Oil tanker owners in Greece, the world’s most powerful shipowning nation, scaled back how much Russian crude they’re hauling, a decision that could ultimately disrupt the flow of Moscow’s petroleum.

The number of Greek-owned tankers going to Russia will fall by a quarter this month compared with last, and is down 60% from June, ship tracking data compiled by Bloomberg show. That may well alarm officials in the Kremlin because the country still needs assistance from foreign vessel operators to get all its barrels to the global market.

Earlier this month, the US Treasury spooked some tanker owners by asking them to explain what they’d done to comply with a Group of Seven price cap on Russian oil. Officials from two Athens-based companies said shortly after that they were treading carefully while they evaluated the situation.

That caution appears to be borne out in ship-tracking compiled by Bloomberg showing that Greek tankers will move just 15 cargoes of Moscow’s flagship Urals crude loaded from ports in the Baltic and Black Sea in November. They moved 20 in October.

A Group of Seven price cap means firms in the European Union are only allowed to move Russian crude if the cargoes cost $60 a barrel or less. Despite Urals having surged above that level in July, the trade didn’t stop.

The apparent decline in Greek involvement has coincided with signs that Russia’s overall exports will also drop. Such a decline would be at odds the aim of the price cap, which is to keep Russian oil flowing while depriving Russia of revenue.

It is still possible that some Greek owners will return to the Russian trade once they’ve had time to fully evaluate the Treasury’s letters.

If the current rates of exports continue, and cargoes already scheduled go ahead as planned, Russia’s crude shipments could be on course to decline by about 150,000 barrels a day this month. That’s similar to the decline in the amount of oil that Greek tankers will move, although it is important to note that Moscow is taking its own steps to limit supply along with others in OPEC+.

Shift Away

Greek-owned vessels still haul about one-fifth of all Russian Urals cargoes and about one in seven of all cargoes of Russian crude, including those shipped from terminals on the country’s Pacific and Arctic coasts, vessel tracking data monitored by Bloomberg show.

The Group of Seven imposed its $60 cap on crude purchases in December 2022 and followed up with thresholds for refined fuels in February of this year. The measures require G-7 shipowners to get attestations from traders stating that the oil was purchased at or below the price limit. If it wasn’t, they are in theory not allowed to provide services.

Until recently, shipowners and insurers have taken such pledges at face value. 

But the letters from the US Treasury, sent to about 30 firms controlling about 100 oil tankers, caused concern among some ship owners. 

A copy of one of the letters, which was seen by Bloomberg, asked for wide-ranging information and documentation about the shipments and the entities involved in them. It threatened prison if recipients didn’t comply in full.

Officials at two insurers also said that the tone of conversations with authorities has shifted in recent weeks, suggesting a stricter implementation of the cap.

US authorities followed up the letters with sanctions against a few specific ships and their owners. So far, these have been little-known companies, most of them ultimately owned by Sovcomflot, the state-run Russian tanker company, according to data compiled by Bloomberg.

The shipment figures for November include cargoes that already left plus all the vessels scheduled to load Russian crude by the end of the month.