Highmark Health said it would reduce its range of offerings on the Affordable Care Act marketplaces, becoming the latest insurer to retrench amid steep financial losses.

The big Pittsburgh-based nonprofit company said it would continue to sell plans related to the federal health overhaul in all of the areas it currently serves, which span Pennsylvania, Delaware and West Virginia. But “we will have less products in the market overall,” said David L. Holmberg, the company’s chief executive, who said Highmark had lost $318 million on its individual health-law plans in the first six months of 2015, after rolling out a very broad array of options that had attracted many consumers with chronic conditions who required costly care.