Pittsburgh-based health insurer Highmark's enrollment both on and off the federal exchanges dropped from 350,000 in February 2015 to 195,000 in February 2016, according to the Pittsburgh Tribune-Review.
In addition, Pennsylvania's largest insurer — which lost $773 million on the 2015 Affordable Care Act marketplace — saw a 5 percent membership decrease in its employer-sponsored and Medicare Advantage Plans.
"Our share in the market was considerably higher than we had anticipated in 2014 and 2015, and I think now what you're seeing is a market adjustment," said Alexis Miller, Highmark's senior vice president of individual and small group markets, according to the report.
To solve the problem, Highmark officials said the insurer has increased 2016 premium costs by an average of 20 percent.
This announcement comes nearly one month after a UPMC analysis found Highmark isn't the top insurer in Western Pennsylvania anymore. Instead, the western portion of the state is now a "tripartite" market, with UPMC, Highmark and other national insurers each owning about one third of the marketplace.