The questions raised by the latest crash go to the heart of Boeing’s business. The single-aisle 737 Max, the American plane maker’s challenger to Airbus’s A320 jet, was Boeing’s best-selling plane ever. It first started flying in 2017 and by this January, the company had delivered more than 350 of the planes, which sell for $120 million apiece.

About 5,000 more are on order.

It was unclear how the groundings of the 737 Max might affect Boeing’s bottom line. The cost to the company would be significant if regulators in the United States decided to follow suit and take the fleet out of service temporarily.

Such occurrences are rare.

If the 737 Max is taken out of service, Boeing might have to compensate airlines for delayed deliveries. The company might also have to invest in redesigning or updating the aircraft. And Boeing could face lawsuits filed by the families of those killed in the Ethiopian Airline crash.

Carter Copeland, an analyst at Melius Research, estimated that Boeing could face nearly $1 billion in costs if regulators grounded its 737 Max fleet for three months. He said his analysis was based partly on the expenses incurred by Boeing when the F. A.A. ordered the company’s 787s to stop flying temporarily in 2013 because of a problem with the plane’s battery system.

The drop in Boeing’s stock on Monday wiped almost $13 billion off the company’s market value.



“That speaks to the fear,” Mr. Copeland said. “Right now there is a very difficult to quantify risk that people need a substantial discount to stomach.”

The decision by China’s Civil Aviation Administration to ground the planes hurts Boeing in a region where the company has been able to sell a large number of them. Chinese airlines have ordered at least 104 737 Max planes, and have taken delivery of at least 70.