Are elevated long-term yields driven by fiscal strain rather than AI borrowing?
Core argument: Robin Brooks argues that long-term Treasury yields failed to fall during the late-2026 AI equity sell-off, contradicting the view that AI capital expenditure and hyperscaler debt issuance have been the primary force pushing yields higher.
The black line shows daily data from the start of 2026 for the two-year Treasury yield.The blue line is the 10-year yield and the purple line is the 10y10y forward yield. If the AI bubble were a material driver of the rise in long-term yields, the purple line should have fallen this week alongside the blue and black ones. It didn’t and that in my mind further cements the case for the fiscal risk premium. The midterm elections and the AI sell-off that’s ensued have given us the perfect natural experiment to disentangle what’s going on with long-term yields. They’re up because of mounting fiscal stress, not because of AI. Once the war ends - and it will - we’ll be left with all the structural challenges the US and others in the G10 face. The fact that we’re rapidly running out of fiscal space is top of that list.

