Boeing shares fell 6.6 percent on Monday, closing with their worst daily performance since February 2016.

The aerospace giant's stock opened positive at $360.55 a share before turning around and selling off throughout the day. Much of Boeing's decline came after a report that the United States is preparing to add tariffs to all remaining Chinese imports if trade talks between Presidents Donald Trump and Xi Jinping fail.

"Boeing is the largest exporter, any new tariffs impact them directly. They export about 80 percent of what they build and they build 90 percent of that in the United States," Jefferies analyst Sheila Kahyaoglu told CNBC. "When Trump does this sort of stuff he needs to be mindful because Boeing is such a large employer."

The Dow Jones Industrial Average fell around 200 points on Monday, with Boeing contributing 160 points against the Dow. An announcement of new taxes against goods from China could occur as early as December and target the rest of the imports from the Asian nation that are not already subject to tariffs. The total would amount to about $257 billion worth, according to the report.

Boeing stock is down 9.5 percent in October despite a strong third-quarter earnings report on Oct. 24. The stock is on pace for its worst monthly performance since falling 16.9 percent in January 2016.

Boeing raised its 2018 earnings forecast in the recent report, as the company heads toward what looks to be a record year for revenue. CEO Dennis Muilenberg said on the company's third-quarter conference call that Boeing maintains "a long-term view" on the trade environment.

"In particular on the U.S. / China relationship, we're very engaged with our Chinese airline customers and leadership in China, along with the U.S. government and both countries are interested a healthy aerospace industry," Muilenberg said.

Additionally, a brand-new Boeing 737 MAX 8 jet operated by Lion Air crashed into the Java Sea off Indonesia on Monday, the first accident of its kind for the variant of the top-selling plane. Indonesian transportation and safety officials are searching for voice and data recorders and other clues to determine the cause of the crash. There were 189 people on board the flight to Pangkal Pinang, according to Indonesia's Transportation Ministry.

– CNBC's Chris Hayes contributed to this report.

WATCH: Brand new Boeing 737 MAX 8 crashes into Java Sea