An oil-storage tank operated by Rosneft in Tuapse, Russia. The European Union has blocked its companies from doing most business with the Russian producer. A group of under-the-radar commodity traders are cashing in on Russian oil , stepping in to buy and transport crude to customers as their bigger rivals retreat from the market. Little-known merchants including Paramount Energy & Commodities SA and Coral Energy Pte. Ltd. are buying unwanted Russian oil at deep discounts. For taking on the risk, the companies can make $20 million or more on one cargo depending on the size of the tanker, according to traders. That is up from $600,000 before the war.