A tenth of a percentage point of extra productivity growth — well within the range of plausible near-term AI effects — raises the fundamental value of U.S. government debt by $1.3 trillion. If markets fully priced this in, nominal Treasury yields would fall by about 70 basis points. Half a percentage point of extra growth would raise the value of the debt by $6.5 trillion. For context: under the CBO baseline, the debt-to-GDP ratio rises from 100% today to 172% by 2055. Under the +0.5pp scenario, it stabilizes near 124%. Debt-to-GDP stops exploding. That is an enormous change in the fiscal outlook, and it comes from a rate of growth only modestly above the post-2000 average… There is a second, subtler point. Because revenue scales as GDP^1.07, the fundamental value of the debt is a convex function of productivity growth. A +1pp growth shock raises value by 108%; a −1pp shock only lowers it by 87%. That asymmetry means bondholders gain from uncertainty, not just from higher expected growth.…