CNBC Daily Open: U.S. tech shares pull back amid growing AI bubble worries

Individual equities and separate sectors popped Wednesday, but collectively, their moves weren't forceful enough to lift indexes.

Beleaguered American chipmaker Intel is finding itself in slightly less prickly situations lately. Its shares jumped 6.4% Wednesday on reports that it is seeking an investment from Apple — which would form a ménage à trois with Nvidia and the U.S. government.

Still, the Nasdaq Composite lost 0.34% as major artificial intelligence names such as Nvidia and Oracle retreated. Traders presumably took profit, or fled because of worries that OpenAI's $850 billion buildout is overly ambitious or looking like a bubble.

Across the Atlantic, European defense stocks jumped after U.S. President Donald Trump said Wednesday that "Ukraine, with the support of the European Union, is in a position to fight and WIN all of Ukraine back in its original form."

That's a sharp reversal from his earlier suggestions that Ukraine and Russia "need to discuss the possible exchanges of territory" (which sounds like a euphemism for "Ukraine might have to cede land to Russia").

However, while the Stoxx Europe Aerospace and Defense Index climbed 1.47%, the broader Stoxx Europe 600 fell 0.19%.

On days like these, it looks like being a trader of individual stocks has its advantages over investing in exchange-traded funds.

The Trump administration could hit robotics and medical equipment with tariffs. The probes, which began Sept. 2, will assess if such imports threaten U.S. national security, according to Federal Register filings. If they result in tariffs, the duties will apply on top of country-specific tariffs.

OpenAI will use Nvidia's investment to lease Nvidia chips. The $100 billion promised — which will be in cash — will mostly flow back to Nvidia even though OpenAI is free to choose how to deploy the money. That's raising concerns that Nvidia's investment goes straight back to its revenue in a circular manner.

Xiaomi is scouting for Europe showroom locations. That's part of the Chinese tech giant's plan to start selling its electric vehicles in the region in 2027. Xiaomi might even manufacture its cars there in the future, a company executive told CNBC.

U.S. stocks see back-to-back losses. On Wednesday, major U.S. indexes fell as tech shares continued pulling back, although Intel popped 6.4%. Asia-Pacific markets mostly rose Thursday. Shares of China's largest vehicle exporter, Chery Automobile, shot up during its Hong Kong debut.

[PRO] Europe is losing its lead over the U.S. Earlier this year, when U.S. President Donald Trump announced tariffs, European markets outperformed U.S. equities. But the tide is turning — here's how fund managers are reacting to this development.