The US Treasury Funding Advantage Since 1860

We provide the first consistent historical estimate of US Treasury funding advantage, as measured by term structures of yield spreads between comparable highest-grade US corporate bonds and Treasurys. We construct a new dataset with monthly prices, cash-flows, and ratings for US corporate bonds over 1860-2024. We adjust yield curve estimation techniques to account for tax treatments and embedded options. Existing index-based spreads have mismeasured US funding advantage on long-term bonds in the post-WWI period, particularly during high inflation episodes. An asset pricing model for US funding advantage finds that standard risk factors, not quantity changes, explain most variation in spreads.