NorthWestern Energy Group, Inc.

Previous wording

NorthWestern Energy Group, doing business as NorthWestern Energy, provides electricity and/or natural gas to approximately 842,100 customers in Montana, South Dakota, Nebraska and Yellowstone National Park. Our operations in Montana and Yellowstone National Park are conducted through our subsidiary, NW Corp, and our operations in South Dakota and Nebraska are conducted through our subsidiary, NWE Public Service. For a discussion of NorthWestern’s business strategy, see Management’s Discussion and Analysis of Financial Condition and Results of Operations in the NorthWestern Energy Group Annual Report on Form 10-K for the year ended December 31, 2024.

Current wording

NorthWestern Energy Group, doing business as NorthWestern Energy, provides electricity and/or natural gas to approximately 850,300 customers in Montana, South Dakota, Nebraska and Yellowstone National Park. Our operations in Montana and Yellowstone National Park are conducted through our subsidiary, NW Corp, and our operations in South Dakota and Nebraska are conducted through our subsidiary, NWE Public Service. For a discussion of NorthWestern’s business strategy, see Management’s Discussion and Analysis of Financial Condition and Results of Operations in the NorthWestern Energy Group Annual Report on Form 10-K for the year ended December 31, 2025.

Previous wording

On August 18, 2025, we entered into the Merger Agreement with Black Hills and Merger Sub that provides for an all-stock merger of equals between NorthWestern and Black Hills. The Merger Agreement provides for Merger Sub to merge with and into NorthWestern, with NorthWestern continuing as the surviving entity and a direct wholly owned subsidiary of Black Hills, which would assume a new corporate name as the resulting parent company of the combined corporate group. The Merger will combine the strengths of both companies, resulting in an organization with greater scale, financial stability, and operational expertise. It is designed to create a stronger, more resilient energy company focused on delivering safe, reliable, and affordable energy solutions to customers. Under the provisions of Accounting Standards Codification Topic 805, which requires the identification of an acquirer in a business combination, Black Hills is the accounting acquirer. Pursuant to the Merger Agreement, at the effective time of the Merger, each share of common stock of NorthWestern issued and outstanding as of immediately prior to closing will be converted into the right to receive 0.98 validly issued, fully paid and non-assessable shares of Black Hills Common Stock. See Note 2 - Pending Merger with Black Hills Corporation to the Condensed Consolidated Financial Statements included herein for additional information regarding this pending Merger.

Current wording

On August 18, 2025, we entered into the Merger Agreement with Black Hills and Merger Sub that provides for an all-stock merger of equals between NorthWestern and Black Hills. The Merger Agreement provides for Merger Sub to merge with and into NorthWestern, with NorthWestern continuing as the surviving entity and a direct wholly owned subsidiary of Black Hills, which would assume a new corporate name of Bright Horizon Energy as the resulting parent company of the combined corporate group. The Merger will combine the strengths of both companies, resulting in an organization with greater scale, financial stability, and operational expertise. It is designed to create a stronger, more resilient energy company focused on delivering safe, reliable, and affordable energy solutions to customers. Under the provisions of Accounting Standards Codification Topic 805, which requires the identification of an acquirer in a business combination, Black Hills is the accounting acquirer. Pursuant to the Merger Agreement, at the effective time of the Merger, each share of common stock of NorthWestern issued and outstanding as of immediately prior to closing will be converted into the right to receive 0.98 validly issued, fully paid and non-assessable shares of Black Hills Common Stock. See Note 2 - Pending Merger with Black Hills Corporation to the Condensed Consolidated Financial Statements included herein for additional information regarding this pending Merger.

Previous wording

As you read this discussion and analysis, refer to our Condensed Consolidated Statements of Income, which present the results of our operations for the three and nine months ended September 30, 2025 and 2024.

Current wording

As you read this discussion and analysis, refer to our Condensed Consolidated Statements of Income, which present the results of our operations for the three months ended March 31, 2026 and 2025.

Previous wording

HOW WE PERFORMED AGAINST OUR THIRD QUARTER 2024 RESULTS

Current wording

HOW WE PERFORMED AGAINST OUR FIRST QUARTER 2025 RESULTS

Previous wording

In July 2025, we entered into a nonbinding letter of intent with Quantica Infrastructure to evaluate the transmission infrastructure and generation resources needed to support their proposed need. We had previously disclosed in December 2024, two separate nonbinding letters of intent to provide electric supply services for data centers being developed in Montana. The combined energy service requirement associated with these letters of intent is currently expected to be 175 megawatts beginning in late 2027, or earlier, with growth of up to 1,100 megawatts or more by 2030. We have signed a development agreement with Sabey, and are working with each of these parties to execute electric service agreements.

Current wording

As previously disclosed, we have signed development agreements with both Sabey Data Centers and Atlas Power Holdings LLC to provide electric supply services for data centers being developed in Montana. In April 2026, we signed a development agreement with Quantica Infrastructure to evaluate the transmission infrastructure and generation resources needed to support their proposed need. The combined energy service requirement associated with these development agreements is currently expected to be 150 megawatts beginning in late 2027, with growth of up to approximately 1,500 megawatts or more by 2030. We are working with each of these parties to execute electric service agreements.

Previous wording

Resources and regulatory mechanisms to be utilized for serving these requests are pending further evaluation and regulatory considerations.

Current wording

Resources and regulatory mechanisms, such as the LNL Rule discussed above, to be utilized for serving these requests are pending further evaluation and regulatory considerations.

Previous wording

As previously disclosed, we entered into definitive agreements with Avista and Puget to acquire their respective interests in Colstrip Units 3 and 4 for $0 and expect to complete these acquisitions on January 1, 2026. Accordingly, we will be responsible for associated operating costs beginning on January 1, 2026, which we will not collect through utility base rates, until requested in a future Montana rate review. Puget and Avista will remain responsible for their respective pre-closing share of environmental and pension liabilities attributed to events or conditions existing prior to the closing of the transaction and for any future decommissioning and demolition costs associated with the existing facilities that comprise their interests. At closing, we will reimburse Puget and Avista for the proportionate amount of the long-term capital enhancement work they each funded subsequent to executing the definitive agreements and up until the acquisition close date.

Current wording

As previously disclosed, we entered into definitive agreements with Avista and Puget to acquire their respective interests in Colstrip Units 3 and 4 for $0 and completed these acquisitions on January 1, 2026. Accordingly, we are responsible for the associated operating costs beginning on January 1, 2026, which we will not collect through utility base rates until requested in a future Montana rate review. Puget and Avista will remain responsible for their respective pre-closing share of environmental, AROs, and pension liabilities attributed to events or conditions existing prior to the closing of the transaction and for any future decommissioning and demolition costs associated with the existing facilities that comprise their interests.

Previous wording

Avista Interests - The 222 megawatts of generation capacity from Colstrip Units 3 and 4 to be acquired from Avista (Avista Interests) was identified as a key element in our strategy to achieve resource adequacy for customers, as outlined in our 2023 Montana Integrated Resource Plan. Noting the costs associated with operating this resource are not currently reflected in utility customer rates, in August 2025, we filed a temporary PCCAM tariff waiver request with the MPSC that would provide a near-term cost-recovery mechanism expected to largely offset approximately $18.0 million in annual incremental operating and maintenance costs associated with the Avista Interests. This waiver requests that the MPSC allow us to keep 100 percent of the net revenue associated with certain designated power sales contracts up to the amount of the operating and maintenance expenses we incur associated with our Avista Interest. Under the PCCAM design, market sales, which include long-term power sales contracts, flow back to retail customers as a reduction to energy supply costs and would be subject to the 90/10 sharing mechanism. Furthermore, the waiver request indicates that any net revenues from the designated contracts exceeding the operating and maintenance expenses associated with our Avista Interest would continue to flow back to retail customers through the PCCAM as a reduction to energy supply costs. We expect a decision from the MPSC by the first quarter of 2026.

Current wording

Avista Interests - The 222 megawatts of generation capacity from Colstrip Units 3 and 4 acquired from Avista (Avista Interests) on January 1, 2026, was identified as a key element in our strategy to achieve resource adequacy for customers, as outlined in our 2023 Montana Integrated Resource Plan. Noting the costs associated with operating this resource are not currently reflected in utility customer rates, in August 2025, we filed a temporary PCCAM tariff waiver request with the MPSC that could provide a near-term cost-recovery mechanism to offset a portion of the approximately $18.0 million in annual incremental operating and maintenance costs associated with the Avista Interests. This waiver requested that the MPSC allow us to keep 100 percent of the net revenue associated with certain designated power sales contracts up to the amount of the operating and maintenance expenses we incur associated with our Avista Interests. Furthermore, the waiver request indicated that any net revenues from the designated contracts exceeding the operating and maintenance expenses associated with our Avista Interests would continue to flow back to retail customers. In January 2026, the MPSC approved our PCCAM tariff waiver request on an interim basis with final approval or denial subject to the ongoing PCCAM docket process.

Previous wording

Puget Interests - The incremental interest in Colstrip Units 3 and 4 to be acquired from Puget (Puget Interests) increases our ownership share of the facility to 55 percent and provides an increase in voting share in determining strategic direction and investment decisions at the facility. While we expect our future opportunity to serve large load customers may be supported by this resource, we expect to sell excess capacity in the near term. We expect to sign a contract in the fourth quarter of 2025 to sell the dispatchable capacity and associated energy from the Puget Interest beginning January 1, 2026, through late 2027. Revenues from this agreement are expected to largely offset the estimated $30.0 million of annual incremental operating and maintenance costs associated with the Puget Interests. In addition, in October 2025, we submitted a request to the FERC for approval of cost-based rates for our subsidiary that will own the Puget Interests. We expect this rate approval to be effective by January 1, 2026.

Current wording

Puget Interests - The 370 megawatts of generation capacity from Colstrip Units 3 and 4 acquired from Puget (Puget Interests) on January 1, 2026, increases our ownership share of the facility to 55 percent and provides an increase in voting share in determining strategic direction and investment decisions at the facility. Unlike the Avista Interests, we do not currently need this capacity to serve existing customers in Montana. As such, the Puget Interests are held by our FERC regulated subsidiary to isolate the costs associated with this acquired interest from our Montana retail customers. While we expect our future opportunity to serve growing customer demand, including large-load customers, may be supported by this resource, in October 2025, we signed a contract to sell the dispatchable capacity and associated energy from the Puget Interests beginning January 1, 2026, through late 2027. Revenues from this agreement are expected to largely offset the estimated $30.0 million of annual incremental operating and maintenance costs associated with the Puget Interests. In addition, in October 2025, we submitted a request to the FERC for approval of cost-based rates for our subsidiary that will own the Puget Interests. In February 2026, the FERC approved both the cost-based rates and the contract rates retroactive to January 1, 2026. In March 2026, two MPSC commissioners, in their individual capacity, filed a motion with the FERC requesting a rehearing that largely reiterated arguments previously rejected by the FERC. We anticipate that the FERC will rule on this motion in the second quarter of 2026. If the FERC denies the motion, its order will stand. If the FERC grants the motion, it could reopen all or some portion of the proceedings.

Previous wording

The Southwest Power Pool (SPP) has recently updated its resource accreditation and Planning Reserve Margin (PRM) requirements in response to growing reliability concerns. As a result, SPP is requiring additional accredited capacity by 2030 to meet the updated PRM targets. In October 2025, we submitted a project with the Southwest Power Pool (SPP) under their Expedited Resource Adequacy Study program for the construction of a 131 MW natural gas generating facility located in Aberdeen, South Dakota, to meet regional capacity needs by 2030. Anticipated costs for this project are approximately $300 million. This project represents incremental capital expenditures not currently reflected in our five year estimated capital expenditure forecast included within Management’s Discussion and Analysis in the NorthWestern Energy Group Annual Report on Form 10-K for the year ended December 31, 2024. We expect to update our capital expenditures forecast in the first half of 2026 upon the completion of the transmission interconnection study regarding the necessary transmission upgrades needed for this additional generation capacity.

Current wording

The SPP has recently updated its resource accreditation and PRM requirements in response to growing reliability concerns. As a result, SPP is requiring additional accredited capacity by 2030 to meet the updated PRM targets. In October 2025, we submitted a project with the SPP under their Expedited Resource Adequacy Study program for the construction of a 131 MW natural gas generating facility located in Aberdeen, South Dakota, to meet regional capacity needs by 2030. Anticipated costs for this project are approximately $300.0 million.

Previous wording

In December 2024, we signed a nonbinding memorandum of understanding (MOU) with North Plains Connector LLC, a wholly owned subsidiary of Grid United, to own 10 percent (300 megawatts) of the North Plains Connector (NPC) Consortium project. The project is entering the permitting phase and we expect initial regulatory filings in 2026. Construction is expected to commence in 2028, with the project expected to be operational by 2032. Under the terms of the MOU, Grid United will continue to fund the development of the NPC and we will make our investment decision when the regulatory approvals and permits are in place. The project is a critical infrastructure investment that aligns with our commitment to providing reliable and affordable energy to our customers while also supporting broader grid resilience efforts in the region.

Current wording

In December 2024, we signed a nonbinding memorandum of understanding (MOU) with North Plains Connector LLC, a wholly owned subsidiary of Grid United, to own 10 percent (300 megawatts) of the NPC Consortium project. The project is entering the permitting phase. Currently, construction is planned to commence in 2028, subject to receipt of regulatory approvals, with the project expected to be operational by 2032. Under the terms of the MOU, Grid United will continue to fund the development of the NPC and we will make our investment decision when the regulatory approvals and permits are in place. The project is a critical infrastructure investment that aligns with our commitment to providing reliable and affordable energy to our customers while also supporting broader grid resilience efforts in the region.

Previous wording

The Montana Legislature approved House Bill 490 in April 2025, with broad bipartisan support in both the House (90-0) and Senate (40-8), and the Governor signed this bill into law in May 2025. This bill requires development, approval, and implementation of electric facilities providers' wildfire mitigation plans. Importantly, House Bill 490 helps address some preexisting liability risks facing electric facilities providers in Montana. It changes Montana law, recognizing utilities' obligation to provide a public service for customers that is different from typical businesses; circumscribes certain damages; and enacts liability protections related to wildfire and wildfire prevention efforts involving providers. More specifically, House Bill 490 precludes common law strict liability claims for damages related to wildfire and electric activities or wildfire mitigation activities; establishes a statutory standard of care, supplanting common law causes of action and other theories of recovery; and creates a rebuttable presumption that an electric facilities provider acted reasonably if it substantially followed an approved wildfire mitigation plan. The legislation also defines the availability of damages by allowing noneconomic personal injury damages only when there is bodily injury and punitive damages only when an injured party proves by clear and convincing evidence that an electric facilities provider's actions were grossly negligent or intentional. We filed our wildfire mitigation plan with the MPSC in August 2025 for review and approval.

Current wording

The South Dakota Legislature approved Senate Bill 36, and the Governor signed this bill into law, in March 2026. It precludes common law strict liability claims for utility operations alleged to have caused wildfire-related damages; establishes a statutory standard of care, supplanting common law causes of action and other theories of recovery; and creates a rebuttable presumption that a valid and current wildfire mitigation plan is reasonable preparation for, and mitigation of, wildfire risk. The legislation also defines the availability of damages by allowing noneconomic personal injury damages only when there is bodily injury and punitive damages only when an injured party proves by clear and convincing evidence that a qualified utility acted with willful and wanton misconduct and the qualified utility's willful and wanton misconduct was the actual and proximate cause of damages to the plaintiff. We anticipate filing our wildfire mitigation plan with the SDPUC in the second half of 2026.

Previous wording

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 and commercial 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. 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.

Current wording

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 and commercial customers. We measure this effect based on the number of customers, temperature variances, and the amount of electricity or natural gas historically used per degree of temperature. Degree-day, which is the difference between the average daily actual temperature and a baseline temperature of 65 degrees, is used to estimate the amount of energy required to maintain comfortable indoor temperature levels based on each day's average temperature. 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.

Previous wording

Consolidated utility margin for the three months ended September 30, 2025 was $300.1 million as compared with $257.3 million for the same period in 2024, an increase of $42.8 million, or 16.6 percent. Primary components of the change in utility margin include the following (in millions):

Current wording

Consolidated utility margin for the three months ended March 31, 2026 was $352.0 million as compared with $328.4 million for the same period in 2025, an increase of $23.6 million, or 7.2 percent. Primary components of the change in utility margin include the following (in millions):

Previous wording

Acquisition of Energy West Montana Operations

Current wording

Electric retail volumes were driven by unfavorable weather partly offset by customer growth. Natural gas retail volumes were driven by unfavorable weather partly offset by customer growth and the acquisition of Energy West operations.

Previous wording

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. For the three months ended September 30, 2025, we under-collected supply costs of $21.1 million resulting in an increase to our under collection of costs, and recorded a decrease in pre-tax earnings of $2.3 million (10 percent of the PCCAM Base cost variance). For the three months ended September 30, 2024, we over-collected supply costs of $5.9 million resulting in a reduction to our under collection of costs, and recorded an increase in pre-tax earnings of $0.7 million (10 percent of the PCCAM Base cost variance).

Current wording

Under the PCCAM, net supply costs higher or lower than the PCCAM base rate (PCCAM Base) (excluding qualifying facility (QF) costs) were allocated 90 percent to Montana customers and 10 percent to shareholders. Effective February 1, 2026 the cost sharing mechanism of the PCCAM was suspended on a temporary basis pending further review by the MPSC. For the three months ended March 31, 2026, we under-collected supply costs of $20.7 million resulting in an increase to our under collection of costs, and recorded a decrease in pre-tax earnings of $0.7 million (10 percent of the PCCAM Base cost variance for January 2026). For the three months ended March 31, 2025, we under-collected supply costs of $24.3 million resulting in an increase to our under collection of costs, and recorded a decrease in pre-tax earnings of $2.7 million (10 percent of the PCCAM Base cost variance).

Previous wording

Consolidated operating expenses, excluding fuel, purchased supply and direct transmission expense, were $219.7 million for the three months ended September 30, 2025, as compared with $189.4 million for the three months ended September 30, 2024. Primary components of the change include the following (in millions):

Current wording

Consolidated operating expenses, excluding fuel, purchased supply and direct transmission expense, were $237.8 million for the three months ended March 31, 2026, as compared with $203.7 million for the three months ended March 31, 2025. Primary components of the change include the following (in millions):

Previous wording

Consolidated operating income for the three months ended September 30, 2025 was $80.3 million as compared with $67.9 million in the same period of 2024. This increase was primarily due to new rates, customer usage, electric transmission revenues, and natural gas transportation revenues. These were partly offset by unfavorable weather in Montana, higher operating, administrative, and general costs, including merger-related costs, depreciation, Montana property tax tracker collections, and non-recoverable Montana electric supply costs.

Current wording

Consolidated operating income for the three months ended March 31, 2026 was $114.1 million as compared with $124.7 million in the same period of 2025. This decrease was primarily due to retail volumes, operating, administrative, and general costs, including merger-related costs and costs associated with our additional ownership interests in Colstrip Units 3 and 4, and depreciation expense. These were offset in part by new rates, transmission revenues, and lower non-recoverable Montana electric supply costs.

Previous wording

Consolidated interest expense was $38.4 million for the three months ended September 30, 2025 as compared with $33.4 million for the same period of 2024. This increase was due to higher borrowings and interest rates and lower capitalization of Allowance for Funds Used During Construction (AFUDC).

Current wording

Consolidated interest expense was $39.9 million for the three months ended March 31, 2026 as compared with $36.5 million for the same period of 2025. This increase was due to higher borrowings and interest rates partly offset by higher capitalization of Allowance for Funds Used During Construction (AFUDC).

Previous wording

Consolidated other income was $5.1 million for the three months ended September 30, 2025 as compared with $9.1 million for the same period of 2024. This decrease was primarily due to lower capitalization of AFUDC and higher non-service component pension expense.

Current wording

Consolidated other income was $3.1 million for the three months ended March 31, 2026 as compared with $3.9 million for the same period of 2025. This decrease was primarily due to higher non-service component pension expense and a decrease in the value of deferred shares held in trust for deferred compensation partly offset by higher capitalization of AFUDC.

Previous wording

The following table summarizes the differences between our effective tax rate and the federal statutory rate (in millions):

Current wording

The following table summarizes the differences between our effective tax rate and the federal statutory rate (dollars in millions):

Previous wording

For the three months ended September 30, 2025, we under-collected supply costs of $21.1 million resulting in an increase to our under collection of costs, and recorded a decrease in pre-tax earnings of $2.3 million (10 percent of the PCCAM Base cost variance). For the three months ended September 30, 2024, we over-collected supply costs of $5.9 million resulting in a reduction to our under collection of costs, and recorded an increase in pre-tax earnings of $0.7 million (10 percent of the PCCAM Base cost variance).

Current wording

Effective February 1, 2026 the cost sharing mechanism of the PCCAM was suspended on a temporary basis pending further review by the MPSC. For the three months ended March 31, 2026, we under-collected supply costs of $20.7 million resulting in an increase to our under collection of costs, and recorded a decrease in pre-tax earnings of $0.7 million (10 percent of the PCCAM Base cost variance for January 2026). For the three months ended March 31, 2025, we under-collected supply costs of $24.3 million resulting in an increase to our under collection of costs, and recorded decrease in pre-tax earnings of $2.7 million (10 percent of the PCCAM Base cost variance).

Previous wording

As of September 30, 2025, our total net liquidity was approximately $262.2 million, including $6.2 million of cash and cash equivalents and $256.0 million of revolving credit facility availability with no letters of credit outstanding.

Current wording

As of March 31, 2026, our total net liquidity was approximately $230.9 million, including $5.9 million of cash and cash equivalents and $225.0 million of revolving credit facility availability with no letters of credit outstanding.

Previous wording

As of September 30, 2025, cash, cash equivalents, and restricted cash were $30.5 million as compared with $29.0 million as of December 31, 2024 and $27.9 million as of September 30, 2024. Cash provided by operating activities totaled $338.3 million for the nine months ended September 30, 2025 as compared with $343.9 million during the nine months ended September 30, 2024. The changes in cash flows from operating activities generally follow the results of operations, as discussed above in the consolidated results of operations for the nine months ended September, 2025, and are affected by changes in working capital. The decrease in cash provided by operating activities is primarily due to merger transaction costs, lower collections of accounts receivable balances due to timing of colder weather, and an increase in our net cash outflows for energy supply costs, as shown in the table below, partly offset by the proceeds from production tax credits transferred.

Current wording

As of March 31, 2026, cash, cash equivalents, and restricted cash were $27.6 million as compared with $30.7 million as of December 31, 2025 and $80.1 million as of March 31, 2025. Cash provided by operating activities totaled $159.4 million for the three months ended March 31, 2026 as compared with $153.4 million during the three months ended March 31, 2025. The changes in cash flows from operating activities generally follow the results of operations, as discussed above in the consolidated results of operations for the three months ended March 31, 2026, and are affected by changes in working capital. The increase in cash provided by working capital is primarily due to a decrease in our net cash outflows for energy supply costs, as shown in the table below.

Previous wording

Cash used in investing activities totaled $418.5 million during the nine months ended September 30, 2025, as compared with $405.1 million during the nine months ended September 30, 2024. Plant additions during the first nine months of 2025 include maintenance additions of approximately $261.3 million and capacity related capital expenditures of $113.2 million. Plant additions during the first nine months of 2024 included maintenance additions of approximately $216.5 million and capacity related capital expenditures of approximately $184.0 million. During the nine months ended September 30, 2025, we completed the acquisition of the Energy West Operations for $35.9 million. See Note 3 - Acquisition of Energy West Operations to the Condensed Consolidated Financial Statements included herein for additional information regarding this acquisition.

Current wording

Cash used in investing activities totaled $116.1 million during the three months ended March 31, 2026, as compared with $96.7 million during the three months ended March 31, 2025. Plant additions during the first three months of 2026 include maintenance additions of approximately $80.0 million and capacity related capital expenditures of $36.1 million. Plant additions during the first three months of 2025 included maintenance additions of approximately $55.6 million and capacity related capital expenditures of approximately $36.5 million.

Previous wording

Cash provided by financing activities totaled $81.7 million during the nine months ended September 30, 2025, as compared with $63.9 million during the nine months ended September 30, 2024. During the nine months ended September 30, 2025, cash provided by financing activities reflects proceeds from the issuance of long-term debt of $500.0 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, net repayments under our revolving lines of credit of $44.0 million, and payment of dividends of $121.0 million. During the nine months ended September 30, 2024, cash provided by financing activities reflects proceeds from the issuance of long-term debt of $215.0 million and short-term borrowings of $100.0 million, partly offset by payment of dividends of $118.9 million, repayment of 1.00 percent, $100.0 million of Montana First Mortgage Bonds, and net repayments under our revolving lines of credit of $32.0 million.

Current wording

Cash used in financing activities totaled $46.4 million during the three months ended March 31, 2026, as compared with $5.6 million during the three months ended March 31, 2025. During the three months ended March 31, 2026, cash used in financing activities reflects payment of dividends of $41.0 million and net repayments under our revolving lines of credit of $4.0 million. During the three months ended March 31, 2025, cash used in financing activities reflects net repayments under our revolving lines of credit of $362.0 million and payment of dividends of $40.3 million, partly offset by proceeds from the issuance of long-term debt of $400.0 million.

Previous wording

As of September 30, 2025 and 2024, the outstanding balances of our credit facilities were $369.0 million and $286.0 million, respectively. As of October 24, 2025, the availability under our credit facilities was approximately $278.0 million, and there were no letters of credit outstanding.

Current wording

As of March 31, 2026 and 2025, the outstanding balances of our credit facilities were $400.0 million and $51.0 million, respectively. As of April 24, 2026, the availability under our credit facilities was approximately $240.0 million, and there were no letters of credit outstanding.

Previous wording

(1)Represents cash payments for long-term debt and excludes $14.5 million of debt discounts and debt issuance costs, net.

Current wording

(1)Represents cash payments for long-term debt and excludes $12.1 million of debt discounts and debt issuance costs, net.

Previous wording

(3)Certain QFs require us to purchase minimum amounts of energy at prices ranging from $124 to $130 per MWH through 2029. Ourestimated gross contractual obligation related to these QFs is approximately $183.7 million. A portion of the costs incurred to purchase this energy is recoverable through rates authorized by the MPSC, totaling approximately $166.1 million.

Current wording

(3)One QF requires us to purchase minimum amounts of energy at prices ranging from $124 to $130 per MWH through 2028. Ourestimated gross contractual obligation related to this QF is approximately $154.7 million. A portion of the costs incurred to purchase this energy is recoverable through rates authorized by the MPSC, totaling approximately $141.3 million.

Previous wording

(4)We have entered into various purchase commitments, largely purchased power, electric transmission, coal and natural gas supply and natural gas transportation contracts. These commitments range from one to 26 years. The energy supply costs incurred under these contracts are generally recoverable through rate mechanisms approved by the MPSC.

Current wording

(4)We have entered into various purchase commitments, largely purchased power, electric transmission, coal and natural gas supply and natural gas transportation contracts. These commitments range from one to 24 years. The energy supply costs incurred under these contracts are generally recoverable through rate mechanisms approved by the MPSC.

Previous wording

(5)Contractual interest payments include our revolving credit facilities, which have a variable interest rate. We have assumed an average interest rate of 5.51 percent on the outstanding balance through maturity of the facilities.

Current wording

(5)Contractual interest payments include our revolving credit facilities, which have a variable interest rate. We have assumed an average interest rate of 5.02 percent on the outstanding balance through maturity of the facilities.