Berkshire Hathaway has been selling stocks and accumulating cash, a clear sign that Warren Buffett is worried about elevated valuations.

The S&P 500 ( ^GSPC -0.50% ) crashed when President Trump announced sweeping tariffs in April. But the index has since rebounded 33% from its low and is currently on the verge of delivering a positive return for the fifth consecutive month.

The economy has been more resilient than investors initially feared, and S&P 500 earnings were better than expected in the first and second quarters. Nevertheless, Warren Buffett recently sent investors a $177 billion warning and history says the stock market could struggle over the next few years.

Here's what you should know.

Berkshire Hathaway sold a net total of $177 billion in stock over the last 11 qua

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