The mine threat outlasts any deal

Naval mines are the cheapest way to close a strait, and the most expensive to clear. A diplomatic agreement that ends overt hostilities does not, by itself, end the mine threat — and the difference between the two is what tends to keep insurance multiples elevated long after a ceasefire is announced.

Mining is asymmetric warfare in its purest form.

A modern moored or bottom-influence mine costs in the low five figures. Mine-countermeasures vessels — purpose-built ships with degaussed hulls and remotely operated underwater vehicles — cost in the hundreds of millions. The clearance operation itself is slow, painstaking, and risk-bearing for the clearance crews. Those economics define the political appeal of mining as a coercive tool: a small inventory of cheap weapons can hold a critical waterway hostage for months.

The Tanker War is the pattern.

From 1984 to 1988, Iran and Iraq attacked roughly 450 commercial vessels in the Gulf using a combination of mines, anti-ship missiles, and small-boat raids. The eventual American intervention — Operation Earnest Will, which reflagged Kuwaiti tankers and provided US Navy escort — only partially restored normal commerce. Insurance multiples remained elevated for the duration of the war and for months after the ceasefire, because the mines that had been laid were still in the water. Operation Praying Mantis in 1988 — which destroyed multiple Iranian platforms and warships — did not end the mine clearance.

Modern inventories are larger and more capable.

Iranian naval doctrine has prioritised mine warfare for four decades. Open-source estimates of the IRGC and IRIN combined mine inventory range from several thousand to upwards of five thousand units, including Soviet-era moored mines, Chinese EM-52 rocket-propelled mines, and indigenously-produced bottom-influence variants. Delivery platforms include purpose-built minelayers, modified merchant hulls, fast attack craft, and small craft operated by IRGC Naval Forces. The operational pattern in any closure scenario would mix observable laying (deterrent signalling) with covert laying (residual threat).

Clearance is a coalition operation.

The standing mine-countermeasures forces capable of operating in the Gulf are concentrated in three navies: the US (with Avenger-class MCMs forward-deployed to Bahrain and incoming replacements based on the LCS hull), the Royal Navy (with Hunt-class), and the Royal Saudi and Emirati navies (with smaller fleets focused on coastal protection). NATO standing mine-countermeasures groups can deploy if requested. The operation requires a diplomatic mandate, area control to prevent fresh laying during clearance, and a tolerable risk-acceptance posture from clearance crews — none of which is automatic after a ceasefire.

The insurance market reads the residual risk directly.

Lloyd's Joint War Committee delistings — when an area is removed from the listed-area schedule and reverts to peacetime pricing — typically lag the underlying ceasefire by months. The 1988 Tanker War ended in August; full insurance normalisation took until well into 1989. The 1990–91 Gulf War had a similar pattern: post-war mine clearance in Kuwaiti waters continued into 1992, and JWC delisting tracked that operational reality rather than the political timeline.

Why ceasefires often look more durable than the market does.

A ceasefire is a political event with a clear timestamp. Mine clearance is an operational process with no clear timestamp. The market reads both: war-risk insurance multiples decline gradually as MCM operations make verifiable progress, not in a step-change at the moment of a diplomatic announcement. That gap — between the political and the operational reality — is the structural reason an apparent "deal" can leave the strait still operationally contested for months.

What to watch.

• Lloyd's JWC listed-area updates.
• Mine-countermeasures deployment announcements (US 5th Fleet, RN, NATO SNMCMG2).
• Insurance multiple trajectory after any announced ceasefire — slow decline, not a step change.
• IMO Notice-to-Mariner advisories for the Gulf and Gulf of Oman.
• Carrier reinstatement announcements: Maersk, MSC, CMA CGM, Hapag-Lloyd typically reinstate transit only after JWC delisting.

Live insurance multiple and carrier postures at straits.live. War-risk insurance mechanics at /war-risk-insurance-explained.