It’s the start of a holiday-shortened trading week, and shares in Intel (INTC) and Advanced Micro Devices (AMD) are falling as China reportedly moves to block the use of their chips; the European Union has opened a probe into Apple (AAPL), Google parent Alphabet (GOOGL), and Facebook parent Meta Platforms (META) under a sweeping new tech law; data on sales of new homes in February are due after existing home sales for the month surprised on the upside; United Airlines (UAL) shares are slipping as regulators could stop it from adding new routes; and Masimo (MASI) stock is surging on the medical-devices firm’s spinoff plan. U.S. stock futures are down. Here’s what investors need to know today. 

1. Intel, AMD Shares Fall as China Reportedly Looks to Block Use of Their Chips

Shares of Intel Corp. (INTC) and Advanced Micro Devices Inc. (AMD) were both more than 3% lower in premarket trading following a report by the Financial Times that China plans to block the use of chips from both companies in government computers. The new guidelines, part of a Chinese campaign to replace foreign technology with homegrown solutions, will mean U.S. microprocessors from Intel and AMD are phased out of government PCs and servers. The moves will affect both firms; China was Intel’s largest market last year, providing 27% of its $54 billion in sales, while the country accounted for 15% of AMD’s $23 billion in sales, according to the report. The guidelines also seek to sideline Microsoft Corp.'s (MSFT) Windows operating system in favor of domestic options. Microsoft shares fell 0.7% in premarket trading.

2. EU Launches Probe into Apple, Alphabet, Meta Under Sweeping New Law

The European Union on Monday opened an investigation into Apple Inc. (AAPL), Google parent Alphabet Inc. (GOOGL), and Facebook parent Meta Platforms Inc. (META), in its first probe under the sweeping new Digital Markets Act tech legislation. “Today, the Commission has opened non-compliance investigations under the Digital Markets Act (DMA) into Alphabet’s rules on steering in Google Play and self-preferencing on Google Search, Apple’s rules on steering in the App Store and the choice screen for Safari and Meta’s ‘pay or consent model,’” the Commission said in a statement. Apple and Alphabet are being investigated for blocking businesses from telling their users about cheaper options outside of their respective app stores. Apple, which is also reportedly set to launch its Vision Pro headset in China this year, was fined around $2 billion (1.8 billion euros) by the EU recently for "abusive App store rules." Shares of Alphabet, Apple and Meta were all down less than 1% in premarket trading.

3. February New Home Sales Data Expected to Show 2.1% Rise on Month

Data on sales of new homes in the U.S. for February are due today, with analysts expecting a seasonally adjusted annual rate of 675,000, according to a survey of economists by Dow Jones Newswires and The Wall Street Journal, up 2.1% from 661,000 in January. The numbers are due after data last week showed that February’s sales of existing homes saw a surprising 9.5% jump, the fastest pace of sales since March 2023, as more people put up their homes for sale. Still, those sales were 3.3% down on the year as high mortgage rates continue to weigh on homebuying and selling.

4. United Slips as FAA Reportedly Weighs Curbs on New Routes  

United Airlines Holdings Inc. (UAL) shares were down about 4% in premarket trading following a report that U.S. aviation authorities are considering drastic measures to curb its growth, including preventing the carrier from adding new routes, following a series of safety incidents. The Federal Aviation Administration has discussed temporary actions it may take with the airline’s leadership in recent days, according to Bloomberg. In addition to route restrictions, United may be barred from flying paying customers on newly delivered aircraft. Among United’s headline-grabbing incidents this month: A plane in Houston ran off the taxiway and another lost a tire departing from San Francisco.

5. Medical Devices Firm Masimo Jumps on Plan to Spin Off Consumer Unit 

Shares in Masimo Corp. (MASI) were up more than 13% in premarket trading after the company announced late Friday that it is planning a spinoff of its consumer unit to improve the profitability of its primary healthcare business. The Irvine, Calif.-based medical devices company said it expects the separation to include its consumer audio and consumer health products, including the Stork baby monitor and the Freedom smartwatch, but said it will retain its professional healthcare and telehealth products.