Currency crisis

A currency crisis is conventionally defined as a speculative attack on a currency that forces a sharp devaluation or a collapse of the exchange-rate regime. In empirical work, crises are often identified by a large depreciation (e.g., exceeding 30% per year) or by a substantial loss of reserves. The classic mechanism involves a fixed exchange rate: if investors believe the peg is inconsistent with fundamentals—such as excessive money growth or fiscal deficits—they sell the currency, forcing the central bank to defend the peg by spending reserves. When reserves run low, the peg breaks, and the currency depreciates abruptly.¹

First-generation models (Krugman, 1979) explain crises as the inevitable result of expansionary policies; second-generation models (Obstfeld, 1994) emphasize self-fulfilling prophecies and multiple equilibria; third-generation models focus on balance-sheet effects and financial fragility, as seen in the Asian crisis.²

Currency crises have punctuated economic history. The Latin American debt crisis of the 1980s, the European Exchange Rate Mechanism crisis of 1992–93 (which forced the UK to exit the ERM on Black Wednesday), and the Mexican peso crisis of 1994–95 are landmark cases. The Asian Financial Crisis of 1997–98 began in Thailand with the collapse of the baht and spread to Indonesia, South Korea, and others, causing severe recessions and social upheaval.³

More recent episodes include the Argentine crisis of 2001–02, the Russian ruble crisis of 2014, and the Turkish lira crisis of 2018. Each crisis has unique triggers—commodity price shocks, political instability, or capital flow reversals—but common threads include large current-account deficits, short-term foreign debt, and weak banking systems.⁴

Currency crises are typically caused by a combination of macroeconomic imbalances, financial vulnerabilities, and investor psychology. High inflation, overvalued real exchange rates, and unsustainable external debt are classic preconditions. Sudden stops in capital inflows, often triggered by global interest rate hikes or risk aversion, can precipitate a crisis even in economies with sound fundamentals.⁵

The consequences are severe: currency depreciation raises the cost of imports, fuels inflation, and increases the burden of foreign-currency debt, often leading to bankruptcies and banking crises. Output falls, unemployment rises, and poverty increases. Crises can also have contagion effects, spreading to neighboring countries through trade and financial linkages, as seen in Asia and Europe.⁶

Beyond the headline episodes, currency crises have many subtle dimensions. For instance, the 1992 ERM crisis was partly triggered by the high cost of German reunification, which forced the Bundesbank to keep interest rates high, making the pound and lira unsustainable. The 1994 Mexican crisis was preceded by the assassination of a presidential candidate, which shook investor confidence. In 2015, the Swiss National Bank abruptly abandoned its franc-euro peg, causing a massive appreciation—a crisis in reverse.⁷

Lesser-known figures include economist Robert Mundell, whose work on optimum currency areas underpinned the euro, and Carmen Reinhart and Kenneth Rogoff, who compiled the most comprehensive database of financial crises. The role of 'original sin'—the inability of developing countries to borrow in their own currency—is a key structural vulnerability. Also notable is the use of capital controls as a crisis-prevention tool, as in Malaysia in 1998, which was initially criticized but later seen as effective.⁸

Speculative attack

A massive sale of a currency by investors betting on its devaluation.

Fixed exchange rate

A regime where the currency's value is pegged to another currency or basket.

Sudden stop

An abrupt halt in capital inflows to a country.

Original sin

The inability of a country to borrow abroad in its own currency.