
Long-term debt type	Maturity as of December 31, 2025	Weighted average interest rate (%)		Outstanding balance as of December 31, (in millions)
				2025		2024
Senior notes:
NiSource	August 2025	0.950	%	$	—	$	1,250.0
NiSource	May 2027	3.490	%	1,000.0		1,000.0
NiSource	December 2027	6.780	%	3.0		3.0
NiSource	March 2028	5.250	%	1,050.0		1,050.0
NiSource	July 2029	5.200	%	600.0		600.0
NiSource	September 2029	2.950	%	750.0		750.0
NiSource	May 2030	3.600	%	1,000.0		1,000.0
NiSource	February 2031	1.700	%	750.0		750.0
NiSource	June 2033	5.400	%	450.0		450.0
NiSource	April 2034	5.350	%	650.0		650.0
NiSource	July 2035	5.350	%	900.0		—
NiSource	December 2040	6.250	%	152.6		152.6
NiSource	June 2041	5.950	%	347.4		347.4
NiSource	February 2042	5.800	%	250.0		250.0
NiSource	February 2043	5.250	%	500.0		500.0
NiSource	February 2044	4.800	%	750.0		750.0
NiSource	February 2045	5.650	%	500.0		500.0
NiSource	May 2047	4.375	%	1,000.0		1,000.0
NiSource	March 2048	3.950	%	750.0		750.0
NiSource	June 2052	5.000	%	350.0		350.0
NiSource	April 2055	5.850	%	1,500.0		—
Total senior notes				$	13,253.0	$	12,103.0
Junior subordinated notes:
NiSource	November 2054	6.950	%	$	500.0	$	500.0
NiSource	March 2055	6.375	%	500.0		500.0
NiSource	July 2056	5.750	%	1,000.0		—
Total junior subordinated notes				$	2,000.0	$	1,000.0
Medium term notes:
NiSource	May 2027	7.990	%	$	29.0	$	29.0
NIPSCO	June 2027 to August 2027	7.644	%	58.0		58.0
Columbia of Massachusetts	December 2025	6.430	%	—		10.0
Columbia of Massachusetts	February 2028	6.260	%	5.0		5.0
Total medium term notes				$	92.0	$	102.0
Finance leases:
NiSource Corporate Services	January 2026 to September 2027	4.350	%	$	5.0	$	14.6
NIPSCO	December 2027 to December 2063	5.480	%	165.5		124.3
Columbia of Ohio	December 2035 to March 2052	6.110	%	81.7		85.6
Columbia of Virginia	July 2029 to November 2039	5.620	%	16.2		15.2
Columbia of Kentucky	May 2027	5.360	%	0.1		0.1
Columbia of Pennsylvania	March 2030 to May 2035	4.430	%	5.5		6.4
Total finance leases				$	274.0	$	246.2
Less: Unamortized issuance costs and discounts				(141.5)		(95.5)
Less: Current portion of long term debt				(19.7)		(1,281.2)
Total Long-Term Debt				$	15,457.8	$	12,074.5

•In June 2025, we completed the issuance and sale of an additional $750.0 million of 5.850% senior unsecured notes maturing in 2055 (the "2055 Notes"). The terms of the 2055 Notes, other than the issue date and the price to the public, are identical to the terms of, and constitute a reopening of, our 5.850% senior unsecured notes maturing in 2055 issued in March, 2025. With the incremental issuance, we now have $1.5 billion of 5.850% senior unsecured notes maturing in 2055. In June 2025, we also completed the issuance and sale of $900.0 million of 5.350% senior unsecured notes maturing in 2035 (the "2035 Notes"). The issuances of the 2055 Notes and the 2035 Notes in June, 2025 resulted in approximately $1.616 billion of total net proceeds after discount and debt issuance costs.

•In November 2025, we completed the issuance and sale of $1.0 billion of 5.750% fixed-to-fixed reset rate junior subordinated notes maturing in 2056, which resulted in approximately $984.3 million of net proceeds after debt issuance costs. The subordinated notes bear interest (i) from and including November 2025 to, but excluding, July 2031 at a rate of 5.75% per annum and (ii) from and including July 2031, during each five-year reset period at a rate per annum equal to the five-year U.S. treasury rate (determined as described in the prospectus supplement filed with the SEC in November 2025) as of the then most recent reset interest determination date plus a spread of 2.035%, to be reset on each reset date; provided that the interest rate during any reset period will not reset below 5.750% per annum. At our option, we may redeem some or all of the subordinated notes during specified periods, and upon the occurrence of certain ratings or tax events, all as described in the prospectus supplement. In accordance with terms of the subordinated notes, we have the right, from time to time, to defer the payment of interest on the outstanding subordinated notes on one or more occasions for up to ten consecutive years. In the event that we were to exercise such right to defer interest on the subordinated notes, we would not be able to pay cash dividends on the common stock during the periods in which such payments were deferred.

•In May 2024, we completed the issuance and sale of $500.0 million of 6.950% fixed-to-fixed reset rate junior subordinated notes maturing in 2054, which resulted in approximately $493.4 million of net proceeds after debt issuance costs. The subordinated notes bear interest (i) from and including May 2024 to, but excluding, November 2029 at a rate of 6.950% per annum and (ii) from and including November 2029, during each five-year reset period at a rate per annum equal to the five-year U.S. treasury rate (determined as described in the prospectus supplement filed with the SEC in May 2024) as of the then most recent reset interest determination date plus a spread of 2.451%, to be reset on each reset date. At our option, we may redeem some or all of the subordinated notes during specified periods, and upon the occurrence of certain ratings or tax events, all as described in the prospectus supplement. In accordance with terms of the subordinated notes, we have the right, from time to time, to defer the payment of interest on the outstanding subordinated notes on one or more occasions for up to ten consecutive years. In the event that we were to exercise such right to defer interest on the subordinated notes, we would not be able to pay cash dividends on the common stock during the periods in which such payments were deferred.

•In September 2024, we completed the issuance and sale of $500.0 million of 6.375% fixed-to-fixed reset rate junior subordinated notes maturing in 2055, which resulted in approximately $493.6 million of net proceeds after debt issuance costs. The subordinated notes bear interest (i) from and including September 2024 to, but excluding, March 2035 at a rate of 6.375% per annum and (ii) from and including March 2035, during each five-year reset period at a rate per annum equal to the five-year U.S. treasury rate (determined as described in the prospectus supplement filed with the SEC in September 2024) as of the then most recent reset interest determination date plus a spread of 2.527%,

to be reset on each reset date. At our option, we may redeem some or all of the subordinated notes during specified periods, and upon the occurrence of certain ratings or tax events, all as described in the prospectus supplement. In accordance with terms of the subordinated notes, we have the right, from time to time, to defer the payment of interest on the outstanding subordinated notes on one or more occasions for up to ten consecutive years. In the event that we were to exercise such right to defer interest on the subordinated notes, we would not be able to pay cash dividends on the common stock during the periods in which such payments were deferred.

We are also subject to certain other non-financial covenants under the revolving credit facility. Such covenants include a limitation on the creation or existence of new liens on our assets, generally exempting liens on utility assets, purchase money security interests, preexisting security interests and an additional subset of assets equal to $500 million. An asset sale covenant generally restricts the sale, conveyance, lease, transfer or other disposition of our assets to those dispositions that are for a price not materially less than fair market of such assets, that would not materially impair our ability to perform obligations under the revolving credit facility, and that together with all other such dispositions, would not have a material adverse effect. The covenant also restricts dispositions to no more than 15% of our consolidated total assets as of the last day of our fiscal year then most recently ended for which financial statements have been delivered. Additionally, the revolving credit facility requires us to own directly or indirectly at least 70% of NIPSCO. The revolving credit facility also includes a cross-default provision, which triggers an event of default under the credit facility in the event of an uncured payment default relating to any indebtedness of us or any of our subsidiaries in a principal amount of $100.0 million or more.

Our indentures generally do not contain any financial maintenance covenants. However, our indentures are generally subject to cross-default provisions ranging from uncured payment defaults of $5.0 million to $50.0 million, and limitations on the incurrence of liens on our assets, generally exempting liens on utility assets, purchase money security interests, preexisting security interests and an additional subset of assets capped at 10% of our consolidated net tangible assets.