Commodity firms will find it much harder to buy and sell Russian oil from the middle of this month, according to the world’s biggest independent crude trader, as Europe tightens sanctions on Moscow for invading Ukraine.

Russia’s exports of crude and oil products have probably dropped by around 1 million barrels a day from 7.5 million before the attack in late February, Mike Muller, head of Asia at Vitol Group, said Sunday on a podcast produced by Dubai-based Gulf Intelligence. They could fall further after May 15, he said.

Many trading houses interpret European Union regulations as prohibiting them from dealing with Russian state energy companies beyond then.

“We’re virtually on top of that date where the international banking system just cannot make payments to Russian entities work,” Muller said. “EU sanctions prohibit a whole number of things from May 15.”

There will be a “different reality” even for companies that have until now kept up Russian energy purchases because they have contractual obligations to fulfill, he said.

Geneva-based Vitol, which traded 7.6 million barrels of crude and refined oil a day in 2021, said last month that it intends to stop dealing in Russian-origin products by the end of this year.

Oil jumped to a multi-week high of around $110 a barrel last week as the EU moved closer to formally banning imports from Russia. The bloc intends to sanction Russian crude in six months and oil products by the end of the year to punish the Kremlin for the war. Some members, notably Hungary, are trying to prevent a ban, however.

Many traders, shippers, insurers and banks are already shunning Russian energy for fear of breaching existing financial sanctions or to avoid reputational damage.

Some smaller merchants will continue dealing with Russia beyond this month, said Muller. Still, there will be delays and bottlenecks as they struggle to find shippers and insurers willing to take on exposure to Russian barrels.

“An entire segment of the shipping market will need to be dedicated to this trade,” Muller said. “There are many words for it, but it’s clearly not mainstream. The oil will trade at a discount and the ships will trade at a premium because the ship owner engaging in this business may find his ships aren’t accepted by anybody else for some time to come.”

Few nations beyond the U.S. and Europe have imposed sanctions on Russia and many are keen to buy more of its oil, which is being sold with hefty discounts.

India, one of the world’s biggest crude importers, has increased purchases from Russia since the invasion and is trying to get even bigger price deductions, Bloomberg reported last week. Germany has invited Indian Prime Minister Narendra Modi to a Group of Seven leaders’ summit next month as a special guest, part of an effort to forge a broader international alliance against Moscow.