One of the country’s largest health insurers warned Thursday that it may leave the ObamaCare exchanges within two years, a shock that could send major ripple effects through the marketplace.

At a shareholder meeting Thursday, UnitedHealthcare cast doubt on its ability to carry plans on the healthcare law’s exchanges beyond 2016, offering a more grim financial outlook than it had previously expected.

The company said in a statement it is “evaluating the viability of the insurance exchange product segment and will determine during the first half of 2016 to what extent it can continue to serve the public exchange markets in 2017.”

It also projected that its fourth quarter revenue will be $425 million less than expected — amounting to 26 cents in earnings per share.

The company also announced it has pulled back on marketing plans for 2016.