The study of currency crisis in economics often begins with the so-called first generation models.
Developed primarily in the late 1970s and early 1980s, these models explain why countries with fixed exchange rate regimes are vulnerable to speculative attacks when their economic policies are inconsistent with maintaining the peg.
The most famous contribution comes from Paul Krugman’s 1979 model, which formalized the mechanisms by which unsustainable policies inevitably lead to crisis.
Core Idea of the First Generation Models
The central premise is that a government running persistent fiscal and monetary imbalances—such as financing deficits through money creation—cannot indefinitely maintain a fixed exchange rate.
Eventually, the contradictions between domestic policy and the exchange rate commitment are exposed.
Rational investors, seeing that the government’s foreign exchange reserves are being depleted, will preemptively sell the domestic currency.
This results in a sudden speculative attack that forces the government to abandon the peg.
Thus, in first generation models, crises are seen as inevitable outcomes of unsustainable policies, rather than random events caused by panic or self-fulfilling expectations.
Mechanism of the Krugman Model (1979)
Krugman’s model works through the following logic:
- Fixed Exchange Rate Commitment
The government promises to maintain a fixed exchange rate against a foreign currency (often the U.S. dollar). - Fiscal Deficit and Money Creation
The government runs persistent fiscal deficits. To finance them, it either borrows or prints money. Money creation increases domestic credit. - Loss of Foreign Exchange Reserves
To defend the fixed exchange rate, the central bank must sell foreign reserves in exchange for the domestic currency. Over time, as domestic credit grows, reserves steadily decline. - Investor Expectations
Rational investors know that reserves will eventually run out. They anticipate the timing of the inevitable devaluation. - Speculative Attack
Before reserves are completely exhausted, investors attack the currency. They convert domestic currency into foreign assets all at once, draining reserves instantly. - Collapse of the Peg
The central bank is forced to abandon the fixed rate, and the domestic currency depreciates sharply.
This model shows that a crisis does not come as a surprise; it is predictable and based on fundamentals.
Key Assumptions of First Generation Models
- Governments pursue inconsistent policies, such as financing deficits through money creation while trying to keep a fixed exchange rate.
- Investors are rational and forward-looking; they attack the currency when they know the peg is unsustainable.
- Crises occur suddenly but predictably, based on observable fundamentals like reserve levels and deficits.
- The economy operates under a fixed or pegged exchange rate regime, which is inherently vulnerable if policies diverge from stability.
Real-World Examples
Several currency crises in the 1970s and 1980s fit the first generation model well:
- Latin American crises (1970s–1980s): Countries such as Argentina and Chile maintained fixed exchange rates while running large fiscal deficits. Foreign reserves were drained until pegs collapsed.
- Mexico (1982): Heavy borrowing and deficits led to reserve depletion, forcing a peso devaluation.
These episodes illustrate how policy inconsistency directly created vulnerabilities that triggered speculative attacks.
Criticisms of First Generation Models
While highly influential, first generation models are limited in their explanatory power:
- Not All Crises Were Predictable
Some crises occurred even when fundamentals appeared sound, such as the European Exchange Rate Mechanism (ERM) crisis in 1992. - Role of Expectations Understated
By focusing only on fundamentals, the model underestimates the possibility of self-fulfilling crises, where pessimistic expectations alone can trigger collapse. - Banking and Financial Linkages Ignored
The model does not account for the interplay between currency and banking crises, which became central in later episodes such as the Asian Financial Crisis (1997).
These shortcomings led economists to develop second generation models in the 1990s, which emphasized the role of expectations, multiple equilibria, and government trade-offs.
First generation models, especially Krugman’s 1979 framework, provide a powerful explanation of why fixed exchange rate regimes collapse when economic policies are unsustainable.
They highlight the inevitability of crises when governments try to reconcile fiscal indiscipline with currency stability.
However, while these models explain many crises of the 1970s and 1980s, they cannot fully account for later, more complex episodes where expectations and financial sector weaknesses played a larger role.
Still, they remain a cornerstone of international finance theory and a starting point for understanding currency crises.