We follow the accounting and reporting requirements of ASC Topic 980, which provides that regulated entities account for and report assets and liabilities consistent with the economic effect of regulatory rate-making procedures when the rates established are designed to recover the costs of providing the regulated service and it is probable that such rates will be charged and collected from customers. Certain expenses and credits subject to utility regulation or rate determination normally reflected in income or expense are deferred on the balance sheet and are recognized in the income statement as the related amounts are included in customer rates and recovered from or refunded to customers. We assess the probability of collection for all of our regulatory assets each period.


At December 31, (in millions)	2024		2023
Regulatory Assets
Unrecognized pension and other postretirement benefit costs (see Note 16)	$	485.3	$	561.6
Deferred pension and other postretirement benefit costs (see Note 16)	45.3		59.7
Environmental costs (see Note 19-D.)	42.8		40.6
Regulatory effects of accounting for income taxes (see Note 1-N. and Note 15)	172.0		163.5
Under-recovered gas and fuel costs (see Note 1-J.)	82.3		12.7
Depreciation	214.9		201.9

Post-in-service carrying charges	280.8		269.9



Safety activity costs	203.7		206.6
DSM programs	17.8		25.0
Retired coal generating stations	617.0		682.0
Losses on commodity price risk programs (See Note 13)	6.5		24.4
Deferred property taxes	75.9		72.3
Renewable energy investments	81.3		60.8
WAM system filing	21.5		—
Customer assistance programs	24.4		—
Other	105.8		79.2
Total Regulatory Assets	$	2,477.3	$	2,460.2
Less: Current Portion	319.9		214.3
Total Noncurrent Regulatory Assets	$	2,157.4	$	2,245.9


At December 31, (in millions)	2024		2023
Regulatory Liabilities
Over-recovered gas and fuel costs (see Note 1-J.)	$	21.4	$	144.5
Cost of removal (see Note 11)	482.8		597.2
Regulatory effects of accounting for income taxes (see Note 1-N. and Note 15)	827.0		849.9
Deferred pension and other postretirement benefit costs (see Note 16)	40.4		54.0
Gains on commodity price risk programs (See Note 13)	28.7		23.3
Customer assistance programs	9.4		19.8
Off-system sales sharing	21.4		19.0
Renewable energy investments (See Note 1-S. and Note 4)	77.0		18.1
Rate refunds	16.6		16.1
Other	57.0		47.4
Total Regulatory Liabilities	$	1,581.7	$	1,789.3
Less: Current Portion	150.5		278.6
Total Noncurrent Regulatory Liabilities	$	1,431.2	$	1,510.7

Regulatory assets, including under-recovered gas and fuel costs and depreciation, of approximately $671.3 million and $716.4 million as of December 31, 2024 and 2023, respectively, are not earning a return on investment. These costs are recovered over a remaining life of between 15 and 75 years.

Unrecognized pension and other postretirement benefit costs. Represents the deferred other comprehensive income or loss of the actuarial gains or losses and the prior service costs or credits that arise during the period but that are not immediately recognized as components of net periodic benefit costs by certain subsidiaries that will ultimately be recovered through base rates.

Deferred pension and other postretirement benefit costs. Primarily relates to the difference between defined benefit plan expense recorded by certain subsidiaries due to regulatory orders and the corresponding expense that would otherwise be recorded in accordance with GAAP. This balance is driven by Columbia of Ohio deferrals.

Environmental costs. Includes certain recoverable costs related to gas plant sites, disposal sites or other sites onto which material may have migrated, the recovery of which is to be addressed in future base rates, billing riders or tracking mechanisms of certain of our subsidiaries.

Under-recovered gas and fuel costs. Represents the difference between the costs of gas and fuel, as well as energy acquired through power purchase agreements, including NIPSCO's own renewable projects, and the recovery of such costs in revenue and is used to adjust future billings for such deferrals on a basis consistent with applicable state-approved tariff provisions. Recovery of these costs is achieved through tracking mechanisms.

Depreciation. Represents differences between depreciation expense incurred on a GAAP basis and that prescribed through regulatory order. The majority of this balance is driven by Columbia of Ohio's IRP and CEP deferrals.

Post-in-service carrying charges. Represents deferred debt-based carrying charges incurred on certain assets placed into service but not yet included in customer rates. The majority of this balance is driven by Columbia of Ohio's IRP and CEP deferrals.

Safety activity costs. Represents the difference between costs incurred by certain of our subsidiaries in eligible safety programs in compliance with PHMSA regulations in excess of those being recovered in rates. The majority of this balance is driven by Columbia of Ohio, which began recovery in March 2023 through base rates.

Retired coal generating stations. Represents the net book value of Units 7 and 8 of Bailly Generating Station that was retired during 2018 and the net book value of Units 14 and 15 of R.M. Schahfer Generating Station retired in 2021. These amounts are currently being amortized at a rate consistent with their inclusion in customer rates. The August 2023 NIPSCO electric rate case order extends the recovery of, and on, the net book value of the stations by the end of 2034 and implements a revenue credit for the retired units. The credit is based on the difference between the year-end value of Units 14 and 15 and the most recent value established in the last base rate case proceeding or credit compliance filing.

Losses on commodity price risk programs. Represents the unrealized losses related to certain of our subsidiary's commodity price risk programs. These programs help to protect against the volatility of commodity prices and these amounts are collected from customers through their inclusion in customer rates.

WAM system filing. Represents the deferral of certain costs, including depreciation and amortization incurred in connection with improvements to its information technology systems through the design, development, and implementation of a new WAM program for the scheduling, dispatch, and execution of work and the management of underlying assets.

Over-recovered gas and fuel costs. Represents the difference between the cost of gas and fuel, as well as energy acquired through power purchase agreements, including NIPSCO's own renewable projects and, the recovery of such costs in revenues and is the basis to adjust future billings for such refunds on a basis consistent with applicable state-approved tariff provisions. Refunding of these revenues is achieved through tracking mechanisms.

Regulatory effects of accounting for income taxes. Represents amounts owed to customers for deferred taxes collected at a higher rate than the current statutory rates and liabilities associated with accelerated tax deductions owed to customers. Balance includes excess deferred taxes recorded upon implementation of the TCJA in December 2017, net of amounts amortized through 2024 and federal tax credits generated by Cavalry solar facility that are passed back to customers. For discussion of the regulatory impact of the NIPSCO Minority Interest Transaction on deferred taxes, see Note 15, "Income Taxes," for additional details.

Gains on commodity price risk programs. Represents the unrealized gains related to certain of our subsidiary's commodity price risk programs. These programs help to protect against the volatility of commodity prices, and these amounts are passed back to customers through their inclusion in customer rates.

Renewable energy investments. Represents the regulatory deferral of certain amounts representing the timing difference between the profit earned from the JVs and the amount included in regulated rates to recover our approved investments in consolidated JVs. The offset to the regulatory liability associated with our renewable investments is recorded in "Depreciation expense" on the Statements of Consolidated Comprehensive Income. Refer to Note 1, "Nature of Operations and Summary of Significant Accounting Policies - S. Noncontrolling Interest," Note 4, "Noncontrolling Interests," and Note 9, "Property, Plant and Equipment," for additional information.

In March 2024, NIPSCO filed a petition with the IURC to issue an order modifying its November 22, 2023 order to approve direct ownership of the Gibson project. Also, in March 2024, NIPSCO filed a petition with the IURC to issue an order modifying its June 29, 2021 order to approve direct ownership of the Fairbanks project. Hearings for both the Gibson project and Fairbanks project were held in June 2024 and July 2024, respectively, with orders approving direct ownership of both projects received in August 2024.

In September 2023, NIPSCO filed a request for issuance of a CPCN for an approximately 400 MW natural gas peaking generation facility with the IURC, which was supplemented in January 2024 based on updates on availability of certain key equipment. A final order was received in October 2024 approving the request.

On February 7, 2025, NIPSCO and certain intervening parties filed a Joint Stipulation and Settlement Agreement with the IURC. New rates proposed to be implemented in 2 steps, with implementation of Step 1 rates effective no later than September 2025 and Step 2 rates to be effective no later than March 2026.