Government debt is often treated as the canonical safe asset, but its safety depends on more than sovereign solvency. This paper develops a theory in which safe government-debt claims are produced jointly by a solvent fiscal authority and a financial system that absorbs rollover risk. The government compensates that service through an excess yield on its debt; households receive the safe return net of the rollover-insurance premium. As the debt stock rises, rollover exposure rises relative to financial capacity, and the excess yield required to preserve safety increases […]