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: Pharmaceutical maker Akorn's (Nasdaq: AKRX) shares are up 12% today on high volume.

So what: The company didn't release any news, but the stock spiked about 40 minutes into the trading day today after a big buy order. More than 2 million shares have traded hands, far exceeding the normal 580,000.

Now what: Buying on a trading spike like this can be dangerous for long-term investors. A big buyer came into the market trading a lot of shares early in the day; support may not last long if that buyer leaves the market. This move just seems a little fishy to me. I'm going to sit this rally out and wait for some real news.

Interested in more info on Akorn? Add it to your watchlist.