Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of mega health insurer UnitedHealth (NYSE: UNH) jumped 10% today after the company released earnings.

So what: Revenue rose 9.7% to $25.43 billion, beating estimates of $24.95 billion. But the real news was on the bottom line where earnings per share reached $1.22, crushing analysts' estimates of $0.89.

Now what: Investors were concerned that new rules put in place by last year's health care law would pinch profits so all eyes were on UnitedHealth today. With UnitedHealth showing that insurers can still make money while meeting medical loss ratios, the entire sector is moving higher today. WellPoint (NYSE: WLP), Aetna (NYSE: AET), and Coventry Health Care (NYSE: CVH) are all trading higher on relief that bellwether UnitedHealth posted strong results.

Interested in more info on UnitedHealth? Add it to your watchlist.

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