Warren Buffett Is Sending a Clear Warning As 2026 Approaches: 3 Things Investors Should Do

Legendary investor Warren Buffett knows a thing or two about the stock market. Over the years, he's become a master at adjusting the Berkshire Hathaway (NYSE: BRK.B) (NYSE: BRK.A) stock portfolio based on where he thinks the economy is headed.

His recent portfolio adjustments should be a huge red flag for investors. In fact, Buffett is doing something he's never done before, and if you're hoping to maximize your portfolio returns in 2026, you'll want to pay attention.

Here's the unprecedented warning Buffett has offered, and three things you can do to protect yourself and your portfolio.

Image source: The Motley Fool.

A never-before-seen cash hoard

Berkshire Hathaway's investing portfolio is famous for its stock holdings, but Buffett has always kept some of his portfolio in cash.

The amount of cash Buffett keeps on hand usually rises and falls with the broader market's valuation, as measured by the S&P 500 Shiller CAPE ratio. For example, during the COVID-19 pandemic lockdowns, the Shiller CAPE ratio rose above 35 for the first time since 2001. Buffett reacted by holding Berkshire's cash position fairly steady at a then-record high of almost $150 billion. In 2022, when the Shiller CAPE ratio slipped back below 30, Buffett promptly spent down Berkshire's cash position to just $105.4 billion.

Today, Berkshire's cash position is much, much higher than even $150 billion. In fact, Berkshire currently has $381.7 billion in cash and equivalents sitting on the sidelines, more than twice as much as the previous peak. Meanwhile, the Shiller CAPE ratio now sits at 39.42. The only time it's been higher was during the dot-com bubble of 1999-2000.

For Buffett, hoarding cash is a sign that he thinks the market is overvalued. He may even be anticipating a major stock market drop in 2026.

The good news is that Buffett's actions can serve not only as a warning but as a guide for less-experienced investors in three key ways.

1. Don't sell everything

Even if you're convinced the market is about to drop, panic-selling your entire stock portfolio is probably a bad idea. For one thing, timing the market is extremely tricky. If you sell today, you may miss out on tomorrow's gains. And even if you sell at the right time, you risk waiting too long to buy back in and missing out on the early stages of a market rebound.

Buffett has been a net stock seller -- that is, selling more stocks than he buys in terms of dollar amount -- for the last 12 consecutive quarters. But he hasn't sold anywhere close to everything: Berkshire still has $267.2 billion of stock holdings!

Meanwhile, many of the stocks Berkshire has sold have been partial positions. For example, although Buffett reduced Berkshire's position in Apple by 41.8 million shares last quarter, he still retains $60.7 billion worth of Apple stock. Buffett's measured buying and selling are both a representation of his longtime faith in the power of the U.S. stock market and an example to investors of how not to overreact to concerning economic indicators.

2. Don't assume everything's overvalued

One of Buffett's famous quotes is that "It's far better to buy a wonderful company at a fair price than a fair company at a wonderful price." Although he wrote those words in 1989, they still ring true today.

But it's especially telling that Buffett didn't say "a wonderful stock" or "a wonderful investment," but "a wonderful company." Just because the overall market looks overvalued right now doesn't mean there aren't still great businesses that are fairly priced. You may just have to look a little harder for them.

Even Buffett is still buying stocks in quality businesses. In the most recent quarter, in fact, Berkshire bought more than $5 billion in various stocks, including shares of Google parent Alphabet, insurer Chubb, and Domino's Pizza.

3. Do keep some cash on hand

It's always a good idea to have some cash available. And when you think the market is overvalued, it's a good idea to have even more of it available. A readily available cash position is wise to have in case of an emergency, and handy to have if an opportunity comes up in the market and you want to act quickly.

Buffett currently has a record amount of cash on hand, which may not be right for everyone. However, if there is a big market correction in 2026 and stocks on your watch list suddenly become much cheaper, you (and Buffett's Berkshire Hathaway) will probably find plenty of ways to put that cash to use.

John Bromels has positions in Alphabet, Apple, and Berkshire Hathaway. The Motley Fool has positions in and recommends Alphabet, Apple, Berkshire Hathaway, and Domino's Pizza. The Motley Fool has a disclosure policy.