Our analysis finds that aggregate measures of leverage in an economy, such as the ratio of total debt to GDP, are in and of themselves not a reliable guide to the sustainability of debt or the likely speed or extent of deleveraging. Our historic case studies include economies that have gone through painful and significant deleveraging with relatively low debt-to-GDP levels, as well as countries that have maintained very high levels for many years. To assess the likelihood of deleveraging going forward, one needs to take a very granular approach and look at individual sectors. Even within sectors, one must use multiple lenses to assess the sustainability of debt, including the rate of growth of leverage, debt servicing
capacity, and the borrowers’ vulnerability to income interruptions or sharp increases in interest rates.