Russia’s main crude grade is still selling well below international benchmarks — and a Group of Seven-imposed price cap — but a huge amount of money for delivering it continues to go into the hands of mystery middlemen.

The country’s flagship Urals grade averaged about $52 a barrel so far this month at the Baltic Sea port of Primorsk, according to data from Argus Media. The G-7 only allows firms to provide key services such as insurance and tankers for Russian oil exports if the barrels cost $60 or less.

However, the gap between the export price and the import price in India stood at about $12 a barrel so far in June. The size of that spread matters because, multiplied by export volumes, it implies about about $900 million a month is going into the hands of a web of intermediary firms — traders, shipbrokers and tanker owners — whose affiliations are unclear. The gap has nevertheless whittled down, having averaged $13 in May and $15 in April.

Even so, Urals is still trading at hefty discounts to international prices. Large amounts of oil trades relative to Dated Brent, a physical price benchmark anchored in the North Sea. Urals averaged about $23 less than the marker so far this month, about the same as in May, but a slightly smaller discount than in April, according to Argus data.

The European Union banned seaborne imports of Russian crude back in December, the same time as the price cap was introduced. The prohibition forced Russian barrels to discount to compete for buyers in Asia.

Argus Media’s prices are central to determining the price cap.