# EDGAR Filing Document

**Accession Number:** 0001111711
**File Stem:** 0001193125-26-228913
**Filing Date:** 2026-5
**Character Count:** 73914
**Document Hash:** b1a423e23a24eaffbf06bbdf7225b154
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-26-228913.hdr.sgml**: 20260518

**ACCESSION NUMBER**: 0001193125-26-228913

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 15

**CONFORMED PERIOD OF REPORT**: 20260518

**ITEM INFORMATION**: Other Events

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20260518

**DATE AS OF CHANGE**: 20260518

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** NISOURCE INC.
- **CENTRAL INDEX KEY:** 0001111711
- **STANDARD INDUSTRIAL CLASSIFICATION:** ELECTRIC & OTHER SERVICES COMBINED [4931]
- **ORGANIZATION NAME:** 01 Energy & Transportation
- **EIN:** 352108964
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 8-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-16189
- **FILM NUMBER:** 26993165

**BUSINESS ADDRESS:**
- **STREET 1:** 801 EAST 86TH AVE
- **CITY:** MERRILLVILLE
- **STATE:** IN
- **ZIP:** 46410-6272
- **BUSINESS PHONE:** 2196475200

**MAIL ADDRESS:**
- **STREET 1:** 801 EAST 86TH AVE
- **CITY:** MERRILLVILLE
- **STATE:** IN
- **ZIP:** 46410-6272

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** NISOURCE INC/DE
- **DATE OF NAME CHANGE:** 20001103

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** NEW NISOURCE INC
- **DATE OF NAME CHANGE:** 20000412

?xml version='1.0' encoding='ASCII'? 8-K

### UNITED STATES

### SECURITIES AND EXCHANGE COMMISSION

#### Washington, D.C. 20549

### FORM 8-K

#### CURRENT REPORT

#### Pursuant to Section 13 OR 15(d)

#### of the Securities Exchange Act of 1934

#### Date of Report (Date of earliest event reported): May 18, 2026

## NiSource Inc.

#### (Exact Name of Registrant as Specified in Charter)

---

| | | |
|:---|:---|:---|
| **DE** | **001-16189** | **35-2108964** |
| **(State or other jurisdiction**<br> **of incorporation)** | **(Commission**<br> **file number)** | **(I.R.S. Employer**<br> **Identification No.)** |

---

---

| | |
|:---|:---|
| **801 East 86th Avenue**<br> **Merrillville, Indiana** | **46410** |
| **(Address of Principal Executive Offices)** | **(Zip Code)** |

---

#### Registrant's telephone number, including area code: (614) 460-6000
Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2 (b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4 (c))

Securities registered pursuant to Section 12(b) of the Act:

---

| | |
|:---|:---|
| **Title of Each Class** | **Name of Each Exchange**<br> **on Which Registered** |
| Common Stock, par value $0.01 per share NI | NYSE |

---

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

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---

| | |
|:---|:---|
| **Item 8.01** | **Other Events.**  |

---

#### Senior Notes Due 2031 and 2036
On May 11, 2026, NiSource Inc. (the "Company") and BNP Paribas Securities Corp., BofA Securities, Inc., MUFG Securities Americas Inc. and U.S. Bancorp Investments, Inc., as Lead Underwriters, entered into a Terms Agreement (the "Terms Agreement") with respect to the offering and sale of $500,000,000 aggregate principal amount of the Company's 4.750% Notes due 2031 (the "2031 Notes") and $750,000,000 aggregate principal amount of the Company's 5.300% Notes due 2036 (the "2036 Notes" and, together with the 2031 Notes, the "Notes") under the Company's Registration Statement on Form S-3 (File No. 333- 291167) (the "Registration Statement"). The Terms Agreement incorporates by reference the provisions of the Company's Underwriting Agreement, dated November 30, 2017 (a form of which was filed with the Securities and Exchange Commission (the "SEC") on November 30, 2017).

The sale closed on May 18, 2026. The Notes were issued pursuant to an Indenture, dated as of November 14, 2000, between the Company, as issuer and successor-in-interest to NiSource Finance Corp., and The Bank of New York Mellon, as successor trustee, as amended and supplemented. The Company intends to use the net proceeds from the sale of the Notes for general corporate purposes, including to finance capital expenditures, for working capital and to repay existing indebtedness.

The preceding is a summary of the terms of the Notes and is qualified in its entirety by reference to the forms of the 2031 Notes and the 2036 Notes, filed as Exhibits 4.1 and 4.2 to this Current Report on Form 8-K, respectively, which are incorporated herein by reference. The Company is filing Exhibit 5.1 with this Current Report on Form 8-K in connection with the Registration Statement.

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| | |
|:---|:---|
| **Item 9.01** | **Financial Statements and Exhibits.**  |

---

(d) Exhibits

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| | |
|:---|:---|
| Exhibit<br>Number | Description |
| 4.1 | [Form of 4.750% Notes due 2031](d119463dex41.htm) |
| 4.2 | [Form of 5.300% Notes due 2036](d119463dex42.htm) |
| 5.1 | [Opinion of McGuireWoods LLP](d119463dex51.htm) |
| 23.1 | [Consent of McGuireWoods LLP (included in Exhibit 5.1)](d119463dex51.htm) |
| 104 | Cover page Interactive Data File (embedded within the Inline XBRL document) |

---

#### Cautionary Statement Concerning Forward-Looking Statements
This current report on Form 8-K contains forward-looking statements that are not historical facts, including statements about the anticipated use of proceeds from the sale of the Notes. These statements are based on current expectations and assumptions, which management believes are reasonable, and on information currently available to management, but are necessarily subject to various risks and uncertainties. In addition to the risk that these assumptions prove to be inaccurate, factors that could cause actual results to differ materially from those contemplated by the forward-looking statements include factors disclosed in the Company's Annual Report on Form 10-K for the year ended December 31, 2025, and its subsequent filings with the SEC, which are available on the Company's website at www.nisource.com and on the SEC's website at www.sec.gov. The Company undertakes no obligation to publicly update or revise any forward-looking statements, whether due to new information, future events or otherwise, except to the extent required by law.

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#### SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

NiSource Inc. <br> (Registrant)

---

| | | |
|:---|:---|:---|
| Date: May 18, 2026 | By: | /s/ Shawn Anderson |
|  |  | Shawn Anderson |
|  |  | Executive Vice President and Chief Financial Officer |

---

## Exhibit 4.1

**Exhibit 4.1** 

UNLESS THIS GLOBAL NOTE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("<u>DTC</u>"), NEW YORK, NEW YORK, TO NISOURCE INC. OR ITS AGENT OR AGENTS FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY GLOBAL NOTE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO., OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

TRANSFERS OF THIS GLOBAL NOTE SHALL BE LIMITED TO TRANSFERS IN WHOLE, BUT NOT IN PART, TO NOMINEES OF DTC OR TO A SUCCESSOR THEREOF OR SUCH SUCCESSOR'S NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL NOTE SHALL BE LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE RESTRICTIONS SET FORTH IN THE INDENTURE REFERRED TO ON THE REVERSE HEREOF.

---

| | |
|:---|:---|
| No.: [__] | $[____] |

---

CUSIP No.: 65473P BA2

ISIN No.: US65473PBA21

4.750% Notes due 2031

NiSource Inc., a Delaware corporation, promises to pay to [____], or registered assigns, the principal sum of $[______] Dollars on May 18, 2031.

Interest Payment Dates: May 18 and November 18, beginning November 18, 2026.

Record Dates: (i) if all of the Notes are in book-entry form represented by one or more Global Securities, the Business Day immediately preceding the applicable Interest Payment Date and (ii) if any of the Notes are not in book-entry form represented by one or more Global Securities, on each May 1 and November 1 (whether or not a Business Day) (each such date in clauses (i) and (ii), a "<u>Regular Record Date</u>").

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Additional provisions of this Note are set forth on the other side of this Note.

Dated:

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| | |
|:---|:---|
| NISOURCE INC. | NISOURCE INC. |
| By: |  |
| Name: | Tchapo Napoe |
| Title: | Vice President, Treasurer and Corporate Finance |

---

---

| | |
|:---|:---|
| ATTEST: | ATTEST: |
| By: |  |
| Name: | Ashley Bancroft |
| Title: | Assistant Corporate Secretary |

---

**[SIGNATURE PAGE TO GLOBAL NOTE NO. 1]** 

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TRUSTEE'S CERTIFICATE OF AUTHENTICATION

This is one of the Notes of the series referred to

in the within-mentioned Indenture.

---

| | |
|:---|:---|
| Dated: | Dated: |
| THE BANK OF NEW YORK MELLON, as | THE BANK OF NEW YORK MELLON, as |
| Trustee | Trustee |
| By: |  |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Authorized Officer |

---

**[SIGNATURE PAGE TO GLOBAL NOTE NO. 1]** 

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4.750% Notes due 2031

1. Interest

NiSource Inc., a Delaware corporation (such corporation, and its successors and assigns under the Indenture hereinafter referred to, being herein called the "<u>Company</u>"), promises to pay interest on the principal amount of this Note at the rate per annum shown above. The Company will pay interest semiannually on May 18 and November 18 of each year, beginning November 18, 2026. Interest on the Notes will accrue from the most recent date to which interest has been paid or, if no interest has been paid, from May 18, 2026. Interest will be computed on the basis of a 360-day year of twelve 30-day months. The Company will pay interest on overdue principal and premium at the above rate and will pay interest on overdue installments of interest at such rate to the extent lawful.

2. Method of Payment

The Company will pay interest on the Notes (except defaulted interest) to the Persons who are registered Holders of Notes at the close of business on the Regular Record Date next preceding each Interest Payment Date even if Notes are canceled after the Regular Record Date and on or before the Interest Payment Date. Holders must surrender Notes to a Paying Agent to collect principal payments. The Company will pay principal and interest in money of the United States that at the time of payment is legal tender for payment of public and private debts. Payments in respect of the Notes represented by a Global Note (including principal, premium, if any, and interest) will be made by wire transfer of immediately available funds to the accounts specified by DTC, as Depositary.

3. Paying Agent and Security Registrar

Initially, the Trustee will act as Paying Agent and Security Registrar. The Company may appoint and change any Paying Agent or Security Registrar without notice to the Holders. The Company may act as Paying Agent or Security Registrar.

4. Indenture

The Company issued the Notes under an Indenture dated as of November 14, 2000, by and between the Company, in its own capacity and as successor to NiSource Finance Corp., and the Trustee (as successor trustee) (as amended and supplemented, the "<u>Indenture</u>") and pursuant to an Officers' Certificate of the Company dated May 18, 2026 (the "<u>Officers' Certificate</u>"). The terms of the Notes include those stated in the Indenture and the Officers' Certificate and those made part of the Indenture by reference to the Trust Indenture Act of 1939 (15 U.S.C. sections 77aaa-77bbbb) as in effect on the date of the Officers' Certificate (the "<u>Act</u>"). Capitalized terms used herein and defined in the Indenture but not defined herein have the respective meanings ascribed thereto in the Indenture. The Notes are subject to all such terms, and Holders of Notes are referred to the Indenture and the Act for a statement of those terms.

The Notes are senior unsecured obligations of the Company. The Notes issued on the original issue date will be treated as a single class for all purposes under the Indenture. The Indenture contains covenants that limit the ability of the Company and its Subsidiaries (other than Utilities) to incur additional indebtedness and create liens on assets unless the total amount of all the secured debt would not exceed 10% of Consolidated Net Tangible Assets (excluding the Utilities). These covenants are subject to important exceptions and qualifications.

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5. Optional Redemption

Prior to April 18, 2031 (one month prior to the maturity date of the Notes) (the "<u>Par Call Date</u>"), the Company will have the right to redeem the Notes, at its option, in whole or in part, at any time and from time to time, at a Redemption Price (expressed as a percentage of principal amount and rounded to three decimal places) equal to the greater of (1)(a) the sum of the present values of the remaining scheduled payments of principal and interest thereon discounted to the Redemption Date (assuming the Notes matured on the Par Call Date) on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate plus 12.5 basis points less (b) interest accrued to the Redemption Date, and (2) 100% of the principal amount of the Notes to be redeemed, plus, in either case, accrued and unpaid interest thereon to, but excluding, the Redemption Date.

On or after the Par Call Date, the Company will have the right to redeem the Notes, at its option, in whole or in part, at any time and from time to time, at a Redemption Price equal to 100% of the principal amount of the Notes being redeemed plus accrued and unpaid interest thereon to, but excluding, the Redemption Date.

"<u>Treasury Rate</u>" means, with respect to any Redemption Date, the yield determined by the Company in accordance with the following two paragraphs.

The Treasury Rate shall be determined by the Company after 4:15 p.m., New York City time (or after such time as yields on U.S. government securities are posted daily by the Board of Governors of the Federal Reserve System), on the third Business Day preceding the Redemption Date based upon the yield or yields for the most recent day that appear after such time on such day in the most recent statistical release published by the Board of Governors of the Federal Reserve System designated as "Selected Interest Rates (Daily)—H.15" (or any successor designation or publication) ("<u>H.15</u>") under the caption "U.S. government securities–Treasury constant maturities–Nominal" (or any successor caption or heading) ("<u>H.15 TCM</u>"). In determining the Treasury Rate, the Company shall select, as applicable: (1) the yield for the Treasury constant maturity on H.15 exactly equal to the period from the Redemption Date to the Par Call Date (the "<u>Remaining Life</u>"); or (2) if there is no such Treasury constant maturity on H.15 exactly equal to the Remaining Life, the two yields – one yield corresponding to the Treasury constant maturity on H.15 immediately shorter than and one yield corresponding to the Treasury constant maturity on H.15 immediately longer than the Remaining Life – and shall interpolate to the Par Call Date on a straight-line basis (using the actual number of days) using such yields and rounding the result to three decimal places; or (3) if there is no such Treasury constant maturity on H.15 shorter than or longer than the Remaining Life, the yield for the single Treasury constant maturity on H.15 closest to the Remaining Life. For purposes of this paragraph, the applicable Treasury constant maturity or maturities on H.15 shall be deemed to have a maturity date equal to the relevant number of months or years, as applicable, of such Treasury constant maturity from the Redemption Date.

If on the third Business Day preceding the Redemption Date H.15 TCM is no longer published, the Company shall calculate the Treasury Rate based on the rate per annum equal to the semi-annual equivalent yield to maturity at 11:00 a.m., New York City time, on the second Business Day preceding such Redemption Date of the United States Treasury security maturing on, or with a maturity that is closest to, the Par Call Date, as applicable. If there is no United States Treasury security maturing on the Par Call Date but there are two or more United States Treasury securities with a maturity date equally distant from the Par Call Date, one with a maturity date preceding the Par Call Date and one with a maturity date following the Par Call Date, the Company shall select the United States Treasury security with a maturity date preceding the Par Call Date. If there are two or more United States Treasury securities maturing on the Par Call Date or two or more United States Treasury securities meeting the criteria of the preceding sentence, the Company shall select from among these two or more United States Treasury securities the United States

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Treasury security that is trading closest to par based upon the average of the bid and asked prices for such United States Treasury securities at 11:00 a.m., New York City time. In determining the Treasury Rate in accordance with the terms of this paragraph, the semi-annual yield to maturity of the applicable United States Treasury security shall be based upon the average of the bid and asked prices (expressed as a percentage of principal amount) at 11:00 a.m., New York City time, of such United States Treasury security, and rounded to three decimal places.

The Trustee shall have no duty to calculate the Redemption Price.

6. Tax Credit Event Redemption

If a Tax Credit Event occurs, the Company will have the right to redeem the Notes, at its option, in whole but not in part, at a Redemption Price equal to 101% of the principal amount of the Notes being redeemed plus accrued and unpaid interest thereon to, but excluding, the Redemption Date.

Notice of any redemption of the Notes upon the occurrence of a Tax Credit Event (i) may only be sent by the later of (a) the end of the calendar year in which the Notes were issued and (b) six months after the date of issuance of the Notes and (ii) shall be accompanied by a certificate from an officer of the Company stating that a Tax Credit Event has occurred.

The consummation of a redemption of the Notes upon a Tax Credit Event may be subject to the Paying Agent's receipt of the required redemption moneys on or before the Redemption Date (and in such case no redemption shall occur unless such moneys have been received by the Paying Agent on or before such date).

A "Tax Credit Event" has occurred if, in the Company's reasonable determination, there exists a material risk, due to the Notes (considered together with other debt) having been issued, as part of an original issuance, to one or more "specified foreign entities," as defined in Section 7701(a)(51)(B) of the Internal Revenue Code of 1986, as amended (the "Code"), that the Company or any of its affiliates would be unable to utilize or otherwise ineligible to claim any tax credits otherwise allowed under Section 38 of the Code.

7. Notice of Redemption

Notice of any redemption will be mailed or electronically delivered (or otherwise transmitted in accordance with the depositary's procedures) at least 10 days but not more than 60 days before the Redemption Date to each Holder of Notes to be redeemed in accordance with Section 106 of the Indenture. In the case of a partial redemption, if the Notes to be redeemed are held in certificated form, selection of the Notes for redemption will be made by the Trustee, by lot. No Notes of a principal amount of $2,000 or less will be redeemed in part. If any Note is to be redeemed in part only, the notice of redemption that relates to such Note will state the portion of the principal amount of the Note to be redeemed. A new Note in a principal amount equal to the unredeemed portion of the original Note will be issued in the name of the Holder of the original Note upon surrender for cancellation of the original Note. For so long as the Notes are held by DTC (or another depositary), the redemption of the Notes, including selection of the Notes for redemption, shall be done in accordance with the policies and procedures of the depositary and may be made on a pro rata pass-through distribution of principal basis. The Company will not know the exact Redemption Price until approximately two (2) to three (3) Business Days before the Redemption Date. Therefore, the notice of redemption will only describe how the Redemption Price will be calculated. Unless the Company defaults in payment of the Redemption Price, on and after the Redemption Date interest will cease to accrue on the Notes or portions thereof called for redemption.

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8. Additional Notes

The Company may, without the consent of the Holders of the Notes, create and issue additional Notes ranking equally with the Notes in all respects, including having the same terms (except for the price to public, the issue date and the initial interest accrual date and the first Interest Payment Date, as applicable), so that such additional Notes shall be consolidated and form a single series with the Notes and shall have the same terms as to status, redemption or otherwise as the Notes. Such additional Notes will have the same CUSIP number as the Notes being authenticated on the date hereof, provided that such additional Notes are part of the same issue as the Notes being authenticated on the date hereof for U.S. federal income tax purposes. If such additional Notes are not part of the same issue for U.S. federal income tax purposes, such additional Notes must be issued with a separate CUSIP number. No additional Notes may be issued if an Event of Default has occurred and is continuing with respect to the Notes.

9. Denominations; Transfer; Exchange

The Notes are in registered form without coupons in denominations of $2,000 principal amount and integral multiples of $1,000. A Holder may transfer or exchange Notes in accordance with the Indenture. The Security Registrar may require a Holder, among other things, to furnish appropriate endorsements or transfer documents and to pay any taxes and fees required by law or permitted by the Indenture. The Security Registrar need not register the transfer or exchange of any Notes selected for redemption (except, in the case of a Note to be redeemed in part, the portion of the Note not to be redeemed) for a period of fifteen (15) Business Days before a selection of Notes to be redeemed.

10. Persons Deemed Owners

The registered Holder of this Note may be treated as the owner of it for all purposes.

11. Unclaimed Money

If money for the payment of principal or interest remains unclaimed for two years, the Trustee or Paying Agent shall pay the money back to the Company at its request. After any such payment, Holders entitled to the money must look only to the Company and not to the Trustee or the Paying Agent for payment.

12. Satisfaction and Discharge

Under the Indenture, the Company can terminate its obligations with respect to the Notes not previously delivered to the Trustee for cancellation when those Notes have become due and payable or will become due and payable at their Stated Maturity within one year or are to be called for redemption within one year under arrangements satisfactory to the Trustee for giving notice of redemption. The Company may terminate its obligations with respect to the Notes by depositing with the Trustee, as funds in trust dedicated solely for that purpose, an amount sufficient to pay and discharge the entire indebtedness on the Notes. In that case, the Indenture will cease to be of further effect and the Company's obligations will be satisfied and discharged with respect to the Notes (except as to the Company's obligations to pay all other amounts due under the Indenture and to provide certain Officers' Certificates and Opinions of Counsel to the Trustee). At the expense of the Company, the Trustee will execute proper instruments acknowledging the satisfaction and discharge.

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13. Amendment, Waiver

Subject to certain exceptions set forth in the Indenture, (i) the Indenture may be amended with the written consent of the Holders of a majority in principal amount of the then Outstanding Securities of each series affected by such amendment, (ii) the Notes may be amended with the written consent of the Holders of at least a majority in principal amount of the Outstanding Notes and (iii) any default or noncompliance with any provision may be waived with the written consent of the Holders of a majority in principal amount of the Outstanding Notes. Subject to certain exceptions set forth in the Indenture, without the consent of any Holder, the Company and the Trustee shall be entitled to amend the Indenture to, among other things, cure any ambiguity, defect or inconsistency, or to evidence the succession of another Person as obligor under the Indenture, or to add to the Company's covenants or to surrender any right or power conferred on the Company under the Indenture, or to add events of default, or to secure the Notes, or to evidence or provide for the acceptance or appointment by a successor Trustee or facilitate the administration of the trusts under the Indenture by more than one trustee, or to conform the Indenture to any amendment of the Act.

14. Defaults and Remedies

Under the Indenture, Events of Default include: (i) a default by the Company in the payment of any interest upon any Note and the continuance of such default for 60 days; (ii) a default by the Company in the payment of principal of or any premium on any Note when due at Maturity, on redemption, by declaration or otherwise, and the continuance of such default for three (3) Business Days; (iii) a default by the Company in the performance of or breach of any covenant or warranty in the Indenture and continuance of such default for 90 days after written notice has been given to the Company by the Trustee or to the Company and the Trustee by the Holders of at least 33% in principal amount of the Outstanding Notes; (iv) a default by the Company under any bond, debenture, note or other evidence of indebtedness for money borrowed by the Company, or the Company defaults under any mortgage, indenture or instrument under which there may be issued, secured or evidenced indebtedness constituting a failure to pay in excess of $50,000,000 of the principal or interest when due and payable, subject to certain cure rights; or (v) certain events of bankruptcy, insolvency or reorganization involving the Company. If an Event of Default occurs and is continuing, the Trustee or the Holders of at least 33% in principal amount of the Outstanding Notes may declare all the Notes to be due and payable immediately.

Holders may not enforce the Indenture or the Notes except as provided in the Indenture. The Trustee may refuse to enforce the Indenture or the Notes unless it receives indemnity or security satisfactory to it. Subject to certain limitations, Holders of a majority in principal amount of the Notes may direct the Trustee in its exercise of any trust or power. The Trustee may withhold from Holders notice of any continuing default (except a default in payment of principal or interest) if it determines that withholding notice is in the interest of the Holders.

15. Trustee Dealings with the Company

Subject to certain limitations imposed by the Act, the Trustee under the Indenture, in its individual or any other capacity, may become the owner or pledgee of Notes and may otherwise deal with and collect obligations owed to it by the Company or its Affiliates and may otherwise deal with the Company or its Affiliates with the same rights it would have if it were not Trustee.

16. No Recourse Against Others

A director, officer, employee or stockholder, as such, of the Company or the Trustee shall not have any liability for any obligations of the Company under the Notes or the Indenture or for any claim based on, in respect of or by reason of such obligations or their creation. By accepting a Note, each Holder waives and releases all such liability. The waiver and release are part of the consideration for the issue of the Notes.

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17. Authentication

This Note shall not be valid until an authorized signatory of the Trustee (or an Authenticating Agent) signs the certificate of authentication on the other side of this Note in accordance with requirements set forth in the Indenture and the Officers' Certificate.

18. Abbreviations

Customary abbreviations may be used in the name of a Holder or an assignee, such as TEN COM (=tenants in common), TEN ENT (=tenants by the entireties), JT TEN (=joint tenants with rights of survivorship and not as tenants in common), CUST (=custodian), and U/G/M/A (=Uniform Gift to Minors Act).

19. CUSIP and ISIN Numbers

Pursuant to a recommendation promulgated by the Committee on Uniform Security Identification Procedures, the Company has caused the applicable CUSIP number to be printed on the Notes and has directed the Trustee to use such CUSIP number in any notice of redemption as a convenience to the Holders. To the extent such number has been issued, the Company has caused the applicable ISIN number to be similarly printed on the Notes and has similarly instructed the Trustee. No representation is made as to the accuracy of such numbers either as printed on the Notes or as contained in any notice of redemption and reliance may be placed only on the other identification numbers placed thereon.

20. Governing Law.

THIS NOTE SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE INTERNAL LAWS OF THE STATE OF NEW YORK, WITHOUT GIVING EFFECT TO CONTRARY CONFLICT OF LAWS OR CHOICE OF LAWS PROVISIONS OF THE STATE OF NEW YORK OR ANY OTHER JURISDICTION.

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The Company will furnish to any Holder upon written request and without charge to the Holder a copy of the Indenture. Requests may be made to:

NiSource Inc.

801 East 86th Avenue

Merrillville, Indiana 46410

Attention: Corporate Secretary

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ASSIGNMENT FORM

To assign this Note, fill in the form below: I or

we assign and transfer this Note to

(Print or type assignee's name, address and zip

code) (Insert assignee's soc. Sec. or tax I.D. No.)

and irrevocably appoint ________________________ agent to transfer this Note on the books of the Company. The agent may substitute another to act for him.

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| | | |
|:---|:---|:---|
| Date:<u> </u> | Your Signature: |  |
|  |  | Sign exactly as your name appears on the other side of this Note. |

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Signature Guarantee:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br> Signature must be guaranteed Signature

Signatures must be guaranteed by an "eligible guarantor institution" meeting the requirements of the Security Registrar, which requirements include membership or participation in the Security Transfer Agent Medallion Program ("STAMP") or such other "signature guarantee program" as may be determined by the Security Registrar in addition to, or in substitution for, STAMP, all in accordance with the Securities Exchange Act of 1934, as amended.

## Exhibit 4.2

**Exhibit 4.2** 

UNLESS THIS GLOBAL NOTE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("<u>DTC</u>"), NEW YORK, NEW YORK, TO NISOURCE INC. OR ITS AGENT OR AGENTS FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY GLOBAL NOTE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO., OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

TRANSFERS OF THIS GLOBAL NOTE SHALL BE LIMITED TO TRANSFERS IN WHOLE, BUT NOT IN PART, TO NOMINEES OF DTC OR TO A SUCCESSOR THEREOF OR SUCH SUCCESSOR'S NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL NOTE SHALL BE LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE RESTRICTIONS SET FORTH IN THE INDENTURE REFERRED TO ON THE REVERSE HEREOF.

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| | |
|:---|:---|
| No.: [___] | $[____] |

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CUSIP No.: 65473P BB0

ISIN No.: US65473PBB04

5.300% Notes due 2036

NiSource Inc., a Delaware corporation, promises to pay to [_____], or registered assigns, the principal sum of $[_____] Dollars on May 18, 2036.

Interest Payment Dates: May 18 and November 18, beginning November 18, 2026.

Record Dates: (i) if all of the Notes are in book-entry form represented by one or more Global Securities, the Business Day immediately preceding the applicable Interest Payment Date and (ii) if any of the Notes are not in book-entry form represented by one or more Global Securities, on each May 1 and November 1 (whether or not a Business Day) (each such date in clauses (i) and (ii), a "<u>Regular Record Date</u>").

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Additional provisions of this Note are set forth on the other side of this Note.

Dated:

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| | |
|:---|:---|
| NISOURCE INC. | NISOURCE INC. |
| By: |  |
| Name: | Tchapo Napoe |
| Title: | Vice President, Treasurer and Corporate Finance |

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| | |
|:---|:---|
| ATTEST: | ATTEST: |
| By: |  |
| Name: | Ashley Bancroft |
| Title: | Assistant Corporate Secretary |

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**[SIGNATURE PAGE TO GLOBAL NOTE NO. 1]** 

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TRUSTEE'S CERTIFICATE OF AUTHENTICATION

This is one of the Notes of the series referred to

in the within-mentioned Indenture.

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| | |
|:---|:---|
| Dated: | Dated: |
| THE BANK OF NEW YORK MELLON, as | THE BANK OF NEW YORK MELLON, as |
| Trustee | Trustee |
| By: |  |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Authorized Officer |

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**[SIGNATURE PAGE TO GLOBAL NOTE NO. 1]** 

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5.300% Notes due 2036

1. Interest

NiSource Inc., a Delaware corporation (such corporation, and its successors and assigns under the Indenture hereinafter referred to, being herein called the "<u>Company</u>"), promises to pay interest on the principal amount of this Note at the rate per annum shown above. The Company will pay interest semiannually on May 18 and November 18 of each year, beginning November 18, 2026. Interest on the Notes will accrue from the most recent date to which interest has been paid or, if no interest has been paid, from May 18, 2026. Interest will be computed on the basis of a 360-day year of twelve 30-day months. The Company will pay interest on overdue principal and premium at the above rate and will pay interest on overdue installments of interest at such rate to the extent lawful.

2. Method of Payment

The Company will pay interest on the Notes (except defaulted interest) to the Persons who are registered Holders of Notes at the close of business on the Regular Record Date next preceding each Interest Payment Date even if Notes are canceled after the Regular Record Date and on or before the Interest Payment Date. Holders must surrender Notes to a Paying Agent to collect principal payments. The Company will pay principal and interest in money of the United States that at the time of payment is legal tender for payment of public and private debts. Payments in respect of the Notes represented by a Global Note (including principal, premium, if any, and interest) will be made by wire transfer of immediately available funds to the accounts specified by DTC, as Depositary.

3. Paying Agent and Security Registrar

Initially, the Trustee will act as Paying Agent and Security Registrar. The Company may appoint and change any Paying Agent or Security Registrar without notice to the Holders. The Company may act as Paying Agent or Security Registrar.

4. Indenture

The Company issued the Notes under an Indenture dated as of November 14, 2000, by and between the Company, in its own capacity and as successor to NiSource Finance Corp., and the Trustee (as successor trustee) (as amended and supplemented, the "<u>Indenture</u>") and pursuant to an Officers' Certificate of the Company dated May 18, 2026 (the "<u>Officers' Certificate</u>"). The terms of the Notes include those stated in the Indenture and the Officers' Certificate and those made part of the Indenture by reference to the Trust Indenture Act of 1939 (15 U.S.C. sections 77aaa-77bbbb) as in effect on the date of the Officers' Certificate (the "<u>Act</u>"). Capitalized terms used herein and defined in the Indenture but not defined herein have the respective meanings ascribed thereto in the Indenture. The Notes are subject to all such terms, and Holders of Notes are referred to the Indenture and the Act for a statement of those terms.

The Notes are senior unsecured obligations of the Company. The Notes issued on the original issue date will be treated as a single class for all purposes under the Indenture. The Indenture contains covenants that limit the ability of the Company and its Subsidiaries (other than Utilities) to incur additional indebtedness and create liens on assets unless the total amount of all the secured debt would not exceed 10% of Consolidated Net Tangible Assets (excluding the Utilities). These covenants are subject to important exceptions and qualifications.

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5. Optional Redemption

Prior to February 18, 2036 (three months prior to the maturity date of the Notes) (the "<u>Par Call Date</u>"), the Company will have the right to redeem the Notes, at its option, in whole or in part, at any time and from time to time, at a Redemption Price (expressed as a percentage of principal amount and rounded to three decimal places) equal to the greater of (1)(a) the sum of the present values of the remaining scheduled payments of principal and interest thereon discounted to the Redemption Date (assuming the Notes matured on the Par Call Date) on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate plus 15.0 basis points less (b) interest accrued to the Redemption Date, and (2) 100% of the principal amount of the Notes to be redeemed, plus, in either case, accrued and unpaid interest thereon to, but excluding, the Redemption Date.

On or after the Par Call Date, the Company will have the right to redeem the Notes, at its option, in whole or in part, at any time and from time to time, at a Redemption Price equal to 100% of the principal amount of the Notes being redeemed plus accrued and unpaid interest thereon to, but excluding, the Redemption Date.

"<u>Treasury Rate</u>" means, with respect to any Redemption Date, the yield determined by the Company in accordance with the following two paragraphs.

The Treasury Rate shall be determined by the Company after 4:15 p.m., New York City time (or after such time as yields on U.S. government securities are posted daily by the Board of Governors of the Federal Reserve System), on the third Business Day preceding the Redemption Date based upon the yield or yields for the most recent day that appear after such time on such day in the most recent statistical release published by the Board of Governors of the Federal Reserve System designated as "Selected Interest Rates (Daily)—H.15" (or any successor designation or publication) ("<u>H.15</u>") under the caption "U.S. government securities–Treasury constant maturities–Nominal" (or any successor caption or heading) ("<u>H.15 TCM</u>"). In determining the Treasury Rate, the Company shall select, as applicable: (1) the yield for the Treasury constant maturity on H.15 exactly equal to the period from the Redemption Date to the Par Call Date (the "<u>Remaining Life</u>"); or (2) if there is no such Treasury constant maturity on H.15 exactly equal to the Remaining Life, the two yields – one yield corresponding to the Treasury constant maturity on H.15 immediately shorter than and one yield corresponding to the Treasury constant maturity on H.15 immediately longer than the Remaining Life – and shall interpolate to the Par Call Date on a straight-line basis (using the actual number of days) using such yields and rounding the result to three decimal places; or (3) if there is no such Treasury constant maturity on H.15 shorter than or longer than the Remaining Life, the yield for the single Treasury constant maturity on H.15 closest to the Remaining Life. For purposes of this paragraph, the applicable Treasury constant maturity or maturities on H.15 shall be deemed to have a maturity date equal to the relevant number of months or years, as applicable, of such Treasury constant maturity from the Redemption Date.

If on the third Business Day preceding the Redemption Date H.15 TCM is no longer published, the Company shall calculate the Treasury Rate based on the rate per annum equal to the semi-annual equivalent yield to maturity at 11:00 a.m., New York City time, on the second Business Day preceding such Redemption Date of the United States Treasury security maturing on, or with a maturity that is closest to, the Par Call Date, as applicable. If there is no United States Treasury security maturing on the Par Call Date but there are two or more United States Treasury securities with a maturity date equally distant from the Par Call Date, one with a maturity date preceding the Par Call Date and one with a maturity date following the Par Call Date, the Company shall select the United States Treasury security with a maturity date preceding the Par Call Date. If there are two or more United States Treasury securities maturing on the Par Call Date or two or more United States Treasury securities meeting the criteria of the preceding sentence, the Company shall select from among these two or more United States Treasury securities the United States

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Treasury security that is trading closest to par based upon the average of the bid and asked prices for such United States Treasury securities at 11:00 a.m., New York City time. In determining the Treasury Rate in accordance with the terms of this paragraph, the semi-annual yield to maturity of the applicable United States Treasury security shall be based upon the average of the bid and asked prices (expressed as a percentage of principal amount) at 11:00 a.m., New York City time, of such United States Treasury security, and rounded to three decimal places.

The Trustee shall have no duty to calculate the Redemption Price.

6. Tax Credit Event Redemption

If a Tax Credit Event occurs, the Company will have the right to redeem the Notes, at its option, in whole but not in part, at a Redemption Price equal to 101% of the principal amount of the Notes being redeemed plus accrued and unpaid interest thereon to, but excluding, the Redemption Date.

Notice of any redemption of the Notes upon the occurrence of a Tax Credit Event (i) may only be sent by the later of (a) the end of the calendar year in which the Notes were issued and (b) six months after the date of issuance of the Notes and (ii) shall be accompanied by a certificate from an officer of the Company stating that a Tax Credit Event has occurred.

The consummation of a redemption of the Notes upon a Tax Credit Event may be subject to the Paying Agent's receipt of the required redemption moneys on or before the Redemption Date (and in such case no redemption shall occur unless such moneys have been received by the Paying Agent on or before such date).

A "Tax Credit Event" has occurred if, in the Company's reasonable determination, there exists a material risk, due to the Notes (considered together with other debt) having been issued, as part of an original issuance, to one or more "specified foreign entities," as defined in Section 7701(a)(51)(B) of the Internal Revenue Code of 1986, as amended (the "Code"), that the Company or any of its affiliates would be unable to utilize or otherwise ineligible to claim any tax credits otherwise allowed under Section 38 of the Code.

7. Notice of Redemption

Notice of any redemption will be mailed or electronically delivered (or otherwise transmitted in accordance with the depositary's procedures) at least 10 days but not more than 60 days before the Redemption Date to each Holder of Notes to be redeemed in accordance with Section 106 of the Indenture. In the case of a partial redemption, if the Notes to be redeemed are held in certificated form, selection of the Notes for redemption will be made by the Trustee, by lot. No Notes of a principal amount of $2,000 or less will be redeemed in part. If any Note is to be redeemed in part only, the notice of redemption that relates to such Note will state the portion of the principal amount of the Note to be redeemed. A new Note in a principal amount equal to the unredeemed portion of the original Note will be issued in the name of the Holder of the original Note upon surrender for cancellation of the original Note. For so long as the Notes are held by DTC (or another depositary), the redemption of the Notes, including selection of the Notes for redemption, shall be done in accordance with the policies and procedures of the depositary and may be made on a pro rata pass-through distribution of principal basis. The Company will not know the exact Redemption Price until approximately two (2) to three (3) Business Days before the Redemption Date. Therefore, the notice of redemption will only describe how the Redemption Price will be calculated. Unless the Company defaults in payment of the Redemption Price, on and after the Redemption Date interest will cease to accrue on the Notes or portions thereof called for redemption.

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8. Additional Notes

The Company may, without the consent of the Holders of the Notes, create and issue additional Notes ranking equally with the Notes in all respects, including having the same terms (except for the price to public, the issue date and the initial interest accrual date and the first Interest Payment Date, as applicable), so that such additional Notes shall be consolidated and form a single series with the Notes and shall have the same terms as to status, redemption or otherwise as the Notes. Such additional Notes will have the same CUSIP number as the Notes being authenticated on the date hereof, provided that such additional Notes are part of the same issue as the Notes being authenticated on the date hereof for U.S. federal income tax purposes. If such additional Notes are not part of the same issue for U.S. federal income tax purposes, such additional Notes must be issued with a separate CUSIP number. No additional Notes may be issued if an Event of Default has occurred and is continuing with respect to the Notes.

9. Denominations; Transfer; Exchange

The Notes are in registered form without coupons in denominations of $2,000 principal amount and integral multiples of $1,000. A Holder may transfer or exchange Notes in accordance with the Indenture. The Security Registrar may require a Holder, among other things, to furnish appropriate endorsements or transfer documents and to pay any taxes and fees required by law or permitted by the Indenture. The Security Registrar need not register the transfer or exchange of any Notes selected for redemption (except, in the case of a Note to be redeemed in part, the portion of the Note not to be redeemed) for a period of fifteen (15) Business Days before a selection of Notes to be redeemed.

10. Persons Deemed Owners

The registered Holder of this Note may be treated as the owner of it for all purposes.

11. Unclaimed Money

If money for the payment of principal or interest remains unclaimed for two years, the Trustee or Paying Agent shall pay the money back to the Company at its request. After any such payment, Holders entitled to the money must look only to the Company and not to the Trustee or the Paying Agent for payment.

12. Satisfaction and Discharge

Under the Indenture, the Company can terminate its obligations with respect to the Notes not previously delivered to the Trustee for cancellation when those Notes have become due and payable or will become due and payable at their Stated Maturity within one year or are to be called for redemption within one year under arrangements satisfactory to the Trustee for giving notice of redemption. The Company may terminate its obligations with respect to the Notes by depositing with the Trustee, as funds in trust dedicated solely for that purpose, an amount sufficient to pay and discharge the entire indebtedness on the Notes. In that case, the Indenture will cease to be of further effect and the Company's obligations will be satisfied and discharged with respect to the Notes (except as to the Company's obligations to pay all other amounts due under the Indenture and to provide certain Officers' Certificates and Opinions of Counsel to the Trustee). At the expense of the Company, the Trustee will execute proper instruments acknowledging the satisfaction and discharge.

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13. Amendment, Waiver

Subject to certain exceptions set forth in the Indenture, (i) the Indenture may be amended with the written consent of the Holders of a majority in principal amount of the then Outstanding Securities of each series affected by such amendment, (ii) the Notes may be amended with the written consent of the Holders of at least a majority in principal amount of the Outstanding Notes and (iii) any default or noncompliance with any provision may be waived with the written consent of the Holders of a majority in principal amount of the Outstanding Notes. Subject to certain exceptions set forth in the Indenture, without the consent of any Holder, the Company and the Trustee shall be entitled to amend the Indenture to, among other things, cure any ambiguity, defect or inconsistency, or to evidence the succession of another Person as obligor under the Indenture, or to add to the Company's covenants or to surrender any right or power conferred on the Company under the Indenture, or to add events of default, or to secure the Notes, or to evidence or provide for the acceptance or appointment by a successor Trustee or facilitate the administration of the trusts under the Indenture by more than one trustee, or to conform the Indenture to any amendment of the Act.

14. Defaults and Remedies

Under the Indenture, Events of Default include: (i) a default by the Company in the payment of any interest upon any Note and the continuance of such default for 60 days; (ii) a default by the Company in the payment of principal of or any premium on any Note when due at Maturity, on redemption, by declaration or otherwise, and the continuance of such default for three (3) Business Days; (iii) a default by the Company in the performance of or breach of any covenant or warranty in the Indenture and continuance of such default for 90 days after written notice has been given to the Company by the Trustee or to the Company and the Trustee by the Holders of at least 33% in principal amount of the Outstanding Notes; (iv) a default by the Company under any bond, debenture, note or other evidence of indebtedness for money borrowed by the Company, or the Company defaults under any mortgage, indenture or instrument under which there may be issued, secured or evidenced indebtedness constituting a failure to pay in excess of $50,000,000 of the principal or interest when due and payable, subject to certain cure rights; or (v) certain events of bankruptcy, insolvency or reorganization involving the Company. If an Event of Default occurs and is continuing, the Trustee or the Holders of at least 33% in principal amount of the Outstanding Notes may declare all the Notes to be due and payable immediately.

Holders may not enforce the Indenture or the Notes except as provided in the Indenture. The Trustee may refuse to enforce the Indenture or the Notes unless it receives indemnity or security satisfactory to it. Subject to certain limitations, Holders of a majority in principal amount of the Notes may direct the Trustee in its exercise of any trust or power. The Trustee may withhold from Holders notice of any continuing default (except a default in payment of principal or interest) if it determines that withholding notice is in the interest of the Holders.

15. Trustee Dealings with the Company

Subject to certain limitations imposed by the Act, the Trustee under the Indenture, in its individual or any other capacity, may become the owner or pledgee of Notes and may otherwise deal with and collect obligations owed to it by the Company or its Affiliates and may otherwise deal with the Company or its Affiliates with the same rights it would have if it were not Trustee.

16. No Recourse Against Others

A director, officer, employee or stockholder, as such, of the Company or the Trustee shall not have any liability for any obligations of the Company under the Notes or the Indenture or for any claim based on, in respect of or by reason of such obligations or their creation. By accepting a Note, each Holder waives and releases all such liability. The waiver and release are part of the consideration for the issue of the Notes.

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17. Authentication

This Note shall not be valid until an authorized signatory of the Trustee (or an Authenticating Agent) signs the certificate of authentication on the other side of this Note in accordance with requirements set forth in the Indenture and the Officers' Certificate.

18. Abbreviations

Customary abbreviations may be used in the name of a Holder or an assignee, such as TEN COM (=tenants in common), TEN ENT (=tenants by the entireties), JT TEN (=joint tenants with rights of survivorship and not as tenants in common), CUST (=custodian), and U/G/M/A (=Uniform Gift to Minors Act).

19. CUSIP and ISIN Numbers

Pursuant to a recommendation promulgated by the Committee on Uniform Security Identification Procedures, the Company has caused the applicable CUSIP number to be printed on the Notes and has directed the Trustee to use such CUSIP number in any notice of redemption as a convenience to the Holders. To the extent such number has been issued, the Company has caused the applicable ISIN number to be similarly printed on the Notes and has similarly instructed the Trustee. No representation is made as to the accuracy of such numbers either as printed on the Notes or as contained in any notice of redemption and reliance may be placed only on the other identification numbers placed thereon.

20. Governing Law.

THIS NOTE SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE INTERNAL LAWS OF THE STATE OF NEW YORK, WITHOUT GIVING EFFECT TO CONTRARY CONFLICT OF LAWS OR CHOICE OF LAWS PROVISIONS OF THE STATE OF NEW YORK OR ANY OTHER JURISDICTION.

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The Company will furnish to any Holder upon written request and without charge to the Holder a copy of the Indenture. Requests may be made to:

NiSource Inc.

801 East 86th Avenue

Merrillville, Indiana 46410

Attention: Corporate Secretary

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ASSIGNMENT FORM

To assign this Note, fill in the form below: I or

we assign and transfer this Note to

(Print or type assignee's name, address and zip

code) (Insert assignee's soc. Sec. or tax I.D. No.)

and irrevocably appoint ________________________ agent to transfer this Note on the books of the Company. The agent may substitute another to act for him.

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| | | |
|:---|:---|:---|
| Date: | Your Signature: |  |
|  |  | Sign exactly as your name appears on the other side of this Note. |

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Signature Guarantee:

Signature must be guaranteed Signature

Signatures must be guaranteed by an "eligible guarantor institution" meeting the requirements of the Security Registrar, which requirements include membership or participation in the Security Transfer Agent Medallion Program ("STAMP") or such other "signature guarantee program" as may be determined by the Security Registrar in addition to, or in substitution for, STAMP, all in accordance with the Securities Exchange Act of 1934, as amended.

## Exhibit 5.1

**Exhibit 5.1**![LOGO](g119463g0515210214050.jpg)

May 18, 2026

NiSource Inc.

801 East 86th Avenue

Merrillville, Indiana 46410

**<u>NiSource Inc.</u>**

**<u>4.750% Notes due 2031</u>**

**<u>5.300% Notes due 2036</u>**

Ladies and Gentlemen:

We refer to the Registration Statement on Form S-3 (File No. 333-291167) (the "<u>Registration Statement</u>"), filed by NiSource Inc., a Delaware corporation (the "<u>Company</u>"), with the Securities and Exchange Commission (the "<u>SEC</u>"). Pursuant to the Registration Statement, the Company is offering $500,000,000 aggregate principal amount of its 4.750% Notes due 2031 and $750,000,000 aggregate principal amount of its 5.300% Notes due 2036 (together, the "<u>Notes</u>"), as described in the Company's Prospectus, dated October 30, 2025 (the "<u>Base Prospectus</u>") and Prospectus Supplement, dated May 11, 2026 (the "<u>Prospectus Supplement</u>" and, together with the Base Prospectus, the "<u>Prospectus</u>"). The Registration Statement became effective upon filing on October 30, 2025. This opinion letter is being furnished in accordance with the requirements of Item 16 of Form S-3 and Item 601(b)(5)(i) of Regulation S-K promulgated under the Securities Act of 1933, as amended (the "<u>Securities Act</u>").

The Notes are being issued under that certain indenture dated as of November 14, 2000 (the "<u>Original Indenture</u>"), between the Company (as successor to NiSource Finance Corp.) and The Bank of New York Mellon, as successor trustee (the "<u>Trustee</u>"), as supplemented by the Second Supplemental Indenture dated as of November 20, 2017 (the "<u>Supplemental Indenture</u>" and, together with the Original Indenture, the "<u>Indenture</u>"), and are being offered to the public in accordance with the Terms Agreement, dated May 11, 2026 (the "<u>Terms Agreement</u>"), among the Company and BNP Paribas Securities Corp., BofA Securities, Inc., MUFG Securities Americas Inc. and U.S. Bancorp Investments, Inc., as lead underwriters of the underwriters named therein. The Terms Agreement incorporates by reference the provisions of that certain Underwriting Agreement dated November 30, 2017 (the "<u>Underwriting Agreement</u>" and, together with the Terms Agreement, the "<u>Agreements</u>"). Capitalized terms used and not defined herein shall have the meanings assigned to them in the Registration Statement or the Indenture.

**<u>Documents Reviewed</u>**

In connection with this opinion letter, we have examined the following documents:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) the Registration Statement;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) the Base Prospectus;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) the Prospectus Supplement;

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d) the Original Indenture;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(e) the Supplemental Indenture;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(f) the global note certificates, dated May 18, 2026, representing the Notes of each series;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(g) the Terms Agreement; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(h) the Underwriting Agreement.

The documents referred to in clauses (d) through (f) above are referred to collectively as the "<u>Subject Documents</u>" and each, individually, as a "<u>Subject Document</u>."

In addition we have examined and relied upon the following:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(i) a certificate from the Assistant Corporate Secretary of the Company certifying as to (A) true and correct copies of the Amended and Restated Certificate of Incorporation, as amended, and the Amended and Restated Bylaws of the Company, as amended (together, the "<u>Organizational Documents</u>") and (B) the resolutions of the Board of Directors of the Company authorizing (1) the filing of the Registration Statement by the Company and (2) the offer, sale and issuance of the Notes by the Company pursuant to the Agreements (the "<u>Authorizing Resolutions</u>"); and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(ii) originals, or copies identified to our satisfaction as being true copies, of such other records, documents, instruments, certificates of officers of and statements of the Company, and certificates and assurances of public officials, as we have deemed necessary for the purposes of this opinion letter.

"<u>Applicable Law</u>" means the Delaware General Corporation Law (the "<u>DGCL</u>") and the laws of the State of New York.

**<u>Assumptions Underlying Our Opinions</u>**

For all purposes of the opinions expressed herein, we have assumed, without independent investigation, the following:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) <u>Factual Matters</u>. To the extent that we have reviewed and relied upon (i) certificates of the Company or authorized representatives thereof, (ii) representations of the Company set forth in the Subject Documents and (iii) certificates and assurances from public officials, all of such certificates, representations and assurances are accurate with regard to factual matters and all official records (including filings with public authorities) are properly indexed and filed and are accurate and complete.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) <u>Authentic and Conforming Documents</u>. All documents submitted to us as originals are authentic, complete and accurate, and all documents submitted to us as copies conform to authentic original documents.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) <u>Signatures; Legal Capacity</u>. The signatures of individuals who have signed or will sign the Subject Documents are genuine. All individuals who have signed or will sign the Subject Documents have the legal capacity to execute such Subject Documents.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d) <u>Organizational Status, Power and Authority of Certain Parties</u>. All parties to the Subject Documents (other than any individual) (i) are validly existing and in good standing in their respective jurisdictions of formation, except that no such assumption is made as to the Company as of the date hereof and (ii) have the power and authority to execute, deliver and perform the Subject Documents and the documents required or permitted to be delivered and performed thereunder, except that no such assumption is made as to the Company as of the date hereof.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(e) <u>Authorization, Execution and Delivery of Subject Documents by Certain Parties</u>. The Subject Documents and the documents required or permitted to be delivered thereunder have been duly authorized by all necessary corporate, limited liability company, business trust, partnership or other action on the part of the parties thereto and have been duly executed and delivered by such parties, except that no such assumptions are made as to the Company as of the date hereof.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(f) <u>Subject Documents Binding on Certain Parties</u>. The Subject Documents and the documents required or permitted to be delivered thereunder are valid and binding obligations enforceable against the parties thereto in accordance with their terms, except that no such assumption is made as to the Company as of the date hereof.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(g) <u>Noncontravention</u>. Neither the issuance of the Notes by the Company or the execution and delivery of the Subject Documents by any party thereto nor the performance by such party of its obligations thereunder will conflict with or result in a breach of (i) the certificate or articles of incorporation, bylaws, certificate or articles of organization, operating agreement, certificate of limited partnership, partnership agreement, trust agreement or other similar organizational documents of any such party, except that no such assumption is made as to the Company as to the Organizational Documents as of the date hereof, (ii) any law or regulation of any jurisdiction applicable to any such party except that no such assumption is made as to the Company as to any Applicable Law as of the date hereof, or (iii) any order, writ, injunction or decree of any court or governmental instrumentality or agency applicable to any such party or any agreement or instrument to which any such party may be a party or by which its properties are subject or bound, except that no such assumption is made as to the Company as to the Subject Documents as of the date hereof.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(h) <u>Governmental Approvals</u>. All consents, approvals and authorizations of, or filings with, all governmental authorities that are required as a condition to the issuance of the Notes by the Company or to the execution and delivery of the Subject Documents by the parties thereto or the performance by such parties of their obligations thereunder have been obtained or made, except that no such assumption is made with respect to any consent, approval, authorization or filing that is applicable to the Company as of the date hereof.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(i) <u>No Mutual Mistake, Amendments, etc</u>. There has not been any mutual mistake of fact, fraud, duress or undue influence in connection with the issuance of the Notes as contemplated by the Registration Statement and the Prospectus. There are no oral or written statements or agreements that modify, amend or vary, or purport to modify, amend or vary, any of the terms of the Subject Documents except for, in the case of the terms of the Indenture, the officers' certificates establishing the terms of the Notes.

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**<u>Our Opinions</u>**

Based on and subject to the foregoing and the exclusions, qualifications, limitations and other assumptions set forth in this opinion letter, we are of the opinion that:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1. <u>Organizational Status</u>. The Company is a validly existing corporation under the laws of the Delaware and is in good standing under such laws.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2. <u>Power and Authority</u>. The Company has the corporate power and authority to issue the Notes.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3. <u>Validity of the Notes</u>. When (i) the Notes have been issued and sold as contemplated by the Registration Statement, the Agreements and the Prospectus, (ii) the Company has received the consideration provided for in the Prospectus Supplement and the Agreements, and (iii) the Notes have been authenticated in accordance with the provisions of the Indenture, the Notes will constitute the valid and binding obligations of the Company, enforceable against the Company in accordance with their terms, under the laws of State of New York.

**<u>Matters Excluded from Our Opinions</u>**

We express no opinion with respect to the following matters:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) <u>Indemnification and Change of Control</u>. The enforceability of any agreement relating to (i) indemnification, contribution or exculpation from costs, expenses or other liabilities or (ii) changes in the organizational control or ownership of any party, which agreement (in the case of clause (i) or clause (ii)) is contrary to public policy or Applicable Law.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) <u>Jurisdiction, Venue, etc</u>. The enforceability of any agreement to submit to the jurisdiction of any specific federal or state court (other than the enforceability in a court of the State of New York of any such agreement to submit to the jurisdiction of a court of the State of New York), to waive any objection to the laying of the venue, to waive the defense of *forum non conveniens* in any action or proceeding referred to therein, to waive trial by jury, to effect service of process in any particular manner or to establish evidentiary standards, and any agreement regarding the choice of law governing any Subject Document (other than the enforceability in a court of the State of New York or in a federal court sitting in the State of New York and applying New York law to any such agreement that the laws of the State of New York shall govern).

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) <u>Remedies</u>. The enforceability of any provision in any Subject Document to the effect that rights or remedies are not exclusive, that every right or remedy is cumulative and may be exercised in addition to any other right or remedy, that the election of some particular remedy does not preclude recourse to one or more others or that failure to exercise or delay in exercising rights or remedies will not operate as a waiver of any such right or remedy.

**<u>Qualifications and Limitations Applicable to Our Opinions</u>**

The opinions set forth above are subject to the following qualifications and limitations:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) <u>Applicable Law</u>. Our opinions are limited to the Applicable Law, and we do not express any opinion concerning any other law.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) <u>Bankruptcy</u>. Our opinions are subject to the effect of any applicable bankruptcy, insolvency (including, without limitation, laws relating to preferences, fraudulent transfers and equitable subordination), reorganization, moratorium and other similar laws affecting creditors' rights generally.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) <u>Equitable Principles</u>. Our opinions are subject to the effect of general principles of equity (regardless of whether considered in a proceeding in equity or at law), including, without limitation, concepts of materiality, reasonableness, good faith and fair dealing. In applying such principles, a court, among other things, might limit the availability of specific equitable remedies (such as injunctive relief and the remedy of specific performance), might not allow a creditor to accelerate maturity of debt or exercise other remedies upon the occurrence of a default deemed immaterial or for non-credit reasons or might decline to order a debtor to perform covenants in a Subject Document.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d) <u>Unenforceability of Certain Provisions</u>. Provisions contained in the Notes or the Subject Documents which require waivers or amendments to be made only in writing may be unenforceable or ineffective, in whole or in part. The inclusion of such provisions, however, does not render any of the Notes or the Subject Documents invalid as a whole.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(e) <u>Choice of New York Law and Forum</u>. To the extent that any of our opinions relate to the enforceability of the choice of New York law or any choice of New York forum provisions of any Subject Document, our opinion is rendered in reliance upon N.Y. Gen. Oblig. Law §§ 5-1401 and 5-1402 and N.Y. CPLR 327(b) and is subject to the qualification that such enforceability may be limited by principles of public policy, comity and constitutionality. We express no opinion as to whether a United States federal court would have subject-matter or personal jurisdiction over a controversy arising under the Subject Documents.

**<u>Miscellaneous</u>**

The foregoing opinions are being furnished only for the purpose referred to in the first paragraph of this opinion letter. Our opinions are based on statutes, regulations and administrative and judicial interpretations which are subject to change. We undertake no responsibility to update or supplement these opinions subsequent to the date hereof. Headings in this opinion letter are intended for convenience of reference only and shall not affect its interpretation. We hereby consent to the filing of this opinion as an exhibit to the Company's Current Report on Form 8-K filed on the date hereof, to the incorporation by reference of this opinion of counsel into the Registration Statement, and to the reference to our firm in the Prospectus Supplement under the caption "Legal Matters." In giving this consent, we do not admit that we are within the category of persons whose consent is required by Section 7 of the Securities Act or the rules and regulations of the SEC promulgated thereunder.

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| Very truly yours, |
| /s/ McGuireWoods LLP |

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