Foreign oil tanker owners are expected to make a slow return to Iran despite the lifting of many sanctions as insurers tread carefully, leaving shipping players unwilling to pick up cargoes as quickly as Tehran has wanted.
A nuclear deal between world powers - known as the P5+1 - and Iran led to the removal on Saturday of international oil export prohibitions as well as restrictions on banking, insurance and shipping for Tehran.
With U.S. sanctions still in place, which exclude U.S. persons, banks and insurers from trading with Iran including dollar business, shipping and marine insurance sources say many foreign companies are likely to take their time.
They are also mindful of sanctions being reimposed in a "snap back" if Iran reneges on commitments.
"In shipping terms, we think the impact will be a slow development. The initial oil sales will be the oil currently stored on (Iranian) ships in the Persian Gulf," said Paddy Rodgers, chief executive of oil tanker company Euronav .
"It will take time for this increase in production to be transported on the commercial tanker fleet given the financial sanctions still in place and reluctance of insurance providers to cover given the snapback provisions in the P5+1 agreement."
"So, any additional increase in Iranian barrels being produced will be shipped on Iranian vessels."
Securing international insurance cover as well as reconnecting with the international banking system will be key to determine how quickly Iran can ramp up oil exports and re-engage with the foreign shipping sector.
Third-party liability insurance and pollution cover for vessels is provided by P&I clubs - marine insurers owned by shipping clients and reinsured internationally.
"There will be a time period whilst all financial services and businesses sit there and work out what the opportunities are, what the risks are before re-engaging," said Mike Salthouse, deputy global director with ship insurer North of England P&I Association.
"Some of the teething issues will need to be worked through."
Salthouse said since the 2008 financial crisis, the financial services industry had become more focused on compliance, which included sanctions regulations.
"There is probably less appetite for risk in the world today than in 2010 and we are all much more aware of the risks presented by any jurisdiction that presents compliance-type issues," he said.
Sanctions also remain on Iran's hardline elite Revolutionary Guards and their affiliates, which play a major role in the country's economy.
Washington slapped new sanctions on companies accused of supporting Iran's ballistic missile programme, drawing an angry response from Iranian officials.
"There will also be a continuing issue of having to take care about not supporting transactions with sanctions targets where designations remain in place," a separate ship insurance source said.
"And one suspects that banks might prove to be slow to be willing to support transactions involving Iran again, especially any transactions in U.S. dollars, with continuing irritant effects for all doing business there."
Another ship insurer, Swedish Club, said the continued U.S. sanctions could mean "U.S. insurers and reinsurers in various global marine reinsurance programs may be unable to meet their obligations and pay a claim with an Iranian nexus".
Opportunities
Industry association Intertanko, whose independent members own the majority of the world's tanker fleet, said the removal of sanctions opened up opportunities for owners.
"We foresee a cautious return, given U.S. domestic sanctions may well still limit reinsurance," said Intertanko's general counsel, Michele White.
"It will also mean a return from storage to regular trade of the Iranian tanker fleet, both increasing available tonnage and oil onto an already saturated market."
Iran's oil exports have fallen to just over 1 million barrels per day (bpd), from a peak of more than 3 million bpd in 2011 - before the imposition of tougher sanctions.
Iranian officials have said repeatedly in recent days that they were ready to raise output by half a million bpd.
Oil held by Iran on its domestic tankers in floating storage is estimated by shipping sources to be more than 40 million barrels as the country struggles to offload supplies because of a global glut.
Sources say as many as 22 to 25 tankers are holding oil, both crude and its derivative condensate, which is expected to hit world markets at some stage.
Iran's fleet will also need to secure the return of ship classification societies, after being cut off from this international market since 2012. Such companies verify safety and environmental standards for ships - vital for securing insurance and making calls at international ports.
Britain's Lloyd's Register said on Monday it was working on resuming services, while Norwegian-headquartered DNV GL said it was considering "re-entering the Iranian market".
Another leading classification player - France's Bureau Veritas - said it planned to give Iranian ship owners "full support to assist their re-entry into global service", without providing further details.