Spiegel & McDiarmid LLP attorneys achieved a major victory for ratepayers in the Midcontinent Independent System Operator (MISO) region. On June 5, 2026, the D.C. Circuit denied petitions for review brought by MISO transmission owners and upheld FERC orders that required the MISO transmission owners to refund hundreds of millions of dollars for excessive rates they had been collecting from ratepayers since September 2016.

At issue was the return on equity component of transmission rates in MISO, which had been at 12.38% when customers brought a complaint in 2013. After more than a decade of litigation, FERC set a new, 9.98% return on equity and ordered refunds based on this lower rate back to 2016—when FERC first acted on the complaint. MISO transmission owners argued that FERC lacked authority to order refunds back to 2016, but the court found that FERC acted within its authority to correct errors that the court previously identified in FERC’s earlier orders. The result means hundreds of millions of dollars in refunds to ratepayers.

Spiegel attorneys Jeff Bayne, Steve Pearson, and David Pomper represented the Mississippi Public Service Commission, Missouri Public Service Commission, and Missouri Joint Municipal Electric Utility Commission. Jeff Bayne argued the case before the D.C. Circuit on behalf of the customer intervenors.

A copy of the decision is linked here.