This article presents archival data on rebuilding costs and interest rates from the Corporation of London, 1666–83, to analyse how, in the absence of banking or capital market finance, the London Corporation funded the rebuilding of London after the Great Fire. The City borrowed from its citizens and outside investors at rates much lower than previously thought to replace vital services and to support large improvement works. Lenders were reassured by the Corporation's reputation, and its borrowing was partly secured by future coal tax receipts. The records show that funding from these sources was forthcoming and would have covered the costs. Most of the rebuilding was completed in less than a decade; but having invested in public goods without generating the expected flows of income in the form of improved fees, fines, and rents, the City defaulted in 1683.