S&P 500, Nasdaq end higher on Amazon-OpenAI deal

STORY: Wall Street's main indexes ended mixed on Monday, with the Dow dropping nearly half a percent, the S&P 500 ticking up marginally and the Nasdaq gaining almost half a percent.Among the major drivers to the upside, Amazon gained 4% after it announced it struck a $38 billion deal with OpenAI. The move comes in the wake of strong earnings from Amazon that sent its stock soaring more than 9% on Friday.But macroeconomic concerns clouded market optimism, with the Fed's next move becoming increasingly unclear given the lack of economic data due to the ongoing government shutdown.Sam Miller is CEO and co-founder of Kasheesh."The markets today, I think we're seeing a mixed environment. [FLASH] Amazon posted really strong earnings on Friday and a bunch of other major AI companies like Palantir, AMD, and Supermicro are sharing profits this week, fueling a lot of investor optimism. The trade war with China seems to be easing following leadership talks, but this comes again against the backdrop of a prolonged 35-day U.S. government shutdown."Among other stock moves, shares of healthcare companies UnitedHealth Group and Merck weighed on the Dow, falling more than 2% and 4%, respectively.Shares of Nvidia gained more than 2% after President Trump said the AI chipmaker's most advanced microchips will be reserved for U.S. companies and kept out of China and other countries.And shares of Kimberly-Clark slid more than 14.5% after it was revealed the consumer goods company will buy Tylenol maker Kenvue for more than $40 billion. Shares of Kenvue soared more than 12%.