May 15—Trading was halted for stock in PNM Resources and Avangrid Inc. for more than an hour Monday after the New Mexico Supreme Court issued an order in the companies' case appealing state regulators' rejection of a merger request.

The proposed merger will not be remanded to the state Public Regulation Commission for reconsideration by a new panel of commissioners, the high court said Monday, responding to a joint request in March from the utility companies and the commission.

Justices instead scheduled oral arguments for the appeal Sept. 12.

The utility companies announced the court's decision in statements issued Monday afternoon.

"We received the court's order and we are reviewing it," PNM spokesman Ray Sandoval wrote in an email.

Avangrid spokeswoman Joanie Griffin declined to comment on the court's decision.

PRC spokesman Patrick Rodriguez wrote in an email Monday "the commission respects the Supreme Court's decision, and we await the start of oral arguments on September 12."

The merger was unanimously rejected by former commissioners in December 2021 after a monthslong proceeding that involved several renewable energy advocacy groups, local governments and the state attorney general. The utilities appealed the commission's decision in January 2022.

Two newly appointed commissioners then signed onto a March 8 joint motion with the utilities seeking "remand and rehearing" of the merger case. The third commissioner, Patrick O'Connell, had recused himself from the case shortly after taking his position in January.

Commissioners James Ellison and Gabriel Aguilera acknowledged in April they had erred when they signed onto the joint motion because a rehearing of the merger case would run afoul of the commission's procedural rules. They expressed interest, instead, in motions to "reopen" the case.

In a disclosure filing April 20, emails between Avangrid attorneys and those representing the commission showed communications that had taken place from January to March about the content of the joint motion to the court, including how such a proceeding to reconsider the merger would move forward and whether the record would be reopened.

Groups including the New Mexico Foundation for Open Government and Indivisible Albuquerque raised concerns the commission had violated the state Open Meetings Act or taken part in improper ex parte communications — or talks with just one side of a case they would soon rule on.

State Attorney General Raúl Torrez responded to the commission's joint motion with the utilities, warning of the possibility the merger case would be "decided behind closed doors."

Clean energy advocacy group New Energy Economy, which has opposed the proposed merger, also opposed the joint motion from the regulators and utilities, arguing a rehearing would place more burden on intervening parties and limit due process in the case.

The organization's executive director, Mariel Nanasi, said Monday the court's ruling "upheld due process."

"The Court's ruling today is a vindication of our rights as New Mexicans to protection from arbitrary legal reversals at the behest and under the influence of powerful corporations," Nanasi wrote in a statement. "The system of regulatory oversight intended to protect ordinary New Mexicans from utility overreach was threatened."