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: Fortune Brands (NYSE: FO) jumped 10% in early market trading on news Bill Ackman's hedge fund Pershing Square has taken an 11% stake in the company.

So what: When a famous investor like Bill Ackman takes a stake in a company, other investors listen. Ackman made a big move into both Fortune Brands and retailer J.C. Penney (NYSE: JCP) so he could be betting on a consumer recovery with these moves.

Now what: Following a famous investor isn't a bad idea, but today's move is a typical reaction to this type of news. When the dust settles, if you still think Fortune Brands is a good buy Ackman is a good investor to follow. I think the market will settle down in the days to come, so there's no reason to rush into Fortune Brands today. But if you've been looking at Fortune Brands, Ackman may reinforce your investment thesis.