3.4 Exchange Rate Regimes, Currency Pegs, Dollarization & Special Drawing Rights

3.4 Exchange Rate Regimes, Currency Pegs, Dollarization & Special Drawing Rights

1. Why Regime Type Changes the Investment Problem

Two emerging markets with identical inflation and growth can present entirely different currency risk profiles purely because of the exchange rate regime each operates. A pegged currency does not eliminate currency risk; it changes its distribution. Under a peg, day-to-day volatility is near zero and then, occasionally, a devaluation delivers in one day what a floating currency would have delivered gradually over years.

This matters directly for portfolio construction. Historical volatility measured on a pegged currency will understate risk, and a mean-variance optimizer fed that number will overweight the exposure. The consultant's job is to recognize that the absence of observed volatility under a peg is a policy commitment, not a risk characteristic.

2. The Spectrum of Regimes

Exchange rate arrangements sit on a continuum from complete rigidity to complete flexibility.

Dollarization deserves particular attention because it is frequently misunderstood as risk elimination. Ecuador, El Salvador, and Panama use the US dollar as legal tender. The country gains immediate credibility and eliminates exchange rate risk against the dollar, but it forfeits monetary policy entirely, loses seigniorage revenue, and gives up its central bank's lender-of-last-resort capacity — it cannot create the currency in which its banking system's deposits are denominated. It also imports US monetary policy regardless of whether US conditions match domestic conditions.

A currency board is the next-strictest arrangement: the monetary authority is legally required to hold foreign reserves at least fully covering the monetary base and to exchange domestic currency for the anchor at a fixed rate on demand. Hong Kong's linked exchange rate system is the best-known durable example. Argentina's 1991–2002 convertibility regime is the best-known failure, and it illustrates the mechanism: a currency board removes the option to inflate, so when a fiscal or competitiveness problem arises, the adjustment must come through wages, prices, and output — and if that adjustment is politically infeasible, the arrangement breaks.

3. The Impossible Trinity

The central organizing principle is the impossible trinity (or trilemma): a country can achieve at most two of the following three simultaneously.

                     Free Capital Mobility
                            /\
                           /  \
                          /    \
                         /      \
                        /        \
      Fixed Exchange   /__________\   Independent
           Rate                        Monetary Policy

     Pick any two. The third must be surrendered.

This is why a country running a peg while wanting to cut rates for domestic reasons and permitting free capital movement will eventually face a speculative attack: the market recognizes the inconsistency before the policymaker concedes it. The 1992 sterling exit from the Exchange Rate Mechanism and the 1997 Asian crisis are the canonical cases.

4. Regime Choice and Portfolio Risk

Practical consequences a consultant should carry into an international allocation:

• Pegged-currency assets have understated historical volatility. Adjust expectations upward or model devaluation as a discrete scenario rather than trusting the standard deviation.
• Regime changes are discrete and rarely pre-announced. A peg abandonment produces a step change, not a drift, so continuous hedging programmes sized to historical volatility will be badly under-hedged at the moment of the break.
• Capital controls are a repatriation risk, not merely a return risk. A country maintaining a peg with controls may restrict the conversion or transfer of proceeds, which is why market accessibility drives index classification.
• Currency-mismatch exposure compounds regime risk. A pegged-currency borrower with foreign-currency debt faces a solvency event, not just a valuation event, when the peg breaks.

5. Special Drawing Rights

The Special Drawing Right (SDR) is an international reserve asset created by the International Monetary Fund to supplement member countries' official reserves. Candidates should hold three facts:

1. It is not a currency. It is a potential claim on the freely usable currencies of IMF members, and it cannot be used to buy goods directly.
2. Its value derives from a basket of five currencies: the US dollar, euro, Chinese renminbi, Japanese yen, and British pound. The basket composition and weights are reviewed by the IMF, ordinarily every five years.
3. SDRs are allocated to members in proportion to their IMF quotas. A general allocation increases every member's unconditional reserve assets at once, which is why allocations are used as a global liquidity tool during systemic stress — most prominently the large general allocation made in August 2021.

The renminbi's inclusion in the basket in 2016 was significant chiefly as an official recognition of the currency's role in the international system rather than as a change to how SDRs function.

6. Fixed versus Floating: The Trade-Off Summarized

Neither regime is superior in the abstract. Small, open, trade-dependent economies with weak monetary credibility often gain more from importing discipline than they lose in flexibility; large, diversified economies with credible institutions almost always float, because the ability to let the exchange rate absorb shocks is worth more than the certainty a peg provides.