AMR, parent company of American Airlines, was halted four or five times this morning (Tuesday). The reason (personnel changes, disappointing November traffic) is really not as material as the fact of the trading halts.

American Airlines aircrafts.

AMR is in the Russell 1000, a basket of the 1,000 largest stocks in the U.S. All the stocks in the Russell 1000 are governed by one single stock trading rule: a five-minute trading pause if the transaction price of the security moves ten percent or more from a price in the preceding five-minute period.