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 American Pacific (UNKNOWN:APFC.DL) jumped 19% today after the chemical company agreed to be bought out by H.I.G Capital.

So what: H.I.G plans to begin a tender offer by Jan. 24 to acquire American Pacific's outstanding shares of common stock for $46.50 per share, close to where the stock is trading today. If the tender is completed successfully the rest of the shares will be acquired through a second-step merger at the same price. The total deal is valued at $392 million.  

Now what: With shares already trading at nearly the tender offer, I don't see much reason not to sell today. Some investors may hold on for a higher offer, but the downside risk is that the deal falls through. I'd be a seller today and move on to the next opportunity after a nice gain.