PNM Resources files for transmission formula rate increase PNM Resources' New Mexico utility, PNM, filed a request with the Federal Energy Regulatory Commission, or FERC, for a $3.2M transmission rate increase and permission to adjust transmission rates annually based on an approved formula. The request will not impact retail rates for New Mexico customers, only wholesale customers who use PNM transmission lines to deliver power. PNM has asked for FERC approval by March 2013. The filing proposes a return on equity of 10.81%, based on a rate base of $317.5M and a revenue requirement of $82.1M. Once approved, an annual adjustment will be made each June to update for the prior year's costs reflected in the latest FERC Form 1 filing.