Shares of Boeing fell as much as 8 percent on Monday following news of a deadly plane crash involving a 737 MAX 8, which affected exchange-traded funds (ETFs) like the iShares US Aerospace & Defense ETF (BATS: ITA).

With a 13.03 percent weighting in Boeing, ITA was down 1.29 percent as of 12:30 p.m. ET.

ITA tracks the Dow Jones U.S. Select Aerospace & Defense Index composed of U.S. equities in the aerospace and defense sector that includes manufacturers, assemblers and distributors of aircraft and aircraft parts. After declining 7.21 percent in 2018, ITA is up 20.98 percent thus far in 2019, according to Morningstar performance figures.

The crash of Ethiopian Airlines Flight 302 took place shortly after takeoff, taking the lives of all 157 people on board. It was the second deadly crash in span of less than six months involving a 737 MAX 8, which is Boeing’s top-selling plane.

Last October, a 737 MAX 8 operated by Indonesian carrier Lion Air fell into the Java Sea just shortly after takeoff, taking all 189 lives on board. Ethiopia, China and Indonesia were among the countries that were quick to ground Boeing 737 MAX 8 planes with regard to safety concerns.

In the meantime, airlines followed suit like Ethiopian Airlines and Cayman Airways. Flight attendants and members of the public took to Twitter to voice their concerns or request to change flights involving Boeing 737 MAX 8 planes.

“Safety is our number one priority and we are taking every measure to fully understand all aspects of this accident, working closely with the investigating team and all regulatory authorities involved,” Boeing said in a statement. “The investigation is in its early stages, but at this point, based on the information available, we do not have any basis to issue new guidance to operators.”

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