8 Empirical Evidence of the Sources of Hyperinflation and Falling Currency

Jean Clément
Published Date:
February 2005
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The Democratic Republic of the Congo (DRC) experienced hyperinflation throughout the 1990s. For instance, from October 1990 to December 1995, the cumulative increase in prices was 6.3 billion percent, while the local currency underwent a free fall on the parallel foreign exchange market. This chapter reviews the DRC’s experience of hyperinflation and falling currency. Section I describes the causes and consequences of such dramatic hyperinflation and prolonged currency depreciation; Section II analyzes the theoretical and empirical bases of the policies that were implemented to break the vicious circle of hyperinflation and falling currency; and Section III highlights the main conclusions and their policy implications.

Section I. Causes and Macroeconomic Consequences of Hyperinflation in the DRC

Causes of Hyperinflation

The primary cause of hyperinflation in the DRC lay in the uncontrolled budgetary deficit financed by money creation. There was a strong correlation among the fiscal deficit (on a cash basis), net credit to the government, and the average inflation rate (as measured by the CPI). The deficit arose from the breakdown of public administration against the backdrop of political instability, governance problems, civil strife, and war. In this context, there was an extraordinary weakening of fiscal performance, as evidenced by the fall in fiscal revenue and the collapse of the expenditure control system.

Reflecting the drop in revenue and the surging of expenditure, the government cash deficit reached extremely high levels. In the absence of external borrowing options, recourse was taken to central bank credit to finance the budget.1 As a result, the government accounted for the bulk of the increase in money, thereby completely crowding out the private sector. Broad money grew by 160 percent in 1998, 382 percent in 1999, and 493 percent in 2000, while net credit to the government surged by 104 percent, 392 percent, and 317 percent, respectively, during the same three years.

Macroeconomic Consequences of Hyperinflation

The vicious circle of hyperinflation led to a breakdown of financial intermediation, an uncontrolled spiral of exchange rate depreciation, increased dollarization, and it compounded the fall in fiscal revenue. Moreover, by creating macroeconomic instability and uncertainty, and jeopardizing the transactions role of money, hyperinflation also had a contractionary impact on key macroeconomic variables, such as investment, savings, GDP, and real wages.

Financial disintermediation

Owing to the collapse of the domestic payments system, banks ceased operating as financial institutions. Sight deposits represented less than 2 percent of broad money over the 1996–2000 period, and were largely demonetized, as checks and bank transfers were used almost exclusively for transactions with the central government, at a steep discount. A shortage of banknotes prevented banks from withdrawing excess reserves from the central bank. The excess reserves of commercial banks were equivalent to about 50 percent of their local currency deposit base. In the absence of formal financial intermediation, banking activity was confined to the brokerage of foreign exchange transactions between importers and exporters.2

Depreciation of the parallel market exchange rate

As a direct consequence of the hyperinflation, the parallel market exchange rate experienced a sharp depreciation. There was a strong correlation between the inflation rate and the parallel exchange rate, suggesting that the latter truly reflected the differential of inflation rates, as predicted by the theory of relative purchasing power. Since the fixing of the official exchange rate, the gap between the official and parallel exchange rates widened, rising from 44 percent at the end of 1998 to about 600 percent in May 2001.


As in most cases of hyperinflation, several years of hyperinflation left a trail of strong inertial inflationary expectations and an extensive dollarization of the economy,3 based on informal institutions and arrangements centered on exchange bureaus. The dollarization was fueled both by currency substitution and asset-substitution practices. The quoting of prices in foreign currency terms (U.S. dollars and Belgian francs) was pervasive, and most people, including wage earners, relied on foreign currency as a store of value.

Decline in fiscal revenue

Hyperinflation reduced nonmining government revenue in real terms, thereby contributing to rising fiscal deficits. This adverse impact came about through two channels: (1) Because the tax system was not indexed, the usual lags in collection, combined with manipulated delays in payment, led to the erosion of real revenues. This negative effect is known as the Tanzi-Olivera effect.4 The importance of the Tanzi-Olivera effect in the context of hyperinflation has been underscored by Dornbusch (1993). (2) With the deterioration in tax compliance, the tax yield of a given tax structure declined. Moreover, the tax base shrank as a result of the decline in economic activity and the thriving nonofficial economy.

Depressed investment and saving

As shown by Fischer (1993) and Barro (1995), hyperinflation has a negative impact on capital formation by creating macroeconomic instability and uncertainty. This negative impact on investment spending in real terms was also present in the case of the DRC. In parallel with the decline in investment, domestic saving was discouraged by interest rates that were substantially negative in real terms. In addition, as hyperinflation made the holding of real balances more expensive than consumption, households consumed more and saved less.

Output contraction

The negative impact on output came about mainly through the investment channel. In the DRC, prolonged depressed investment led to a sharp decline in output.

Decline in real wages

Several years of hyperinflation all but eroded real wages in both the private and public sectors. Data compiled by the central bank show that in the private sector the real wage index declined by more than 99 percent during 1996–99. The decline could be attributed to inelastic labor supply and to an insufficiently flexible wage setting in the face of hyperinflation. In the public sector, wages also experienced a sharp decline in real terms, despite frequent wage increases. The erosion of wages depressed the consumption of wage earners (considered to have a high marginal propensity to consume), thereby contributing to output contraction.

Section II. Breaking the Vicious Circle of Hyperinflation and Falling Currency

Breaking the vicious circle of hyperinflation and falling currency in the DRC required a decisive stabilization policy, underpinned by a strong political will. The experience gained from short-lived stabilization efforts in 1995 and 1997 clearly showed how to lend credibility to the anti-inflation strategy: a substantial tightening of the fiscal stance was key to breaking the vicious circle of hyperinflation and falling currency. The anti-inflation program, therefore, included revenue-enhancing and expenditure-restraining measures. However, improving revenue collection and effectively controlling expenditure required strong political commitment. As described in Chapter 2, the new government of the DRC demonstrated its commitment in this area.

Analytical Framework for Stabilization Program

The following analytical model, which captures the specificities of the DRC’s economy, shows how the recourse to money creation for financing large fiscal deficits created hyperinflation dynamics.

Consider an open economy with exogenous output (yt).

Government deficit

The government cannot issue bonds to the public and finances its primary deficit solely through seignorage, while interest payments on foreign public debt are accumulated as arrears. The government budget in nominal terms is given by the following:

where gt is noninterest expenditure (as a share of nominal GDP), μt is government revenue (as a share of nominal GDP), and Pt is the price of output.

The financing of the deficit is given by:

where M˙t is the change in nominal money stock at a given time t.

Money market equilibrium

The demand for money can be summarized by the quantity equation:

where income velocity of money, Vt, is assumed to be variable, as is the case in a country with high inflation.

We further assume that velocity is a linear function of money growth:

where ^ denotes the percentage change. This specification of velocity implies that inflation expectations are adaptive.

Household decisions

We assume that the country’s financial system is largely underdeveloped and the economy is highly dollarized. Accordingly, the nominal wealth of the representative household consists of nominal money stock and foreign currency (because of the extensive dollarization of the economy). The constraint on the household budget flow is given by the following:

where Et denotes the official exchange rate, which is fixed; Etp the parallel market rate; Ft the stock of foreign currency; α the share of transactions carried out at the official rate; and Ct nominal consumption.

For simplicity, we assume that consumption is a share of nominal GDP (Ct = δt · Ptyt).

Balance of payments

As is the case in the DRC, we assume that the country is faced with no external borrowing options and does not service its external debt, and therefore incurs arrears in external interest payments and amortization. Therefore, in the absence of private capital flows in the capital account, the change in foreign reserves is equal to the current account excluding interest payments:

where Xt denotes exports, which are assumed exogenous in dollar terms (Χt = (α · Et + (1 – α) · Etp) · X), and IMt is imports defined as a fixed share of GDP (IMt = m · Ptyt).

The parallel market rate is defined by a modified version of the relative purchasing power theory:

where Pt* denotes the foreign price level. This equation captures the fact that in the DRC the depreciation of the parallel market rate is highly correlated with the inflation rate.

Goods market equilibrium

The above model is closed and fully determined. Combining equations (1), (2), (5), and (6) yields the market-clearing condition on the goods market:

Solution of the Model: Hyperinflation Dynamics

The model can be solved to show how large fiscal deficits can generate hyperinflation dynamics, which, in turn leads to uncontrolled depreciation of the parallel market exchange rate.

The linear approximation of the percentage change of equation (3) yields the inflation rate5

where σ1 and σ2 are parameters. For simplicity, we assume that real output growth is zero.

From equation (3), Mt is given by

Equations (1) and (2) imply that

Substituting equations (10) and (11) in (9) yields

equation (12) clearly shows how uncontrolled fiscal deficits can trigger a spiral of hyperinflation and falling currency. First, past fiscal deficits financed through seignorage lead to an exponential growth in the income velocity of money, which, in turn, affects the current inflation rate. Second, the current deficit (gt – μt) also has a direct impact on the current inflation rate. Through equation (7), the hyperinflation spiral will translate into a spiral of exchange rate depreciation. Thus, the only way of breaking a vicious circle of hyperinflation and falling currency is to drastically reduce the fiscal deficit, which will lead to a decline in income velocity.

Empirical Evidence for the DRC

Exchange rate dynamics

We estimate equation (7) using monthly data over the period 1990–2000. By applying the ordinary least squares method to the data, we obtain the following results:

Examining the results, we observe that the estimated λ is positive, in accordance with prior expectations. The estimated value suggests that a 1 percent increase in the inflation differential will lead to 1.03 percent depreciation in the parallel market exchange rate. As to the significance of the estimated slope coefficient, the null hypothesis that there is no relationship between inflation and exchange rate depreciation can be rejected at a 0.01 percent level of significance. As the estimated intercept coefficient is not statistically different from zero, we reestimate the equation without an intercept, which gives the following results:

Inflation dynamics

The data used are annual data for the period 1990–2000. Given the short span of the data, these estimates should be interpreted with caution, because the robustness of the results would need to be tested on longer data series.

We estimate the following modified version of the inflation equation:

where DEFGt is the government cash deficit as a share of GDP, and V^t is the percentage change in income velocity of money. The ordinary least squares regression’s results are as follows:

As the estimated intercept coefficient is not statistically significant, we also run the regression without an intercept:

Both estimated coefficients are overwhelmingly significant, and their signs are in accordance with prior expectations. The coefficient of the budget deficit is very large, implying a rapid disinflation in response to a small decline in the budget deficit ratio from its current level. Indeed, in 2001 the implementation of restrained monetary and fiscal policies, centered on strict adherence to a monthly treasury cash-flow plan, led to the breaking of hyperinflation and the stabilization of the exchange rate under the floating exchange rate system introduced in May 2001. Inflation decelerated sharply from a monthly average of 18 percent during the period January–May preceding the stabilization program (an annualized rate of 632 percent) to 0.7 percent during June–December 2001 (an annualized rate of 8.8 percent). The difference between the official exchange rate (reference rate) and the free market rate fell from about 600 percent prior to June 2001 to less than 1 percent at the end of December 2001.

Section III. Concluding Remarks

The monetization of fiscal deficits was identified as the primary source of hyperinflation in the DRC. The spiral of hyperinflation led to negative economic consequences, including a spiral of exchange rate depreciation, financial disintermediation, depressed investment and saving, and output contraction.

Based on the proposed analytical framework, a substantial tightening of fiscal policy, coupled with a money-based stabilization program, was implemented and succeeded in breaking the vicious cycle of hyperinflation in the DRC. As expected, in light of the strong relationship between inflation and the exchange rate, breaking the cycle of hyperinflation stabilized the exchange rate, while, at the same time, the parallel market exchange rate premium vanished.


    BarroRobert1995“Inflation and Economic Growth,”Bank of England Quarterly BulletinVol. 35 (May) pp. 16676.

    DornbuschRudiger1993“Lessons from Experiences with High Inflation” in Stabilization Debt and Reform: Policy Analysis for Developing Countries (New York: Harvester Wheatsheaf).

    FischerStanley1993“The Role of Macroeconomic Factors in Growth,”Journal of Monetary EconomicsVol. 32 (December) pp. 485512.

    OliveraJ.H.1967“Money, Prices and Fiscal Lags: A Note on the Dynamics of Inflation,”Banca Nationale del lavoro Quarterly ReviewVol. 20 (September) pp. 25867.

    TanziVito1977“Inflation, Lags in Collection and the Real Value of Tax Revenue,”Staff PapersInternational Monetary FundVol. 24 pp. 15467.

    TanziVito1978“Inflation, Real Tax Revenue, and the Case for Inflationary Finance: Theory with an Application to Argentina,”Staff PapersInternational Monetary FundVol. 25 (September) pp. 41751.

The accumulation of external payments arrears with multilateral and bilateral creditors prevented the contracting of new loans.

See Chapter 9 on financial intermediation.

More than 85 percent of private sector bank deposits were denominated in foreign exchange, and foreign currency circulated widely.

See Olivera (1967) and Tanzi (1977, 1978).

For high inflation, the sum of money and velocity growth rates is no longer a good approximation of the actual inflation rate.

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