The fervour around artificial intelligence has reached a fever pitch. For months, investors have piled into AI-related equities, driving valuations to dizzying heights. But the first tremors of a correction are now being felt across London’s Square Mile. Is the AI stock bubble about to burst?
Over the past week, a sell-off in major US tech stocks has spilled into European markets. The FTSE 100, heavily weighted with miners and banks, has been relatively insulated. Yet the AIM index, home to several speculative AI plays, has suffered a 12% drawdown. The trigger? A sobering regulatory bulletin from the Financial Conduct Authority (FCA) warning of “irrational exuberance” in AI-linked securities.
“We are seeing a classic bubble pattern,” says Dr. Elena Marchetti, a behavioural finance expert at the London School of Economics. “Retail investors are piling in based on narrative, not earnings. When the hype cycle turns, the correction will be violent.”
Indeed, the numbers are stark. The Bloomberg Artificial Intelligence Index has tripled in value since 2023, while the average price-to-earnings ratio of constituents stands at 45x, far above the historical norm of 20x. Companies with little more than a press release about AI integration have seen their shares double.
Take the case of CogniCore Systems, a UK-based startup with £2 million in revenue and a market cap of £1.2 billion. “This is absurd,” says Julian Vane, Technology & Innovation Lead at Vane Advisory. “We are in a collective hallucination where a company that runs a few GPUs in a data centre is valued like a pharmaceutical giant. The maths does not add up.”
Despite the exuberance, there are clear signals of underlying weakness. A recent report from Goldman Sachs found that only 12% of firms using AI have seen a measurable productivity gain. “The technology is transformative,” says Vane, “but we are years away from broad commercialisation. The market has skipped ahead to the last chapter of the story.”
British investors should also be wary of currency risks. The strong pound, buoyed by higher interest rates, is eroding returns for those holding dollar-denominated AI stocks. “A 20% gain in Tesla is wiped out if sterling strengthens by the same amount,” notes Vane. “Hedging is essential, but most retail investors do not account for this.”
The FCA’s intervention has been met with mixed reactions. Some applaud the regulator for trying to prevent a crash. Others argue that government should not play kingmaker in technological innovation. “This is not about stifling progress,” says a senior FCA official. “It is about protecting the savers who are putting their life savings into firms that may not exist in three years.”
What does this mean for the average British investor? Diversification is key. “If you have 30% of your portfolio in AI stocks, it is time to rebalance,” advises Sarah Jenkins, a chartered financial planner at Kingswood Wealth. “Look at sectors that benefit from AI adoption, not just the hype. Industrial robotics, cybersecurity, and digital infrastructure are more grounded.”
There is also a geopolitical dimension. The US-China tech war has created winners and losers. British firms that supply hardware to Chinese AI companies face potential export controls. “The market is pricing in a rosy scenario,” says Vane. “But trade tensions are escalating. The next black swan could come from Beijing or Washington, not from a data centre in Swindon.”
For contrarian investors, a correction might be an opportunity. “Buy fear, sell greed,” says Jenkins. “If the bubble bursts, there will be genuine bargains. Companies like Darktrace and Ocado have real AI capabilities. Their valuations will recover once the noise dies down.”
But timing the market is a fool’s errand. “You cannot catch a falling knife,” warns Vane. “The wise approach is to drip-feed investments over time. That way, you average out the peaks and troughs.”
As the news cycle churns, one thing is clear: the AI revolution is real, but the stock market is a storytelling machine. Right now, the story has become an epic fiction. When the editor calls for a rewrite, the headline will be brutal. British investors, brace yourselves.
