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 dairy company Dean Foods (NYSE: DF) jumped 11% today after the company was upgraded by an analyst.

So what: Never fear Dean Foods, Goldman Sachs (NYSE: GS) is here. Today the investment bank upgraded shares to a buy from hold and said shares could double from here. Investors could hardly contain themselves. With 2.5 hours left in trading, 10.4 million shares have already switched hands.

Now what: We Fools take anything an analyst says with a grain of salt -- to say the least -- but the points Goldman Sachs brings up are exactly why investors own Dean Foods. The milk business was in such rough shape recently that there’s nowhere to go but up. I’m not sure if EPS will grow 72% in 2012 and 24% in 2013, as Goldman thinks, but if shares pull back after the upgrade bump I may be interested in buying into this comeback story.

Interested in more info on Dean Foods? 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.