Filed Pursuant to Rule 424(b)(2)
Registration No. 333-215833

PROSPECTUS SUPPLEMENT

(To Prospectus Dated September 24, 2018)

$1,500,000,000

CenterPoint Energy, Inc.

$500,000,000 3.60% Senior Notes due 2021

$500,000,000 3.85% Senior Notes due 2024

$500,000,000 4.25% Senior Notes due 2028

This is an offering of $500,000,000 aggregate principal amount of 3.60% Senior Notes due 2021 (the “2021 notes”), $500,000,000 aggregate principal amount of 3.85% Senior Notes due 2024 (the “2024 notes”) and $500,000,000 aggregate principal amount of 4.25% Senior Notes due 2028 (the “2028 notes” and, together with the 2021 notes and the 2024 notes, the “notes”). The 2021 notes will bear interest at a rate of 3.60% per year from, and including, the date of issuance and will mature on November 1, 2021. The 2024 notes will bear interest at a rate of 3.85% per year from, and including, the date of issuance and will mature on February 1, 2024. The 2028 notes will bear interest at a rate of 4.25% per year from, and including, the date of issuance and will mature on November 1, 2028. We will pay interest on the 2021 and 2028 notes on May 1 and November 1 of each year, beginning on May 1, 2019. We will pay interest on the 2024 notes on February 1 and August 1 of each year beginning on February 1, 2019. The notes are subject to optional redemption prior to maturity at the applicable redemption prices described under the caption “Description of the Notes — Optional Redemption.”

We intend to use the net proceeds from this offering to fund a portion of the Merger Consideration (as defined herein) for our proposed merger with Vectren Corporation (the “Vectren Merger”) as described herein under the heading “Summary Information — Recent Developments — Proposed Merger with Vectren” and to pay related fees and expenses. However, the completion of this offering is not contingent upon the completion of the Vectren Merger. If we do not consummate the Vectren Merger on or prior to October 31, 2019, or if, on or prior to such date, the Merger Agreement (as defined herein) is terminated, we will be required to redeem all of the outstanding notes at a redemption price equal to 101% of the principal amount of the notes plus accrued and unpaid interest, if any, to, but excluding, the date of such special mandatory redemption as described under the caption “Description of the Notes — Special Mandatory Redemption.” The notes may also be redeemed at our option, in whole but not in part at any time before October 31, 2019, at a redemption price equal to 101% of the aggregate principal amount thereof plus accrued and unpaid interest thereon to, but excluding, the date of such redemption, if we determine, in our reasonable judgment, that the Vectren Merger will not be consummated on or before 5:00 p.m. (New York City time) on October 31, 2019. See “Description of the Notes — Special Optional Redemption.”

The notes will be issued in minimum denominations of $2,000 and integral multiples of $1,000 in excess thereof. The notes will be unsecured and will rank equally with our other unsecured and unsubordinated indebtedness. The notes will be structurally subordinated to all existing and future indebtedness and other liabilities of our subsidiaries.

Investing in the notes involves risks. See “Risk Factors” beginning on page S-11 of this prospectus supplement and on page 3 of the accompanying prospectus.

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

The underwriters expect to deliver the notes in book-entry form only through the facilities of The Depository Trust Company and for the accounts of its participants, including, Clearstream Banking, société anonyme and Euroclear S.A./N.V., as operator of the Euroclear System, against payment in New York, New York on or about October 5, 2018.

Joint Book-Running Managers

Senior Co-Managers

Co-Managers

Prospectus Supplement dated October 3, 2018

This document consists of two parts, which should be read together. The first part is this prospectus supplement, which describes the specific terms of the notes, the specific terms of this offering and supplements and updates information contained in the accompanying prospectus and the documents incorporated by reference into this prospectus supplement and the accompanying prospectus. The second part, the accompanying prospectus, provides more general information about the notes and other securities that may be offered from time to time using such prospectus, some of which general information does not apply to this offering. Generally, when we refer to the prospectus, we are referring to both parts of this document combined. You should read this prospectus supplement and the accompanying prospectus together with any written communication prepared by us or on our behalf in connection with this offering together with the additional information described in this prospectus supplement under the headings “Where You Can Find More Information” and “Incorporation By Reference.”

We have not, and the underwriters have not, authorized anyone to provide any information or to make any representations other than those contained or incorporated by reference in this prospectus supplement, the accompanying prospectus and any written communication prepared by us or on our behalf. We and the underwriters take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. We are not, and the underwriters are not, making an offer to sell the notes and are not soliciting an offer to buy the notes in any jurisdiction where the offer or sale is not permitted. The information we have included in this prospectus supplement or the accompanying prospectus is accurate only as of the date of this prospectus supplement or the accompanying prospectus, as the case may be, and any information we have incorporated by reference is accurate only as of the date of the document incorporated by reference. Our businesses, financial condition, results of operations and prospects may have changed since these respective dates.

Any information contained in this prospectus supplement or the accompanying prospectus or in a document incorporated by reference in this prospectus supplement or the accompanying prospectus will be deemed to be modified or superseded to the extent that a statement contained in this prospectus supplement or in any other subsequently filed document that is also incorporated by reference in this prospectus supplement modifies or supersedes that statement. Any statement so modified or superseded will not be deemed, except as so modified or superseded, to constitute a part of this prospectus supplement. See “Incorporation By Reference” in this prospectus supplement.

The Bank of New York Mellon Trust Company, National Association, in each of its capacities referenced herein, including, but not limited to, trustee, security registrar and paying agent, has not participated in the preparation of this prospectus supplement or the accompanying prospectus and assumes no responsibility for its content.

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TABLE OF CONTENTS

Prospectus Supplement

Prospectus

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RISK FACTORS

In addition to the following information about risks, you should consider carefully the risk factors and risks identified or referenced in our Annual Report on Form 10-K for the fiscal year ended December 31, 2017 (the “2017 Form 10-K”) and our Quarterly Reports on Form 10-Q for the quarterly periods ended March 31, 2018 and June 30, 2018 (the “2nd Quarter 2018 Form 10-Q”), which are incorporated by reference in this prospectus supplement and the accompanying prospectus, as they may be amended, supplemented or superseded from time to time by other reports that we subsequently file with the Securities and Exchange Commission (the “SEC”), together with the other information contained or incorporated by reference in this prospectus supplement and the accompanying prospectus, before making an investment in the notes.

Risks Related to the Notes

A change in our credit ratings or the ratings of the notes could adversely affect the market price of the notes.

On April 24, 2018, Moody’s placed CenterPoint Energy, Inc.’s credit ratings for its senior unsecured debt on negative outlook and S&P placed its long-term ratings on CenterPoint Energy Inc. on CreditWatch with negative implications. Moody’s and S&P indicated that their actions were triggered by the proposed acquisition of Vectren and our expected increased leverage relating to our proposed financing of the Vectren Merger. Moody’s indicated that a one notch downgrade is likely if the Vectren Merger is financed as we have proposed. S&P, however, noted that its ratings action reflected the potential of a one to two notch downgrade. By maintaining our current business risk profile and consummating the Series A Preferred Stock Offering, the Depositary Shares Offering and the Common Stock Offering, we are targeting a BBB or better credit rating upon consummation of the Vectren Merger. A BBB rating would reflect a one notch downgrade from our current credit rating. We cannot guarantee that we will be able to achieve our targeted credit rating. Both agencies also indicated that a downgrade could occur at or before the closing of the Vectren Merger. The negative outlook by Moody’s and S&P, any downgrade of our credit ratings by S&P, Fitch Ratings, Moody’s or any other rating agency, or any additional negative outlook on our credit ratings may adversely affect the market price of our debt securities, Common Stock, the Series A Preferred Stock, the Depositary Shares and the Series B Preferred Stock and could make it more costly for us to issue debt securities, to borrow under our credit facilities and to raise certain other types of financing, including in connection with the Vectren Merger.

Credit ratings reflect only the views of the issuing rating agency or agencies and are not recommendations to purchase, sell or hold any particular security, including the notes. In addition, credit ratings do not reflect market prices or suitability of a security for a particular investor, and any future credit rating of the notes may not reflect all risks related to us and our business or the structure or market value of the notes.

We cannot assure you that an active trading market will develop for the notes.

Each series of notes will be a new issue of securities for which currently there is no established trading market. We do not intend to apply for the listing of the notes on any securities exchange or for quotation of the notes on any dealer quotation system. We cannot assure you that a trading market will develop for the notes. Even if a market for the notes does develop, we cannot assure you that there will be liquidity in that market or that the notes might not trade for less than their original value or face amount. The liquidity of any market for the notes will depend on the number of holders of the notes, the interest of securities dealers in making a market in the notes and other factors. If a liquid market for the notes does not develop, you may be unable to resell the notes for a long period of time, if at all. This means you may not be able to readily convert your notes into cash, and the notes may not be accepted as collateral for a loan.

Even if a market for the notes develops, trading prices could be higher or lower than the initial offering price. The price of the notes will depend on many factors, including prevailing interest rates, our operating results and the market for similar securities. Declines in the market prices for debt securities generally may also materially and adversely affect the liquidity of the notes, independent of our financial performance.

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Our existing indebtedness, and any future indebtedness, may adversely affect our future financial and operating flexibility and our ability to service the notes.

As of June 30, 2018, we, on an unconsolidated basis, had approximately $0.6 billion aggregate principal amount of indebtedness outstanding, $0.5 billion of which was unsecured, excluding principal amounts under our 2.0% Zero-Premium Exchangeable Subordinated Notes due 2029. Excluding subsidiaries issuing transition and system restoration bonds, as of June 30, 2018, our subsidiaries had approximately $6.10 billion aggregate principal amount of third-party indebtedness outstanding, of which approximately $3.30 billion was secured, as well as other liabilities. In addition, we had the ability to borrow an additional $2.3 billion under our credit facilities and commercial paper program, collectively, subject to certain limitations. As of June 30, 2018, we have also entered into the Commitment Letter with a syndicate of lenders providing, subject to customary conditions, for a $5.0 billion, 364-day senior unsecured Bridge Facility to backstop a portion of our obligation to pay the Merger Consideration. Assuming we are able to issue a sufficient amount of the notes, we intend to terminate all remaining commitments under the Bridge Facility promptly following the issuance of the notes. However, upon the termination of such commitments under the Bridge Facility, the aggregate commitments by lenders under our Revolving Credit Facility will increase by an additional $1.6 billion. Our existing indebtedness and the additional debt we may incur in the future for, among other things, working capital, capital expenditures, acquisitions or operating activities may adversely affect our liquidity and, therefore, our ability to make principal and interest payments on the notes.

The indenture governing the notes will permit us to incur additional debt, which would be equal in right of payment to the notes. If we incur any additional indebtedness, including trade payables, that ranks equally with the notes, the holders of that debt would be entitled to share ratably with you in any proceeds distributed in connection with any insolvency, liquidation, reorganization, dissolution or other winding up of us. This may have the effect of reducing the amount of proceeds paid to you. If new debt is added to our current debt levels, the related risks that we now face could intensify.

The notes will be structurally subordinated to existing and future indebtedness and other liabilities of our subsidiaries.

Other than the Series A Preferred Units in Enable that we hold directly, we derive all our operating income from, and hold all our assets, including our other interests in Enable, through our subsidiaries. As a result, we will depend on distributions from our subsidiaries and Enable to meet our payment obligations under any debt securities, including the notes and our other obligations. In general, these subsidiaries are separate and distinct legal entities and have no obligation to pay any amounts due on our debt securities or to provide us with funds for our payment obligations, whether by dividends, distributions, loans or otherwise. In addition, provisions of applicable law, such as those limiting the legal sources of dividends, limit our subsidiaries’ ability to make payments or other distributions to us, and our subsidiaries could agree to contractual restrictions on their ability to make distributions.

Our right to receive any assets of any subsidiary, and therefore the right of our creditors to participate in those assets, will be structurally subordinated to the claims of that subsidiary’s creditors, including trade creditors. In addition, even if we were a creditor of any subsidiary, our rights as a creditor would be effectively subordinated to any security interest in the assets of that subsidiary and any indebtedness of the subsidiary senior to that held by us. Excluding subsidiaries issuing transition and system restoration bonds, as of June 30, 2018, our subsidiaries had approximately $6.1 billion aggregate principal amount of third-party indebtedness outstanding, of which approximately $3.3 billion was secured, as well as other liabilities.

The provisions of the notes will not necessarily protect you in the event of a highly leveraged transaction.

The terms of the notes will not necessarily afford you protection in the event of a highly leveraged transaction that may adversely affect you, including a reorganization, recapitalization, restructuring, merger or

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other similar transactions involving us or our subsidiaries, whether or not in connection with a change of control. The indenture does not limit the amount of debt we or our subsidiaries may issue. As a result, we could enter into any such transaction even though the transaction could adversely affect our capital structure or credit ratings or otherwise adversely affect the holders of the notes. If we incur secured debt, the notes will be effectively junior to such debt to the extent of the value of the collateral securing such debt. These transactions may not involve a change in voting power or beneficial ownership or result in a downgrade in the ratings of the notes. The indenture does not contain provisions that permit the holders of the notes to require us to redeem or repurchase the notes in the event of a takeover, recapitalization or similar transaction.

CenterPoint Energy expects to incur significant additional indebtedness and has issued a significant amount of preferred stock in connection with the Vectren Merger. As a result, it may be more difficult for CenterPoint Energy to pay or refinance its debts, pay dividends on its preferred stock or take other actions, and CenterPoint Energy may need to divert cash to fund debt service payments or preferred stock dividend payments.

As discussed under “Summary — Recent Developments — Vectren Merger Financing” and “Summary — Recent Developments — Sources and Uses,” CenterPoint Energy expects to incur significant additional indebtedness to finance the Merger Consideration and related transaction costs. The Vectren Merger will constitute a “Change of Control” under the governing documents of approximately $1.30 billion of debt of Vectren subsidiaries. While the Vectren Merger will not result in an event of default under such debt documents nor will it compel holders of such debt to tender their debt, the Vectren subsidiaries will be required to offer to repurchase such debt at par upon the closing of the Vectren Merger. Additionally, CenterPoint Energy has issued Series A Preferred Stock and Series B Preferred Stock to fund a portion of the Merger Consideration. Moreover, CenterPoint Energy plans to fund a significant portion of the Merger Consideration through sales of the notes offered hereby and commercial paper. The increase in CenterPoint Energy’s debt service obligations resulting from this additional indebtedness and preferred stock dividend obligations could have a material adverse effect on the results of operations, financial condition and prospects of the combined company.

CenterPoint Energy’s increased indebtedness and outstanding preferred stock could:

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Based on the current and expected results of operations and financial condition of CenterPoint Energy and its subsidiaries and the anticipated financing structure for the Vectren Merger, CenterPoint Energy believes that its cash flow from operations, together with the proceeds from borrowings, issuances of equity and debt securities in the capital markets and distributions from its interests in Enable will generate sufficient cash on a consolidated basis to make all of the principal and interest payments when such payments are due under CenterPoint Energy’s and its current subsidiaries’ existing credit facilities, indentures and other instruments governing their outstanding indebtedness and under the indebtedness anticipated to be incurred to fund the Merger Consideration. However, CenterPoint Energy’s expectation is subject to numerous estimates, assumptions and uncertainties, and there can be no assurance that CenterPoint Energy will be able to make such payments of principal and interest or repay or refinance such borrowings and obligations when due. Vectren and its subsidiaries will not guarantee any indebtedness of CenterPoint Energy or any of its other subsidiaries, nor will any of them have any obligation to provide funds, whether in the form of dividends, loans or otherwise, to enable CenterPoint Energy to pay dividends on its common stock, the Series A Preferred Stock, the Series B Preferred Stock and related depositary shares or CenterPoint Energy and its other subsidiaries to make required debt service payments. As a result, the Vectren Merger will substantially increase CenterPoint Energy’s debt service obligations without any assurance that CenterPoint Energy will receive any cash from Vectren or any of its subsidiaries to assist CenterPoint Energy in servicing its indebtedness, paying dividends on its common stock, Series A Preferred Stock, Series B Preferred Stock and related depositary shares or meeting its other cash needs.

CenterPoint Energy is committed to maintaining its credit ratings at investment grade. To maintain these credit ratings, CenterPoint Energy may consider it appropriate to reduce the amount of its indebtedness outstanding following the Vectren Merger. CenterPoint Energy may seek to reduce this indebtedness with the proceeds from the issuance of equity securities. However, the ability of CenterPoint Energy to raise additional equity financing after completion of the Vectren Merger will be subject to market conditions and a number of other risks and uncertainties, including whether the results of operations of the combined company meet the expectations of investors and securities analysts. There can be no assurance that CenterPoint Energy will be able to issue additional equity securities after the Vectren Merger on terms that it considers acceptable or at all, or that CenterPoint Energy will be able to reduce the amount of its outstanding indebtedness after the Vectren Merger, should it elect to do so, to a level that permits it to maintain its investment grade credit ratings.

If the proposed Vectren Merger is consummated and this offering results in aggregate net cash proceeds significantly less than contemplated by this prospectus supplement, we may incur a substantially greater amount of debt under the Bridge Facility, the Revolving Credit Facility or our commercial paper program. This additional debt could adversely affect our business, including by restricting our ability to engage in additional transactions or incur additional indebtedness or resulting in a downgrade or other adverse action with respect to our credit rating.

In connection with the proposed Vectren Merger, we expect to incur up to approximately $2.31 billion of additional indebtedness, and if and to the extent that this offering is completed for less proceeds than anticipated, we would fund any shortfall with borrowings under the Bridge Facility, the Revolving Credit Facility or our

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commercial paper program. Our net consolidated borrowing costs, which cannot be predicted at this time, will depend on rates in effect from time to time, the structure of the debt, taxes and other factors.

In addition, any borrowings under the Bridge Facility will mature 364 days after they are incurred. We may not be able to refinance borrowings under the Bridge Facility on favorable terms or at all before their maturity. In addition, the interest rate applicable to borrowings under the Bridge Facility will increase at the end of each three-month period after the borrowing date. Accordingly, we may incur additional interest expense if we are unable to refinance borrowings under the Bridge Facility before the interest rate increases take effect.

Our credit ratings impact the cost and availability of future borrowings and, accordingly, our cost of capital. Our credit ratings at any time will reflect each rating organization’s then opinion of our financial strength, operating performance and ability to meet our debt obligations. There can be no assurance that we will achieve a particular rating or maintain a particular rating in the future. Any reduction in our credit ratings may limit our ability to borrow at interest rates consistent with the interest rates that have been available to us prior to the proposed Vectren Merger, and may subject us to additional covenants under our debt instruments. Any impairment of our ability to obtain future financing on favorable terms could have an adverse effect on our ability to refinance the Bridge Facility, if drawn, with the issuance of debt securities and commercial paper or alternatives to the Bridge Facility on terms more favorable than under the Bridge Facility.

This offering is not contingent upon the completion of the Vectren Merger. If we do not consummate the Vectren Merger on or prior to October 31, 2019, or if, on or prior to such date, the Merger Agreement is terminated, we will be required to redeem all of the outstanding notes and we may not have the financial resources necessary to effect such redemption.

This offering is not contingent upon the completion of the Vectren Merger. Our ability to consummate the Vectren Merger is subject to various conditions, certain of which are beyond our control. The Merger Agreement contains certain provisions permitting its termination under certain circumstances. If we do not consummate the Vectren Merger on or prior to October 31, 2019, or if, on or prior to such date, the Merger Agreement is terminated, we will be required to redeem all outstanding notes at a redemption price equal to 101% of the aggregate principal amount of the notes plus accrued and unpaid interest, if any, to, but excluding, the date of such special mandatory redemption. See “Description of the Notes — Special Mandatory Redemption” in this prospectus supplement. The Notes may also be redeemed at our option, in whole but not in part, at any time before October 31, 2019, at a redemption price equal to 101% of the aggregate principal amount thereof plus accrued and unpaid interest thereon to, but excluding, the date of such redemption, if we determine, in our reasonable judgment, that the Vectren Merger will not be consummated on or before 5:00 p.m. (New York City time) on October 31, 2019. If we redeem notes pursuant to the special mandatory redemption or special optional redemption, you may not obtain the return that you expected on your investment in the notes that are so redeemed. In particular, we cannot assure that you will be able reinvest your redemption proceeds in an investment with a return that is as high as the return you would have earned on the notes that we redeemed and that have a similar level of investment risk.

Whether or not the special mandatory redemption is ultimately triggered, the existence of the mandatory redemption provisions may adversely affect the trading prices of the notes that are subject to those provisions until such time, if any, as the Vectren Merger is consummated.

We will not be required to deposit the proceeds from the issuance of the notes into an escrow account pending completion of the Vectren Merger, nor will we be required to grant any security interest in or other lien on those proceeds to secure any mandatory redemption of the notes. If we are required to redeem the notes, whether because the Vectren Merger is not completed by a specified date, the Merger Agreement is terminated or under similar circumstances, our ability to pay the redemption price may be limited by our financial resources at the time and the terms of our debt instruments and other instruments and agreements, and it is possible that we will not have sufficient financial resources available to satisfy our obligations to redeem any or all of the notes.

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Any failure to pay the mandatory redemption price of the notes of any series when due would constitute an event of default with respect to the notes of such series pursuant to the indenture under which those notes are issued and could have a material adverse effect on our business, results of operations and financial condition and the market prices of our securities, including the notes offered hereby.

The unaudited pro forma condensed combined financial information included and incorporated by reference in this prospectus supplement and the accompanying prospectus is presented for illustrative purposes only and does not purport to represent what the financial position or results of operations of the combined company would have been had the Vectren Merger been completed on the dates assumed for purposes of that pro forma information, nor does it represent the actual financial position or results of operations of the combined company following the Vectren Merger, if consummated.

The unaudited pro forma condensed combined financial information included and incorporated by reference in this prospectus supplement and the accompanying prospectus is presented for illustrative purposes only, is based on numerous adjustments, assumptions and estimates, is subject to numerous other uncertainties and does not purport to reflect what the combined company’s financial position or results of operations would have been had the Vectren Merger been completed as of the dates assumed for purposes of that pro forma financial information, nor does it reflect the financial position or results of operations of the combined company following the Vectren Merger, if consummated.

For purposes of the unaudited pro forma condensed combined financial information, the estimated Merger Consideration has been preliminarily allocated to the identifiable assets acquired and liabilities assumed based on limited information presently available to estimate fair values. The Merger Consideration will be allocated among the relative fair values of the identifiable assets acquired and liabilities assumed based on their estimated fair values as of the date of the Vectren Merger. The relative fair values of the assets acquired and liabilities assumed are estimates, which are subject to change pending further review. The actual amounts recorded at the completion of the Vectren Merger, if completed, may differ materially from the information presented in the unaudited pro forma condensed combined financial information.

The unaudited pro forma condensed combined financial information has also been prepared on the assumption that the Vectren Merger and the related financings will be completed on the terms and in accordance with the assumptions set forth under “Unaudited Pro Forma Condensed Combined Financial Information” included in this prospectus supplement and incorporated by reference in this prospectus supplement and the accompanying prospectus. Any changes in these assumptions would result in a change in the unaudited pro forma condensed combined financial information, which could be material. In addition, because none of the potential methods of financing the Vectren Merger will be contingent upon completion of any of the other, it is possible that one or more of such methods of financing will not be completed. It is also possible that such financings, if completed, will not generate the anticipated amount of net proceeds, which may require us to obtain additional or alternative financing, and we may not be able to obtain additional or alternative financing on terms we consider acceptable, or at all. See “Unaudited Pro Forma Condensed Combined Financial Information” and each of our and Vectren’s consolidated financial statements included or incorporated by reference in this prospectus supplement and the accompanying prospectus.

Our and Vectren’s actual financial positions and results of operations prior to the Vectren Merger and that of the combined company following the Vectren Merger, if consummated, may not be consistent with, or evident from, the unaudited pro forma condensed combined financial information included and incorporated by reference in this prospectus supplement and the accompanying prospectus. In addition, the assumptions or estimates used in preparing the unaudited pro forma condensed combined financial information may not prove to be accurate and may be affected by a broad range of factors.

Although the unaudited pro forma condensed combined financial information included and incorporated by reference in this prospectus supplement includes sensitivity analyses that are intended to assist you in quantifying

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the impact of changes in certain of the assumptions used in preparing such pro forma information, those sensitivity analyses reflect the pro forma impact of only a limited number of those assumptions and therefore do not allow you to quantify the impact of changes in any of the other assumptions made in calculating this pro forma information and changes in certain of those other assumptions may have a material impact on the unaudited pro forma condensed combined financial information. Likewise, the sensitivity analyses we have provided do not necessarily address the impact of all possible changes in the relevant assumptions. We do not intend to provide you with unaudited pro forma condensed combined financial information that reflects the amount, interest rate or any of the other actual terms of this offering.

As a result of the foregoing, purchasers of the notes should not place undue reliance on unaudited pro forma condensed combined financial information included and incorporated by reference in this prospectus supplement and the accompanying prospectus.

The Vectren Merger will significantly increase our goodwill and other intangible assets.

Following the Vectren Merger we will have a significant amount of goodwill and other intangible assets on our consolidated financial statements that are subject to impairment based upon future adverse changes in our business or prospects. The impairment of any goodwill and other intangible assets may have negative impact on our consolidated results of operations.

Litigation filed against Vectren and the members of the Vectren board of directors could result in the payment of damages following completion of the Vectren Merger.

In connection with the Vectren Merger, seven purported Vectren shareholders filed separate lawsuits against Vectren and the members of the Vectren board of directors under the federal securities laws in the United States District Court for the Southern District of Indiana challenging the adequacy of the disclosures made in Vectren’s proxy statement in connection with the Vectren Merger. All seven actions allege violations of Sections 14(a) and 20(a) of the Exchange Act and Rule 14a-9 promulgated thereunder based on various alleged omissions of material information from the proxy statement.

The lawsuits seek, among other things, to enjoin the Vectren Merger or, if the Vectren Merger is consummated, to rescind the Vectren Merger or award rescissory damages, and other relief. Vectren and the Vectren director defendants filed a motion to dismiss on August 15, 2018. On August 22, 2018, the court denied the interim lead plaintiffs’ preliminary injunction, which sought to halt the Vectren shareholder vote on the Vectren Merger. Pursuant to a stipulation entered on September 4, 2018, the case may proceed once the lead plaintiff (when appointed) files a consolidated amended complaint.

The outcome of this litigation is uncertain. If a dismissal is not granted or a settlement is not reached, the lawsuits could prevent or delay completion of the Vectren Merger and result in substantial costs to CenterPoint Energy, including any costs associated with indemnification. Additional lawsuits may be filed against Vectren or the directors and officers of Vectren in connection with the Vectren Merger. The defense or settlement of any lawsuit or claim that remains unresolved at the time the Vectren Merger is consummated may adversely affect the combined company’s business, financial condition, results of operations and cash flows.

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RATIO OF EARNINGS TO FIXED CHARGES

The following table sets forth our historical ratio of earnings to fixed charges for the periods indicated. The ratios are calculated pursuant to the applicable rules of the SEC.

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USE OF PROCEEDS

We estimate that the net proceeds to us from this offering, after deducting issuance costs and discounts payable by us for this offering, will be approximately $1.486 billion. We intend to use the net proceeds from this offering, the Series A Preferred Stock Offering, the Depositary Shares Offering and the Common Stock Offering, as well as issuances of commercial paper and cash on hand, to fund the Merger Consideration and to pay related fees and expenses. See “Summary — Recent Developments.” However, this offering is not contingent on the completion of the Vectren Merger, and there can be no assurance that the Vectren Merger will be consummated on the terms described herein or at all. If we do not consummate the Vectren Merger on or prior to October 31, 2019, or if, on or prior to such date, the Merger Agreement is terminated, we will be required to redeem all of the outstanding notes on the Special Mandatory Redemption Date (as defined herein) at a redemption price equal to 101% of the principal amount of the notes plus accrued and unpaid interest, if any, to, but excluding, the Special Mandatory Redemption Date as described under the caption “Description of the Notes — Special Mandatory Redemption.” The notes may also be redeemed at our option, in whole but not in part at any time before October 31, 2019, at a redemption price equal to 101% of the aggregate principal amount thereof plus accrued and unpaid interest thereon to, but excluding, the date of such redemption, if we determine, in our reasonable judgment, that the Vectren Merger will not be consummated on or before 5:00 p.m. (New York City time) on October 31, 2019. See “Description of the Notes — Special Optional Redemption.”

Pending application of the net proceeds of this offering for the foregoing purposes, we expect to use the net proceeds to repay commercial paper and other short-term indebtedness that were issued or incurred for general corporate and working capital purposes or invest such net proceeds in various instruments which may include, but would not be limited to, short- and intermediate-term, interest-bearing obligations, including bank deposits and certificates of deposit with financial institutions having investment-grade ratings, U.S. government obligations or money market funds primarily invested in securities issued by the U.S. government or its agencies.

On June 30, 2018, we had $565 million of commercial paper borrowings, which had a weighted-average maturity of 17 days and a weighted-average interest rate of 2.37%. For information regarding the interest rate and maturity of our other debt, see Note 13 to our Financial Statements in the 2017 Form 10-K as updated by our other filings with the SEC.

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CAPITALIZATION

The following table sets forth our consolidated short-term debt and capitalization as of June 30, 2018:

The following table does not give effect to the issuances of commercial paper or drawing on the Bridge Facility or the Revolving Credit Facility to finance a portion of the Merger Consideration and related fees and expenses.

This table should be read in conjunction with our consolidated financial statements and related notes thereto and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” included in the 2017 Form 10-K and the 2nd Quarter 2018 Form 10-Q.

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UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION

The Unaudited Pro Forma Condensed Combined Financial Statements (pro forma financial statements) have been derived from the historical consolidated financial statements of CenterPoint Energy, Inc. (CenterPoint Energy) and Vectren Corporation (Vectren). The following pro forma financial statements should be read in conjunction with:

On April 21, 2018, CenterPoint Energy entered into an Agreement and Plan of Merger (Merger Agreement), by and among CenterPoint Energy, Vectren and Pacer Merger Sub, Inc., an Indiana corporation and wholly-owned subsidiary of CenterPoint Energy (Merger Sub). Pursuant to the Merger Agreement, on and subject to the terms and conditions set forth therein, Merger Sub will merge with and into Vectren (Vectren Merger), with Vectren continuing as the surviving corporation in the Vectren Merger and becoming a wholly-owned subsidiary of CenterPoint Energy.

The Unaudited Pro Forma Condensed Combined Statements of Income (pro forma statements of income) for the six months ended June 30, 2018, and the year ended December 31, 2017, give effect to the Vectren Merger as if it were completed on January 1, 2017. The Unaudited Pro Forma Condensed Combined Balance Sheet (pro forma balance sheet) as of June 30, 2018, gives effect to the Vectren Merger as if it were completed on June 30, 2018.

The historical financial information has been adjusted in the pro forma financial statements to give effect to pro forma events that are (i) directly attributable to the Vectren Merger, (ii) factually supportable and (iii) with respect to the statements of income, expected to have a continuing impact on the combined results following the Vectren Merger.

The Vectren Merger will be accounted for as an acquisition of Vectren common shares by CenterPoint Energy and will follow the acquisition method of accounting for business combinations. The pro forma financial statements reflect an aggregate purchase price of approximately $6.0 billion in cash, based upon the “Merger Consideration” (as defined in the Merger Agreement) of $72.00 per share for each share of common stock of Vectren issued and outstanding immediately prior to close of the Vectren Merger.

CenterPoint Energy has obtained committed financing in the form of a $5.0 billion senior unsecured bridge term loan facility (Bridge Facility) from Goldman Sachs Bank USA, Morgan Stanley Senior Funding, Inc. and a syndicate of lenders. CenterPoint Energy intends to terminate all remaining commitments under the Bridge Facility promptly following the planned issuance of unsecured senior notes (Senior Notes Issuance). As a result, these pro forma financial statements assume that CenterPoint Energy will not borrow any amounts under the Bridge Facility. To the extent, however, there were any borrowings under the Bridge Facility, such borrowings would be classified as short-term debt in current liabilities.

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For purposes of the pro forma financial statements, CenterPoint Energy has assumed the receipt of gross proceeds from the following transactions (three of which have been completed) to fund, after payment of issuance costs and discounts, the approximately $6 billion gross cash consideration Vectren Merger purchase price (see Note 3 for further details):

However, in lieu of drawing on the Revolving Credit Facility, CenterPoint Energy anticipates financing that portion of the Vectren Merger reflected above with commercial paper, subject to then current market conditions, as well as with cash on hand. CenterPoint Energy’s financing assumptions for the commercial paper issuances (Remaining Merger Debt Financings) are detailed in the accompanying notes but are not reflected in the pro forma statements of income or pro forma balance sheet.

Assumptions and estimates underlying the pro forma adjustments are described in the accompanying notes, which should be read with the pro forma financial statements. Because the pro forma financial statements have been prepared based on preliminary estimates, the total amounts recorded at the date of the Vectren Merger may differ materially from the information presented in the pro forma financial statements. These estimates are subject to change pending further review of the assets acquired and liabilities assumed in the Vectren Merger and the final purchase price of the Vectren Merger.

The pro forma financial statements have been presented for illustrative purposes only and are not necessarily indicative of the results of operations and financial position that would have been achieved had the pro forma events taken place on the dates indicated, or the future consolidated results of operations or financial position of the combined company.

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CENTERPOINT ENERGY, INC.

UNAUDITED PRO FORMA CONDENSED COMBINED BALANCE SHEET

June 30, 2018

See Notes to Unaudited Pro Forma Condensed Combined Financial Statements

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CENTERPOINT ENERGY, INC.

UNAUDITED PRO FORMA CONDENSED COMBINED BALANCE SHEET — (continued)

June 30, 2018

See Notes to Unaudited Pro Forma Condensed Combined Financial Statements

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CENTERPOINT ENERGY, INC.

UNAUDITED PRO FORMA CONDENSED COMBINED STATEMENTS OF INCOME

For the Six Months Ended June 30, 2018

See Notes to Unaudited Pro Forma Condensed Combined Financial Statements

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CENTERPOINT ENERGY, INC.

UNAUDITED PRO FORMA CONDENSED COMBINED STATEMENT OF INCOME

For the Year Ended December 31, 2017

See Notes to Unaudited Pro Forma Condensed Combined Financial Statements

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CENTERPOINT ENERGY, INC.

NOTES TO UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS

The pro forma statements of income for the six months ended June 30, 2018, and the year ended December 31, 2017, give effect to the Vectren Merger as if it were completed on January 1, 2017. The pro forma balance sheet as of June 30, 2018, gives effect to the Vectren Merger as if it were completed on June 30, 2018.

The pro forma financial statements have been derived from the historical consolidated financial statements of CenterPoint Energy and Vectren. Certain financial statement line items included in Vectren’s historical presentation have been reclassified to conform to corresponding financial statement line items included in CenterPoint Energy’s historical presentation (see Note 6). These reclassifications have no material impact on the historical operating income, net income, total assets, total liabilities or shareholders’ equity reported by CenterPoint Energy or Vectren. The historical consolidated financial statements have been adjusted in the pro forma financial statements to give effect to pro forma events that are (i) directly attributable to the Vectren Merger, (ii) factually supportable and (iii) with respect to the pro forma statements of income, expected to have a continuing impact on the combined results following the Vectren Merger.

Assumptions and estimates underlying the pro forma adjustments are described in these notes, which should be read in conjunction with the pro forma financial statements. Since the pro forma financial statements have been prepared based upon preliminary estimates, the final amounts recorded at the date of the Vectren Merger may differ materially from the information presented. These estimates are subject to change pending further review.

The Vectren Merger is reflected in the pro forma financial statements as an acquisition of Vectren by CenterPoint Energy, based on the guidance provided by accounting standards for business combinations. Under these accounting standards, the total estimated purchase price is allocated as described in Note 2 to the pro forma financial statements, and the assets acquired and the liabilities assumed have been measured at estimated fair value.

Vectren’s regulated operations are comprised of electric generation and electric and natural gas energy delivery services. These operations are subject to the rate-setting authority of the Federal Energy Regulatory Commission, the Indiana Utility Regulatory Commission and the Public Utilities Commission of Ohio, and are accounted for pursuant to U.S. generally accepted accounting principles, including the accounting guidance for regulated operations. The rate-setting and cost-recovery provisions currently in place for Vectren’s regulated operations provide revenues derived from costs including a return on investment of assets and liabilities included in rate base. Thus, the fair values of Vectren’s tangible and intangible assets and liabilities subject to these rate-setting provisions approximate their carrying values, and the pro forma financial statements do not reflect any net adjustments related to these amounts. Therefore, the excess purchase price over carrying value of net assets attributable to regulated operations is estimated to be comprised entirely of goodwill. The carrying values of Vectren’s non-regulated property, plant and equipment, which consists primarily of vehicles and equipment, and long-term debt, including the elimination of debt issuance costs, as of June 30, 2018, were reviewed and determined to approximate fair value; therefore, no fair value adjustment was reflected in the pro forma financial statements related to these balances.

The accounting policies used in the preparation of the pro forma financial statements are those described in CenterPoint Energy’s audited consolidated financial statements as of and for the year ended December 31, 2017. CenterPoint Energy performed a preliminary review of Vectren’s accounting policies to determine whether any adjustments were necessary to ensure comparability in the pro forma financial statements. At this time, CenterPoint Energy is not aware of any differences that would have a material effect on the pro forma financial statements, including any differences in the timing of adoption of new accounting standards, except for certain

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amounts that have been reclassified to conform to CenterPoint Energy’s financial statement presentation (see Note 6). Upon completion of the Vectren Merger, or as more information becomes available, CenterPoint Energy will perform a more detailed review of Vectren’s accounting policies. As a result of that review, differences may be identified between the accounting policies of the two companies that, when conformed, could have a material impact on the pro forma financial statements. The 2017 historical statements of income for CenterPoint Energy and Vectren do not reflect new accounting standards retrospectively adopted on January 1, 2018.

CenterPoint Energy reviewed the historical financial information for intercompany transactions and found no eliminations were necessary. Transaction costs recorded in the historical income statement have been excluded from the pro forma statements of income as they reflect nonrecurring charges directly related to the Vectren Merger. However, the transaction costs not recorded in the historical balance sheet are reflected in the pro forma balance sheet as an increase in other current liabilities and a decrease in retained earnings.

The pro forma financial statements do not reflect the realization of any expected cost savings or other synergies from the Vectren Merger as a result of restructuring activities following the completion of the Vectren Merger. Certain of Vectren employment agreements contain severance or other termination arrangements; however, the pro forma financial statements do not reflect any such payments under these arrangements as employment decisions have not been finalized.

The estimated purchase price consideration of approximately $6.0 billion is based on the cash price of $72.00 per outstanding share of common stock of Vectren. The value of the purchase price consideration could change based on the actual number of shares of common stock of Vectren issued and outstanding immediately prior to the Vectren Merger.

CenterPoint Energy has performed a preliminary valuation analysis of the fair market value of Vectren’s assets and liabilities. The following table summarizes the allocation of the preliminary purchase price as of the acquisition date (in millions):

This preliminary purchase price allocation has been used to prepare pro forma adjustments in the pro forma balance sheet and pro forma statements of income. CenterPoint Energy has not completed a final valuation

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analysis necessary to determine the fair market values of all of Vectren’s assets and liabilities or the allocation of its purchase price. The final allocation could differ materially from the preliminary allocation used in the pro forma adjustments and, as such, no assurances can be provided regarding the preliminary purchase accounting. The final allocation may include (1) changes in fair values of property, plant and equipment, (2) changes in allocations to intangible assets and goodwill and (3) other changes to assets and liabilities.

CenterPoint Energy sometimes refers to the planned issuances of commercial paper as its Remaining Merger Debt Financings. The actual size and terms of, and amounts of proceeds CenterPoint Energy receives from its Senior Notes Issuance and Remaining Merger Debt Financings will depend on, among other things, market conditions at the time of its Senior Notes Issuance and Remaining Merger Debt Financings and such other factors as CenterPoint Energy deems relevant and may differ, perhaps substantially, from the size, terms and amounts CenterPoint Energy has assumed in this Note 3 to the pro forma financial statements.

For purposes of the pro forma financial statements, CenterPoint Energy has assumed the receipt of gross proceeds from the following transactions (three of which have been completed) to fund, after payment of issuance costs and discounts, the approximately $6 billion gross cash consideration Vectren Merger purchase price further described below:

However, in lieu of drawing on the Revolving Credit Facility, CenterPoint Energy anticipates financing the portion of the Vectren Merger reflected as borrowings under the Revolving Credit Facility above with its Remaining Merger Debt Financings, subject to then current market conditions, as well as with cash on hand. CenterPoint Energy’s financing assumptions for its Remaining Merger Debt Financings are detailed below but are not reflected in the pro forma statements of income or pro forma balance sheet.

CenterPoint Energy obtained commitments by lenders for a $5.0 billion, 364-day Bridge Facility to provide flexibility for the timing of the acquisition financing and fund, in part, amounts payable by CenterPoint Energy in connection with the Vectren Merger. Upon execution of the Bridge Facility, CenterPoint Energy deferred debt issuance costs of $25 million in other assets, of which $7 million was amortized as debt issuance expense in the historical financial statements as of and for the six months ended June 30, 2018. CenterPoint Energy intends to terminate all remaining commitments under the Bridge Facility promptly following the planned Senior Notes Issuance. As a result, these pro forma financial statements assume that CenterPoint Energy will not borrow any amounts under the Bridge Facility. To the extent, however, there were any borrowings under the Bridge Facility, such borrowings would be classified as short-term debt in current liabilities.

On August 22, 2018, CenterPoint Energy completed the issuance of 800,000 shares of its Series A Preferred Stock for $790 million, net of $10 million of issuance costs and discounts, with an aggregate liquidation value of $800 million. The Series A Preferred Stock accrue dividends in cash, calculated as a percentage of the aggregate liquidation value, at a fixed annual rate of 6.125% per annum to, but excluding, September 1, 2023, and at an annual rate of 3-month LIBOR plus a spread of 3.270% thereafter.

On October 1, 2018, CenterPoint Energy completed the issuance of 977,500 shares of its Series B Preferred Stock for $950 million, net of $28 million of issuance costs and discounts, with an aggregate liquidation value of

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$978 million and a per share liquidation value of $1,000. Each share of Series B Preferred Stock is represented by 20 depositary shares offered and sold to the public. At the mandatory conversion date, each outstanding share of Series B Preferred Stock will be converted into a variable number of shares of Common Stock, depending on a preceding 20-day volume-weighted-average-price of Common Stock and subject to possible adjustment pursuant to the terms of the Series B Preferred Stock. Once declared by the Board of Directors, CenterPoint Energy will pay dividends in cash or shares of Common Stock, calculated as a percentage of the aggregate liquidation value, at a rate of 7% per annum.

Additionally, on October 1, 2018, CenterPoint Energy completed the issuance of 69,633,027 shares of its Common Stock at a public offering price of $27.25 per share for $1,844 million, net of $54 million of issuance costs and discounts.

For purposes of the pro forma financial statements, CenterPoint Energy has presented its planned Senior Notes Issuance of $1.5 billion aggregate principal amount, net of issuance costs of $12 million. CenterPoint Energy has assumed a weighted average interest rate on the Senior Notes Issuance of 3.9% based on current market conditions.

In May 2018, CenterPoint Energy entered into an amendment to its Revolving Credit Facility that will increase the aggregate commitments from $1.7 billion to $3.3 billion effective the earlier of (i) the termination of all commitments by certain lenders to provide the Bridge Facility and (ii) the payment in full of all obligations (other than contingent obligations) under the Bridge Facility and termination of all commitments to advance additional credit thereunder, and in each case, so long as the Merger Agreement has not been terminated pursuant to the terms thereof without consummation of the Vectren Merger. For purposes of the pro forma financial statements, CenterPoint Energy has assumed the balance of the purchase price consideration will be met by borrowings of $910 million under the Revolving Credit Facility at a weighted-average interest rate of 3.8%. Interest expense reflected in the pro forma financial statements includes arranger and commitments fees, as well as estimated interest on drawn amounts based on current 1-month LIBOR of 2.26% as of September 28, 2018, plus applicable rate under the Revolving Credit Facility, assuming current CenterPoint Energy Inc. issuer credit ratings.

In lieu of borrowings under the Revolving Credit Facility, CenterPoint Energy intends to consummate the Remaining Merger Debt Financings aggregating up to $910 million of commercial paper, with an assumed weighted-average interest rate of 2.35% per annum. This assumed rate is based on borrowing costs for commercial paper under current market conditions. The actual interest rate on the Remaining Merger Debt Financings will be based on market conditions at the time and may differ, perhaps substantially, from the rate assumed for purposes of the pro forma financial statements. Furthermore, any cash on hand may be used to reduce the Remaining Merger Debt Financings. However, there is no guarantee that CenterPoint Energy will be able to consummate the Remaining Merger Debt Financings as planned or at all.

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The pro forma adjustments are based on our preliminary estimates and assumptions that are subject to change. The pro forma adjustments are based upon available information and certain assumptions that management believes are reasonable. The following adjustments have been reflected in the pro forma balance sheet:

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