Sovereign debt: who borrows, in what currency, for how long

Who is a sovereign borrower, and why are they different?

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sovereign debt is debt issued by a national government. What sets it apart from every private issuer is the legal power to tax economic activity in its jurisdiction. Taxes are the main source of repayment. Tariffs, usage fees and the cash flows of government-owned firms come second.

The size of the public sector varies widely. In some countries the national government provides most public goods; in others, regional governments, local governments and agencies do. That is why non-sovereign issuers exist alongside the sovereign (see the third lesson of this module).

Private firms report on an accrual basis. Public sector accounts often use cash accounting, which leaves out the depreciation of roads and bridges and the accrual of unfunded pensions. So analysts look at the economic balance sheet , which sets expected future tax revenue (the claims) against promised future spending (the obligations), next to the financial balance sheet of debt, reserves and assets.

How do developed and emerging market sovereigns differ?

A developed market sovereign has a strong, stable, well-diversified economy. Its budget is mostly recurring outlays financed by broad individual and business taxes, so fiscal policy is stable and transparent. Its debt is in a major reserve currency. Together these features let it issue what is often called default-risk-free debt, with unconstrained access to every maturity.

An emerging market sovereign usually grows faster but with a less stable, less diversified economy that swings more over the cycle. It often leans on one or two dominant industries, such as commodities, and holds more state-owned firms. Its budget priorities, such as new infrastructure, can exceed what domestic taxes cover, which leads to external or supranational funding.

	Developed market	Emerging market
Economy	large, stable, diversified	faster growth, less diversified, often a dominant industry and state-owned firms
Budget	recurring spending, broad tax base, transparent	investment needs exceed tax revenue, so external or supranational funding
Currency	major reserve currency	often restricted (limited convertibility)
Market access	all maturities, treated as default-risk-free	shorter domestic maturities; foreign currency abroad

Emerging market debt is often in a restricted domestic currency , one with limited convertibility into other currencies because it is illiquid. Restrictions can limit foreign investment and make long maturities hard to sell in the local currency.

What is the difference between domestic and external debt?

domestic debt is issued in the local currency and held mostly by local banks, funds and other domestic investors. external debt is owed to foreign creditors. It combines loans from supranational organizations with debt in a foreign currency held by foreign private investors (for example, dollar or euro bonds).

Sovereign debtrepaid first from taxes

• Domestic debt Use it local currency, held mostly by local institutions
• External debt Memorize owed to foreign creditors
  • Supranational loans Use it from development lenders
  • Foreign-currency bonds Memorize USD or EUR bonds held abroad; the issuer must earn that currency
  • Local-currency bonds held abroad Use it some emerging sovereigns, mostly with stable currencies

A developed market investor in a dollar bond from an emerging sovereign no longer faces the direct currency risk of a local-currency bond. The indirect risk remains. Returns depend on the issuer earning enough foreign currency, from exports, tourism, remittances and capital inflows, to pay interest and principal. A country that borrows heavily abroad while its foreign-currency income and reserves shrink can default on external debt even while it keeps paying its domestic debt.

Not all external debt is in a foreign currency. Some emerging sovereigns, especially those whose currencies have been stable, sell local-currency bonds to foreign investors.

What does a sovereign issue?

government debt management decides the composition of debt (short or long term, fixed or floating, local or foreign currency). Fiscal policy decides the level: deficits add to borrowing, surpluses reduce it.

Sovereign instrumentschosen by the debt management office

• Treasury bills Memorize 1 to 12 months, usually zero-coupon, sold at a discount
• Treasury notes and bonds Memorize medium and long term
  • Fixed-rate, local currency Use it the most common
  • Floating-rate, inflation-linked, foreign-currency Know the idea less common
• Guaranteed debt Know the idea issued by others, backed by the sovereign (for example conforming mortgage securities)

Treasury bills mature in 1 to 12 months, usually pay no coupon and are sold at a discount to par. Treasury notes and bonds are medium- and long-term. Fixed-rate bonds in the local currency are the most common, but sovereigns also issue floating-rate, inflation-linked and foreign-currency bonds. Some governments also guarantee other issuers’ debt, such as qualifying mortgage-backed securities, which makes it a form of sovereign debt.

Why do governments issue long-term debt?

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Ricardian equivalence is the sovereign counterpart of the Modigliani–Miller theorem: under strict conditions, the maturity a government chooses does not change the present value of the taxes taxpayers will pay. The conditions are that taxpayers smooth consumption, form rational expectations that tax cuts mean later tax rises, face perfect capital markets and care about their descendants.

Taken literally, the theorem says the government should borrow at the shortest maturity to avoid the term premium and save interest. Real markets break the conditions, and heavy reliance on short debt creates rollover risk : refinancing costs are uncertain, so budgets and tax rates become volatile.

So in practice governments spread debt across maturities and issue on a regular, predictable schedule. They can still flex the size of short-term sales to absorb uneven tax receipts. Very short government securities often stand in for bank deposits, and investors accept a slightly lower yield for that safety and liquidity. That is a liquidity premium : it lowers the yield and belongs to short bills.

Sovereigns also keep issuing long bonds because they give the whole market something it needs. Regular issues at set maturities are benchmark securities , the risk-free yardstick used to price other debt.

Long government bonds supplythe benefit is market-wide, not only for the budget

• Risk-free benchmark Memorize yields for pricing all other debt
• Interest rate hedging Use it manage rate risk apart from credit risk
• Collateral Memorize preferred for repos and derivatives
• Policy and reserve assets Use it central bank operations and foreign exchange (FX) reserves

Go deeper Why cash accounts miss pension promises and depreciation

A cash-based account records money in and money out in the year it moves. A promise to pay pensions in 30 years costs nothing this year, and a road wears out without any payment. Neither shows up until the cash flows. The economic balance sheet counts them now, as obligations set against the claim on future taxes. That is why it is the better guide to how much a government can safely borrow.

Go deeper What happens when a sovereign suspends a benchmark maturity

If a government sees surpluses and a lower need to borrow, it may stop issuing one maturity. The market loses its benchmark at that point, so yields can move sharply on supply fears, and the nearest maturity becomes the reference until issuance resumes. The episode shows how much the market relies on regular issues.

Go deeper Floating-rate and inflation-linked sovereign bonds: who buys them

Floating-rate bonds suit investors who want little interest rate risk, such as banks. Inflation-linked bonds suit pension funds and insurers whose obligations rise with prices. For the issuer, the cost shifts with short rates or inflation, which is one more reason to spread across instruments.

Exam tip Follow the currency: debt in a reserve currency is the safest; debt in a foreign currency still needs the issuer to earn that currency.