Sovereign default

A sovereign default is the failure of a national government to meet the legal terms of its debt contracts, whether by missing a scheduled payment, restructuring debt on terms less favorable to creditors than originally agreed, or unilaterally repudiating obligations. Defaults can occur on debt issued under domestic law (typically in local currency) or on external debt issued under foreign law (often in U.S. dollars or euros).

Unlike corporate bankruptcy, there is no global court with binding authority over sovereigns. Restructurings are negotiated through ad hoc mechanisms: the Paris Club for official bilateral creditors, the London Club for commercial bank loans, and bondholder committees for marketable debt. The IMF often provides bridge financing conditional on policy adjustment. Since the 2000s, most new sovereign bonds include collective action clauses (CACs) to bind holdout creditors to a supermajority restructuring vote.

Defaults are driven by some combination of insolvency (debt levels exceeding plausible repayment capacity), illiquidity (inability to roll over short-term debt during market stress), and unwillingness to pay (a political choice to prioritize domestic spending). Consequences typically include loss of capital market access, currency depreciation, banking-sector stress, sharp output contractions, and downgrades by rating agencies (a "Selective Default" or "SD" rating from S&P, for example).

Notable cases include:

• Argentina (2001): defaulted on roughly USD 100 billion, then spent over a decade litigating with holdout creditors, including the NML Capital v. Argentina proceedings in U.S. courts.
• Russia (1998): defaulted on ruble-denominated GKO bonds and devalued the currency.
• Greece (2012): executed the largest sovereign debt restructuring in history (PSI), imposing losses on private bondholders.
• Sri Lanka (2022): announced a pre-emptive default on external debt amid a foreign-exchange crisis.
• Zambia (2020): the first African default of the COVID-19 era, later restructured under the G20 Common Framework.

For MUN and policy researchers, sovereign default sits at the intersection of international finance, development, and questions of creditor coordination, including the growing role of China as a bilateral lender.