On September 1, 2026, German 10-year yields reached their highest since 2011 and Japanese 10-year yields their highest since the late 1990s, driven by heavy issuance for deficits and AI data centers. The 10-year Treasury yield later hit 5.3% and the 30-year 5.66%, both the highest since 2002, before a strong 10-year auction and a 19-basis-point one-day drop took the 10-year back below 5% on October 22. The contested question is whether this is a fiscal spiral or a supply shock from hyperscaler borrowing: credit default swaps are tightening and analysts find the fiscal risk premium small, while others point to a $2 trillion deficit and more than $1 trillion in annual interest costs.