(Bloomberg) — All across Wall Street, day by day, the headlong rush into the most popular trades, from tech stocks to gold to cryptocurrencies, has given way to a sudden retreat from risk.

There’s been no single cause, like there was last April when President Donald Trump’s trade war sent markets into a fearful tailspin. Instead, it’s been a slow drumbeat of news that is sowing anxiety about valuations that many suspected had already run up too far — and causing investors to pull back all at once.

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That was clear again on Thursday, when the S&P 500 slid 1.2%, its third straight daily decline, and the Nasdaq 100 extended its deepest slide since April. Software stocks extended their tumble after artificial-intelligence startup Anthropic rolled out a new model that’s designed to carry out financial research, the second time this week the company has jolted markets, underscoring the competitive threat from the new technology.

Silver — which had tracked gold to record highs — cratered 20%. Bitcoin dropped more than 13%, erasing all of the gains seen since Trump’s election 15 months ago, as investors unwound money-losing trades financed with borrowed money. US Treasuries rallied, resuming their usual role as a haven of last resort. And after the closing bell, Amazon.com Inc. plunged more than 11% when it said it plans to invest $200 billion this year, far more than the amount forecast by analysts who’ve grown increasingly concerned that tech companies are overspending on AI.

“People are definitely going more defensive,” said Brian Frank, president and portfolio manager at Frank Funds. “It’s more of like a shoot first and ask questions later type environment.”

Those jitters spilled into Asian markets on Friday, with South Korean stocks sinking over 5% at one point and chipmakers Samsung Electronics Co. and SK Hynix Inc. among the biggest drags. The markets showed some signs of steadying ahead of the US trading day, with Bitcoin stabilizing and stock futures edging up.

The recent activity marks a strong shift from the mood on Wall Street heading into the year, when strategists were predicting that stocks were poised for the longest winning streak in nearly two decades. The forecasts rested on expectations that the AI boom would continue, the surprisingly resilient economy would keep bolstering corporate profits and that the Federal Reserve would dial down interest rates.