US stocks lose their footing at the open as tariff and AI worries take hold again. Marvell Technology sees a slowdown in data center business.

Shares of Marvell Technology (MRVL 2.05%), which makes semiconductors for the data infrastructure market, dropped 14.9% in Wednesday's after-hours trading session following the co

Key Takeaways U.S. equities dipped at midday as confusion over the new tariffs by President Donald Trump led to market uncertainty.Artificial intelligence chip shares tumbled following Marvell Technology's results.

Semiconductor stock Marvell Technology Inc (NASDAQ:MRVL) is up 2.7% to trade at $88.13 at last glance, brushing off today's headwinds, though it was earlier on track for its seventh loss in nine days.

Marvell stock is getting crushed after posting its Q4 results yesterday. Sales, earnings, and guidance actually beat the average Wall Street targets. But investors apparently wanted bigger performance beats in order to support the stock's valuation amid wider risk factors.

Uncertainty about the impact of new U.S. tariffs weighed on stocks, along with worries about tightening chip export curbs, and competition from China as Alibaba unveiled its latest AI reasoning model, which it said rivals offerings from DeepSeek and ChatGPT maker OpenAI. Alibaba shares climbed about 1%.

Nvidia sells the lion’s share of the parallel compute underpinning AI training, and it has a very large – and probably dominant – share of AI inference.

Marvell Technology's shares closed down 19.8%, marking their worst day in more than two decades and weighing on rival chipmakers' stocks on Thursday, after an in-line revenue forecast gave investors another reason to be jittery about spending on AI infrastructure as a years-long rally shows signs of cooling.

The AI chipmaker offered an upbeat second-quarter outlook that was a silver lining in the otherwise downtrodden AI trade.