Dow notches record high close, traders bet on end to shutdown

STORY: U.S stocks ended mixed on Tuesday, with the Dow gaining more than 1% to close at a record high, the S&P 500 adding two-tenths of a percent and the tech-heavy Nasdaq shedding a quarter of a percent.Optimism over an end to the record-long U.S. government shutdown fueled gains, but jitters about sky-high valuations of AI-related stocks weighed on the Nasdaq, says Sam Stovall, chief investment strategist at CFRA Research."Tech stocks certainly have been quite volatile over the past week, and I think there are two reasons for that: valuations and concerns over monetization. Tech right now represents 36% of the weighting of the S&P 500 and really has been driving this market. From a valuation perspective, however, investors are getting a bit concerned because the S&P is trading more than two standard deviations above the mean in terms of its 20-year relative P/E ratio, and it's at about a 40-plus percent premium to that P/E ratio. Tech stocks, however, have traded as much as a 73% premium to that 20-year average P/E ratio. So what's been happening is I think investors are saying, you know, we've done very, very well, but maybe we should take some profits while we can."Shares of AI chip leader Nvidia lost 3% after Japanese technology investor SoftBank Group disclosed it sold all of its Nvidia shares for $5.8 billion.Shares of Nvidia-backed CoreWeave slumped over 16% after the cloud computing firm trimmed its annual revenue forecast due to data center hiccups.And shares of Nvidia rival AMD gained in extended trading after the company said it expects the market for its data center chips will grow to $1 trillion by 2030.