The crowd underpriced the closure, then overpriced all 12 reopenings — and beat “nothing ever changes” by 0.0045.
The crowd has been wrong about this strait in both directions, and both times it was the same mistake. The two closure contracts that resolved YES opened at 20% and 33%. They are the two worst scores on the board. Since the closure, every one of the 12 dated reopening markets has resolved NO, opening at a mean 44%. Betting on an open strait lost going in and lost coming out.
Score them and the aggregate is thinner than it looks. Brier is the mean squared error of the daily YES price, so 0 is perfect and lower is better. Across all 15 resolved markets the mean is 0.1288. A forecaster who simply answered no to every question — no closure while the strait was open, no reopening while it was shut — scores 0.1333. Months of trading beat it by 0.0045.
The optimism was not front-loaded either. 8 of the 12 reopening contracts traded above their own opening price at some point before expiring worthless, taking the mean peak to 54% against a mean open of 44%. On average these markets grew more confident of a reopening as the deadline they would miss came closer.
| Market | Life | Open | Peak | Final | Result | Brier |
|---|---|---|---|---|---|---|
| Iran closes Hormuz in 2025 Polymarket | 01-23 → 01-01 | 14% | 52% | 0.1% | NO | 0.023 |
| Iran closes Hormuz by 2027 Polymarket | 11-05 → 03-14 | 20% | 100% | 100.0% | YES | 0.575 |
| Iran closes Hormuz 7+ days before 2027 Kalshi | 01-09 → 03-11 | 33% | 99% | 99.0% | YES | 0.415 |
| Reopen Apr 30 Polymarket | 03-09 → 05-12 | 69% | 69% | 0.1% | NO | 0.060 |
| Reopen before Jul 2026 Kalshi | 03-18 → 07-08 | 65% | 80% | 0.1% | NO | 0.178 |
| Reopen end of May Polymarket | 03-31 → 06-02 | 65% | 77% | 0.1% | NO | 0.123 |
| Reopen end of June Polymarket | 04-14 → 07-07 | 70% | 88% | 0.1% | NO | 0.159 |
| Reopen before Aug 2026 Kalshi | 04-14 → 08-05 | 64% | 81% | 1.0% | NO | 0.168 |
| Reopen May 15 Polymarket | 04-22 → 05-19 | 19% | 19% | 0.1% | NO | 0.009 |
| Reopen Jul 31 Polymarket | 05-11 → 08-04 | 53% | 76% | 0.1% | NO | 0.138 |
| Reopen before Jun 15 2026 Kalshi | 05-16 → 06-17 | 14% | 36% | 1.0% | NO | 0.009 |
| Reopen Jun 15 Polymarket | 05-26 → 06-23 | 16% | 16% | 0.1% | NO | 0.003 |
| Reopen Jul 15 Polymarket | 06-13 → 07-21 | 43% | 46% | 0.1% | NO | 0.043 |
| Reopen before Jul 15 2026 Kalshi | 06-16 → 07-22 | 37% | 37% | 1.0% | NO | 0.025 |
| Reopen Jul 7 Polymarket | 06-25 → 07-17 | 13% | 19% | 0.1% | NO | 0.003 |
Survivorship caveat: only markets that have already resolved are scorable, and while the strait stays closed a dated reopen market can only die NO — the hindsight benchmark is unbeatable by construction, which is part of why the aggregate edge above is the number to look at rather than the reopen column alone.
Computed, not asserted — every number here is derived from public data: official EIA Brent closes via FRED, IMF PortWatch transit counts, Polymarket and Kalshi odds, and source-linked curated events. Method and caveats · Atom feed · llms.txt
https://chokepointdata.com/analysis/prediction-market-scoreboard/