## Parameterizing Debt Maturity

_IMF Working Papers, April 23, 2021_

## Source details

**Canonical URL:** [Parameterizing Debt Maturity](https://www.imf.org/en/publications/wp/issues/2021/04/23/parameterizing-debt-maturity-50299)

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## Bibliographic details
- Authors: Philip Barrett, Christopher Johns
- Published: April 23, 2021
- Series: IMF Working Papers
- DOI: https://doi.org/10.5089/9781513582511.001

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### Overview
- Purpose: Examine ways to summarize the maturity structure of public debts using a small number of parameters.
- Core contribution: Identification of a unique parametric form—portfolios of bonds with exponential coupons—that does not arbitrarily restrict debt issuance.
- Scope: Analysis of historical and recent government debt for multiple countries to evaluate parametric descriptions of maturity.

### Dataset and Method
- Novel dataset: All promised future payments for government debt compiled for:
  - United States and United Kingdom from every month since 1869.
  - More recent data for Peru, Poland, Egypt, and Nigeria.
- Parametric approach: Portfolios of bonds with exponential coupons.
- Comparison benchmark: The most popular alternative parametric form (unnamed here) is used for comparative accuracy.

### Key Findings
- Accuracy:
  - The exponential-coupon parametric form "more accurately describes changes in debt maturity for these six countries" compared to the most popular alternative.
- Historical interpretation:
  - The exponential-coupon form "gives a quite different interpretation of historical debt maturity" relative to the alternative.
- Cross-country consistency:
  - Parameter estimates are "relatively similar across countries," enabling comparative analysis.
- Applicability:
  - The method can be applied to analyze past debt movements and to monitor changes in debt maturity where data are partial or incomplete.

### Applications and Policy Implications
- Monitoring:
  - Use the parametric form for ongoing monitoring of debt maturity structures, including in countries with incomplete data.
- Analysis:
  - Apply parameter estimates to reinterpret historical maturity patterns and to assess issuance practices without arbitrary restrictions.
- Practical utility:
  - Because parameter estimates show cross-country similarity, the approach supports comparative surveillance and diagnostic work on public-debt maturity.

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_Source: https://www.imf.org/en/publications/wp/issues/2021/04/23/parameterizing-debt-maturity-50299_