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.

Fool contributor Travis Hoium does not have a position in any company mentioned. You can follow Travis on Twitter at @FlushDrawFool, check out his personal stock holdings or follow his CAPS picks at TMFFlushDraw.

UnitedHealth Group and WellPoint are Motley Fool Inside Value selections. Coventry Health Care and UnitedHealth Group are Motley Fool Stock Advisor picks. Motley Fool Options has recommended a diagonal call position on UnitedHealth Group. The Fool owns shares of UnitedHealth Group. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.