But the day after American Airlines Flight 5342 collided with a U.S. Army helicopter in Washington, D.C., killing all 67 people onboard, shares of the company were trading just 2.5% lower. The decline grew four days later,

While landing at Ronald Reagan Washington National Airport in Washington, D.C., on Wednesday shortly before 9 p.m., American Airlines Flight 5342 collided with an Army Black Hawk helicopter and crashed into the icy Potomac River.

Wednesday night’s crash of an American Airlines commuter plane in Washington could be one of the worst disasters for the Fort Worth-based airline in more than two decades.