Biggest stock losers

Shares of AMR Corporation, parent of American Airlines, plummeted last November after it declared bankruptcy. In 2011, the company lost $2 billion, compared with a loss of $417 million a year earlier amid higher fuel costs and a tepid economic recovery.

American posted losses for four consecutive years following the September 11, 2001 terrorist attacks. It responded by trying to lower its notoriously high labor costs, but union talks broke down. Now AMR Corporation is working to emerge from bankruptcy under relatively new CEO Tom Horton. In November, Horton said the company's near-term future would include job and flight reductions as it tries to cut expenses and leave bankruptcy in 15 months. Meanwhile, US Airways is angling for a merger with the bankrupt airline.

NEXT: 5. American International Group