AI giant Anthropic said on Monday it has confidentially filed for a US initial public offering, teeing up a watershed moment for Wall Street's AI frenzy.Tech stocks continue to lead the Nasdaq Composite and S&P 500 in a record-breaking market rally, while... AI giant Anthropic said on Monday it has confidentially filed for a US initial public offering, teeing up a watershed moment for Wall Street's AI frenzy.Tech stocks continue to lead the Nasdaq Composite and S&P 500 in a record-breaking market rally, while Elon Musk's SpaceX is set to price its IPO this month and Anthropic rival OpenAI, led by Sam Altman, is waiting on deck.U.S. stocks were mixed on Monday afternoon, with the Nasdaq up 0.3%, the S&P 500 up 0.1% and the Dow industrials off 0.3%. Salesforce rose 10% on Monday, following a report that its stake in Anthropic is valued at $5 billion.Comments:Matt Kennedy, senior strategist at Renaissance Capital, New York"It's true that many private tech unicorns have sat on the sidelines waiting for an IPO market that would grant them their desired valuations. That is not the case with Anthropic and other "elite" AI developers.""Virtually any private round Anthropic raised would have met equal or greater enthusiasm in public markets. There is insatiable demand for these companies among public investors. It's really more the holdovers from the 2021 cycle that are having a harder time hitting their private valuations."Harrison Rolfes, senior late-stage company research analyst at Pitchbook, California"Anthropic filing a confidential S-1 today starts the clock on what will be the most scrutinized public offering in tech history, and the number that determines everything is not the $965B valuation or the $47B revenue run rate. It is gross margin, which no one outside Anthropic has ever seen, and which will either validate or collapse the entire narrative the private markets have been pricing for three years."Nate Elliott, AI analyst at Emarketer, New York"We're about to find out whether the market thinks AI is a consumer story or an enterprise story. Because while Claude has built a solid enterprise user base, it's just not competitive as a consumer AI platform. Emarketer forecasts that only 5.4% of US internet users will use Claude in 2026, far behind the 36.6% who will use ChatGPT and the 27.4% who will use Gemini. The good news for Anthropic: more than 60% of US AI users say they use these tools for work, and we believe that percentage will only grow."Brian Mulberry, chief market strategist at Zacks Investment Management, Colorado"So the question we want to see answered more clearly is when would Anthropic be reliably cash flow positive leading to real EPS growth? There is no doubt that the demand for Claude product at the Enterprise level is huge as agentic capabilities grow, and also there are key strategic partnerships that help provide capital and infrastructure as a way of feeding the growth are all positives for the IPO but for establishing a valuation lacking some of the important details becomes