We're witnessing one of the most dramatic declines by major, well-capitalized stocks in recent memory. Health insurance giant ...

Shares of UnitedHealth Group ( UNH 3.45%) are plummeting this week. The company's stock is down 27.4% as of 12:29 p.m. ET. The collapse comes as the S&P 500 ( ^GSPC 0.27%) gained 4.7% and the ...

CEO Andrew Witty this week has sent shockwaves through an already tumultuous healthcare sector. Investors in UNH stock have ...