Schrodinger’s Strait, Schrodinger’s Market

By Benjamin Picton, Senior Market Strategist at Rabobank

Erwin Schrodinger famously proposed a thought experiment to illustrate the apparent absurdity of quantum mechanics when applied to the macroscopic world. In the theoretical experiment, Schrodinger’s eponymous cat, contained in a box with a radioactive atom, a Geiger counter and a vial of poison, exists in a state of superposition whereby it is simultaneously both alive and dead until the box is opened.

And so it is with the Strait of Hormuz, which exists in a state of both openness and closedness until a ship actually attempts the transit.

On Friday Iranian Foreign Minister Araghchi posted on X that the Strait was “completely open” to all commercial vessels for the duration of the 10-day ceasefire between Israel and Lebanon. Markets reacted swiftly, the S&P500 rose 1.20% to close at a new all-time high and the Brent crude front future fell more than 9% to settle at $90.38/bbl – its lowest weekly close since the war began. Even dated Brent (the physical oil price for immediate delivery) fell by more than 15% to $98.95/bbl – its lowest level since March 11th, which was the immediate aftermath of Trump’s comment that the war in Iran is “very complete”.

The all important dated brent is plunging pic.twitter.com/rPRiOMp0BV

— zerohedge (@zerohedge) April 17, 2026

However, the joy of financial markets has now turned to ash in our mouths as the Iranian Revolutionary Guard Corps moved to re-establish (or re-assert?) the closure of the Strait. Several vessels were turned back over the course of the weekend and two were fired upon by the IRGC, prompting the Indian government to summon the Iranian ambassador to protest. Al Jazeera reports that more than a dozen ships attempted to transit the Strait in the brief time that it was open – including 8 successful transits of oil and gas tankers – but shipping had ground to a standstill again by Sunday.

And rejected: the two tankers taking the neutral route, Minerva Evropi and Nissos Keros, have turned around; the Sanmar Herald which appears to be taking the Iran-sanctioned Larak island route is proceeding. https://t.co/aceBI7ki0B pic.twitter.com/gmkM37iA1U

— zerohedge (@zerohedge) April 18, 2026

Also on Sunday, the US Navy seized the MV Touska, an Iranian-flagged cargo ship that had been attempting to break the blockade en-route from Gaolan in China to the Iranian port of Banda Abbas. After a 6-hour radio standoff, the USS Spruance fired its main gun to disable the Touska’s propulsion systems before the vessel was boarded by US marines, marking the first known use of force in enforcing the blockade. The Washington Post reports that Gaolan is a known port of origin for sodium perchlorate, the primary oxidizer in solid rocket fuel for Iranian ballistic missiles.

U.S. Marines depart amphibious assault ship USS Tripoli (LHA 7) by helicopter and transit over the Arabian Sea to board and seize M/V Touska. The Marines rappelled onto the Iranian-flagged vessel, April 19, after guided-missile destroyer USS Spruance (DDG 111) disabled Touska’s… pic.twitter.com/mFxI5RzYCS

— U.S. Central Command (@CENTCOM) April 20, 2026

Thus, the seizure of the Touska marks a potential point of escalation for both sides. The IRGC has nominated lifting the US blockade as a red line for opening the Strait, which they say would need to be done under Iranian auspices, and the US has threatened secondary sanctions against any country that provides Iran with weapons.

Unsurprisingly, markets this morning are once again repricing the status of the Strait and the diminished prospect for a peace agreement ahead of the expected expiry of the US-Iran ceasefire on Wednesday. Brent crude has opened 7% higher, high beta FX is being sold sharply, and US equity futures are pointing to losses of ~0.8% at market open.

IRGC commander Vahidi is reported to have said that the Strait will open “by order of the [Supreme] Leader, not by the tweets of some idiot” in an apparent reference to Araghchi, highlighting the divisions between the IRGC and the civilian government in Tehran. US Senator Lindsey Graham has summarized the situation succinctly by tweeting “the guy in the suit (Araghchi) is not in charge. It’s the guys with the guns (the IRGC) who are in charge.”

Unfortunately, the US has been negotiating with the guys in the suits. This may be what Donald Trump was referring to when he previously said that regime change has already taken place. This also means that the progress that US negotiators have reportedly made with Iranian chief negotiator Ghalibaf are likely subject to an IRGC veto.

Ghalibaf himself has been issuing defiant tweets over the weekend peppered with oil trading advice and mini tutorials on how to use a Bloomberg terminal to effectively ‘monitor the situation’. One suspects that these are ghost-written by the IRGC in a similar fashion to the proclamations of Mojtaba Khamenei, who still hasn’t been seen since the war started.

Vibe-trading digital oil is like vibe-hedging in treasuries during Hormuz risk-off. Both share one house of cards that works on paper.
Difference: oil at least has Dated Brent. Treasuries? Vibes all the way down.

EUCRBRDT Index GP

— محمدباقر قالیباف | MB Ghalibaf (@mb_ghalibaf) April 19, 2026

With Wednesday’s ceasefire expiry looming as a critical risk event for markets, the Wall Street Journal reports that Vice President J.D. Vance is set to lead a fresh round of peace talks with Iran in Pakistan on Tuesday. Awkwardly, there is no confirmation so far that the Iranians will turn up. Multiple outlets are citing Iranian state media reports that Iran will not be attending the talks due to the unreasonableness of US demands and the ongoing blockade of Iranian ports. Meanwhile, the US has been moving more and more military assets toward the region, including the Gerald R. Ford and George H.W. Bush carrier strike groups.

So, while we have Schrodinger’s Strait we also have Schrodinger’s market where we are simultaneously in the grip of the largest energy shock in history (according to the IEA) with physical shortages of loads of things needed for 21st century life, but this is also incredibly bullish and stock indices remain close to all-time highs.

Wrapping your head around this paradox might approach the impenetrability of quantum mechanics.