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 secon ...

NEW YORK (AP) — Wall Street stumbled to a third straight loss on Thursday as U.S. stocks gave back more of their big gains for the year so far. The S&P 500 fell 0.5% and marked its longest losing streak in more than a month. The Dow Jones Industrial Average dropped 173 points, or 0.4%, and the Nasdaq composite sank 0.5%. All three indexes are still near their records set at the start of the week, though. Stocks felt pressure from reports showing the U.S. economy may be stronger than economists thought. W ...

In many ways, it's the same kind of thinking at work now. There's a small handful of technology companies producing -- or at least promising -- incredible growth. Only now, rather than the advent of the internet, it's the advent of artificial intelligence that's driving the bullishness. (In the interest of fairness, unlike far too many dot-com companies then, most of today's AI-related outfits at least have a shot at eventually becoming profitable.)What gives? Why are investors willing to pay premium prices ...