Does higher public debt raise real interest rates much?
Core argument: The debt-to-GDP ratio in advanced economies rose from 75 percent in 2019 to 82 percent in 2022, which under standard assumptions implies an increase in the real return on capital of no more than 15–30 basis points.
Summers has argued that the increase in public debt due to the fiscal response to COVID will lead, other things equal, to an increase in r [real return on capital]. He is right about the sign of the increase in public debt’s impact on r, but the effect is likely to be quite small. The debt-to-GDP ratio in advanced economies has increased only from 75 percent in 2019 to 82 percent in 2022; under standard assumptions, this implies an increase in r of no more than 15–30 basis points. That would be insufficient to offset the pre-COVID downward trend in safe rates, let alone to close the gap between r and g [growth rate of output.]
















