世界银行-津巴布韦货币和汇率政策扭曲的财政成本（英）-2025_27页_1mb

Working Paper Summary: Fiscal Costs of Monetary and Exchange Rate Policy Distortions in Zimbabwe

Introduction

The study examines the fiscal costs of monetary and exchange rate policy distortions in Zimbabwe, focusing on revenue losses from three main channels: the Olivera-Tanzi effect (inflation-related tax payment lags), customs duty loss due to an overvalued official exchange rate, and reduced tax revenue from informalization. Between 2020 and 2023, these distortions resulted in cumulative revenue losses of approximately US$3.1 billion (0.22% of GDP), significantly reducing government tax collection.

Key Findings

1. Olivera-Tanzi Effect

• High inflation erodes real tax revenue despite generating some short-term "inflation tax" benefits.
• A cumulative net loss of US$1.38 billion was estimated from payment lags, outweighing gains from inflation tax (US$1.4 billion).
• For each percentage increase in inflation, tax collection lags reduced the real value of revenue by about 0.45 percentages.

2. Customs Duty Loss from Overvalued Exchange Rate

• An overvalued official exchange rate reduced customs revenue.
• The average monthly loss ranged from US$3.36 million to US$27.49 million, averaging US$12.13 million.
• Conservative estimates show a cumulative loss of US$582.22 million from import customs duties.

3. Revenue Loss from Informalization

• High inflation correlated with increased informal economic activity, reducing formal tax collection.
• Using inflation as a proxy, informalization rose by about 7.2% annually in response to monetary policies.
• This contributed to a revenue loss of roughly US$1.15 billion.

Aggregate Impact

• Total Revenue Loss (2020-2023): Approximately US$3.1 billion (or 2.5% of GDP).
• Distribution: Most losses came from inflation lags (44%) and informalization (37%), with customs duties contributing 19%.

Policy Implications

• Addressing monetary and exchange rate distortions is critical for improving government revenue.
• Removing exchange rate controls and stabilizing prices could substantially boost fiscal revenues and help bridge Zimbabwe's financing gap.
• Long-term reforms are needed, as the benefits of reduced distortions take time to fully materialize.

Conclusion

The research demonstrates that stabilization policies should prioritize curbing inflation and exchange rate misalignments to protect revenue collection and foster sustainable economic growth.