Blackout window opens. Insiders can sell. Huge runup makes nice opportunity for them to take a ton off the table. You gotta buy into tomorrow's weakness. This one follows TK higher when insider selling gets flushed out.
Maybe I can try to explain... Executives buy and sell stock in their company. To prevent insider manipulation of stock, these stocks can only be traded at certain times of the year (the "window"). These windows are just after earnings and typically are 1 month long. After the window closes, there is a blackout... in which executives can no longer trade stock. Often, when a company has a big run up; execs will sell stock during the window. This can at times create a sell off when people regard this as "insider" knowledge that the company is headed into trouble. The sell off can also create a buy opportunity, if the stock falls below its true value. I've seen it go both ways though... insiders sell, stock goes down.... insiders sell, stock goes up. Life in the Market!!