Bernard Tyson, chief executive of insurer Kaiser Permanente, said Thursday that the company would be sticking with the Obamacare exchanges, despite acknowledging that they were unstable.

Tyson, speaking at the Wall Street Journal’s Future of Healthcare event in New York, said the exchanges were not in a “death spiral,” as Mark Bertolini, Aetna’s chairman and CEO, said at a Wall Street Journal event in February.