The long-running fight over what Midwestern utilities can charge for high-voltage power lines just ended in a big refund order, and ratepayers came out ahead. On June 5, the D.C. Circuit denied in part and dismissed in part petitions by Midcontinent Independent System Operator transmission owners, leaving in place a Federal Energy Regulatory Commission remand that requires retroactive refunds spanning roughly eight years. The decision caps a drawn-out battle over the return-on-equity component that utilities use to set transmission rates across the MISO footprint.
The dispute stems from customer complaints filed in November 2013 and February 2015, followed by a stack of FERC rulings that were later revisited after earlier court review. On October 17, 2024, FERC set a replacement base return on equity of 9.98% and ordered refunds running from Sept. 28, 2016, through Oct. 17, 2024. Those remedial steps, along with the remand record that framed the appeal, are laid out in the commission’s materials. FERC provides the full administrative background.
What the court said
The D.C. Circuit brushed aside transmission owners’ central claim that FERC’s remedy violated the Federal Power Act’s 15-month statutory refund limit. In the court’s words, “FERC acted within its authority in backdating relief” to line up the remedy with the court’s earlier vacatur, and the panel found the utilities had not shown they were entitled to the extraordinary relief they were asking for. The opinion effectively greenlights FERC’s move, in this case, to tailor a fix to the scope of its prior error. D.C. Circuit has the full decision.
Why it matters for customers and utilities
On the ground, the ruling means refunds and interest now have to be pushed through MISO’s regional settlement systems and will flow to load-serving entities and, eventually, retail customers under existing allocation rules. Transmission owners have been signaling this hit in public filings for a while. ITC Holdings, for instance, reported paying out $7 million in refunds in the first quarter of 2026 and carrying about $1 million in remaining refund liabilities as of March 31, 2026, and other regulated owners have reported similar adjustments in their SEC disclosures. Analysts are combing through the decision for what it implies for utility balance sheets, future rate cases and the next round of ROE skirmishes. See recent company and trade coverage from ITC Holdings, WEC Energy Group and RTO Insider.
The next steps may look procedural, but they are far from trivial. Transmission owners can still seek rehearing en banc at the D.C. Circuit or ask the Supreme Court to take a look, while MISO keeps working with members to sort out the detailed refund mechanics. Legal watchers say the decision gives FERC more confidence in its remedial toolkit after a vacatur, even as fights over methodology, interest and settlement logistics remain very much alive. Legal trade outlets are tracking potential appeals and compliance schedules; Law360 is among those following the procedural twists.
Legal takeaways
On paper, the case is about a narrow statutory issue: how far back FERC can reach when correcting a rate it later finds unlawful. In practice, the ripple effects touch utility investment signals and the predictability of transmission returns. Consumer advocates are calling the outcome a victory for restoring “just and reasonable” rates, while utilities warn that retroactive remedies can unsettle the capital needed to build big-ticket grid projects. Law firms and practitioners tracking the docket say the opinion backs FERC’s authority after a vacatur, yet leaves room for parties to keep pressing on how those powers are applied in future proceedings. For additional legal perspective, see commentary from energy law firms and advocacy groups, including analysis from Spiegel & McDiarmid.
