Iran's oil exports accelerated to a recent record in April, indicating Tehran is seeking to maximize revenue ahead of the U.S. President Donald Trump's upcoming decision on the 2015 nuclear deal and the possible re-imposition of sanctions.
Exports of crude and condensate — a grade of ultra-light crude oil — hit 2.767 million barrels a day last month, according to data from Tanker Trackers. That was an increase from 2.104 million in March.
Official estimates from Iran's oil ministry put April's figure at 2.617 million barrels a day, the highest since implementation of the Joint Comprehensive Plan of Action (JCPOA) nuclear deal in January 2016, according to the ministry's Twitter account.
Benchmark oil prices have hit levels not seen since 2014, reflecting fears about supply disruptions from Iran to Venezuela and as the Organization of Petroleum Exporting Countries cuts supply in a bid to normalize inventories.
Recent appointments to Trump's national security and foreign policy team — including former U.N. ambassador John Bolton to national security advisor — suggest Washington will adopt a harder stance against Iran.
"Iran has opened the gates, drawing inventories wherever possible and monetizing shipments and sales," said John Driscoll, director of JTD Energy Services in Singapore and a former oil trader whose career spans nearly 40 years. "They are preparing for a JCPOA rollback. You can bet John Bolton's mustache on it."
Robin Mills, CEO of Qamar Energy and a former Shell executive added: "It does appear Iran is trying to draw down all its storage ahead of the JCPOA deadline in case it has problems exporting it later."
Trump will announce on Tuesday whether he will withdraw from the Iran nuclear deal and a senior U.S. official said it was unclear if efforts by European allies to address Trump's concerns would be enough to save the pact, Reuters reported.
Trump gave no indication of which way he was leaning on Monday, saying only in a Twitter post he would announce his decision at 2 p.m. Eastern on Tuesday.
Benchmark oil prices slid by as much as 1 percent in Asian trade on Tuesday on expectations Washington may not abandon the Iran deal entirely but keep the threat of sanctions pressure alive while insisting on an overhaul of the Obama-era agreement.
"Trump will distance himself from the nuclear deal, but the road to sanctions reinstatement is long and bumpy," said Gal Luft, co-director of the Institute for the Analysis of Global Security.
Oil markets are faced with a range of scenarios on the possible course of action the Trump administration may take, though strategists contacted by CNBC on Monday were in broad agreement that Trump would abandon the deal and re-impose sanctions.
"The possibility that waivers on sanctions are not renewed ... is very high," said Harry Tchilinguirian, global head of commodity markets strategy and senior oil market analyst at BNP Paribas.
Ole Hansen, head of commodity strategy at Saxo Bank, said the decision would be a "binary event" with an upside risk of $5 while the downside could be $5 to $10.
Long positions or speculative bullish bets in the oil futures market — in anticipation of a failure of the Iran deal — may unwind swiftly should the outcome be more benign, leading to a sharp retracement in the price.
Crude futures in New York have rallied more than 15 percent so far this year and money managers' bullish stance on the benchmark is close to double the levels seen in October.
"Speculative length is so staggeringly high that, in fact, anything can bring about the price correction, whether it's soft tones from the White House or an increased nervousness on financial markets," said Eugen Weinberg, head of commodity research at Commerzbank.
Strategists are hard-pressed to quantify how much Iranian oil would be taken off international markets if sanctions returned, and when the loss would be material. Much depends on whether Tehran's customers would fall into line and comply with U.S. sanctions. Qamar Energy's Mills said "higher-end estimates" of over 500,000 barrels a day "look excessive given the much lesser international support for sanctions this time."
Saxo's Hansen said, assuming "U.S. friendly countries" in Europe, Japan and South Korea cooperate and cut imports from Iran completely, it could amount to 750,000 barrels a day. "Such an outcome would have a significant impact on global balances and would support current and probably even higher prices." Saudi Arabia is unlikely to step in with extra barrels unless the spike extends beyond $80 a barrel, he added.
Russia and China, however, "can offer a lifeline" to Iran, said JTD Energy's Driscoll. "As a major exporter who has successfully coped with U.S.-imposed sanctions for several years, Russia can become a critical ally for Iran."
Meanwhile, China's yuan-denominated Shanghai crude oil futures launched in March "may offer Iran a reprieve for surplus crude that can circumvent U.S. financial sanctions and dollar-denominated transactions," Driscoll said.
That said, if Trump restores core U.S. sanctions, under U.S. law he must wait at least 180 days before targeting banks of nations that fail to cut significantly their purchases of Iranian oil.
"Even if sanctions are imposed, there is no impact on Iranian oil exports until November 12, 2018 at the earliest," said Fereidun Fesharaki, chairman of energy consultancy Facts Global Energy and a former energy advisor to the prime minister of Iran in the 1970s. "We continue to maintain that there is a high likelihood of creating roadblocks for Iran, but not necessarily reducing Iran's oil exports substantially."