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 Penn Virginia (NASDAQOTH:PVAHQ) jumped 12% today after billionaire George Soros increased his stake in the energy producer.

So what: Soros now holds a 9.53% and also sent a letter to the board of directors that reiterated his belief that a sale is the best way to unlock value. Soros has criticized the company's management in the past and believes that recent sales in the energy space indicate there are multiple buyers that would be willing to pay more for the company than the stock is worth.  

Now what: Thus far, management hasn't acquiesced to Soros' demands, but investors clearly think he's getting the upper hand. However, following a big investor into a stock like this is dangerous because they often have greater capabilities to create change and unlock value in their shares than the average investor. I don't think this alone is a reason to buy and wouldn't change the investment thesis today.