Bab al-Mandeb Strait is effectively closed to commercial shipping by September 30, 2026.
The wording, the opening probability, and the counter-signal below were fixed when this call was published. Updates revise the reading — never the record: the verdict is graded against the opening call.
The trajectory
The record since
- 10 Sep 26 Houthi forces are nearing full control of Mocha and Dhubab flanking Bab al-Mandeb, positioning to threaten Perim Island -- a material shift from the terrain picture a week ago. Held below the aligned Polymarket book (8% for the same Sept 30 threshold) because land control of the coast is not itself a shipping closure; the mechanism that would actually trigger this call -- a direct attack on or interdiction of a transiting vessel near the strait's narrows -- hasn't fired yet.
- 11 Sep 26 Houthi forces captured Zuqar Island and reached the Hanish Islands, with an unconfirmed claim (Al-Araby only, not independently verified) that they've also taken Perim itself -- a further material advance beyond last week's Mocha/Dhubab picture. Polymarket's aligned contract rose to 13 percent; we move up modestly but stay above market, since island and shoreline control still isn't the vessel attack near the strait's narrows that would actually trigger this call.
- 12 Sep 26 Houthi forces completed control of both shores of Bab al-Mandeb -- capturing Mayun (Perim) Island a day after the port of Mokha -- and spokesman Yahya Saree explicitly warned only Saudi-flagged vessels are unsafe. We move up modestly but stay well above the aligned Polymarket contract (9 percent for the same September 30 threshold), since holding both shores still isn't the vessel attack or enforced interdiction that would actually trigger a closure.
- 14 Sep 26 Houthi forces completed capture of Greater and Lesser Hanish -- the last two Bab al-Mandeb islands outside their control -- giving them uncontested physical control of the entire strait, while Saudi Arabia's alternate Red Sea export route (the East-West pipeline) remains shut with Reuters-sourced industry estimates putting Yanbu's reserve cover at just five to seven days; still short of the enforced-interdiction trigger this call requires, but the chokepoint's fallback option is now failing at the same moment full territorial control is achieved.
- 18 Sep 26 Italy's decision to bypass the EU's own Aspides mission and deploy warships unilaterally is itself a signal European capitals now treat normal commercial transit through the strait as unrecoverable in the near term -- reinforcing, though not yet meeting, this call's bar for an effectively-closed strait.
What would overturn it
A confirmed attack on a transiting commercial vessel, or an enforced Houthi closure with actual interdictions, before September 30 is the signal we're wrong; continued threats and territorial gains without a materialized attack on shipping is the signal we're right.
Against the market
Bab el-Mandeb Strait effectively closed by September 30?
us 47% · Polymarket 6%Market snapshot 6% on 7 Sep 26.
The verdict
Miss Resolved 5 Oct 26.
The strait was not effectively closed: traffic halved to about 15-30 daily crossings after Houthis seized Perim, and Aug transits were still ~1,165.
Threat-driven chokepoint closure calls overstate: traffic falls sharply but near-zero transits needs a blanket blockade, not selective targeting.
As logged at issue
Yemen/Red Sea: we think it's unlikely -- a Polymarket contract on this exact question puts it at about six percent, and we lean only a little above that -- that Bab al-Mandeb is effectively closed to commercial shipping by September 30, even with Houthi forces now cutting the last supply road to Mokha and holding ground overlooking the strait's southern approaches. A confirmed attack on a transiting commercial vessel before that date is the signal we're wrong.
Cite this call
The Cursus Publicus, Call 2026-09-07-02 — recorded 7 Sep 26. https://archive.cursuspublic.us/calls/2026-09-07-02.html