AI Rally vs. Surging Yields: Global Stocks Walk a Tightrope

As the final week of September unfolds, global equity markets are caught between resurgent enthusiasm for artificial intelligence and a fresh spike in government bond yields. A weekly review from a UK investment firm notes that the S&P 500 gained about 1.2% and the Nasdaq roughly 2% last week, powered by renewed buying in mega‑cap tech names tied to generative AI, including Microsoft and Meta.

At the same time, the US 10‑year Treasury yield briefly touched 5.23%, its highest level since 2007, and bond‑market volatility jumped. That combination—rising long‑term discount rates alongside richly valued growth stocks—poses a dilemma for investors worldwide. Do they continue to lean into high‑growth technology and AI beneficiaries, or rotate toward cheaper, cash‑rich value and defensive sectors better suited to a “higher for longer” rate regime?

Upcoming US data on consumer spending and business investment will be key tests of how well households and companies can cope with borrowing costs above 5%. For investors in Japan and Europe, US yield moves feed directly into equity valuations and currency trends at home. For now, equity indices are holding up thanks to AI‑linked optimism, but the message from the bond market is getting harder to ignore, turning global stocks into a balancing act between growth stories and the gravity of higher rates.