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: Corrections Corporation of America (NYSE: CXW) dropped nearly 12% in intraday trading today, after announcing an expansion of and extension to its share buyback program.

So what: CCA will increase the aggregate amount of share repurchases from $250 million to $350 million. The final date of the program, which began in February 2010, was extended to Dec. 31, 2012.

Now what: Today's change provides the company with an average of about $7 million per month to spend on share repurchases, only about half the $14 million per month the program has averaged since it began. The slower pace could act as a drag on earnings growth, because the share count probably won't continue to decline at its previous pace. The company explained that its board decided to limit the size of the buyback budget "after considering the limitations on restricted payments … under the Company's revolving credit facility and outstanding indentures."