Boeing shareholders have filed a class action lawsuit against the aircraft maker, accusing it of withholding information on safety deficiencies in its 737 MAX planes which led to two deadly crashes within six months.
Boeing, fighting its biggest crisis in years, has been developing an upgrade to software that is under scrutiny in the Ethiopian Airlines accident and a Lion Air 737 MAX crash that killed all 189 on board on October 29.
The suit, which seeks damages for alleged securities fraud violations, said Boeing's market value plunged by almost US$20 billion after an Ethiopian Airlines jet crashed shortly after take off on March 10, killing all 157 on board.
Boeing hid from investors and passengers that it "prepared its own reports and statements to the FAA certifying its planes as safe to fly and that these statements and reports were undermined by Boeing's conflicts of interest in having been delegated authority by the Federal Aviation Administration ("FAA") to examine, test, and help certify its own planes and to provide the safety analysis for the 737 MAX", the suit alleges.
Initial findings from the Ethiopian Airlines crash show faulty readings on the plane's angle-of-attack (AOA) sensor caused the system to automatically push the plane's nose downward. Investigators have preliminarily traced both crashes to a new flight-control system called the Maneuvering Characteristics Augmentation System (MCAS).
Earlier this week, the family of a USA man who died as a result of the crash in Ethiopia filed a lawsuit against the corporation, accusing it of "corporate greed" and "serious misconduct".
The lawsuit is one in a growing list of challenges for the Chicago-based company.
Airlines have stopped ordering Boeing 737 Max planes, according to company's first quarter sales data, a troubling sign for the future of what was previously its fastest selling airplane.
Seeks said that in early March he bought 300 Boeing shares and sold them weeks later, losing more than US$14,000 (NZ$20,697) in the process.
The federal suit also named Boeing CEO Dennis Muilenburg and the chief financial officer, Gregory Smith, as defendants.
Boeing did not immediately respond to a request for comment.
According to Boeing, aircraft orders from January through March saw a massive decline to 95 jets in contrast to the 180 ordered a year earlier, with no orders for the 737 MAX following the grounding across the globe.