US stocks were headed for their worst week since April as worries over lofty valuations deepened a pullback from the market’s most speculative corners, including technology shares and Bitcoin. Futures on the S&P 500 fell 0.4% after erasing gains, underscoring the market’s fragility. Nasdaq 100 contracts slipped 0.7%. Bitcoin headed toward $82,000, extending its slump from an all-time high to more than 30%.

With global stocks on track for their steepest drop in seven months, investors are debating how much further the pullback that’s erased $5 trillion from this year’s tech-fueled rally has to run. Traders remain unsettled by lofty valuations, doubts over whether artificial-intelligence spending will pay off and fading prospects for a US interest rate cut next month.

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