Every day, about 10,000 seniors become eligible for Medicare benefits.

Statistics like that have led to an optimistic future outlook for some managed care companies focused on growing their Medicare Advantage business, a form of private insurance for delivering Medicare benefits. But today, after a government regulator released some negative news for insurers focused on these kinds of plans, that optimism is fading away quickly. In the following video health care bureau chief Brenton Flynn runs through the news and what it means for a variety of insurance companies, including United Health (NYSE:UNH), Humana (NYSE:HUM), and Universal American (NYSE:UAM).