13 August 2026
Executive Summary
The Strait of Hormuz remains heavily restricted as attempts to revive the US-Iran interim agreement show no meaningful progress.
Iran continues to insist that the Strait will not fully reopen until Washington meets its conditions, while the United States maintains restrictions against Iranian ports and shipping. Vessel movements through Hormuz fell to a one-week low on Tuesday, with tracking data showing only a fraction of normal pre-conflict traffic.
What is increasingly important for businesses is the “siege” logic developing around regional trade. ‘Siege’ is not a formal legal description of the Strait itself; we are using it here to describe the growing pattern of blockade, counter-blockade, selective maritime access and economic pressure being applied across the region.”
The US has imposed a naval blockade affecting Iranian ports. Iran is restricting passage through Hormuz. Meanwhile, Yemen’s Houthis have declared restrictions against Saudi-linked shipping in what they describe as retaliation for a Saudi “siege” of Yemen. Riyadh rejects that characterisation.
The result is a system of blockade, counter-blockade and selective maritime access rather than one straightforward shipping closure.
UK Impact
For UK businesses, the risk is that maritime restrictions increasingly depend upon who owns the vessel, where it is going, what it carries and which parties are connected with the transaction.
That can affect:
- Vessel availability.
- War-risk insurance.
- Chartering decisions.
- Sanctions compliance.
- Oil and gas pricing.
- Delivery schedules.
- Freight costs.
- Commodity availability.
- Contractual performance.
A ship may technically be capable of travelling through a region but still be commercially unusable because the owner, crew, insurer or bank will not accept the exposure.
There is also an important sanctions complication. Previous proposals involving payments for passage through Hormuz have been regarded by shipping industry participants as potentially unworkable where payments could breach US sanctions or invalidate insurance protection.
Global Impact
The “siege” approach differs from a conventional blockade because the commercial pressure can extend well beyond the immediate waterway.
It can involve:
Ports → ships → insurers → banks → commodity traders → energy producers → customers.
The objective becomes economic pressure rather than simply preventing physical navigation.
Recent developments demonstrate how quickly those pressures can spread. A Houthi attack in the Bab el-Mandeb this week killed crew members and rescuers, while US forces separately disabled a vessel that Washington said was attempting to breach restrictions on Iranian ports.
Saudi Arabia is also increasingly moving some Red Sea oil exports with vessel-tracking systems switched off amid fears of Houthi attacks. This reduces transparency over global energy flows and complicates market analysis, sanctions screening and maritime risk assessment.
Our View
Businesses should now stop modelling Hormuz simply as:
Open or closed.
The more realistic scenarios are:
Open → Restricted → Selective access → Commercially uninsurable → Effectively closed.
Companies should:
- Identify vessel ownership and flag before committing cargo.
- Check whether the cargo itself creates additional targeting risk.
- Confirm insurer approval for the specific voyage.
- Screen every payment recipient involved in passage or port services.
- Review sanctions exposure before agreeing additional transit charges.
- Confirm whether charterparties allow refusal of unsafe routes.
- Monitor changes to port and vessel restrictions throughout the voyage.
- Maintain alternative sources of Gulf-dependent commodities.
- Stress-test supply chains against prolonged selective access.
- Avoid assuming that political announcements automatically restore normal trade.
The key point for clients is this:
A siege strategy does not need to close a trade route completely to damage commerce.
It only needs to make using that route sufficiently uncertain, expensive or legally difficult that businesses stop using it voluntarily.
Risk Indicator: HIGH
Disclaimer
The information contained within these Market Alerts is provided for general market awareness and informational purposes only. It does not constitute financial, legal, investment, regulatory or insurance advice. Whilst every effort has been made to ensure accuracy at the time of publication using multiple reputable and independently verified sources, geopolitical events, legislation, regulation and market conditions may change rapidly. Readers should obtain appropriate professional advice before acting upon any information contained herein.
Invictus Risk Solutions LLP – Helping organisations stay ahead of emerging risks through informed insight and independent analysis.