Russia will see revenue from its biggest single oil tax double to $9 billion in April due to the oil and gas crisis triggered by the U.S. and Israeli attack on Iran, Reuters calculations showed on Thursday.

The Reuters calculation is some of the first concrete evidence of a windfall for Russia, the world's second-largest oil exporter, from the Iran war, which oil traders say has triggered the most serious energy crisis in recent history.

Iran effectively shut the Strait of Hormuz - a route for ​about a fifth of global oil and LNG flows - after U.S. and Israeli airstrikes on Iran at the end of February, sending Brent futures shooting well past $100 per barrel.

Russia's main revenue from its vast oil and gas industry is based on production. Export duty on crude oil has been nullified from the start of 2024 as part of the so-called wider tax manoeuvre, a years-long tax reform of the industry.

According to Reuters calculations based on preliminary production data and oil prices, Russia's mineral extraction tax on oil output will increase in April to around 700 billion roubles ($9 billion) from 327 billion roubles in March. The revenue is up by some 10% from April last year.

For the whole of 2026, Russia has budgeted for 7.9 trillion roubles from the mineral extraction tax.

RUSSIAN ENERGY IN DEMAND

The average price of Russia's Urals crude, used for taxation, jumped to $77 per barrel in March, its highest since October 2023, according to economy ministry data.

That was up 73% from February's $44.59 per barrel and above the level of $59 assumed in this year's state budget.

The Kremlin said on Tuesday there were a huge number of requests for Russian energy from a range of different places amid a grave global energy crisis that was shaking the foundations of the oil and gas markets.

Still, there are limits on the windfall for Russia, and economists inside Russia have repeatedly cautioned that 2026 could be a tough year.

Russia ran a budget deficit of 4.58 trillion roubles, or 1.9% of gross domestic product, in January-March 2026, the finance ministry said on Wednesday.

And Ukraine's attacks on Russian energy infrastructure, with an aim to cripple Moscow's finances, have also contributed to lower earnings and threaten oil production cuts.

The size of the windfall for Russia will ultimately depend on how long the Iran crisis lasts.

($1 = 78.3000 roubles)

-Guy Faulconbridge and Keith Weir/Reuters