On Dec. 12, President-elect Donald Trump attacked the F-35 Joint Strike Fighter on Twitter, saying the cost of the next-generation stealth plane is “out of control.”

A presidential tweet can have some serious corporate repercussions: In subsequent trading, shares in Lockheed Martin, the company that produces the aircraft, dipped more than 4%, and its market value plunged by $4 billion, according to CNBC. To put that in perspective, it’s 1/100th the estimated cost of the weapons program itself, which some believe could reach $400 billion.

Lockheed isn’t the only one. Last week, Trump called out Boeing as well.

Boeing secured a contract in January 2016 to start work on the 747 jets meant to replace the 25-year-old Air Force One planes, which will be phased in early next decade. And although its stock price dipped by 1% after the tweet, it has since recovered.

But companies across the country are feeling the sting of Trump’s Twitter attacks. Northrop Grumman is only a component producer on the F-35, and its stocks hit a one-month low as a result of the tweet. While these companies have more than enough financial capital to withstand such attacks, other smaller contractors may not be so resilient.

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Hopefully these companies fare better than the F-35 in a thunderstorm. Around the same time the president-elect was firing off his tweet, a pair of the stealth aircraft that were scheduled for delivery to Israel — the first installment of 50 planes that have been promised — were grounded for several hours in Italy due to bad weather.