Western shipowners, predominantly Greek companies, have earned over $6.3 billion by selling aging tankers that now form a "shadow fleet" circumventing sanctions to maintain Russia's oil exports. This network of approximately 600 ships, with around 230 vessels originating from European and U.S. sales, moves an estimated 70% of Russia's oil exports. The sales are technically legal as they are made to entities in non-sanctioning jurisdictions like India, Vietnam, and Hong Kong, often involving multiple resales.

More than half of the tankers identified in a collaborative investigation by Follow The Money and OCCRP were sold by 54 Greek-operated companies for at least $3.7 billion. Companies like Tsakos Energy Navigation Ltd, Marla Tankers, and Toro Corp (based in Cyprus) have profited significantly. For instance, Tsakos sold a tanker for 21 million euros that later appeared transporting Russian oil under a new name and flag, while Toro Corp resold six aging tankers for $195.4 million in 2023 and early 2024, earning $111.7 million. Many of these vessels subsequently faced U.K. sanctions after being caught transporting Russian oil.

Despite sanctions, Greek tanker operators continue to ship approved Russian oil, accounting for dozens of shipments monthly and an estimated 20% of overall trade. While this has become more challenging, it remains "doable" according to shipping sources. Greek operators have even regained market share in Russian crude exports, particularly when prices, such as for Urals crude, fall below Western price caps like the G7's $60 per barrel, allowing them to comply with sanctions while providing transport and insurance services. For example, in February, G7-linked tankers lifted 33% of seaborne Russian crude exports, up from 30.1% in January, largely due to the return of Greek operators, as Russia keeps prices below the cap to utilize these services.

The effectiveness of current sanctions is questioned, as the shadow fleet has successfully propped up Russia's oil revenue, which significantly funds its federal budget and war efforts. While direct sales of oil tankers to Russian entities are prohibited, the indirect sales exploit a loophole that allows firms in non-sanctioning countries to acquire these vessels. Experts like Benjamin Hilgenstock of the KSE Institute suggest the sanctions effort has not been effective, although making it harder and more costly for Russia to continue its economic activities is a partial success.