Biggest changeThe following table summarizes the differences between our effective tax rate and the federal statutory rate (in millions): Year Ended December 31, 2024 2023 Income Before Income Taxes $ 214.7 $ 201.6 Income tax calculated at federal statutory rate 45.1 21.0 % 42.4 21.0 % Permanent or flow through adjustments: State income taxes, net of federal provisions 0.4 0.2 0.6 0.3 Flow-through repairs deductions (23.1) (10.8) (25.9) (12.9) Release of unrecognized tax benefits (2024 is inclusive of $4.1 million of related interest previously accrued) (21.0) (9.8) (3.2) (1.6) Production tax credits (11.1) (5.2) (10.3) (5.1) Gas repairs safe harbor method change (7.0) (3.3) — — Amortization of excess deferred income taxes (2.9) (1.4) (2.2) (1.1) Prior year permanent return to accrual adjustments (0.4) (0.2) — — Plant and depreciation of flow through items 9.4 4.4 6.6 3.3 Unregulated Tax Cuts and Jobs Act excess deferred income taxes — — (3.4) (1.7) Reduction to previously claimed alternative minimum tax credit — — 3.2 1.6 Other, net 1.2 0.7 (0.3) (0.1) (54.5) (25.4) (34.9) (17.3) Income Tax (Benefit) Expense $ (9.4) (4.4) % $ 7.5 3.7 % Our effective tax rate typically differs from the federal statutory tax rate primarily due to the regulatory impact of flowing through federal and state tax benefits of repairs deductions, state tax benefit of accelerated tax depreciation deductions (including bonus depreciation when applicable) and production tax credits. 50 ELECTRIC OPERATIONS We have various classifications of electric revenues, defined as follows: • Retail: Sales of electricity to residential, commercial and industrial customers, and the impact of regulatory mechanisms. • Regulatory amortization: Primarily represents timing differences for electric supply costs and property taxes between when we incur these costs and when we recover these costs in rates from our customers, which is also reflected in fuel, purchased supply and direct transmission expense and therefore has minimal impact on utility margin.
Biggest changeThe following table summarizes the differences between our effective tax rate and the federal statutory rate (in millions): Year Ended December 31, 2025 2024 (in dollars) (in percent) (in dollars) (in percent) Income before income taxes $187.6 $214.7 Income tax calculated at federal statutory rate 39.4 21.0 % 45.1 21.0 % State income tax, net of federal provision (1.5) (0.8) 0.4 0.2 Tax Credits Production tax credits (5.9) (3.2) (11.1) (5.2) Other 0.7 0.4 0.7 0.3 Impact of utility ratemaking on income taxes Flow-through repairs deductions (31.0) (16.5) (23.1) (10.8) Amortization of excess deferred income taxes (3.2) (1.7) (2.9) (1.4) AFUDC, net (1.3) (0.7) (2.6) (1.2) Plant and depreciation of flow through items 16.8 9.0 9.4 4.4 Gas repairs safe harbor method change — — (7.0) (3.3) Changes in Unrecognized Tax Benefits Release of unrecognized tax benefits (7.4) (4.0) (16.9) (7.9) Interest and penalties (3.0) (1.6) (1.5) (0.7) Nontaxable and nondeductible items 2.9 1.5 0.4 0.2 Other 0.0 0.1 (0.3) 0.0 (32.9) (17.5) % (54.5) (25.4) % Income Tax Expense (Benefit) and Effective Tax Rate $ 6.5 3.5 % $ (9.4) (4.4) % Our effective tax rate typically differs from the federal statutory tax rate primarily due to the regulatory impact of flowing through federal and state tax benefits of repairs deductions, state tax benefit of accelerated tax depreciation deductions (including bonus depreciation when applicable) and production tax credits. 62 ELECTRIC OPERATIONS We have various classifications of electric revenues, defined as follows: • Retail: Sales of electricity to residential, commercial and industrial customers, and the impact of regulatory mechanisms. • Regulatory amortization: Primarily represents timing differences for electric supply costs and property taxes between when we incur these costs and when we recover these costs in rates from our customers, which is also reflected in fuel, purchased supply and direct transmission expense and therefore has minimal impact on utility margin.
For the twelve months ended December 31, 2024, we under-collected supply costs of $8.0 million resulting in an increase to our under collection of costs, and recorded a decrease in pre-tax earnings of $0.9 million (10 percent of the PCCAM Base cost variance).
For the twelve months ended December 31, 2024, we under-collected supply costs of $8.0 million resulting in an increase to our under collection of costs, and recorded a decrease in pre-tax earnings of $0.9 million (10 percent of the PCCAM Base cost variance).
Our wholesale and other revenues are largely utility margin neutral as they are offset by changes in fuel, purchased supply and direct transmission expenses. 52 NATURAL GAS OPERATIONS We have various classifications of natural gas revenues, defined as follows: • Retail: Sales of natural gas to residential, commercial and industrial customers, and the impact of regulatory mechanisms. • Regulatory amortization: Primarily represents timing differences for natural gas supply costs and property taxes between when we incur these costs and when we recover these costs in rates from our customers, which is also reflected in fuel, purchased supply and direct transmission expenses and therefore has minimal impact on utility margin.
Our wholesale and other revenues are largely utility margin neutral as they are offset by changes in fuel, purchased supply and direct transmission expenses. 64 NATURAL GAS OPERATIONS We have various classifications of natural gas revenues, defined as follows: • Retail: Sales of natural gas to residential, commercial and industrial customers, and the impact of regulatory mechanisms. • Regulatory amortization: Primarily represents timing differences for natural gas supply costs and property taxes between when we incur these costs and when we recover these costs in rates from our customers, which is also reflected in fuel, purchased supply and direct transmission expenses and therefore has minimal impact on utility margin.
For NorthWestern Energy Group, liquidity is primarily provided through its revolving credit facility and dividends from its utility operating subsidiaries, NW Corp and NWE Public Service. These subsidiaries are subject to certain restrictions that may limit the amount of their dividend distributions. See Note 16 - Common Stock to the Consolidated Financial Statements for more information regarding these dividend restrictions.
For NorthWestern Energy Group, liquidity is primarily provided through its revolving credit facility and dividends from its utility operating subsidiaries, NW Corp and NWE Public Service. These subsidiaries are subject to certain restrictions that may limit the amount of their dividend distributions. See Note 18 - Common Stock to the Consolidated Financial Statements for more information regarding these dividend restrictions.
We have assumed an average interest rate of 5.71 percent on the outstanding balance through maturity of the credit facilities. (6) Represents significant firm purchase commitments for construction of planned capital projects. (7) The table above excludes potential tax payments related to unrecognized tax benefits as they are not practicable to estimate.
We have assumed an average interest rate of 5.07 percent on the outstanding balance through maturity of the credit facilities. (6) Represents significant firm purchase commitments for construction of planned capital projects. (7) The table above excludes potential tax payments related to unrecognized tax benefits as they are not practicable to estimate.
In addition, we would need to determine if there was any impairment to the carrying costs of the associated plant and inventory assets. While we believe that our assumptions regarding future regulatory actions are reasonable, different assumptions could materially affect our results. See Note 4 - Regulatory Assets and Liabilities to the Consolidated Financial Statements for further discussion.
In addition, we would need to determine if there was any impairment to the carrying costs of the associated plant and inventory assets. While we believe that our assumptions regarding future regulatory actions are reasonable, different assumptions could materially affect our results. See Note 6 - Regulatory Assets and Liabilities to the Consolidated Financial Statements for further discussion.
Our reported costs of providing pension and other postretirement benefits, as described in Note 14 - Employee Benefit Plans to the Consolidated Financial Statements, are dependent upon numerous factors including the provisions of the plans, changing employee demographics, rate of return on plan assets and other economic conditions, and various actuarial calculations, assumptions, and accounting mechanisms.
Our reported costs of providing pension and other postretirement benefits, as described in Note 16 - Employee Benefit Plans to the Consolidated Financial Statements, are dependent upon numerous factors including the provisions of the plans, changing employee demographics, rate of return on plan assets and other economic conditions, and various actuarial calculations, assumptions, and accounting mechanisms.
For further information on our long-term debt, see Note 11 - Long-Term Debt and Finance Leases to the Consolidated Financial Statements included herein. We generally issue equity securities to fund long-term investment in our business. We evaluate our equity issuance needs to support our plan to maintain a 50 - 55 percent debt to total capital ratio excluding finance leases.
For further information on our long-term debt, see Note 13 - Long-Term Debt and Finance Leases to the Consolidated Financial Statements included herein. We generally issue equity securities to fund long-term investment in our business. We evaluate our equity issuance needs to support our plan to maintain a 50 - 55 percent debt to total capital ratio excluding finance leases.
The amortization of these amounts are offset in retail revenue. • Transmission: Reflects transmission revenues regulated by the FERC. • Wholesale and other are largely utility margin neutral as they are offset by changes in fuel, purchased supply and direct transmission expense. Year Ended December 31, 2024 Compared with Year Ended December 31, 2023 Revenues Change MWHs Avg.
The amortization of these amounts are offset in retail revenue. • Transmission: Reflects transmission revenues regulated by the FERC. • Wholesale and other are largely utility margin neutral as they are offset by changes in fuel, purchased supply and direct transmission expense. Year Ended December 31, 2025 Compared with Year Ended December 31, 2024 Revenues Change MWHs Avg.
Contractual Obligations and Other Commitments We have a variety of contractual obligations and other commitments that require payment of cash at certain specified periods. With the exception of maturities of long-term debt, we anticipate funding these obligations through cash flows from operations. The following table summarizes our contractual cash obligations and commitments as of December 31, 2024.
Contractual Obligations and Other Commitments We have a variety of contractual obligations and other commitments that require payment of cash at certain specified periods. With the exception of maturities of long-term debt, we anticipate funding these obligations through cash flows from operations. The following table summarizes our contractual cash obligations and commitments as of December 31, 2025.
As costs are incurred under the AOC, the surety bonds will be reduced. 59 CRITICAL ACCOUNTING ESTIMATES Management's discussion and analysis of financial condition and results of operations is based on our Consolidated Financial Statements, which have been prepared in accordance with GAAP.
As costs are incurred under the AOC, the surety bonds will be reduced. 71 CRITICAL ACCOUNTING ESTIMATES Management's discussion and analysis of financial condition and results of operations is based on our Consolidated Financial Statements, which have been prepared in accordance with GAAP.
During the year ended December 31, 2024, cash provided by financing activities reflects proceeds from the issuance of long-term debt of $215.0 million, short-term borrowings of $100.0 million, and net issuances under our revolving lines of credit of $95.0 million, partly offset by payment of dividends of $158.6 million and repayment of 1.00 percent, $100.0 million of Montana First Mortgage Bonds.
During the year ended December 31, 2024, cash provided by financing activities reflects proceeds from the issuance of long-term debt of $215.0 million, short-term borrowings of $100.0 million, and net issuances under our revolving lines of credit of $95.0 million, partly offset by payment of dividends of $158.6 million and repayment of $100.0 million of Montana First Mortgage Bonds.
The amortization of these amounts are offset in retail revenue. • Wholesale: Primarily represents transportation and storage for others. Year Ended December 31, 2024 Compared with Year Ended December 31, 2023 Revenues Change Dekatherms Avg.
The amortization of these amounts are offset in retail revenue. • Wholesale: Primarily represents transportation and storage for others. Year Ended December 31, 2025 Compared with Year Ended December 31, 2024 Revenues Change Dekatherms Avg.
Other Obligations - As a co-owner of Colstrip, we provided surety bonds of approximately $15.8 million and $15.7 million as of December 31, 2024 and 2023, respectively, to ensure the operation and maintenance of remedial and closure actions are carried out related to the Administrative Order on Consent Regarding Impacts Related to Wastewater Facilities Comprising the Closed-Loop System at Colstrip Steam Electric Stations, Colstrip Montana (the AOC) as required by the MDEQ.
Other Obligations - As a co-owner of Colstrip, we provided surety bonds of approximately $13.5 million and $15.8 million as of December 31, 2025 and 2024, respectively, to ensure the operation and maintenance of remedial and closure actions are carried out related to the Administrative Order on Consent Regarding Impacts Related to Wastewater Facilities Comprising the Closed-Loop System at Colstrip Steam Electric Stations, Colstrip Montana (the AOC) as required by the MDEQ.
We are taking a proactive and pragmatic approach to replacing these assets while also evaluating the implementation of additional technologies to prepare the overall system for smart grid applications. Over $2.2 billion or 82 percent of our capital forecast above is projected to be spent on our distribution and transmission system.
We are taking a proactive and pragmatic approach to replacing these assets while also evaluating the implementation of additional technologies to prepare the overall system for smart grid applications. Approximately $2.3 billion, or 70 percent, of our capital forecast above is projected to be spent on our distribution and transmission system.
Long-term Debt and Equity We generally issue long-term debt to refinance other long-term debt maturities and borrowings under our revolving credit facilities, as well as to fund long-term capital investments and strategic opportunities. We have $300.0 million of long-term debt maturing in 2025, which we intend to refinance.
Long-term Debt and Equity We generally issue long-term debt to refinance other long-term debt maturities and borrowings under our revolving credit facilities, as well as to fund long-term capital investments and strategic opportunities. We have $105.0 million of long-term debt maturing in 2026, which we intend to refinance.
For further information regarding equity, see Note 16 - Common Stock to the Consolidated Financial Statements included herein.
For further information regarding equity, see Note 18 - Common Stock to the Consolidated Financial Statements included herein.
Based on this analysis as of December 31, 2024, our discount rate for both NorthWestern Energy SD/NE Pension Plan and NorthWestern Energy MT Pension Plan is 5.50 percent and 5.60 percent, respectively. 60 In determining the expected long-term rate of return on plan assets, we review historical returns, the future expectations for returns for each asset class weighted by the target asset allocation of the pension and postretirement portfolios, and long-term inflation assumptions.
Based on this analysis as of December 31, 2025, our discount rate for both NorthWestern Energy SD/NE Pension Plan and NorthWestern Energy MT Pension Plan is 5.20 percent and 5.65 percent, respectively. 72 In determining the expected long-term rate of return on plan assets, we review historical returns, the future expectations for returns for each asset class weighted by the target asset allocation of the pension and postretirement portfolios, and long-term inflation assumptions.
Additionally, the table above excludes reserves for environmental remediation (See Note 18 - Commitments and Contingencies ) and AROs (see Note 6 - Asset Retirement Obligations ) as the amount and timing of cash payments may be uncertain.
Additionally, the table above excludes reserves for environmental remediation (See Note 20 - Commitments and Contingencies ) and AROs (see Note 8 - Asset Retirement Obligations ) as the amount and timing of cash payments may be uncertain.
See additional discussion in Note 18 - Commitments and Contingencies to the Consolidated Financial Statements.
See additional discussion in Note 20 - Commitments and Contingencies to the Consolidated Financial Statements.
Consolidated income tax benefit in 2024 was $9.4 million, as compared to an income tax expense of $7.5 million in 2023. Our effective tax rate for the twelve months ended December 31, 2024 was (4.4) percent as compared with 3.7 percent for the same period of 2023.
Consolidated income tax expense in 2025 was $6.5 million, as compared to an income tax benefit of $9.4 million in 2024. Our effective tax rate for the twelve months ended December 31, 2025 was 3.5 percent as compared with (4.4) 61 percent for the same period of 2024.
See "Non-GAAP Financial Measure" above. Also see "Overall Consolidated Results" above for reconciliation of gross margin to utility margin. Lower electric residential and commercial retail volumes were driven by unfavorable weather in South Dakota impacting residential demand and lower commercial demand in all jurisdictions as compared to the prior year, partly offset by higher industrial demand and customer growth.
See "Non-GAAP Financial Measure" above. Also see "Overall Consolidated Results" above for reconciliation of gross margin to utility margin. Electric retail volumes were driven by favorable weather in South Dakota impacting residential demand, higher Montana commercial demand, and customer growth in all jurisdictions, partly offset by unfavorable weather in Montana, lower commercial demand in South Dakota, and lower industrial demand.
Under the PCCAM, net supply costs higher or lower than the PCCAM base rate (PCCAM Base) (excluding qualifying facility (QF) costs) are allocated 90 percent to Montana customers and 10 percent to shareholders.
Under the PCCAM, net supply costs higher or lower than the PCCAM base rate (PCCAM Base) (excluding QF costs) were allocated 90 percent to Montana customers and 10 percent to shareholders.
(2) Non-GAAP financial measure. See “Non-GAAP Financial Measure” above. Also see "Overall Consolidated Results" above for reconciliation of gross margin to utility margin.
See "Non-GAAP Financial Measure" above. Also see "Overall Consolidated Results" above for reconciliation of gross margin to utility margin.
As of February 7, 2025, our current ratings with these agencies are as follows: 57 Issuer Rating Senior Secured Rating Senior Unsecured Rating Outlook NorthWestern Energy Group Fitch (1) BBB - BBB Stable Moody’s - - - - S&P BBB - - Stable NW Corp Fitch (1) BBB A- BBB+ Stable Moody’s Baa2 A3 Baa2 Stable S&P BBB A- - Stable NWE Public Service Fitch (1) BBB A- BBB+ Stable Moody’s Baa2 A3 - Stable S&P BBB A- - Stable (1) This Fitch Issuer Rating represents the Issuer Default Rating.
As of February 6, 2026, our current ratings with these agencies are as follows: 69 Issuer Rating Senior Secured Rating Senior Unsecured Rating Outlook NorthWestern Energy Group Fitch (1) BBB - BBB Stable Moody’s - - - - S&P BBB - - Positive NW Corp Fitch (1) BBB A- BBB+ Stable Moody’s Baa2 A3 Baa2 Stable S&P BBB A- - Positive NWE Public Service Fitch (1) BBB A- BBB+ Stable Moody’s Baa2 A3 - Stable S&P BBB A- - Stable (1) This Fitch Issuer Rating represents the Issuer Default Rating.
As further discussed in Note 12 - Income Taxes , income tax benefit for the twelve months ended December 31, 2024, includes a $21.0 million benefit related to a reduction in our unrecognized tax benefits, inclusive of $4.1 million of previously accrued interest ($16.9 million net of interest).
Income tax benefit for the twelve months ended December 31, 2024, includes a $21.0 million benefit related to a reduction in our unrecognized tax benefits, inclusive of $4.1 million of previously accrued interest ($16.9 million net of interest).
(3) Certain QFs require us to purchase minimum amounts of energy at prices ranging from $118 to $130 per MWH through 2029. Our estimated gross contractual obligation related to these QFs is approximately $229.0 million. A portion of the costs incurred to purchase this energy is recoverable through rates authorized by the MPSC, totaling approximately $205.8 million.
(3) Certain QFs require us to purchase minimum amounts of energy at prices ranging from $124 to $130 per MWH through 2029. Our estimated gross contractual obligation related to these QFs is approximately $168.6 million. A portion of the costs incurred to purchase this energy is recoverable through rates authorized by the MPSC, totaling approximately $152.8 million.
We recognize tax positions that meet the more-likely-than-not threshold as the largest amount of tax benefit that is greater than 50 percent likely of being realized upon ultimate settlement with a taxing authority that has full knowledge of all relevant information. We have unrecognized tax benefits of approximately $9.6 million as of December 31, 2024.
We recognize tax positions that meet the more-likely-than-not threshold as the largest amount of tax benefit that is greater than 50 percent likely of being realized upon ultimate settlement with a taxing authority that has full knowledge of all relevant information. As of December 31, 2025, we have not recorded any unrecognized tax benefits.
These costs are normally fairly stable across broad volume ranges and therefore do not normally increase or decrease significantly in the short term with increases or decreases in volumes. 46 OVERALL CONSOLIDATED RESULTS Year Ended December 31, 2024 Compared with Year Ended December 31, 2023 Consolidated net income in 2024 was $224.1 million as compared with $194.1 million in 2023, an increase of $30.0 million.
These costs are normally fairly stable across broad volume ranges and therefore do not normally increase or decrease significantly in the short term with increases or decreases in volumes. 58 OVERALL CONSOLIDATED RESULTS Year Ended December 31, 2025 Compared with Year Ended December 31, 2024 Consolidated net income in 2025 was $181.1 million as compared with $224.1 million in 2024, a decrease of $43.0 million.
Our expected long-term rate of return on assets assumptions are 4.58% percent and 6.17% percent on the NorthWestern Energy SD/NE Pension Plan and NorthWestern Energy MT Pension Plan, respectively, for 2025.
Our expected long-term rate of return on assets assumptions are 4.96% percent and 6.3% percent on the NorthWestern Energy SD/NE Pension Plan and NorthWestern Energy MT Pension Plan, respectively, for 2026.
See Note 12 - Income Taxes to the Consolidated Financial Statements for further discussion. 61 NEW ACCOUNTING STANDARDS See Note 2 - Significant Accounting Policies , to the Consolidated Financial Statements, included in Item 8 herein for a discussion of new accounting standards. 62
See Note 14 - Income Taxes to the Consolidated Financial Statements for further discussion. 73 NEW ACCOUNTING STANDARDS See Note 2 - Significant Accounting Policies , to the Consolidated Financial Statements, included in Item 8 herein for a discussion of new accounting standards. 74
Cost Sensitivity The following table reflects the sensitivity of pension costs to changes in certain actuarial assumptions (in thousands): Actuarial Assumption Change in Assumption Impact on Pension Cost Impact on Projected Benefit Obligation Discount rate increase 0.25 % $ 195 $ (11,443) Discount rate decrease (0.25) % 1,171 11,973 Rate of return on plan assets increase 0.25 % (982) N/A Rate of return on plan assets decrease (0.25) % 982 N/A Accounting Treatment We recognize the funded status of each plan as an asset or liability in the Consolidated Balance Sheets.
Cost Sensitivity The following table reflects the sensitivity of pension costs to changes in certain actuarial assumptions (in thousands): Actuarial Assumption Change in Assumption Impact on Pension Cost Impact on Projected Benefit Obligation Discount rate increase 0.25 % $ 127 $ (6,446) Discount rate decrease (0.25) % 25 6,787 Rate of return on plan assets increase 0.25 % (798) N/A Rate of return on plan assets decrease (0.25) % 798 N/A Accounting Treatment We recognize the funded status of each plan as an asset or liability in the Consolidated Balance Sheets.
Our material cash requirements are also related to investment in our business through our capital expenditure program, which is discussed above in the “Significant Infrastructure Investments and Initiatives” section. Our capital expenditures are forecasted to be $531 million in 2025, $549 million in 2026, and $557 million in 2027.
Our material cash requirements are also related to investment in our business through our capital expenditure program, which is discussed above in the “Significant Infrastructure Investments and Initiatives” section. Our capital expenditures are forecasted to be $683 million in 2026, $643 million in 2027, and $667 million in 2028.
See "Non-GAAP Financial Measure" above. Lower electric residential and commercial retail volumes were driven by unfavorable weather in South Dakota impacting residential demand and lower commercial demand in all jurisdictions as compared to the prior year, partly offset by higher industrial demand and customer growth.
See "Non-GAAP Financial Measure" above. Electric retail volumes were driven by favorable weather in South Dakota impacting residential demand, higher Montana commercial demand, and customer growth in all jurisdictions, partly offset by unfavorable weather in Montana, lower commercial demand in South Dakota, and lower industrial demand.
Primary components of the change include the following (in millions): Operating Expenses 2024 vs. 2023 Operating Expenses (excluding fuel, purchased supply and direct transmission expense) Impacting Net Income Depreciation expense due to plant additions and higher depreciation rates $ 17.1 Labor and benefits (1) 7.9 Insurance expense, primarily due to increased wildfire risk premiums 7.7 Property and other taxes not recoverable within trackers 4.4 Litigation outcome (Pacific Northwest Solar) 2.4 Electric generation maintenance 2.0 Non-cash impairment of alternative energy storage investment 1.7 Technology implementation and maintenance 1.5 Uncollectible accounts (1.4) Other (2.3) Change in Items Impacting Net Income 41.0 Operating Expenses Offset Within Net Income Property and other taxes recovered in trackers, offset in revenue 6.4 Pension and other postretirement benefits, offset in other income (1) 4.8 Operating and maintenance expenses recovered in trackers, offset in revenue 2.4 Deferred compensation, offset in other income 0.7 Change in Items Offset Within Net Income 14.3 Increase in Operating Expenses (excluding fuel, purchased supply and direct transmission expense) $ 55.3 (1) In order to present the total change in labor and benefits, we have included the change in the non-service cost component of our pension and other postretirement benefits, which is recorded within other income on our Condensed Consolidated Statements of Income.
Primary components of the change include the following (in millions): Operating Expenses 2025 vs. 2024 Operating Expenses (excluding fuel, purchased supply and direct transmission expense) Impacting Net Income Non-cash regulatory disallowance of certain YCGS capital costs $ 30.9 Depreciation expense due to plant additions and higher depreciation rates 21.9 Electric generation maintenance 9.9 Merger-related costs, primarily including consulting and legal fees 9.3 Wildfire mitigation expense, partly offset by higher base revenues 8.9 Insurance expense, primarily due to increased wildfire risk premiums 7.8 Labor and benefits (1) 7.6 Technology implementation and maintenance 3.5 Property and other taxes not recoverable within trackers 2.1 Uncollectible accounts 1.1 Litigation outcome (Pacific Northwest Solar) (2.4) Non-cash impairment of alternative energy storage investment (1.7) Other 3.0 Change in Items Impacting Net Income 101.9 Operating Expenses Offset Within Net Income Property and other taxes recovered in trackers, offset in revenue 16.3 Deferred compensation, offset in other income 2.1 Operating and maintenance expenses recovered in trackers, offset in revenue 0.8 Pension and other postretirement benefits, offset in other income (1) (2.9) Change in Items Offset Within Net Income 16.3 Increase in Operating Expenses (excluding fuel, purchased supply and direct transmission expense) $ 118.2 (1) In order to present the total change in labor and benefits, we have included the change in the non-service cost component of our pension and other postretirement benefits, which is recorded within other income on our Condensed Consolidated Statements of Income.
Cash provided by operating activities totaled $406.8 million for the year ended December 31, 2024 as compared with $489.2 million for the year ended December 31, 2023.
Cash provided by operating activities totaled $394.5 million for the year ended December 31, 2025 as compared with $406.8 million for the year ended December 31, 2024.
The following table presents additional information about borrowings under our revolving credit facilities during the year ended December 31, 2024 (in millions): Amount outstanding at year end $ 413.0 Daily average amount outstanding $ 237.1 Maximum amount outstanding $ 413.0 Minimum amount outstanding $ 69.0 As of February 7, 2025, availability under our revolving credit facilities was approximately $233.0 million, and there were no letters of credit outstanding.
The following table presents additional information about borrowings under our revolving credit facilities during the year ended December 31, 2025 (in millions): Amount outstanding at year end $ 404.0 Daily average amount outstanding $ 291.0 Maximum amount outstanding $ 415.0 Minimum amount outstanding $ 36.0 As of February 6, 2026, availability under our revolving credit facilities was approximately $229.0 million, and there were no letters of credit outstanding.
Cash Flows The following table summarizes our consolidated cash flows (in millions): Year Ended December 31, 2024 2023 Operating Activities Net income $ 224.1 $ 194.1 Non-cash adjustments to net income 213.5 210.1 Changes in working capital (18.9) 115.6 Other noncurrent assets and liabilities (11.9) (30.6) Cash Provided by Operating Activities 406.8 489.2 Investing Activities Property, plant and equipment additions (549.3) (566.9) Other investing activity (5.2) (3.9) Cash Used in Investing Activities (554.5) (570.8) Financing Activities Proceeds from issuance of common stock, net — 73.6 Issuance of long-term debt 215.0 300.0 Dividends on common stock (158.6) (154.1) Line of credit borrowings (repayments), net 95.0 (132.0) Financing costs (1.1) (4.3) Treasury stock activity 1.2 1.1 Cash Provided by Financing Activities 151.5 84.3 Net Increase in Cash, Cash Equivalents, and Restricted Cash $ 3.8 $ 2.7 Cash, Cash Equivalents, and Restricted Cash, beginning of period $ 25.2 $ 22.5 Cash, Cash Equivalents, and Restricted Cash, end of period $ 29.0 $ 25.2 55 Operating Activities As of December 31, 2024, cash, cash equivalents, and restricted cash were $29.0 million as compared with $25.2 million as of December 31, 2023.
Cash Flows The following table summarizes our consolidated cash flows (in millions): Year Ended December 31, 2025 2024 Operating Activities Net income $ 181.1 $ 224.1 Non-cash adjustments to net income 289.0 213.5 Changes in working capital (61.4) (18.9) Other noncurrent assets and liabilities (14.2) (11.9) Cash Provided by Operating Activities 394.5 406.8 Investing Activities Property, plant and equipment additions (524.5) (549.3) Acquisition of Energy West Operations (35.9) — Other investing activity (10.3) (5.2) Cash Used in Investing Activities (570.7) (554.5) Financing Activities Issuance of long-term debt 602.1 215.0 Issuance of short-term borrowings 50.0 100.0 Repayments on long-term debt (300.0) (100.0) Dividends on common stock (161.4) (158.6) Line of credit (repayments) borrowings , net (9.0) 95.0 Financing costs (4.5) (1.1) Treasury stock activity 0.7 1.2 Cash Provided by Financing Activities 177.9 151.5 Net Increase in Cash, Cash Equivalents, and Restricted Cash $ 1.7 $ 3.8 Cash, Cash Equivalents, and Restricted Cash, beginning of period $ 29.0 $ 25.2 Cash, Cash Equivalents, and Restricted Cash, end of period $ 30.7 $ 29.0 67 Operating Activities As of December 31, 2025, cash, cash equivalents, and restricted cash were $30.7 million as compared with $29.0 million as of December 31, 2024.
As of December 31, 2024, our total consolidated net liquidity was approximately $191.3 million, including $4.3 million of cash and $187.0 million of revolving credit facility availability with no letters of credit outstanding.
As of December 31, 2025, our total consolidated net liquidity was approximately $229.8 million, including $8.8 million of cash and $221.0 million of revolving credit facility availability with no letters of credit outstanding.
Consolidated utility margin in 2024 was $1,080.1 million as compared with $1,001.9 million in 2023, an increase of $78.2 million, or 7.8 percent. 47 Primary components of the change in utility margin include the following (in millions): Utility Margin 2024 vs. 2023 Utility Margin Items Impacting Net Income Base rates $ 62.4 Electric transmission revenue due to market conditions and rates 18.6 Montana interim rates (subject to refund) 4.8 Montana natural gas transportation 2.3 Montana property tax tracker collections 1.1 Non-recoverable Montana electric supply costs (7.9) QF liability adjustment (4.2) Natural gas retail volumes (4.0) Electric retail volumes (0.9) Other (3.0) Change in Utility Margin Impacting Net Income 69.2 Utility Margin Items Offset Within Net Income Property and other taxes recovered in revenue, offset in property and other taxes 6.4 Operating expenses recovered in revenue, offset in operating and maintenance expense 2.4 Production tax credits, offset in income tax expense 0.2 Change in Items Offset Within Net Income 9.0 Increase in Consolidated Utility Margin (1) $ 78.2 (1) Non-GAAP financial measure.
Consolidated utility margin in 2025 was $1,200.8 million as compared with $1,080.1 million in 2024, an increase of $120.7 million, or 11.2 percent. 59 Primary components of the change in utility margin include the following (in millions): Utility Margin 2025 vs. 2024 Utility Margin Items Impacting Net Income Base Rates $ 93.3 Electric transmission revenue due to market conditions and rates 14.0 Montana natural gas transportation 4.8 Electric retail volumes 4.3 Natural gas retail volumes ($4.2 million due to acquisition of Energy West Operations) 2.0 Montana property tax tracker collections (14.2) Non-recoverable Montana electric supply costs (7.3) Other 0.1 Change in Utility Margin Impacting Net Income 97.0 Utility Margin Items Offset Within Net Income Property and other taxes recovered in revenue, offset in property and other taxes 16.3 Production tax credits, offset in income tax expense 6.6 Operating expenses recovered in revenue, offset in operating and maintenance expense 0.8 Change in Items Offset Within Net Income 23.7 Increase in Consolidated Utility Margin (1) $ 120.7 (1) Non-GAAP financial measure.
Heating Degree Days 2024 as compared with: 2024 2023 Historic Average 2023 Historic Average Montana (1) 7,265 7,478 7,791 3% warmer 7% warmer South Dakota 6,501 7,665 7,724 15% warmer 16% warmer Nebraska 5,241 5,893 6,085 11% warmer 14% warmer (1) Montana electric and natural gas heating degree days may differ due to differences in service territory. 53 The following summarizes the components of the changes in natural gas utility margin for the years ended December 31, 2024 and 2023 (in millions): Utility Margin 2024 vs. 2023 Utility Margin Items Impacting Net Income Base rates 11.4 Montana natural gas transportation 2.3 Montana interim rates (subject to refund) 2.0 Retail volumes (4.0) Montana property tax tracker collections (0.1) Other (2.1) Change in Utility Margin Impacting Net Income 9.5 Utility Margin Items Offset Within Net Income Property and other taxes recovered in revenue, offset in property and other taxes 3.0 Operating expenses recovered in revenue, offset in operating and maintenance expense 0.7 Change in Items Offset Within Net Income 3.7 Increase in Utility Margin (1) $ 13.2 (1) Non-GAAP financial measure.
Heating Degree Days 2025 as compared with: 2025 2024 Historic Average 2024 Historic Average Montana (1) 7,207 7,265 7,697 1% warmer 6% warmer South Dakota 6,943 6,501 7,696 7% colder 10% warmer Nebraska 5,719 5,241 6,061 9% colder 6% warmer (1) Montana electric and natural gas heating degree days may differ due to differences in service territory. 65 The following summarizes the components of the changes in natural gas utility margin for the years ended December 31, 2025 and 2024 (in millions): Utility Margin 2025 vs. 2024 Utility Margin Items Impacting Net Income Base rates $ 21.5 Montana natural gas transportation 4.8 Retail volumes ($4.2 million due to acquisition of Energy West Operations) 2.0 Montana property tax tracker collections (3.4) Other 0.2 Change in Utility Margin Impacting Net Income 25.1 Utility Margin Items Offset Within Net Income Property and other taxes recovered in revenue, offset in property and other taxes 3.6 Operating expenses recovered in revenue, offset in operating and maintenance expense (0.3) Change in Items Offset Within Net Income 3.3 Increase in Utility Margin (1) $ 28.4 (1) Non-GAAP financial measure.
Net under-collected supply costs (in millions) Beginning of year End of year Net cash inflows 2023 $ 115.4 $ 7.8 $ 107.6 2024 $ 7.8 $ 5.9 $ 1.9 Improvement in annual net cash inflows $ (105.7) Investing Activities Cash used in investing activities totaled $554.5 million during the year ended December 31, 2024, as compared with $570.8 million during 2023.
Net under-collected energy supply costs (in millions) Beginning of year End of year Net cash inflows (outflows) 2024 $ 7.8 $ 5.9 $ 1.9 2025 $ 5.9 $ 44.8 $ (38.9) Increase in net cash outflows $ (40.8) Investing Activities Cash used in investing activities totaled $570.7 million during the year ended December 31, 2025, as compared with $554.5 million during 2024.
The energy supply costs incurred under these contracts are generally recoverable through rate mechanisms approved by the MPSC, as further described in Note 3 - Regulatory Matters . 58 (5) Contractual interest payments include our revolving credit facilities, which have a variable interest rate.
The majority of our energy supply costs incurred under these contracts are recoverable through rate mechanisms, as further described in Note 6 - Regulatory Assets and Liab ilities . 70 (5) Contractual interest payments include our revolving credit facilities, which have a variable interest rate.
Plant additions during 2024 include capital maintenance additions of approximately $324.0 million and capacity related capital expenditures of approximately $225.3 million. Plant additions during 2023 included capital maintenance additions of approximately $321.9 million and capacity related capital expenditures of approximately $245.0 million.
Plant additions during 2025 include capital maintenance additions of approximately $372.7 million and capacity related capital expenditures of approximately $151.8 million. Plant additions during 2024 included capital maintenance additions of approximately $324.0 million and capacity related capital expenditures of approximately $225.3 million.
This increase was due to higher borrowings and interest rates, partly offset by higher capitalization of AFUDC. 49 Consolidated other income in 2024 was $23.0 million, as compared with $15.8 million in 2023.
Consol idated interest expense in 2025 was $150.4 million, as compared with $131.7 million in 2024. This increase was due to higher borrowings and interest rates, partly offset by lower capitalization of AFUDC. Consolidated other income in 2025 was $12.1 million, as compared with $23.0 million in 2024.
See "Non-GAAP Financial Measure" above. Year Ended December 31, 2024 2023 Change % Change (in millions) Utility Margin Electric $ 871.1 $ 806.1 $ 65.0 8.1 % Natural Gas 209.0 195.8 13.2 6.7 Total Utility Margin (1) $ 1,080.1 $ 1,001.9 $ 78.2 7.8 % (1) Non-GAAP financial measure. See "Non-GAAP Financial Measure" above.
See "Non-GAAP Financial Measure" above. Year Ended December 31, 2025 2024 Change % Change (in millions) Utility Margin Electric $ 963.4 $ 871.1 $ 92.3 10.6 % Natural Gas 237.4 209.0 28.4 13.6 Total Utility Margin (1) $ 1,200.8 $ 1,080.1 $ 120.7 11.2 % (1) Non-GAAP financial measure. See "Non-GAAP Financial Measure" above.
Electric Natural Gas Total 2024 2023 2024 2023 2024 2023 (in millions) Reconciliation of gross margin to utility margin: Operating Revenues $ 1,200.7 $ 1,068.8 $ 313.2 $ 353.3 $ 1,513.9 $ 1,422.1 Less: Fuel, purchased supply and direct transmission expense (exclusive of depreciation and depletion shown separately below) 329.6 262.7 104.2 157.5 433.8 420.2 Less: Operating and maintenance 171.7 166.0 56.1 54.5 227.8 220.5 Less: Property and other taxes 126.5 120.3 37.4 34.3 163.9 154.6 Less: Depreciation and depletion 190.0 174.1 37.6 36.4 227.6 210.5 Gross Margin 382.9 345.7 77.9 70.6 460.8 416.3 Operating and maintenance 171.7 166.0 56.1 54.5 227.8 220.5 Property and other taxes 126.5 120.3 37.4 34.3 163.9 154.6 Depreciation and depletion 190.0 174.1 37.6 36.4 227.6 210.5 Utility Margin (1) $ 871.1 $ 806.1 $ 209.0 $ 195.8 $ 1,080.1 $ 1,001.9 (1) Non-GAAP financial measure.
Electric Natural Gas Total 2025 2024 2025 2024 2025 2024 (in millions) Reconciliation of gross margin to utility margin: Operating Revenues $ 1,270.0 $ 1,200.7 $ 340.6 $ 313.2 $ 1,610.6 $ 1,513.9 Less: Fuel, purchased supply and direct transmission expense (exclusive of depreciation and depletion shown separately below) 306.6 329.6 103.2 104.2 409.8 433.8 Less: Operating and maintenance 224.4 171.7 60.5 56.1 284.9 227.8 Less: Property and other taxes 140.9 126.5 41.2 37.4 182.1 163.9 Less: Depreciation and depletion 208.6 190.0 40.9 37.6 249.5 227.6 Gross Margin 389.5 382.9 94.8 77.9 484.3 460.8 Operating and maintenance 224.4 171.7 60.5 56.1 284.9 227.8 Property and other taxes 140.9 126.5 41.2 37.4 182.1 163.9 Depreciation and depletion 208.6 190.0 40.9 37.6 249.5 227.6 Utility Margin (1) $ 963.4 $ 871.1 $ 237.4 $ 209.0 $ 1,200.8 $ 1,080.1 (1) Non-GAAP financial measure.
During the year ended December 31, 2023, cash provided by financing activities reflects net proceeds from the issuance of long-term debt of $300.0 million and proceeds received from the issuance of common stock of $73.6 million, partly offset by payment of dividends of $154.1 million and net repayments under our revolving lines of credit of $132.0 million.
During the year ended December 31, 2025, cash provided by financing activities reflects proceeds from the issuance of long-term debt of $602.1 million and short-term borrowings of $50.0 million, partly offset by repayment of $300.0 million of Montana and South Dakota First Mortgage bonds, payment of dividends of $161.4 million, and net repayments under our revolving lines of credit of $9.0 million.
Credit Facilities Liquidity is generally provided by internal operating cash flows and the use of our unsecured revolving credit facilities. We utilize availability under our revolving credit facilities to manage our cash flows due to the seasonality of our business and to fund capital investment.
We utilize availability under our revolving credit facilities to manage our cash flows due to the seasonality of our business and to fund capital investment. Cash on hand in excess of current operating requirements is generally used to invest in our business and reduce borrowings.
This change is offset within this table as it does not affect our operating expenses. Consolidated operating income in 2024 was $323.3 million as compared with $300.5 million in 2023. This increase was primarily due to new base rates in Montana and South Dakota, electric transmission revenue, Montana interim rates, subject to refund, and Montana property tax tracker collections.
This change is offset within this table as it does not affect our operating expenses. Consolidated operating income in 2025 was $325.8 million as compared with $323.3 million in 2024. This increase was primarily due to new rates, electric transmission revenue, natural gas transportation revenues, and retail volumes.
We anticipate funding capital expenditures through cash flows from operations, available credit sources, debt issuances and future rate increases. The actual amount of capital expenditures is subject to certain factors including the impact that a material change in operations, available financing, supply chain issues, or inflation could impact our current liquidity and ability to fund capital resource requirements.
The actual amount of capital 68 expenditures is subject to certain factors including the impact that a material change in operations, available financing, supply chain issues, or inflation could impact our current liquidity and ability to fund capital resource requirements. Events such as these could cause us to defer a portion of our planned capital expenditures, as necessary.
Heating degree-days result when the average daily temperature is less than the baseline. Cooling degree-days result when the average daily temperature is greater than the baseline. The statistical weather information in our regulated segments represents a comparison of this data.
Cooling degree-days result when the average daily temperature is greater than the baseline. The statistical weather information in our regulated segments represents a comparison of this data. Fuel, purchased supply and direct transmission expenses are costs directly associated with the generation and procurement of electricity and natural gas.
The 2023-2024 contract year was the last year of the contract that contains variable pricing terms. 48 Year Ended December 31, 2024 2023 Change % Change (in millions) Operating Expenses (excluding fuel, purchased supply and direct transmission expense) Operating and maintenance $ 227.8 $ 220.5 $ 7.3 3.3 % Administrative and general 137.4 117.3 20.1 17.1 Property and other taxes 163.9 153.1 10.8 7.1 Depreciation and depletion 227.6 210.5 17.1 8.1 Total Operating Expenses (excluding fuel, purchased supply and direct transmission expense) $ 756.7 $ 701.4 $ 55.3 7.9 % Consolidated operating expenses, excluding fuel, purchased supply and direct transmission expense, were $756.7 million in 2024, as compared with $701.4 million in 2023.
Year Ended December 31, 2025 2024 Change % Change (in millions) Operating Expenses (excluding fuel, purchased supply and direct transmission expense) Operating and maintenance $ 284.9 $ 227.8 $ 57.1 25.1 % Administrative and general 158.2 137.4 20.8 15.1 Property and other taxes 182.3 163.9 18.4 11.2 Depreciation and depletion 249.5 227.6 21.9 9.6 Total Operating Expenses (excluding fuel, purchased supply and direct transmission expense) $ 874.9 $ 756.7 $ 118.2 15.6 % 60 Consolidated operating expenses, excluding fuel, purchased supply and direct transmission expense, were $874.9 million in 2025, as compared with $756.7 million in 2024.
Cash on hand in excess of current operating requirements is generally used to invest in our business and reduce borrowings. For further information on our credit facilities, see Note 10 - Short-Term Borrowings and Credit Arrangements to the Consolidated Financial Statements included herein.
For further information on our credit facilities, see Note 12 - Short-Term Borrowings and Credit Arrangements to the Consolidated Financial Statements included herein.
Operating and maintenance expenses are costs associated with the ongoing operation of our vertically-integrated utility facilities which provide electric and natural gas utility products and services to our customers. Among the most significant of these costs are those associated with direct labor and supervision, repair and maintenance expenses, and contract services.
These costs are generally collected in rates from customers and may fluctuate substantially with market prices and customer usage. Operating and maintenance expenses are costs associated with the ongoing operation of our vertically-integrated utility facilities which provide electric and natural gas utility products and services to our customers.
Cooling Degree Days 2024 as compared with: 2024 2023 Historic Average 2023 Historic Average Montana 485 441 448 10% warmer 8% warmer South Dakota 778 1,035 752 25% cooler 3% warmer Heating Degree Days 2024 as compared with: 2024 2023 Historic Average 2023 Historic Average Montana (1) 7,033 7,237 7,554 3% warmer 7% warmer South Dakota 6,501 7,665 7,724 15% warmer 16% warmer (1) Montana electric and natural gas heating degree days may differ due to differences in service territory. 51 The following summarizes the components of the changes in electric utility margin for the years ended December 31, 2024 and 2023 (in millions): Utility Margin 2024 vs. 2023 Utility Margin Items Impacting Net Income Base rates $ 51.0 Electric transmission revenue due to market conditions and rates 18.6 Montana interim rates (subject to refund) 2.8 Montana property tax tracker collections 1.2 Non-recoverable Montana electric supply costs (7.9) QF liability adjustment (4.2) Retail volumes (0.9) Other (0.9) Change in Utility Margin Items Impacting Net Income 59.7 Utility Margin Items Offset Within Net Income Property and other taxes recovered in revenue, offset in property and other taxes 3.4 Operating expenses recovered in revenue, offset in operating and maintenance expense 1.7 Production tax credits, offset in income tax expense 0.2 Change in Items Offset Within Net Income 5.3 Increase in Utility Margin (1) $ 65.0 (1) Non-GAAP financial measure.
The following summarizes the components of the changes in electric utility margin for the years ended December 31, 2025 and 2024 (in millions): Utility Margin 2025 vs. 2024 Utility Margin Items Impacting Net Income Base rates $ 71.8 Electric transmission revenue due to market conditions and rates 14.0 Retail volumes 4.3 Montana property tax tracker collections (10.8) Non-recoverable Montana electric supply costs (7.3) Other (0.1) Change in Utility Margin Items Impacting Net Income 71.9 Utility Margin Items Offset Within Net Income Property and other taxes recovered in revenue, offset in property and other taxes 12.7 Production tax credits, offset in income tax expense 6.6 Operating expenses recovered in revenue, offset in operating and maintenance expense 1.1 Change in Items Offset Within Net Income 20.4 Increase in Utility Margin (1) $ 92.3 (1) Non-GAAP financial measure.
For the twelve months ended December 31, 2023, we over collected supply costs of $32.9 million resulting in a reduction to our under collection of costs, and recorded an increase in pre-tax earnings of $7.0 million, which was inclusive of a $3.2 million increase in pre-tax earnings related to the retroactive application of higher PCCAM Base rates to July 1, 2022.
For the twelve months ended December 31, 2025, we under-collected supply costs of $73.9 million resulting in an increase to our under collection of costs, and recorded a decrease in pre-tax earnings of $8.2 million (10 percent of the PCCAM Base cost variance).
For the twelve months ended December 31, 2023, we over collected supply costs of $32.9 million resulting in a reduction to our under collection of costs, and recorded an increase in pre-tax earnings of $7.0 million, which was inclusive of a $3.2 million increase in pre-tax earnings related to the retroactive application of higher PCCAM Base rates to July 1, 2022.
For the twelve months ended December 31, 2025, we under-collected supply costs of $73.9 million resulting in an increase to our under collection of costs, and recorded a decrease in pre-tax earnings of $8.2 million (10 percent of the PCCAM Base cost variance).
This increase was primarily due to a $2.3 million reversal of a previously expensed Community Renewable Energy Project penalty due to a favorable legal ruling, higher capitalization of AFUDC, a decrease in the non-service cost component of pension expense, and an increase in the value of deferred shares held in trust for deferred compensation, offset in part by a $2.5 million non-cash impairment of an alternative energy storage equity investment.
This decrease was primarily due to lower capitalization of AFUDC, a prior year reversal of $2.3 million from a previously disclosed CREP penalty due to a favorable legal ruling, and a $1.3 million expense current year accrual related to an estimated penalty for the CREP informed by a recent MPSC ruling, partly offset by an increase of $2.5 million driven by a prior year non-cash impairment of an alternative energy storage equity investment.
In addition, various regulatory agencies approve the prices for electric and natural gas utility service within their respective jurisdictions and regulate our ability to recover costs from customers. Revenues are also impacted by customer growth and usage, the latter of which is primarily affected by weather and the impact of energy efficiency initiatives and investment.
Factors Affecting Results of Operations Our revenues may fluctuate substantially with changes in supply costs, which are generally collected in rates from customers. In addition, various regulatory agencies approve the prices for electric and natural gas utility service within their respective jurisdictions and regulate our ability to recover costs from customers.
Based on the significant NOL income tax position we have, we anticipate paying minimal cash for income taxes into 2028.
We currently estimate our effective tax rate will range between 14.0 percent to 18.0 percent in 2026. Based on the significant NOL income tax position we have, we anticipate paying minimal cash for income taxes into 2029.
Events such as these could cause us to defer a portion of our planned capital expenditures, as necessary. To fund our strategic 56 growth opportunities, we evaluate the additional capital need in balance with debt capacity and equity issuances that would be intended to allow us to maintain investment grade ratings.
To fund our strategic growth opportunities, we evaluate the additional capital need in balance with debt capacity and equity issuances that would be intended to allow us to maintain investment grade ratings. Short-term Borrowings For further information on our short-term borrowings, see Note 12 - Short-Term Borrowings and Credit Arrangements to the Consolidated Financial Statements included herein.
Very cold winters increase demand for natural gas and to a lesser extent, electricity, while warmer than normal summers increase demand for electricity, especially among our residential customers. We measure this effect using degree-days, which is the difference between the average daily actual temperature and a baseline temperature of 65 degrees.
Revenues are also impacted by customer growth and usage, the latter of which is primarily affected by weather and the impact of energy efficiency initiatives and investment. Very cold winters increase demand for natural gas and to a lesser extent, electricity, while warmer than normal summers increase demand for electricity, especially among our residential customers.
Income tax expense for the twelve months ended December 31, 2023, includes a one-time $3.2 million expense for the reduction of previously claimed alternative minimum tax credits as well as a $3.2 million benefit related to a reduction in our unrecognized tax benefits. We currently estimate our effective tax rate will range between 13.0 percent to 17.0 percent in 2025.
As further discussed in Note 14 - Income Taxes , income tax expense for the twelve months ended December 31, 2025, includes a $10.4 million benefit related to a reduction in our unrecognized tax benefits, inclusive of $3.0 million of previously accrued interest ($7.4 million net of interest).
Customer Counts 2024 2023 $ % 2024 2023 2024 2023 (in thousands) Montana $ 110,215 $ 136,097 (25,882) (19.0) % 13,749 14,008 185,644 183,810 South Dakota 26,884 36,638 (9,754) (26.6) 2,709 3,179 42,577 42,053 Nebraska 21,205 35,539 (14,334) (40.3) 2,294 2,581 37,958 37,793 Residential 158,304 208,274 (49,970) (24.0) 18,752 19,768 266,179 263,656 Montana 59,925 73,721 (13,796) (18.7) 7,782 8,036 26,164 25,725 South Dakota 18,069 25,869 (7,800) (30.2) 2,791 3,169 7,383 7,232 Nebraska 11,432 22,114 (10,682) (48.3) 1,664 1,916 5,056 5,023 Commercial 89,426 121,704 (32,278) (26.5) 12,237 13,121 38,603 37,980 Industrial 1,041 1,392 (351) (25.2) 147 157 237 232 Other 1,352 1,681 (329) (19.6) 207 209 197 190 Total Retail Gas $ 250,123 $ 333,051 $ (82,928) (24.9) % 31,343 33,255 305,216 302,058 Regulatory amortization 19,017 (25,012) 44,029 (176.0) Wholesale and other 44,057 45,271 (1,214) (2.7) Total Revenues $ 313,197 $ 353,310 $ (40,113) (11.4) % Fuel, purchased supply and direct transmission expense (1) 104,238 157,507 (53,269) (33.8) Utility Margin (2) $ 208,959 $ 195,803 $ 13,156 6.7 % (1) Exclusive of depreciation and depletion.
Customer Counts 2025 2024 $ % 2025 2024 2025 2024 (in thousands) Montana $ 120,830 $ 110,215 10,615 9.6 % 14,339 13,749 201,728 185,644 South Dakota 28,948 26,884 2,064 7.7 3,032 2,709 42,952 42,577 Nebraska 25,733 21,205 4,528 21.4 2,414 2,294 37,970 37,958 Residential 175,511 158,304 17,207 10.9 19,785 18,752 282,650 266,179 Montana 68,722 59,925 8,797 14.7 8,691 7,782 28,380 26,164 South Dakota 21,574 18,069 3,505 19.4 3,303 2,791 7,586 7,383 Nebraska 13,784 11,432 2,352 20.6 1,738 1,664 5,114 5,056 Commercial 104,080 89,426 14,654 16.4 13,732 12,237 41,080 38,603 Industrial 2,439 1,041 1,398 134.3 2,140 147 241 237 Other 1,350 1,352 (2) (0.1) 197 207 218 197 Total Retail Gas $ 283,380 $ 250,123 $ 33,257 13.3 % 35,854 31,343 324,189 305,216 Regulatory amortization (305) 19,017 (19,322) (101.6) Transportation, wholesale and other 57,528 44,057 13,471 30.6 Total Revenues $ 340,603 $ 313,197 $ 27,406 8.8 % Fuel, purchased supply and direct transmission expense (1) 103,186 104,238 (1,052) (1.0) Utility Margin (2) $ 237,417 $ 208,959 $ 28,458 13.6 % (1) Exclusive of depreciation and depletion.
These were offset in part by non-recoverable Montana electric supply costs, a less favorable QF liability adjustment, electric and natural gas retail volumes, depreciation, operating, administrative and general costs, and interest expense. Consolidated gross margin in 2024 was $460.8 million as compared with $416.3 million in 2023, an increase of $44.5 million or 10.7 percent.
These were partly offset by higher rates, electric transmission revenue, natural gas transportation revenues, and retail volumes. Consolidated gross margin in 2025 was $484.3 million as compared with $460.8 million in 2024, an increase of $23.5 million or 5.1 percent. This increase was primarily due to higher rates, electric transmission revenue, natural gas transportation revenues, and retail volumes.
Financing Activities Cash provided by financing activities totaled $151.5 million during the year ended December 31, 2024 as compared with $84.3 million during the year ended December 31, 2023.
As discussed above in the “Significant Infrastructure Investments and Initiatives” section, our capital expenditures are forecasted to be $683.0 million in 2026. Financing Activities Cash provided by financing activities totaled $177.9 million during the year ended December 31, 2025 as compared with $151.5 million during the year ended December 31, 2024.
Short-term Borrowings For further information on our short-term borrowings, see Note 10 - Short-Term Borrowings and Credit Arrangements to the Consolidated Financial Statements included herein. NorthWestern Energy Group has $100.0 million of short-term borrowings maturing in 2025, which we intend to refinance.
NorthWestern Energy Group has $150.0 million of short-term borrowings maturing in 2026, which we intend to refinance. Credit Facilities Liquidity is generally provided by internal operating cash flows and the use of our unsecured revolving credit facilities.
Total 2025 2026 2027 2028 2029 Thereafter (in thousands) Long-term debt (1) $ 3,007,660 $ 300,000 $ 105,000 $ — $ 592,660 $ 33,000 $ 1,977,000 Finance leases 5,461 3,596 1,865 — — — — Short-term borrowings 100,000 100,000 — — — — — Estimated pension and other postretirement obligations (2) 50,310 11,310 9,750 9,750 9,750 9,750 N/A QF liability (3) 228,952 60,360 55,393 56,665 42,400 14,134 — Supply and capacity contracts (4) 4,228,637 345,821 365,202 350,381 349,347 350,201 2,467,685 Contractual interest payments on debt (5) 1,650,442 133,927 122,884 120,847 118,780 89,359 1,064,645 Commitments for significant capital projects (6) 66,837 57,975 8,862 — — — $ — Total Commitments (7) $ 9,338,299 $ 1,012,989 $ 668,956 $ 537,643 $ 1,112,937 $ 496,444 $ 5,509,330 (1) Represents cash payments for long-term debt and excludes $12.4 million of debt discounts and debt issuance costs, net.
Total 2026 2027 2028 2029 2030 Thereafter (in thousands) Long-term debt (1) $ 3,298,660 $ 105,000 $ — $ 583,660 $ 33,000 $ 650,000 $ 1,927,000 Finance leases 1,865 1,865 — — — — — Short-term borrowings 150,000 150,000 — — — — — Estimated pension and other postretirement obligations (2) 51,067 12,643 10,206 9,806 9,306 9,106 N/A QF liability (3) 168,592 55,393 56,665 42,400 14,134 — — Supply and capacity contracts (4) 3,883,865 424,471 343,663 340,135 341,470 316,667 2,117,459 Contractual interest payments on debt (5) 1,515,754 142,813 137,144 140,276 109,172 96,182 890,167 Commitments for significant capital projects (6) 51,111 51,111 — — — — $ — Total Commitments (7) $ 9,120,914 $ 943,296 $ 547,678 $ 1,116,277 $ 507,082 $ 1,071,955 $ 4,934,626 (1) Represents cash payments for long-term debt and excludes $12.7 million of debt discounts and debt issuance costs, net.
Lower natural gas retail volumes were driven by unfavorable weather in all jurisdictions partly offset by customer growth. Under the PCCAM, net supply costs higher or lower than the PCCAM base rate (PCCAM Base) (excluding qualifying facility (QF) costs) are allocated 90 percent to Montana customers and 10 percent to shareholders.
Natural gas retail volumes were driven by the acquisition of Energy West, favorable weather in South Dakota and Nebraska, higher commercial demand, and customer growth in all jurisdictions, partly offset by unfavorable weather in Montana.
Our wholesale and other revenues are largely utility margin neutral as they are offset by changes in fuel, purchased supply and direct transmission expenses. 54 LIQUIDITY AND CAPITAL RESOURCES Liquidity We require liquidity to support and grow our business, and use our liquidity for working capital needs, capital expenditures, investments in or acquisitions of assets, and to repay debt.
Natural gas retail volumes were driven by the acquisition of Energy West, favorable weather in South Dakota and Nebraska, higher commercial demand, and customer growth in all jurisdictions, partly offset by unfavorable weather in Montana. 66 LIQUIDITY AND CAPITAL RESOURCES Liquidity We require liquidity to support and grow our business, and use our liquidity for working capital needs, capital expenditures, investments in or acquisitions of assets, and to repay debt.
Customer Counts 2024 2023 $ % 2024 2023 2024 2023 (in thousands) Montana $ 398,790 $ 408,341 $ (9,551) (2.3) % 2,804 2,795 328,420 322,489 South Dakota 70,012 67,888 2,124 3.1 557 603 51,467 51,261 Residential 468,802 476,229 (7,427) (1.6) 3,361 3,398 379,887 373,750 Montana 408,977 431,357 (22,380) (5.2) 3,197 3,238 75,878 74,438 South Dakota 111,813 103,194 8,619 8.4 1,093 1,101 13,084 12,973 Commercial 520,790 534,551 (13,761) (2.6) 4,290 4,339 88,962 87,411 Industrial 46,637 45,958 679 1.5 2,924 2,660 80 79 Other 32,811 32,756 55 0.2 146 134 6,544 6,443 Total Retail Electric $ 1,069,040 $ 1,089,494 $ (20,454) (1.9) % 10,721 10,531 475,473 467,683 Regulatory amortization 24,908 (105,608) 130,516 (123.6) Transmission 97,052 78,436 18,616 23.7 Wholesale and Other 9,701 6,511 3,190 49.0 Total Revenues $ 1,200,701 $ 1,068,833 $ 131,868 12.3 % Fuel, purchased supply and direct transmission expense (1) 329,578 262,755 66,823 25.4 Utility Margin (2) $ 871,123 $ 806,078 $ 65,045 8.1 % (1) Exclusive of depreciation and depletion.
Customer Counts 2025 2024 $ % 2025 2024 2025 2024 (in thousands) Montana $ 406,643 $ 398,790 $ 7,853 2.0 % 2,834 2,804 334,011 328,420 South Dakota 77,894 70,012 7,882 11.3 583 557 51,787 51,467 Residential 484,537 468,802 15,735 3.4 3,417 3,361 385,798 379,887 Montana 408,530 408,977 (447) (0.1) 3,216 3,197 77,305 75,878 South Dakota 120,108 111,813 8,295 7.4 1,061 1,093 13,190 13,084 Commercial 528,638 520,790 7,848 1.5 4,277 4,290 90,495 88,962 Industrial 43,128 46,637 (3,509) (7.5) 2,789 2,924 80 80 Other (1) 34,510 32,811 1,699 5.2 147 146 28,564 28,608 Total Retail Electric $ 1,090,813 $ 1,069,040 $ 21,773 2.0 % 10,630 10,721 504,937 497,537 Regulatory amortization 58,265 24,908 33,357 133.9 Transmission 111,024 97,052 13,972 14.4 Wholesale and Other 9,854 9,701 153 1.6 Total Revenues $ 1,269,956 $ 1,200,701 $ 69,255 5.8 % Fuel, purchased supply and direct transmission expense (2) 306,569 329,578 (23,009) (7.0) Utility Margin (3) $ 963,387 $ 871,123 $ 92,264 10.6 % (1) Included within this line is our lighting customer class, which we have historically counted each lighting district as one customer.