South African study links inflation targeting to bond market risk premia
A South African Reserve Bank working paper by Chloë Allison and Theuns de Wet examines how inflation targeting influences the inflation risk premium embedded in the country's nominal government bond yields. The study finds that inflation expectations anchor the premium in the long run, with short-run fluctuations driven by inflation surprises.
Decomposing inflation's hidden cost
The South African Reserve Bank working paper employs a Fisher-equation-based decomposition to isolate the inflation risk premium (IRP) embedded in nominal government bond yields.
Focusing on the five-year maturity, the researchers extract the IRP from expected inflation, real yields, and liquidity premia.
The analysis spans July 2011 to December 2024, a period marked by the SARB's transition from a 3–6 percent inflation band to an explicit 3 percent midpoint target.
Using a combination of ordinary least squares regressions and autoregressive distributed lag models, the study identifies both static and dynamic relationships.
A key finding is that while the inflation target change itself has no strong direct effect on the IRP, long-run inflation expectations are crucial for anchoring it.
Short-run fluctuations, however, are primarily driven by inflation surprises and tail-risk events.
These results imply that a sustained reduction in inflation expectations, following the shift to a 3 percent inflation target, could contribute to lower nominal yields by reducing the inflation risk premium.
Uncertainty's price tag
The paper outlines a framework for identifying and calculating the inflation risk premium (IRP), which arises from uncertain inflation expectations and volatility.
This premium represents the cost investors demand for holding nominal assets exposed to unanticipated inflation changes.
Measuring IRP is complex, necessitating its distinction from the liquidity risk premium.
The study adapts the classic Fisher equation by incorporating the IRP (φIRP) and adjusting for the liquidity premium (φLIQ) found in inflation-linked bonds.
This yields the formula `φIRP = (yN - yILB) + φLIQ - E[π]`, where `(yN - yILB)` is the breakeven inflation rate.
International literature reviewed in the paper shows IRP estimates varying widely, from 7 to 160 basis points, with differences often attributed to central bank credibility and varying inflation expectations.
Beyond the headline target
This study provides a crucial, yet nuanced, perspective on the effectiveness of inflation targeting in managing bond market risks.
Its finding that the target change itself has no strong direct effect challenges simplistic assumptions about policy impact, even as it confirms the long-term anchoring role of expectations.
For policymakers, this underscores the complex interplay of expectations and market dynamics, suggesting that credibility and consistent communication are as vital as the numerical target itself.