Late‑Stage Stock Bubble Poised to Burst in 2027, Analysts Say

If you’ve been riding the AI‑fuelled market rally these past months, you might want to savor the last few gains because, according to a handful of seasoned analysts, the party could be winding down faster than most of us imagined.

James Reilly, senior markets economist at Capital Economics, doubled‑down on a forecast he’s been touting for a while: the S&P 500 should close 2026 around 8,250 – roughly a 7.7% rise from where it sits today – but then plunge to about 6,500 by the end of 2027. That’s a 21% drop, a move that would feel like a wake‑up call for anyone who believed the AI boom was endless.

Why does Reilly sound the alarm? He points to a checklist that looks eerily familiar to anyone who lived through the dot‑com frenzy. First, valuations are sky‑high: the cyclically adjusted price‑to‑earnings ratio (CAPE) is hovering near its 2000 peak, and the S&P’s earnings yield relative to Treasury bonds is equally lofty. Second, forward earnings growth expectations are stretched – the projected 12‑month EPS increase mirrors the optimism of the early 2000s.

Third, the cash story for the AI giants is turning grim. The combined free‑cash‑flow of the leading hyperscalers is slated to dip negative by 2027, a stark reversal from the flood of cash they’ve been pouring into data‑centers and chips. Fourth, the market’s breadth is narrowing; a handful of mega‑caps are shouldering an outsized share of the index, a classic symptom of a rally that can’t sustain itself.

And then there’s the surge in equity issuance. IPO pipelines and follow‑on offerings are brimming, and history tells us that when companies scramble to raise capital en masse, a bubble is often just weeks away from bursting, not years.

Adding fuel to the fire, Treasury yields have crept up to 4.97% on the 10‑year note, nudging the psychological 5% barrier. Rockefeller International’s chairman Ruchir Sharma warned in a recent FT op‑ed that a decisive breach of that level would usher in “a new era of tighter money,” making it harder for AI megaprojects to secure financing. He notes that yields flirting with 5% also start to compete with nominal GDP growth, threatening debt sustainability as U.S. debt now tops 100% of GDP.

Even long‑time market bull Ed Yardeni is showing cracks in his optimism. He trimmed the odds of his “Roaring 2020s” scenario from 80% to 70% and nudged the bearish probability up to 30%, citing unsettling moves in oil and bond markets.

Bottom line: while the AI wave still has some surf left, the warning signs are stacking up. Investors who can’t stand the idea of a 20%‑plus correction might consider tightening their belts now, before the yields rise higher and the bubble finally bursts.