Global sovereign bond yields just hit their highest level in nearly two decades. A Bloomberg gauge of global bonds climbed to 3.72% on Monday, the highest since mid-2008, marking a fourth straight session of increases. Ten-year Japanese government notes touched 3% for the first time since 1996. UK 30-year yields hit levels last seen in 1998. The 10-year Treasury is back to January 2025 highs. And Australia’s 10-year yield surged to levels last seen in 2011.

The triggers are stacking up: Fed Chair Kevin Warsh’s hawkish tone, renewed US-Iran hostilities pushing oil higher, entrenched inflation running above target for five years, and a wall of government and corporate debt issuance — including a surge in AI-driven tech borrowing potentially crowding out sovereign demand. Markets are now pricing a ~70% chance of a Fed hike this month, a near-certain ECB hike, and an expected BOJ move as well.

I spent my career working with highly indebted countries, and this setup — sticky inflation colliding with wide fiscal deficits across the US, Japan, the UK, and France — is familiar territory. When multiple major economies get squeezed by the same debt-and-inflation dynamic simultaneously, the potential for something to go sideways is not a zero probability. I’ve watched this movie before.
What concerns me most: equities have barely blinked. The AI-led rally has stocks near record highs even as the term premium investors demand for holding long bonds keeps climbing. That’s the same combination that set up the 1987 crash — a stock market roaring ahead while ignoring a spike in bond yields, until it couldn’t anymore.

September and October are historically the worst months for global bonds. We’ll be watching this closely and posting a lot more on sovereign debt stress and the yield-equity divergence in the coming months. Stay tuned.