WellPoint cuts its outlook, sending shivers through shares of insurers

Shares of WellPoint plummeted more than 16 percent in after-hours trading March 10 after the company lowered its profit forecast due to higher medical costs and lower-than-expected insurance enrollments. After the WellPoint news broke, shares of other big health insurers fell. Humana was off by more than 10 percent, Aetna declined by about 10 percent and UnitedHealth Group was down nearly 9 percent.