Everyone I speak to points to a different cause for the downfall … It’s just a giant wall of worry,” Goldberg told Al Jazeera.“There are legitimate concerns about the AI trade, but this level of shift in the markets is driven much more by investor sentiment than any tangible reason.”US tech companies’ huge investments in AI have stoked intense debate about whether a market bubble is forming similar to the one that preceded the 2000 dot-com crash.While some Wall Street analysts view current levels of investment in datacentres and graphics processing units as unsustainable, others argue that AI will revolutionise society to a degree that justifies the eye-watering sums involved.Global AI investment is forecast to reach $2.7 trillion in 2026 and $3.6 trillion in 2027, according to technology insights company Gartner.