AI bubble could burst in 2027, sending S&P 500 down to 5,000, strategist warns

Panmure Liberum market strategy head Joachim Klement warned that the global stock rally could reverse sharply if the AI investment boom loses momentum. He expects the AI trade could unravel as soon as 2027, potentially causing one of the most severe market downturns since the global financial crisis.

Analysis

This is a long-dated scenario, not a timing signal: a 2027 unwind forecast has little standalone value for near-term positioning. The more useful mechanism is the gap between AI-related capital spending and durable customer returns. If monetization disappoints, cuts to data-center budgets could hit semiconductor and equipment suppliers first, then spill into power, cooling, networking and data-center landlords; any credit-funded projects would add refinancing and utilization risk. Broad indices could still fall even if most constituents have limited direct AI exposure, through multiple compression, index concentration and systematic de-risking.

The contrarian case is that productivity gains and recurring software revenue may arrive later than infrastructure spending, making a capex pause a digestion phase rather than a broken theme. A severe market call therefore requires evidence beyond strategist opinion: slowing hyperscaler capex commitments, weaker supplier orders, deteriorating AI product economics, or broad earnings revisions. Near-term catalysts are earnings and guidance; the structural test is whether deployed capacity earns attractive returns over the next 6–18 months. Without that evidence, an outright short risks paying carry while the trade persists.

Key Decisions for Investors

• Do not short equities solely on this forecast. Treat it as a prompt to monitor hyperscaler capex guidance, semiconductor order trends, data-center utilization and monetization disclosures; those are the evidence needed to validate the unwind thesis.
• For portfolio protection, consider staged, defined-risk QQQ or SMH put spreads rather than naked puts or a large outright short. Scale only if capex guidance or supplier orders weaken; the key risk is time decay if the thesis remains a 2027 event.
• A relative-value expression to monitor is short concentrated growth exposure versus long equal-weight U.S. equities (for example, QQQ versus RSP), but initiate only if leadership breadth deteriorates and earnings revisions broaden beyond AI-linked names. This reduces dependence on predicting the exact unwind date.
• Falsify the bearish thesis if major buyers sustain or raise investment plans while reporting improving returns from AI products, and if supplier orders remain firm. Conversely, multiple downward guidance revisions plus widening equity-market weakness would strengthen the case to add hedges.