STORY: US stocks ended mostly lower on Tuesday, with the Dow bucking the trend to notch its third record close in a row, while the S&P 500 shed a third of a percent and the Nasdaq lost about six-tenths of a percent.The S&P 500 was weighed down by shares of Alphabet, which fell after Google's parent said it sold bonds worth $20 billion.The announcement played into investor worries over the hundreds of billions of dollars tech companies are spending this year as they race for AI dominance. Joe Hegener, founder and chief investment officer with Asterozoa Capital Management, shares those concerns."I don't think that the CapEx spend is very sustainable. And so then the question is, what is, the what does GDP print look like sans CapEx spend? And at what point does margin come into play for these AI businesses and these data center build outs? Are the profitability metrics going to be, I have no doubt that at some point the adoption is going to be there. This is a great ubiquitous technology. But I think there are some major implications for the broader economy as it relates to the sheer volume of dollars being thrown at this phenomenon. And how long does that last for?"In the software space, however, shares of Datadog bounded higher Tuesday and led S&P 500 percentage gainers for the day after the cloud-based monitoring and analytics platform beat quarterly estimates.Among other movers, shares of Marriott hit a record high, jumping 8.5% for their biggest daily gain since April after the hotel chain projected a 35% rise in fees from co-branded credit cards, as affluent travelers splurge on luxury vacations.And shares of Spotify soared nearly 15% after the audio-streaming platform forecast first-quarter earnings above expectations, benefiting from strong user growth and price hikes.Meanwhile, data from the Commerce Department showed U.S. retail sales unexpectedly stalled in December as households scaled back spending on vehicles and other big-ticket items.Investors now await the delayed release of January's nonfarm payrolls, due on Wednesday.