When I was actively trading I began to notice a pattern. The Market Makers (proper label given to the big shots) would cause a huge perceived value shift in a single stock every 3 months. Martha Stewart was one of them. They don't just control stock values and price, they influence the media. If you are able to discern patterns well and start trading, you will find this to be true. To recognize such patterns, you have to tap into the Wall Street chatter and compare it with the news and large volume trades.

The secret: The planets align when a gap in the news (not too many large stories on CNN) is proceeded by high volume trading on a stock perceived as having good value (stock is sold in high volume over a week period dropping price) and the Wall street chatter completely avoids said stock.

Timing: Once the media gap is over, it will start reporting on a company slowly building up to a large story. The volume will increase on sells and Wall Street chatter will begin avoiding the stock as it builds in the media.

Takes practice, but practice is free. Try out what I'm saying, you might get the hang of it and buy stock on a company right before they freeze trading on it! Also, this sometimes (although rarely) happens when the Market Makers want to pull off a large shorting of the stock; however, this draws attention from SEC media police.