Federal appeals court leaves 9.98% MISO return in place

Louisiana’s push for another round of MISO refunds came up short, and the disputed 9.98% return stays the benchmark. The D.C. Circuit said the Federal Energy Regulatory Commission, or FERC, had already found that rate was not unjust or unreasonable, so it declined to order refunds in the Second Complaint proceeding. For households and businesses tied to the Midcontinent Independent System Operator grid, that means the same pricing baseline continues to shape electric bills and any retroactive relief claims.

The benchmark the court would not reopen

The fight turned on whether Louisiana regulators could use a later case to relitigate the return on equity, or ROE, after the court had already spoken on the issue. The panel said no. Its earlier MISO Transmission Owners decision already told FERC to apply the return in effect at the time of decision, including in related proceedings.

That left the Louisiana Public Service Commission with no way to force a different rate through this challenge. The court treated the earlier ruling as controlling, which meant FERC had to work from the 9.98% figure rather than start over.

Why the loss matters at the meter

For MISO customers, the decision keeps the disputed rate embedded in the transmission charges that feed their power bills. For transmission owners, it preserves the return that continues to govern the related pricing dispute.

The ruling does not erase the underlying fight over electric costs on the grid, but it does close off another refund path tied to the 9.98% return. Unless a future decision changes the ground rules, the number stays where it is.