Bright Horizon Energy: Decoding the Black Hills-NorthWestern Energy Merger

The proposed merger between Black Hills Corporation and NorthWestern Energy Group, Inc. continues to advance, with major regulatory milestones now reached in Nebraska, Montana, and South Dakota. This stock-for-stock transaction is positioned to create a stronger, more diversified utility across an eight-state service territory. Progress to date reflects successful navigation of complex regulatory processes, negotiated settlements that address stakeholder concerns, and a clear case for long-term strategic and financial benefits.

The following table provides a state-by-state breakdown of the regulatory safeguards, required rate moratoriums, and operational requirements established in the multi-state settlement agreements for the proposed utility merger.

Nebraska: Ratepayer Protections and Enhanced Transparency

In Nebraska, review of the merger (Docket No. NG-128) concluded with formal approval from the Nebraska Public Service Commission on May 19, 2026. The regulatory order binds the utilities to two key multi-party agreements: a consumer-protection settlement with the Public Advocate of Nebraska and a labor-and-safety settlement with the Laborers' International Union of North America. Together, these agreements establish enforceable commitments focused on rate stability, strict cost containment, and localized operational transparency.

A central provision of the approval is the base rate moratorium framework. NorthWestern Energy has agreed not to file for an increase in general base rates under Nebraska Statute before May 1, 2027. Black Hills Nebraska Gas is also under a base rate moratorium through May 1, 2028. These commitments provide defined periods of rate stability, while preserving existing tracker and rider mechanisms, including the Gas Cost Adjustment, System Safety and Integrity Rider, and Weather Normalization Adjustment, as well as incremental charges for new facilities.

The settlement also permits exceptions for unforeseen investments or extraordinary events that impact cost of service by more than $1MM while also providing clear cost-recovery protections. The Joint Applicants will not seek recovery from Nebraska-jurisdictional customers for “Transaction Costs,” including merger negotiation, due diligence, regulatory approval, banking fees, legal fees, or shareholder approval costs. “Golden parachute,” change-in-control, separation, and severance payments for named executives are non-recoverable, as are goodwill and acquisition-premium-related amounts tied to the merger.

For oversight, BH Nebraska Gas and NorthWestern Energy must file annual Capital Expenditure Reports (CapEx Reports) from 2024 through 2029, showing budget-versus-actual costs for major projects over $500k (NorthWestern) and $1MM (BH Nebraska Gas). A new Cost Allocation Manual (CAM) and Intercompany Service Agreements (ISC) must be filed when cost types, allocation methods, factors, or affiliate composition change. Merger-related changes to GAAP, state and federal income tax methodologies, and Net Operating Loss Carryforwards (NOLC) must also be reported in NG-101 filings. These reporting commitments end upon each utility’s next general rate review filing.

Montana: Customer Credits and Operational Commitments

Montana’s merger review (Docket No. 2025.10.078) has resulted in multiple settlements with the Montana Consumer Counsel (MCC), the Montana Large Customer Group (LCG), and the Joint Energy Advocates (JEA). One of the most consequential outcomes is a one-time $10MM bill credit for residential electric and gas customers, to be distributed within 90 days of closing, resulting in a one-time, total credit of approximately $18 per residential customer. The Joint Applicants maintained that the credit was not required to establish public interest but agreed to it as part of the settlement compromise.

As in Nebraska, cost recovery limits are strict. The settlements bar recovery from Montana ratepayers of merger “Transaction Costs,” goodwill or acquisition premium, and executive compensation incurred through closing. The Joint Applicants may pursue post-merger “Transition Costs” in future rate cases, but MCC and LCG expressly retain the right to challenge those requests.

Ring-fencing provisions approved in Docket No. 2022.06.064 remain in effect to protect NorthWestern Energy’s financial integrity from affiliate risk. Reporting obligations include actual-versus-budgeted capital cost reporting for 2026 and 2027 in the first post-merger rate review, as well as CAM updates within 60 days of specified merger-related changes. A comprehensive CAM aligned with NARUC guidelines must be filed with the first post-close rate review.

Integrated Resource Planning (IRP) commitments are also a major component of both the MCC/LCG and JEA settlements. Future electric IRPs must evaluate transmission and generation coordination opportunities with Black Hills to improve customer cost and reliability outcomes in Montana. The JEA settlement also emphasizes evaluation of demand-side management (DSM) and distributed energy resources (DER) in the next IRP. NorthWestern Energy committed to DSM stakeholder meetings with management on numeric thresholds and timelines for DSM expansion and DER optimization.

A JEA-nominated individual will join NorthWestern Energy’s Electric Technical Advisory Committee (ETAC) to provide input on planning, renewable buildout, and DSM/DER strategy. In addition, the City and County of Missoula secured commitments that NorthWestern Energy will continue work on developing and proposing a Green Power Program (GPP) for eligible customers to support new renewable resources in Montana.

South Dakota: Rate Moratoriums and Corporate Presence

The South Dakota Public Utilities Commission (PUC) (Docket No. GE25-001) approved a Settlement Stipulation between the Joint Applicants and Staff on April 29, 2026, establishing key merger conditions. Rate moratoriums are again central: NorthWestern Energy electric base rates cannot increase before January 1, 2028, and natural gas base rates cannot increase before January 1, 2029. Black Hills Power is subject to an electric rate moratorium until September 1, 2028, with an exception for pending Docket EL26-003. As in other states, the moratoriums exclude existing trackers/riders and extraordinary unforeseen events affecting cost of service by more than $1MM.

Another key safeguard is the “Most Favored Nations” clause. If the Joint Applicants agree to, or are ordered to, forgo recovery of merger-related costs in Nebraska or Montana beyond what is listed in the South Dakota stipulation, Black Hills Power and NorthWestern Energy will not seek recovery of those additional costs from South Dakota ratepayers.

South Dakota’s ring-fencing provisions are extensive. Dividend restrictions prohibit NorthWestern Energy and Black Hills Power from issuing dividends if equity falls below 40% of total capital structure. Both utilities must provide secured credit ratings to the Commission on request and notify the Commission within 30 days of any downgrade. If equity drops below 40%, each utility must provide an explanation within 90 days. Financing terms permit participation in a utility money pool and allocation of unsecured debt through an intercompany parent note, subject to Commission approval, to preserve cost-effective access to capital.

The settlement also states that merger-related purchase accounting adjustments, including goodwill, acquisition premium, and “push-down” accounting, will not affect South Dakota rates. Integration costs may be recognized by the Joint Applicants when incurred but must be separately identified and quantified in future rate filings, with the burden on Joint Applicants to prove reasonableness and prudence.

The combined company committed to maintain its corporate headquarters in Rapid City for at least ten years and a corporate office in Sioux Falls for at least five years, with prior notice required for any relocation or discontinuance. Annual Capital Expenditure Reports comparing actual to budgeted plans for 2027–2029 are required, along with annual merger integration status reports through December 31, 2029.

Broader Strategic Implications

Under the transaction, NorthWestern Energy Group will become a direct subsidiary of Black Hills Corporation. The merger is structured to strengthen financial capacity and operating resilience without new debt or complex financing structures. The combined company will serve Arkansas, Colorado, Iowa, Kansas, Montana, Nebraska, South Dakota, and Wyoming.

The following table provides a market-based perspective on the transaction by evaluating five recent comparable public utility mergers and acquisitions compiled from regional financial data, tracking total enterprise values and regulated asset multiples.

This peer group data highlights how the merger aligns with historical multi-state utility market transactions. Ultimately, that larger footprint and scale should improve efficiency and access to cost-effective capital, supporting future investment. With multi-state approvals now tied to concrete customer protections and stronger oversight mechanisms, the merger has a clear regulatory path forward. Rate stability commitments, cost-recovery limits, transparency requirements, and local operational-presence obligations together reflect a balanced framework: capture scale benefits while protecting customers and preserving state regulatory authority.

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