New Mexico has a unique exchange; the state runs the small business portion, and while the individual exchange is also technically state-run, Healthcare.gov is used to enroll people in individual insurance (ie, a federally-supported state-based marketplace). But the exchange is planning to establish its own enrollment platform that will be in use by the fall of 2020.
Normally I'd just use a snippet of the entry, but Norris manages to cover all the relevant angles in just a few paragraphs; I think she'll be OK with me cribbing more of it:
Initially, the state had planned to establish a state-run website for individual enrollments fairly soon after the exchanges went live in the fall of 2013, and that was still in the works until early spring 2015. But in April 2015, the exchange board voted to continue to use Healthcare.gov, as that was viewed as the less-costly alternative.
As of today, there are 12 states which operate their own full ACA exchanges, including their own board of directors, marketing budget, bylaws and tech platform for their enrollment website. 34 states have offloaded just about all of that to the federal exchange, HealthCare.Gov. And then there are five states which are in between: They have their own state-based exchange...but their tech platform is basically piggybacked onto the federal exchange: Arkansas, Kentucky, Nevada, New Mexico and Oregon.
Arkansas and New Mexico always planned on moving off of HC.gov onto their own full exchange platform but never got around to doing so. Kentucky's ("kynect") was working perfectly well from day one, and only made the move to the federal platform after three years because new GOP Governor Matt Bevin decided he didn't like it for whatever reason. New Mexico and Oregon, meanwhile, had such major technical problems at launch that they scrapped their sites after the first year and moved to the Mothership. (As an aside, Hawaii also scrapped their exchange site after the second or third year, but they shut down their entire state-based exchange and moved everything to HC.gov).