Between 7 September and 6 October Russia's Minfin will buy 55.6 billion roubles of foreign currency and gold under the budget rule — 2.5 billion roubles a day, against 6.5 billion the month before. Minfin announced it at noon on 3 September. One figure explains the cut: August oil and gas revenue came in 45.0 billion roubles below the ministry's forecast.
The release
It is three sentences long, and the middle one is the mechanism:
“The expected volume of additional oil and gas revenues of the federal budget is forecast for September 2026 at 100.7 billion roubles. The total deviation of the oil and gas revenues actually received from the expected monthly volume of oil and gas revenues, and of the estimate of the base monthly volume of oil and gas revenues from the base monthly volume of oil and gas revenues, came to −45.0 billion roubles for the results of August 2026. Accordingly, the aggregate volume of funds directed to the purchase of foreign currency and gold will be 55.6 billion roubles.”
A month earlier the same release had a different shape. On 5 August the ministry expected 114.23 billion roubles for August, added a correction of 21.94 billion in its favour, and bought 136.17 billion — 6.5 billion roubles a day.
Where the 45 billion came from
Minfin's monthly budget-rule workbook contains the full calculation, including August. Total oil and gas revenue for the month was 424.0 billion roubles, against a base monthly volume of 427.8 billion. A year earlier August brought in 505.0 billion, so this August was 16.0% lower. Only January of this year was worse — 393.3 billion, the weakest month in the series since 2021.
A minus that is not a collapse
The same workbook has a line that looks worse than the underlying result. Additional oil and gas revenue for August: −3.8 billion roubles. On its own, it suggests that the revenue feeding the budget rule disappeared. This is a calendar artefact, and the footnote to the table explains why:
“the difference between the actual and the expected monthly volume of additional oil and gas revenues for the previous month. The forecast and base volume of receipts from the tax on additional income is distributed evenly within the current quarter across each month of the corresponding quarter.”
The tax on additional income from hydrocarbon extraction is paid quarterly. August is not a payment month — the workbook's line for it shows −1.4 billion roubles, against 396.1 billion in July. The base against which August is measured still includes a third of the quarter's take because the rule spreads it evenly. Comparing an unsmoothed month with a smoothed base produces the −3.8 billion.
The workbook keeps both readings. Its reference line, computed without the even spreading, puts the August correction at −118.0 billion roubles. The line the rule actually uses puts it at −45.0 billion. The 73.0 billion between them is not revenue; it is what the smoothing does to a single month.
Buying against a forecast
The September purchase rests on two numbers pointing in opposite directions. 100.7 billion roubles is the forecast for September. −45.0 billion is the August outturn. Minfin adds them, and the release gives the answer as 55.6 billion; the published figures are rounded to one decimal, and August's release, which gave two, adds up exactly — 114.23 plus 21.94 is 136.17.
So what goes into reserves this month is set mostly by an expectation, while the only completed month available to the ministry came in short. If September repeats August, October's correction takes part of it back. That is the design working as intended, not a failure of it — but it means the monthly number responds first to forecasts and only later to receipts.
The year in one line
The workbook's operations line reads, for 2026: January −192.1 billion roubles, February −226.8 billion, no operations in March or April, then May 110.3, June 208.2, July 123.2, August 136.2 and September 55.6. Negative is a sale, positive a purchase.
February's 226.8 billion is the largest single-month sale since the series begins in 2018, ahead of June 2020 (203.7 billion) and May 2020 (193.1 billion); January 2026 is fourth. Then two months with no operations at all, then five months of buying. September's 55.6 billion is the smallest of those five. It is not the smallest purchase in the series — August 2024 was 24.7 billion — and it is not the first fall inside this year's run either: July was already below June. What differs is where the fall comes from. July's came mostly from a lower forecast, 220.2 billion down to 147.3. September's comes mostly from the correction, which swung from +21.9 billion in August to −45.0.
What this changes in our model
Nothing today. Liquid NWF scores 28 out of 100: 3,692.8 billion roubles, about $46.2 billion, on 1 August. These operations are how the rule converts additional oil and gas revenue into currency and gold for the fund, so a smaller purchase means a smaller flow through that channel. But 55.6 billion roubles is a planned flow for one month, and our indicator is a stock taken from a different Minfin file. For scale only: 55.6 billion is about 1.5% of the liquid part, June's 208.2 billion about 5.6%.
Oil and gas revenue scores 14 — rolling twelve-month real revenue at 56.9% of the 2021 total, through July. August's 424.0 billion is one nominal monthly figure and does not move the indicator: it measures a twelve-month deflated level against 2021. The two can point in different directions at the same time for the same reason the −3.8 line misleads. A month is not a year, and a nominal number is not a real one.
Today we also describe an operation that would change the fund from within, without any oil money at all.
What we do not know
Minfin does not say why August revenue fell short. The release gives one deviation and no breakdown into price, output, exchange rate or excise refunds. The base monthly volume for September is still empty in the workbook, so how demanding this month's threshold is cannot yet be read off the file. The split of the 55.6 billion between currency and gold is not published — the release gives one sum. And the central bank conducts these operations with its own adjustment for the mirroring operations it runs for the fund, so the amount actually reaching the market each day will differ from 2.5 billion roubles; we found no CBR notice for the period beginning 7 September.