Malaysia Airlines shares lost 10 percent on Monday, the first trading day since the company was rocked by the weekend disappearance of a passenger jet with 239 people aboard.
The shares were trading at 0.225 ringgit, or 10 percent lower, mid-morning on the Malaysian stock exchange.
They opened down 16 percent at 0.21 ringgit from Friday's close of 0.25 ringgit and traded as low as 0.205 ringgit before recovering somewhat.
Flight MH370 went missing over waters between Malaysia and Vietnam en route from Kuala Lumpur to Beijing early Saturday. No confirmed evidence of the plane's fate has yet been found.
Malaysia Airlines recorded its fourth straight quarterly loss in the last three months of 2013, chalking up 1.17 billion ($360 million) ringgit in losses.
The national flag carrier has been struggling with losses for years amid stiff competition from budget carrier AirAsia and others.
Analysts have also blamed poor management, change-resistant unions and government interference for the carrier's poor performance.