Published September 11 2026. Building data centres and running the US government have something in common: they cost a lot of money. Tech companies are borrowing heavily to fund the AI build out, just as Washington is borrowing vast sums to fund the US government, and those two borrowing binges may be on a collision course.

Investors are already worried about America’s mounting debt burden and about whether the AI boom has become a bubble. Ruchir Sharma, chair of Rockefeller International and contributing editor to the FT, explains how the two worries might be more closely connected than they first appear, how rising US Treasury yields could raise borrowing costs for AI companies and which number investors should be watching.