President-elect Donald Trump's tweets are causing swings in the stock market, and there's finally an app to prepare.

The stock market app Trigger just added a new feature that will notify users when Trump tweets about a publicly traded stock that they own. The app already provides real-time stock alerts based on economic news, earnings reports and other current events.

"While it’s no surprise that Trump has been actively tweeting since the election, no one anticipated that a single tweet could potentially eradicate billions of dollars in market cap from large companies," the startup wrote in a blog post.

This week, Trump tweeted about General Motors and Toyota, not to mention his earlier proclamations on Boeing and the AT&T-Time Warner merger.

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As Trigger pointed out, professional investors are already responding to Trump's tweets. It's harder for individuals to know what to do when Trump weighs in on their stock. Trigger wants to be the solution.

"His tweets on prices and contracts with public companies have had significant market moving events that make it more difficult for the everyday investor to stay on top of their investments. This increased political 'tweet' risk is familiar to professional investors and hedge funds on Wall Street, which have traders 24/7, smart algorithms and models to account for this tweeting risk. However, individual investors do not have the appropriate tools to react in an automatic fashion," the company wrote.

Set up those alerts before the next 3 a.m. tweetstorm.