China, India, Japan and South Korea are the four biggest buyers of Iranian crude in Asia, and all of them have cut imports. The sanctions are making it hard for refiners who want to continue importing to find shippers, insurers to underwrite trade and banks to clear payments.
Industry sources in Japan said that trading houses and refiners there would reduce Iranian crude imports by about 60,000 barrels per day (bpd) in April.
The EU sanctions on Tehran will close off the European re-insurance market for all tankers carrying Iranian oil anywhere in the world. Reinsurance helps spread the risk when the coverage surpasses what commercial insurers can handle.
Japan and South Korea have lobbied for exemptions to the EU sanctions, but insurance and shipping executives say a complete ban looks likely.