter submitted to a vote of a meeting of stockholders, including the election of directors.

Dividends. The holders of Southwest Gas Holdings common stock are entitled to receive such dividends as the Southwest Gas Holdings board of directors may from time to time declare, subject to any rights of holders of outstanding shares of Southwest Gas Holdings preferred stock.

Liquidation. In the event of any liquidation, dissolution or winding up of Southwest Gas Holdings, whether voluntary or involuntary, the holders of shares of Southwest Gas Holdings common stock, subject to any rights of the holders of outstanding shares of Southwest Gas Holdings preferred stock, are entitled to receive any remaining assets of Southwest Gas Holdings after the discharge of its liabilities.

Rights and Preferences. Holders of Southwest Gas Holdings common stock are not entitled to preemptive rights to subscribe for, or purchase any part of, any new or additional issue of stock or securities convertible into stock. Southwest Gas Holdings common stock does not contain any redemption provisions or conversion rights and is not liable to assessment or further call.

Preferred Stock

Our articles of incorporation authorize our board of directors, without further action by the stockholders, to issue up to 5,000,000 shares of preferred stock, without par value, in one or more series and to fix the rights, preferences, privileges and restrictions granted to, or imposed upon, any such wholly unissued series.

Certain Anti-Takeover Matters

Our articles of incorporation and bylaws contain provisions that may have the effect of discouraging persons from acquiring large blocks of Southwest Gas Holdings' stock or delaying or preventing a change in control of Southwest Gas Holdings. The material provisions which may have such an effect are:

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Transfer Agent and Registrar

EQ Shareowner Services is the registrar and transfer agent for our common stock.

Listing

Our common stock is listed on the New York Stock Exchange under the symbol 'SWX.'

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DESCRIPTION OF DEBT SECURITIES

The following text describes the general terms and provisions of debt securities that Southwest Gas Holdings, Inc. and/or Southwest Gas Corporation may offer from time to time. For purposes of this 'Description of Debt Securities,' 'we,' 'us' and 'our' refer to the relevant issuer of debt securities, Southwest Gas Holdings, Inc. or Southwest Gas Corporation, as the case may be, and not to their respective subsidiaries.

When we offer to sell a particular series of debt securities, we will describe the specific terms of the series in a prospectus supplement. We will also indicate in any applicable prospectus supplement whether the general terms and provisions described in this prospectus apply to a particular series of debt securities. Unless otherwise specified in any applicable prospectus supplement, the senior debt securities will be our direct, unsecured obligations and will rank equally with all of our other unsecured and unsubordinated indebtedness. To the extent we issue secured or subordinated debt securities, the terms will be described in the applicable prospectus supplement.

The debt securities of Southwest Gas Holdings, Inc. will be issued under an indenture between Southwest Gas Holdings, Inc. and The Bank of New York Mellon Trust Company, N.A., as Trustee (the 'Holdings Indenture') in the form included as an exhibit to the registration statement of which this prospectus forms a part. Unless otherwise specified in any applicable prospectus supplement, the debt securities of Southwest Gas Corporation will be issued under the indenture, dated as of June 4, 2020, by and between Southwest Gas Corporation and The Bank of New York Mellon Trust Company, N.A., as Trustee (the 'Corporation Indenture' and, together with the Holdings Indenture, the 'Indentures'). Each Indenture describes the terms of the debt securities and does not limit the amount of debt securities or other unsecured, senior debt we may issue. We have summarized the general terms and provisions of the debt securities to be governed by each Indenture. The summary is not complete and is subject to, and qualified in its entirety by reference to, all provisions of the indenture and the Trust Indenture Act of 1939, as amended (the 'Trust Indenture Act'). A form of each Indenture has been filed as an exhibit to the registration statement that we have filed with the SEC, of which this prospectus forms a part. We encourage you to read the Indentures. Capitalized terms used in this description of our debt securities have the meanings ascribed to them in the applicable Indenture.

General

The terms of each series of debt securities will be established by our board of directors or a committee thereof and set forth or determined in the manner provided in an Officers' Certificate or by a supplemental indenture to the relevant Indenture. The particular terms of each series of debt securities will be described in a prospectus supplement relating to such series.

We may issue debt securities in one or more series with the same or various maturities, at par, at a premium or at a discount. We need not issue all debt securities of one series at the same time and, unless otherwise provided, we may without the consent of the holders of the debt securities of that series reopen a series and issue additional debt securities of that series. We will set forth in a prospectus supplement the aggregate principal amount of any series of debt securities being offered and their specific terms, including, to the extent applicable, the following terms:

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We will provide you with information on the federal income tax considerations and other special considerations applicable to any of these debt securities in the applicable prospectus supplement.

If we denominate the purchase price of any of the debt securities in a foreign currency or currencies or a foreign currency unit or units, or if the principal of, and premium and interest on, any series of debt securities is payable in a foreign currency or currencies or a foreign currency unit or units, we will provide you with information on the restrictions, elections, general tax considerations, specific terms and other information with respect to that issue of debt securities and such foreign currency or currencies or foreign currency unit or units in the applicable prospectus supplement.

Transfer and Exchange

Each debt security will be represented by either one or more global securities registered in the name of The Depository Trust Company, as depositary, or a nominee (which we refer to, in the case of any debt security represented by a global debt security, as a 'book-entry debt security'), or a certificate issued in definitive registered form (which we refer to, in the case of any debt security represented by a certificated security, as a 'certificated debt security') as set forth in the applicable prospectus supplement. Except as set forth in the applicable prospectus supplement, book-entry debt securities will not be issuable in certificated form.

You may transfer or exchange certificated debt securities at any office we maintain for this purpose in accordance with the terms of the indenture. No service charge will be made for any registration of transfer or exchange of certificated debt securities, but we may require payment of a sum sufficient to cover all taxes, assessments or other governmental charges that may be imposed in connection with a transfer or exchange.

You may effect the transfer of certificated debt securities and the right to receive the principal of, and any premium and interest on, certificated debt securities only by surrendering the certificate representing those certificated debt securities and either execution by us, and authentication and delivery by the Trustee, of the certificate to the new holder or execution by us, and authentication and delivery by the Trustee, of a new certificate to the new holder.

Covenants

We will set forth in the applicable prospectus supplement any financial or restrictive covenants applicable to any issue of debt securities.

No Protection in the Event of a Change of Control

Unless we state otherwise in the applicable prospectus supplement, the debt securities will not contain any provisions which may afford holders of the debt securities protection in the event we have a change in control or in the event of a highly leveraged transaction (whether or not such transaction results in a change in control) which could adversely affect holders of debt securities.

Consolidation, Merger and Sale of Assets

We or any guarantor of the debt securities shall not consolidate with or sell, lease or convey all or substantially all of our properties or assets to, or merge with or into, in one transaction or a series of related transactions, any Person unless:

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Events of Default

'Event of Default' means with respect to any series of debt securities, any of the following:

A Default constituting a Covenant Default with respect to a particular series of debt securities (except as to certain events of bankruptcy, insolvency or reorganization) is not an Event of Default until the Trustee (by written notice to us) or the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series (by written notice to us and the Trustee) gives notice of the Default and we do not cure such Default within 90 days after receipt of such notice.

No Event of Default with respect to a particular series of debt securities (except as to certain events of bankruptcy, insolvency or reorganization) necessarily constitutes an Event of Default with respect to any other series of debt securities. The occurrence of certain Events of Default or an acceleration under the relevant Indenture may constitute an event of default under certain indebtedness of ours or our Subsidiaries outstanding from time to time.

In the case of an Event of Default resulting from certain events of bankruptcy, insolvency or reorganization, the principal of and accrued and unpaid interest, if any, on all outstanding debt securities will become and be immediately due and payable without any declaration or other act on the part of the Trustee or any holder of outstanding debt securities. If any other Event of Default with respect to debt securities of any series at the time outstanding occurs and is continuing, then the Trustee or the holders of not less than 25% in principal amount of the outstanding debt securities of that series may, by a notice in writing to us (and to the Trustee if given by the

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holders), declare to be due and payable immediately the principal of and accrued and unpaid interest, if any, on all debt securities of that series. At any time after a declaration of acceleration with respect to debt securities of any series has been made, the holders of a majority in principal amount of the outstanding debt securities of that series may rescind the acceleration and its consequences if all Events of Default, other than the nonpayment of accelerated principal and interest, if any, with respect to debt securities of that series, have been cured or waived as provided in the relevant Indenture. We refer you to the applicable prospectus supplement relating to any series of debt securities that are discount securities for the particular provisions relating to acceleration of a portion of the principal amount of such discount securities upon the occurrence of an Event of Default.

The Indentures provide that the Trustee may refuse to perform any duty or exercise any of its rights or powers under the relevant Indenture unless the Trustee receives indemnity and/or security reasonably satisfactory to it against any loss, liability or expense which might be incurred by it in performing such duty or exercising such right or power. Subject to certain rights of the Trustee, the holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the Trustee or exercising any trust or power conferred on the Trustee with respect to the debt securities of that series.

No holder of any debt security of any series will have any right to pursue any remedy under the relevant Indenture or that series of debt securities, unless:

Notwithstanding any other provision in the relevant Indenture, the holder of any series of debt security will have an absolute and unconditional right to receive payment of the principal, premium and any interest on that debt security on or after the due dates expressed in that series of debt security and to institute suit for the enforcement of payment.

Each Indenture requires us, within 120 days after the end of each fiscal year, to deliver to the Trustee a certificate as to compliance with such Indenture.

Modification and Waiver

We and the Trustee may modify, amend or supplement the relevant Indenture or the debt securities of any series without notice to or the consent of any holder of any debt security:

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We may also modify and amend the relevant Indenture with the written consent of the holders of at least a majority in principal amount of the outstanding debt securities of each series affected by the modifications or amendments. We may not make any modification or amendment without the consent of each affected holder of a series of debt securities then outstanding if that amendment will:

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Except for certain specified provisions, the holders of at least a majority in principal amount of the outstanding debt securities of any series may on behalf of the holders of all debt securities of that series waive our compliance with provisions of the relevant Indenture. The holders of a majority in principal amount of the outstanding debt securities of any series may on behalf of the holders of all the debt securities of such series waive any past default under the relevant Indenture with respect to that series and its consequences, except a default in the payment of the principal, premium or any interest on any debt security of that series; provided, however, that the holders of a majority in principal amount of the outstanding debt securities of any series may rescind an acceleration and its consequences, including any related payment default that resulted from the acceleration.

Discharge of Debt Securities

When all outstanding debt securities of any series will become due and payable at their stated maturity within one year and we have deposited (or caused to be deposited) with the Trustee cash sufficient to pay and discharge all outstanding debt securities of such series on the date of their stated maturity, then we may satisfy and discharge our obligations under the relevant Indenture with respect to such debt securities while they remain outstanding.

No Personal Liability of Directors, Officers, Employees or Stockholders

None of our past, present or future directors, officers, employees or stockholders, as such, will have any liability for any of our obligations under the debt securities or the relevant Indenture or for any claim based on, or in respect or by reason of, such obligations or their creation. By accepting a debt security, each holder waives and releases all such liability. This waiver and release is part of the consideration for the issue of the debt securities. However, this waiver and release may not be effective to waive liabilities under U.S. federal securities laws, and it is the view of the SEC that such a waiver is against public policy.

Governing Law

The Indentures and the debt securities will be governed by, and construed in accordance with, the internal laws of the State of New York.

Concerning the Trustee

The Indentures and provisions of the Trust Indenture Act, which are incorporated by reference therein, contain limitations on the rights of the Trustee, should it become one of our creditors, to obtain payment of claims in certain cases, or to realize on property received in respect of any such claim, as security or otherwise. The Trustee and its affiliates may engage in, and will be permitted to continue to engage in, other transactions with us and our affiliates; provided, however, that if it acquires any conflicting interest (as defined in the Trust Indenture Act), it must eliminate the conflict or resign. The Trust Indenture Act and the relevant Indenture provide that in case an Event of Default shall occur (and be continuing), the Trustee will be required, in the exercise of its rights and powers, to use the same degree of care and skill of a prudent person in the conduct of such person's own affairs. Subject to such provision, the Trustee will be under no obligation to exercise any of its rights or powers under the relevant Indenture at the request of any of the holders of the debt securities issued thereunder, unless they have offered to the Trustee security or indemnity satisfactory to it.

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DESCRIPTION OF GUARANTEES

The debt securities of any series of the applicable issuer may have the benefit of guarantees (each, a 'Guarantee'), by one or more of its subsidiaries (each, a 'Guarantor'). In the case of Southwest Gas Corporation, the debt securities may or may not be guaranteed by Southwest Gas Holdings, Inc., its direct parent. The Guarantees, if any, will be the unsubordinated and, unless otherwise expressly stated in the applicable prospectus supplement, unsecured obligations of the respective Guarantors. The Guarantors of any series of guaranteed debt securities of each issuer may differ from the Guarantors of any other series of guaranteed debt securities of each issuer. In the event Southwest Gas Holdings, Inc. or Southwest Gas Corporation, as applicable, issues a series of guaranteed debt securities, the specific Guarantors of the debt securities of that series will be identified in the applicable prospectus supplement.

If Southwest Gas Holdings, Inc. or Southwest Gas Corporation, as applicable, issues a series of guaranteed debt securities, a description of some of the terms of Guarantees of those debt securities will be set forth in the applicable prospectus supplement. Unless otherwise provided in the prospectus supplement relating to a series of guaranteed debt securities, each Guarantor of the debt securities of such series will unconditionally guarantee the due and punctual payment of the principal of, and premium, if any, and interest, if any, on and any other amounts payable with respect to, each debt security of such series and the due and punctual performance of all of the applicable issuer's other obligations under the applicable Indenture with respect to the debt securities of such series, all in accordance with the terms of such debt securities and the applicable Indenture.

Notwithstanding the foregoing, unless otherwise provided in the prospectus supplement relating to a series of guaranteed debt securities, the applicable Indenture will contain provisions to the effect that the obligations of each Guarantor under its Guarantees and such Indenture shall be limited to the maximum amount as will, after giving effect to all other contingent and fixed liabilities of such Guarantor, result in the obligations of such Guarantor under such Guarantees and such Indenture not constituting a fraudulent conveyance or fraudulent transfer under applicable law. However, there can be no assurance that, notwithstanding such limitation, a court would not determine that a Guarantee constituted a fraudulent conveyance or fraudulent transfer under applicable law. If that were to occur, the court could void the applicable Guarantor's obligations under that Guarantee, subordinate that Guarantee to other debt and other liabilities of that Guarantor or take other action detrimental to holders of the debt securities of the applicable series, including directing the holders to return any payments received from the applicable Guarantor.

The applicable prospectus supplement relating to any series of guaranteed debt securities will specify other terms of the applicable Guarantees, which may include provisions that allow a Guarantor to be released from its obligations under its Guarantee under specified circumstances or that provide for one or more Guarantees to be secured by specified collateral.

Unless otherwise expressly stated in the applicable prospectus supplement, each Guarantee will be the unsubordinated and unsecured obligation of the applicable Guarantor and will rank on a parity in right of payment with all other unsecured and unsubordinated indebtedness and guarantees of such Guarantor. Each Guarantee (other than a secured Guarantee) will be effectively subordinated to all existing and future secured indebtedness and secured guarantees of the applicable Guarantor to the extent of the value of the collateral securing that indebtedness and those guarantees. Consequently, in the event of a bankruptcy, liquidation, dissolution, reorganization or similar proceeding with respect to any Guarantor that has provided an unsecured Guarantee of any debt securities, the holders of that Guarantor's secured indebtedness and secured guarantees will be entitled to proceed directly against the collateral that secures that secured indebtedness or those secured guarantees, as the case may be, and such collateral will not be available for satisfaction of any amount owed by such Guarantor under its unsecured indebtedness and unsecured guarantees, including its unsecured Guarantees of any debt securities, until that secured debt and those secured guarantees are satisfied in full. Unless otherwise provided in the applicable prospectus supplement, the Indentures will not limit the ability of any Guarantor to incur secured indebtedness or issue secured guarantees.

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Unless otherwise expressly stated in the applicable prospectus supplement, each secured Guarantee will be an unsubordinated obligation of the applicable Guarantor and will rank on a parity in right of payment with all other unsecured and unsubordinated indebtedness and guarantees of such Guarantor, except that such secured Guarantee will effectively rank senior to such Guarantor's unsecured and unsubordinated indebtedness and guarantees in respect of claims against the collateral securing that secured Guarantee.

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DESCRIPTION OF DEPOSITARY SHARES

The following description of depositary shares is only a summary and is qualified by any prospectus supplement and deposit agreement and depositary receipt used in connection with the issuance of each series of preferred stock issued through the use of depositary shares. Therefore, you should read carefully the more detailed description that would be contained in any prospectus supplement and form of deposit agreement and depositary receipt, copies of which are incorporated by reference as exhibits to the registration statement of which this prospectus is a part.

We may offer fractional shares of preferred stock by issuing receipts for depositary shares. The shares of any series of preferred stock represented by depositary shares will be deposited with a bank or trust company and the holders will be issued a depositary receipt entitling them, in proportion to the fraction of a share the receipt represents, to all the rights and preferences of the preferred stock, as more fully described above under the heading 'Description of Capital Stock-Preferred Stock.'

The bank or trust company that will be the depositary will function as the intermediary between Southwest Gas Holdings and the holders of the depositary receipts. Dividends and other distributions will be provided to the depositary for ultimate distribution to the holders. Redemption of the depositary shares and voting the underlying preferred stock will also be coordinated through the depositary. Holders will have the right to surrender their depositary receipts to the depositary and be entitled to receive whole shares of preferred stock that are represented by such receipts. Though the preferred stock will continue to have all of the rights and preferences, there may be no market opportunity to trade such stock and once withdrawn from the depositary, it may not be redeposited.

We will pay all transfer and other taxes and governmental charges arising solely from the existence of the depositary arrangement. Southwest Gas Holdings will also pay charges of the depositary in connection with the initial deposit of the preferred stock and the initial issuance of the depositary receipts, any redemption of the preferred stock and any withdrawal of preferred stock by the holder of the depositary shares. Holders will pay other transfer and other taxes and governmental charges and such other charges specifically provided in the deposit agreement for their individual accounts.

DESCRIPTION OF WARRANTS

General

We may issue warrants to purchase debt securities, common stock, preferred stock, depositary shares or any combination of these securities. We may issue the warrants independently or together with any underlying securities, and the warrants may be attached or separate from the underlying securities. We may also issue a series of warrants under a separate warrant agreement to be entered into between us and a warrant agent. The warrant agent will act solely as our agent in connection with the warrants of such series and will not assume any obligation or relationship of agency for or with holders or beneficial owners of warrants.

The following description is a summary of selected provisions relating to the warrants that we may issue. The summary is not complete. When warrants are offered in the future, a prospectus supplement, or other offering material as applicable, will explain the particular terms of those securities and the extent to which these general provisions may apply. The specific terms of the warrants as described in a prospectus supplement will supplement and, if applicable, may modify or replace the general terms described in this section.

This summary and any description of warrants in the applicable prospectus supplement or other offering material is subject to and is qualified in its entirety by reference to all the provisions of any specific warrant document or agreement, which we will file with the SEC for incorporation by reference into this prospectus. See 'Where You Can Find More Information' and 'Incorporation by Reference' for information on how to obtain a copy of a warrant document when it is filed.

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When we refer to a series of warrants, we mean all warrants issued as part of the same series under the applicable warrant agreement.

Terms

The prospectus supplement relating to any warrants that we may offer will contain the specific terms of the warrants. These terms may include the following:

Warrant Agreements

We may issue the warrants in one or more series under one or more warrant agreements, each to be entered into between us and a bank, trust company, or other financial institution as warrant agent. We may add, replace, or terminate warrant agents from time to time. We may also choose to act as our own warrant agent or may choose one of our subsidiaries to do so.

The warrant agent under a warrant agreement will act solely as our agent in connection with the warrants issued under that agreement. The warrant agent will not assume any obligation or relationship of agency or trust for or with any holders of those warrants. Any holder of warrants may, without the consent of any other person, enforce by appropriate legal action, on its own behalf, its right to exercise those warrants in accordance with their terms. Until the warrant is properly exercised, no holder of any warrant will be entitled to any rights of a holder of the warrant property purchasable upon exercise of the warrant.

Form, Exchange, and Transfer

We may issue the warrants in registered form or bearer form. Warrants issued in registered form, i.e., book-entry form, will be represented by a global security registered in the name of a depository, which will be

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the holder of all the warrants represented by the global security. Those investors who own beneficial interests in a global warrant will do so through participants in the depository's system, and the rights of these indirect owners will be governed solely by the applicable procedures of the depository and its participants. In addition, we may issue warrants in non-global form, i.e., bearer form. If any warrants are issued in non-global form, warrant certificates may be exchanged for new warrant certificates of different denominations, and holders may exchange, transfer, or exercise their warrants at the warrant agent's office or any other office indicated in the applicable prospectus supplement or other offering material.

Prior to the exercise of their warrants, holders of warrants exercisable for debt securities will not have any of the rights of holders of the debt securities purchasable upon such exercise and will not be entitled to payments of principal (or premium, if any) or interest, if any, on the debt securities purchasable upon such exercise. Prior to the exercise of their warrants, holders of warrants exercisable for shares of preferred stock or common stock will not have any rights of holders of the preferred stock or common stock purchasable upon such exercise and will not be entitled to dividend payments, if any, or voting rights of the preferred stock or common stock purchasable upon such exercise.

Exercise of Warrants

A warrant will entitle the holder to purchase for cash an amount of securities at an exercise price that will be stated in, or that will be determinable as described in, the applicable prospectus supplement or other offering material. Warrants may be exercised at any time up to the close of business on the expiration date set forth in the applicable prospectus supplement or other offering material. After the close of business on the expiration date, unexercised warrants will become void.

Warrants may be exercised as set forth in the applicable prospectus supplement or other offering material. Upon receipt of payment and the warrant certificate properly completed and duly executed at the corporate trust office of the warrant agent or any other office indicated in the prospectus supplement or other offering material, we will forward, as soon as practicable, the securities purchasable upon such exercise. If less than all of the warrants represented by such warrant certificate are exercised, a new warrant certificate will be issued for the remaining warrants.

DESCRIPTION OF UNITS

General

We may issue units composed of any combination of our debt securities, common stock, preferred stock, and warrants. We will issue each unit so that the holder of the unit is also the holder of each security included in the unit. As a result, the holder of a unit will have the rights and obligations of a holder of each included security. The unit agreement under which a unit is issued may provide that the securities included in the unit may not be held or transferred separately, at any time or at any time before a specified date.

The following description is a summary of selected provisions relating to units that we may offer. The summary is not complete. When units are offered in the future, a prospectus supplement, or other offering material as applicable, will explain the particular terms of those securities and the extent to which these general provisions may apply. The specific terms of the units as described in a prospectus supplement will supplement and, if applicable, may modify or replace the general terms described in this section.

This summary and any description of units in the applicable prospectus supplement or other offering material is subject to and is qualified in its entirety by reference to the unit agreement and, if applicable, collateral arrangements and depositary arrangements relating to such units. We will file these documents with the SEC for incorporation by reference into this prospectus. See 'Where You Can Find More Information' and 'Incorporation by Reference' for information on how to obtain a copy of a document when it is filed.

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The applicable prospectus supplement or other offering material may describe:

The applicable provisions described in this section, as well as those described under 'Description of Debt Securities,' 'Description of Guarantees,' 'Description of Capital Stock' and 'Description of Warrants,' will apply to each unit and to each security included in each unit, respectively.

DESCRIPTION OF RIGHTS

We may from time to time, issue rights to purchase our debt securities, common stock, preferred stock or other securities. The rights may or may not be transferable by the persons purchasing or receiving the rights. In connection with any rights offering, we may enter into a standby underwriting or other arrangement with one or more underwriters or other persons pursuant to which such underwriters or other persons would purchase any offered securities remaining unsubscribed after such rights offering.

Each series of rights will be issued under a separate rights agreement to be entered into, from time to time, between us and a bank or trust company, as rights agent, all as set forth in a prospectus supplement relating to the particular issue of rights. The rights agent will act solely as an agent of ours in connection with the certificates relating to the rights and will not assume any obligation or relationship of agency or trust for or with any holders of rights certificates or beneficial owners of rights.

The following description is a summary of selected provisions relating to rights that we may offer. The summary is not complete. When rights are offered in the future, a prospectus supplement, or other offering material as applicable, will explain the particular terms of those securities and the extent to which these general provisions may apply. The specific terms of the rights as described in a prospectus supplement will supplement and, if applicable, may modify or replace the general terms described in this section.

This summary and any description of units in the applicable prospectus supplement or other offering material is subject to and is qualified in its entirety by reference to the rights agreement and, if applicable, underwriting or other arrangements relating to such rights. We will file these documents with the SEC for incorporation by reference into this prospectus. See 'Where You Can Find More Information' and 'Incorporation by Reference' for information on how to obtain a copy of a document when it is filed.

The applicable prospectus supplement will describe the terms of the rights to be issued, including the following where applicable:

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If less than all of the rights issued in any rights offering are exercised, we may offer any unsubscribed securities directly to persons other than our security holders, to or through agents, underwriters or dealer or through a combination of such methods, including pursuant to standby arrangements, as described in the applicable prospectus supplement.

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PLAN OF DISTRIBUTION

We may sell the securities described in this prospectus from time to time in one or more transactions:

We may sell the securities directly to institutional investors or others who may be deemed to be underwriters within the meaning of the Securities Act, with respect to any resale of the securities. A prospectus supplement will describe the terms of any sale of securities we are offering hereunder. Direct sales may be arranged by a securities broker-dealer or other financial intermediary.

The applicable prospectus supplement will name any underwriter involved in a sale of securities. Underwriters may offer and sell securities at a fixed price or prices, which may be changed, or from time to time at market prices or at negotiated prices. Underwriters may be deemed to have received compensation from us from sales of securities in the form of underwriting discounts or commissions and may also receive commissions from purchasers of securities for whom they may act as agent. Underwriters may be involved in any 'at the market' offering of securities by or on our behalf.

Underwriters may sell securities to or through dealers, and such dealers may receive compensation in the form of discounts, concessions or commissions from the underwriters and/or commissions (which may be changed from time to time) from the purchasers for whom they may act as agent.

Unless we state otherwise in the applicable prospectus supplement, the obligations of any underwriters to purchase securities will be subject to certain conditions precedent, and the underwriters will be obligated to purchase all the securities if any are purchased.

The applicable prospectus supplement will set forth whether or not underwriters may over-allot or effect transactions that stabilize, maintain or otherwise affect the market price of the securities at levels above those that might otherwise prevail in the open market, including, for example, by entering stabilizing bids, effecting syndicate covering transactions or imposing penalty bids.

We will name any agent involved in a sale of securities, as well as any commissions payable to such agent, in a prospectus supplement. Unless we state otherwise in the applicable prospectus supplement, any such agent will be acting on a reasonable efforts basis for the period of its appointment.

If a dealer is utilized in the sale of the securities being offered pursuant to this prospectus, we and/or one or more selling stockholders will sell the securities to the dealer, as principal. The dealer may then resell the securities to the public at varying prices to be determined by the dealer at the time of resale.

Underwriters, dealers and agents participating in a sale of the securities may be deemed to be underwriters as defined in the Securities Act, and any discounts and commissions received by them and any profit realized by them on resale of the securities may be deemed to be underwriting discounts and commissions, under the Securities Act. We may have agreements with underwriters, dealers and agents to indemnify them against certain civil liabilities, including liabilities under the Securities Act, and to reimburse them for certain expenses.

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WHERE YOU CAN FIND MORE INFORMATION

We file annual, quarterly and current reports, proxy statements and other information with the SEC. The SEC maintains an Internet web site that contains reports, proxy and information statements, and other information regarding issuers, including us, that file electronically with the SEC. The public can obtain any documents that we file electronically with the SEC athttp://www.sec.gov. You may also obtain our filings through the New York Stock Exchange, 20 Broad Street, New York, New York 10005, on which our common stock is listed.

We also make available, free of charge, on or through our Internet web site (https://www.swgasholdings.com) our Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K, Proxy Statements on Schedule 14A and, if applicable amendments to those reports filed or furnished pursuant to Section 13(a) of the Exchange Act, as soon as reasonably practicable after we electronically file such material with, or furnish it to, the SEC. Please note, however, that we have not incorporated any other information by reference from our Internet web site, other than the documents listed under the heading 'Incorporation by Reference.'

We have filed with the SEC a registration statement on Form S-3 relating to the securities covered by this prospectus. This prospectus is a part of the registration statement and does not contain all the information in the registration statement. Whenever a reference is made in this prospectus to a contract or other document of ours, the reference is only a summary and you should refer to the exhibits that are a part of the registration statement for a copy of the contract or other document. You may review a copy of the registration statement and the documents incorporated by reference herein through the SEC's Internet web site referenced above.

INCORPORATION BY REFERENCE

The SEC allows us to 'incorporate by reference' into this prospectus the information in other documents that we file with it, which means that we can disclose important information to you by referring you to those documents. The information that we incorporate by reference is considered to be a part of this prospectus.

Any reports that we file with the SEC on or after the date of this prospectus and before the date that the offering of the securities is terminated will automatically update and, where applicable, supersede any information contained in this prospectus or incorporated by reference into this prospectus. This means that you must look at all of the SEC filings that we incorporate by reference to determine if any of the statements in this prospectus or in any documents previously incorporated by reference into this prospectus have been modified or superseded. We specifically incorporate by reference into this prospectus the following documents filed with the SEC (other than, in each case, documents or information deemed furnished and not filed in accordance with SEC rules, including pursuant to Item 2.02 or Item 7.01 of Form 8-K, and no such information shall be deemed specifically incorporated by reference hereby):

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You may obtain a copy of any or all of the documents referred to above which have been or may be incorporated by reference into this prospectus (excluding certain exhibits unless they are specifically incorporated by reference in any such documents) at no cost to you by writing or telephoning us at the following:

Southwest Gas Holdings, Inc.

8360 S. Durango Drive

P.O. Box 98510

Las Vegas, Nevada 89193-8510

Attention: Corporate Secretary

Telephone: (702) 876-7237

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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 by reference to Southwest Gas Holdings, Inc.'s Annual Report on Form 10-K for the year ended December 31, 2019have 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.

The financial statements incorporated in this Prospectus by reference to Southwest Gas Corporation'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.

LEGAL MATTERS

The validity of the securities to be sold hereunder will be passed upon for us by Morrison & Foerster LLP.

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Up to $500,000,000

Common Stock

PROSPECTUS SUPPLEMENT

BNY MELLON CAPITAL MARKETS, LLC

J.P. MORGAN

The date of this prospectus supplement is April 8, 2021.