The stock market is crashing: Here’s what financial experts say you should do with your 401(k) now

Markets are in free fall in response to President Donald Trump's far-reaching tariffs, with all major U.S. indices in the red and expected to close in bear territory . After a long bull run, that can be scary for young investors who aren't accustomed to such turmoil. But experts say the best course of action for those with decades ahead of them until retirement is to take a breath, change the channel from markets news, and leave their 401(k) alone.

The advice may seem simplistic in the face of such an unprecedented economic hit and upending of decades of globalization. And indeed, even those who have followed the markets closely for decades are a little shaken, with some of the wealthiest investors moving away from U.S. equities for safer shores abroad . Even seasoned investors have never seen anything like Trump's actions.

Still, the worst thing to do when the market roils is to act rashly, writes Christine Benz, director of personal finance and retirement planning for Morningstar, a financial markets research firm. With no one knowing what will happen next, decisions should be made very carefully.

401(k) investors, in particular, should absolutely avoid selling off investments at all costs. Though the market is scary, taking an early withdrawal from your 401(k) or IRA means penalties and potentially a tax hit as well. And losing the dollars in there now could have long-term repercussions on wealth accumulation.

"Resist the urge to shift out of stocks entirely," Benz writes . "Such a move could buy you some short-term relief, but it will soon be replaced by another nagging worry: Is it time to get back in?"

Think about it this way. Most gains are made in just a few days every year—if you exit stocks and try to time your way back in (which 100% of advisors will say to avoid doing), you are very likely to miss the rebound. That will hurt how much wealth you will be able to build in the longterm. In fact, 78% of the stock market's best days occur during a bear market or the first two months of a bull market, according to Hartford Funds , an investment management company. 20-, 30-, and even 40-somethings have plenty of time to ride out dips in the market.

"If you missed the market's 10 best days over the past 30 years, your returns would have been cut in half," Hartford Funds writes. "And missing the best 30 days would have reduced your returns by an astonishing 83%."

Take it from Vanguard , the king of the buy-and-hold strategy, which sent an email to clients yesterday encouraging them to "stay the course."

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