Rosenberg says U.S. stocks look increasingly like a bubble, with multiple indicators at extremes unseen in his 40-year career

David Rosenberg said the U.S. stock market increasingly resembles a bubble, with valuations, leverage and investor positioning at extremes he hasn't seen in his 40-year career. Rosenberg is the founder of Toronto-based Rosenberg Research & Associates. He believes the current bull market depends far more on the trajectory of artificial intelligence progress than the stock market's reliance on the tech sector did on the eve of the dot-com bubble's formation. He said he has been buying U.S. Treasurys and overseas stocks in his portfolio, and called the U.S. the "epicenter of the tech boom" for which investors are paying too high a price. "In my 40 years in this business, I don't remember ever seeing this much divergence, extremes and imbalances as I see today, not just in the markets, but also in the economy," he said at the Grant's Annual Fall Conference in New York. "If you don't want me to call it a bubble, I won't. But what I'm seeing now is truly something I've never seen before."