The City is beginning to smell fear. For months, the artificial intelligence sector has been the darling of equity markets, a high-octane narrative fuelled by promises of revolutionary productivity gains and an insatiable appetite for GPUs. But the gloss is fading. This week’s sell-off in major AI-linked stocks has turned heads, and the question on every trader’s lips is no longer “how high?” but “how long until the floor gives way?”
Let’s look at the hard numbers. The NYSE FANG+ Index, a basket of the usual suspects, has shed nearly 8% in the past fortnight. That is not a correction; it is a tremor. Volume has spiked, which tells me retail investors are panicking while institutions quietly trim positions. The put/call ratio on the QQQ ETF has climbed to 1.2, a level historically associated with impending volatility. When the crowd starts buying protection, you know the champagne has gone flat.
The fundamental story has not changed overnight. AI is a genuine technological breakthrough, I grant you. But markets, as we know, are not discounting future cash flows; they are discounting narratives. And the narrative has become stretched. Valuations in the AI space are pricing in decades of monopoly-like profits. Nvidia trades at over 50 times forward earnings, despite a cyclical hardware business that could hit capacity constraints. Microsoft’s AI-related capex is ballooning, yet the revenue return is still vague. This is not investment; it is speculation dressed up in a white lab coat.
Where does this leave the broader market? If the AI bubble bursts, it will not be a quiet affair. The technology sector has accounted for nearly a third of S&P 500 gains this year. A deflation here would expose the fragility of current equity levels, especially with gilt yields crawling back toward 4.5%. The Bank of England, still fighting inflation, cannot afford to ride to the rescue. Fiscal discipline is a joke; the Treasury’s borrowing requirement is already astronomical. Capital flight is a real risk. If risk appetite sours, money will head for the exits: into cash, into short-dated gilts, or out of sterling entirely.
Government spending is the elephant in the room. The Chancellor’s Autumn Statement did nothing to reassure the bond vigilantes. Public sector net borrowing is running at 4% of GDP, and there is no credible plan to close the gap. When the AI fever breaks, investors will focus on the hangover: stagnant productivity, sticky inflation, and a central bank that cannot cut rates without triggering a sterling crisis.
Some will argue that AI is different, that the technology is real, and that a shakeout will separate winners from losers. That may be true in the long run, but long runs have a habit of killing leveraged portfolios. The dot-com bubble had real businesses too, but it took Amazon and Google years to dig out from the wreckage. The parallels are uncomfortable. We have the same cocktail of exuberance, leverage, and regulatory blindness.
For now, I advise caution. The market is not pricing in a crash, but it is pricing in a loss of momentum. That is often the first step toward a disorderly unwind. Keep an eye on credit spreads; if they start to widen, the rot has set in. And for heaven’s sake, do not catch a falling knife. The bottom line is this: when the music stops, the most overvalued chairs get pulled away first. AI is not invincible; it is just expensive. And that is a dangerous place to be.
