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 health insurer MedcoHealth Solutions (NYSE: MHS) got a nasty cold today and fell 11%.

So what: MedcoHealth lost a big pharmacy benefit contract with Blue Cross Blue Shield Association to CVS Caremark (NYSE: CVS). The $3 billion contract begins next year and won't impact MedcoHealth's earnings during 2011.

Now what: This is obviously a big blow for MedcoHealth, but the news hasn't been the boost you might expect for CVS Caremark. CVS' stock is only up 2% on the big win, so it appears investors are focusing on the negative news for MedcoHealth today. I wouldn't jump into MedcoHealth on this dip, but I will take a second look at CVS because the stock was only trading at a 12.4 forward multiple before this big contract is factored into expectations.

Interested in more info on MedcoHealth Solutions? 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.

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.