Highmark headquarters in Pittsburgh.

In a move that could hurt quite a few providers, Highmark, the big Pittsburgh-based nonprofit insurer, has become the latest insurer to trim its offerings.

David L. Holmberg, the company’s chief executive, told The Wall Street Journal that Highmark had lost $318 million on its individual health-law plans in the first six months of 2015, after, as the WSJ said, “rolling out a very broad array of options that had attracted many consumers with chronic conditions who required costly care.”

The paper said the company “was still working on the details of its offerings, but it expects a ‘mix shift’ toward plans that offer more limited choices of health-care providers. Such plans typically have lower premiums than versions with broader networks. About Highmark’s offerings for next year, Mr. Holmberg said: “Is there going to be a trend toward more narrow networks? Yes.”

Many insurers are trying to manage costs by offering plans with considerably tighter controls over the  services  that members use. The idea is to limit consumers’ access to higher-cost health-care providers,  especially hospitals and physicians outside an insurer’s network. This could particularly hit academic medical centers.