Primary Budget Deficit: What Remains Once Debt Interest Is Stripped Out

The primary budget deficit is the gap between government revenue and spending, calculated without the cost of servicing the debt. Interest payments on obligations already issued are subtracted from the overall deficit, and what remains is examined. If a gap persists after that deduction, the state is borrowing not only to pay interest but also to fund its day-to-day operations: salaries, defence, construction projects, transfers. If, on the other hand, the budget moves into surplus once interest is excluded, then the entire borrowing requirement stems from accumulated debt rather than from today's spending decisions.

How the indicator is calculated

The logic is simple, and that is precisely its value. Start with the ordinary budget deficit — the difference between total spending and total revenue. Then remove from the expenditure side the interest the treasury is obliged to pay on previously placed securities and loans. The result is the primary balance: a deficit if it is negative, a surplus if it is positive.

The key property is that interest expenditure is a legacy. Its size is determined by how much was borrowed in the past and at what rate, and today's finance minister cannot change it short of refusing to pay. Everything else in the budget is a matter of current choice. That is why the primary balance is read as a measure of the controllable part of fiscal policy, while the overall deficit is read as a measure of the actual need for money.

Why separate the two if the borrowing has to happen anyway

For the treasury it makes no difference: money is needed to cover the full deficit, and it is raised on the primary market for government debt. The distinction matters not for cash management but for diagnosis.

Imagine a state where spending has been cut hard and taxes are collected diligently, yet the deficit remains large. If the primary balance is in surplus, the diagnosis is a debt trap: the economy is servicing past borrowing, and new issues go towards paying interest on old ones. The cure is not yet another round of spending cuts but lower borrowing costs, economic growth or restructuring.

The opposite picture: the overall deficit is moderate, but the primary balance is also in deficit. This means the debt burden is still cheap and the state is borrowing to meet its current obligations. While rates are low this looks harmless; when they turn, the interest bill starts to climb, and the existing primary gap becomes unsustainable.

Debt arithmetic: the stabilisation condition

The debt-to-GDP ratio stops rising when one condition holds: the primary surplus covers the excess of the interest rate on the debt over the growth rate of the nominal economy. A less obvious corollary follows — when the rate is below nominal GDP growth, the debt ratio can fall even with a primary deficit. A growing economy "erodes" the debt faster than interest accrues.

This is why discussions of fiscal sustainability always pair the primary balance with the relationship between interest rates and growth, rather than relying on a single indicator. The current cost of borrowing for the Russian state can be seen on the yield curve on the OFZ page: the long end of the curve is the very rate at which the debt will have to be refinanced in the future.

What changes for investors

For holders of government securities, the primary balance is a leading signal of supply in the debt market. A persistent primary deficit means the Finance Ministry will come to the market regularly, in volumes that do not depend on market conditions, because the spending is fixed by law. The market responds by demanding a term premium, and long-dated issues are the first to lose value. The composition and parameters of outstanding issues can be found in the bonds section, while auction decisions and budget news appear in the news feed.

For the equity market the transmission channel is indirect but tangible: narrowing the primary deficit often involves tax fine-tuning, which hits the profits of commodity exporters — the heaviest-weighted segment of the Russian equity market. A widening deficit, by contrast, supports demand in the economy but at the same time pushes up inflation and the policy rate, and with the rate, the required return on equities.

Limits of the indicator

The primary balance speaks to the size of the budget gap, not its quality. A deficit channelled into infrastructure that will broaden the tax base and a deficit consumed by current spending look identical in this indicator. It is also silent on the structure of the debt: with the same primary deficit, a state with short-term foreign-currency borrowing is more vulnerable than one with long-term debt in its own currency.

The platform's database does not hold current figures for Russia's primary balance — the indicator is published in the Finance Ministry's budget reporting rather than in market data, and it is more honest to say so than to quote a figure from memory. Related concepts are explained in the glossary.