Jeremy Grantham's GMO has periodically warned of an AI bubble for years now, even while most market onlookers remained bullish. Now, as fears of overexuberance begin to grip the broader market, the famed asset management firm is reiterating its bearish call. "AI looks like a classic investment bubble to us, with very high valuations and signs of rampant speculation," Ben Inker, the co-head of asset allocation at GMO, said in the firm's quarterly letter on November 21."Investors are so desperate to get in e ...