Original Sin — External Debt in Foreign Currency
"Original sin" in economics describes the inability of developing countries to borrow internationally in their own currency, forcing dangerous foreign-currency debt that creates currency mismatch risk.
Effective Debt Increase = Foreign_Debt% × (FX_depreciation%)Barry Eichengreen and Ricardo Hausmann coined "original sin" to describe why most developing countries must borrow in USD, EUR, or other hard currencies rather than their own. When a country borrows in USD but earns revenues in local currency, any depreciation of the local currency increases the real debt burden — even without new borrowing.
This creates a deadly spiral: currency pressure → depreciation → debt-to-GDP rises instantly → investors panic → more depreciation → repeat. The "original sin" is that the country cannot escape this trap through monetary policy — printing local currency devalues it, worsening the dollar debt burden.
Original sin severity is a key input into Noosphere's currency risk assessment. Countries with high foreign-currency debt and low FX reserves are rated significantly higher risk, because a currency shock creates immediate solvency problems regardless of fiscal discipline.
A 30% currency depreciation on a country with 60% of debt in foreign currency causes an instant 18-percentage-point increase in debt/GDP — without any new borrowing.
Argentina's peso-dollar convertibility meant all private debt was effectively dollar-denominated. When the peg broke, debt burden became unmanageable overnight.
$100B sovereign default. Peso -75%. Savings confiscated. Economic collapse -28%.
Foreign currency debt composition and FX reserve coverage are assessed in Layer 2 (Structural Fragility) and Layer 4 (Network Contagion) of the Noosphere Score.
Hungary has significant FX mortgage legacy — currency depreciation creates automatic household debt increase
Original Sin — External Debt in Foreign Currency is one of 15 mathematical concepts powering SIGMA v5.0 scores across 22 countries.