Check out the companies making the biggest moves premarket: AstraZeneca , Bristol Myers Squibb — Shares of the pharmaceutical companies moved in opposite directions after The Financial Times reported that the two were in talks to merger. AstraZeneca fell more than 4%, while Bristol Myers jumped more than 5%. ArcelorMittal — The steelmaker was up more than 2% after it announced it was deepening its technology partnership with Microsoft. ArcelorMittal said Microsoft's Azure will serve as the backbone for plants to modernize its technology systems, and that it will implement other infrastructure services by Microsoft into its systems. Shares of Microsoft were also up 2%. Alibaba — U.S.-listed shares of the Chinese gained 4% after the company unveiled a new AI model on Monday. Qwen3.8-Max is one of the most powerful models in the company's portfolio yet , and it is set to be released officially next week. Ferguson Enterprises — Shares were up nearly 8% after S & P Dow Jones Indices announced on Friday the stock will join the S & P 500 . Ferguson will replace Electronic Arts before the opening bell on Wednesday. eBay — The e-commerce platform tumbled more than 3% after Wells Fargo downgraded the stock to underweight from equal weight. The bank said eBay's acquisition of Depop, which was completed last week, will lead to weaker earnings in fiscal year 2027 and potentially increased spending on marketing to against the newly acquired company's competitors. Memory stocks — Shares of memory storage companies were broadly lower to start the week, following choppy trading last week . SanDisk and Micron Technology were both down more than 3%, while Seagate Technology was off 2.5%. Circle Internet Group — The stablecoin issuer declined 5% after Morgan Stanley downgraded the stock to underweight from equal weight. The bank said the company faces tactical and structural headwinds, including a weaker outlook for USDC, the stable coin tied to the U.S. Dollar, in circulation in 2027.