By Joe Woelfel

Stocks tumbled Monday with the tech-heavy Nasdaq Composite down sharply as Chinese artificial-intelligence startup DeepSeek threatened U.S. dominance in the field.

These stocks were making moves Monday:

Nvidia, the leading maker of AI chips, dropped 12%, and ASML, the Dutch maker of chip-manufacturing machines, fell 8% after news that Chinese AI company DeepSeek developed an open-source large language model that competes with Microsoft-backed OpenAI's ChatGPT and uses less computing power. Semiconductor and software company Broadcom was down 11%.

Vertiv Holdings, the maker of cooling equipment for data centers, plunged 21%, and GE Vernova, the power-generation technology company, was down 19% on concerns DeepSeek means companies won't need vast amounts of electricity to power data centers. Constellation Energy, the largest owner of nuclear power plants in the U.S., was down 18%, and Vistra, another nuclear stock, plunged 22%.

A report from Reuters over the weekend said the Trump administration was working on a plan to save TikTok that involves Oracle and a group of outside investors taking control of the app's global operations. President Donald Trump said he was in talks with multiple people over buying TikTok and likely would have a decision on the app's future within 30 days, according to Reuters. Oracle shares were down 9.1%. Last week, the company, along with OpenAI and SoftBank Group, announced an investment of as much as $500 billion in building artificial-intelligence infrastructure in the U.S. in a joint venture known as Stargate. Microsoft fell 3.6%.

AT&T posted better-than-expected fourth-earnings as the number of customers that signed up for the telecommunication giant's mobile plans topped Wall Street estimates. AT&T touted "solid momentum in gaining profitable 5G and fiber subscribers." The stock rose 6.5%.

SoFi Technologies reported fourth-quarter adjusted earnings and revenue that topped analysts' estimates. Shares of the fintech, however, were falling 11% as earnings guidance for the first quarter and year was below expectations.

Akero Therapeutics surged 112% after the company reported positive preliminary topline results from a Phase 2b study evaluating the efficacy and safety of efruxifermin, its lead product candidate. Akero said the treatment was for use in patients with biopsy-confirmed compensated cirrhosis due to metabolic dysfunction-associated steatohepatitis.

United States Steel fell slightly after The Wall Street Journal, citing people familiar with the matter, reported activist investor Ancora Holdings is preparing to wage a proxy battle at the steel company and wants U.S. Steel to drop its plans to merge with Japan's Nippon Steel. Ancora also seeks the ouster of U.S. Steel CEO David Burritt.

Venture Global was down 7.3% to $22.252. On Friday, the day the stock debuted, shares of the exporter of liquefied natural gas fell 4% to $24, below their initial-public-offering price of $25. The IPO valued Venture Global at $60 billion, the largest initial public offering for a U.S. energy company in history. The IPO was priced in the middle of its $23 to $27 a share range, which was a cut to its earlier range of $40 to $46 a share.

Tesla, the maker of electric vehicles, is scheduled to report fourth-quarter earnings after the closing bell Wednesday. Margins during the period will be closely watched by investors. Analysts expect operating profit margins of about 10.5%, up from about 8% in the same quarter a year earlier. Tesla shares fell 1.5%.

Reports are also expected later in the week from Apple, Microsoft, Meta Platforms, Boeing, Lockheed Martin, Intel, Exxon Mobil, Chevron, Visa, Mastercard, Starbucks, General Motors, Royal Caribbean, Caterpillar, Comcast, United Parcel Service, ASML Holding, T-Mobile, International Business Machines, AbbVie, ServiceNow, Altria, SAP, and RTX.

Write to Joe Woelfel at joseph.woelfel@barrons.com

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January 27, 2025 09:48 ET (14:48 GMT)

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