Scan: Strait of Hormuz traffic returns to normal by December 31?

date	predicted	market price	confidence
2026-09-07	19%	24%	68%
2026-08-31	20%	28%	67%
2026-08-24	25%	34%	58%

1. Planner Fable 5.1 · Fermi decomposition + tool plan

Tools chosen: polymarket_direct polymarket_related kalshi_related claude_news article_search gdelt_news wikipedia code_execution

Sub-questions (Fermi decomposition)

What is the most recent IMF Portwatch 7-day moving average of transit calls for the Strait of Hormuz, and what has its trend been over the past 2-4 weeks?
What was the pre-disruption baseline of daily Hormuz transit calls on Portwatch (i.e., how far is 60 below 'normal') and what is the lowest level reached during the disruption?
What event caused the collapse in Hormuz traffic (Iranian closure, US/Israel-Iran war, mining, attacks on shipping), and is there a ceasefire, negotiated reopening, or naval escort operation underway or expected before December 2026?
Are war-risk insurance premiums, major shipowners (Maersk, Hapag-Lloyd, Frontline, etc.), and Gulf exporters (Saudi, UAE, Qatar, Iraq) signaling a return to Hormuz transits, or are they still rerouting/halting?
In past shipping disruptions (2019 Gulf tanker attacks, Red Sea/Houthi crisis 2023-25, 1980s Tanker War), how long did it take for traffic to recover to ~50% of baseline once hostilities paused?
Is IMF Portwatch still publishing Hormuz transit data continuously without gaps or methodology changes that could affect resolution?
How are sibling Polymarket markets at other thresholds (e.g., 40, 80, 100 transits) and Kalshi markets on Iran ceasefire/Hormuz reopening priced, and are they consistent with the direct market?

Planner reasoning

This is a binary threshold question on IMF Portwatch Hormuz transit calls (7-day MA >= 60), implying a major disruption to Gulf shipping in 2026 that has pushed traffic well below the historical norm (~100-140 daily transits). The key drivers are the current level and trajectory of transit calls, the political/military status of the underlying Iran-related conflict (ceasefire, de-escalation, mines, insurance), and how fast shipping historically rebounds after such disruptions. Market prices on Polymarket and any Kalshi/Polymarket sibling markets (other thresholds, ceasefire markets) provide the anchor and cross-checks.

2. Research Parallel tool calls

tool	status	time	items	summary
polymarket_direct	OK	0.2s	1	## This Market's Polymarket Data Strait of Hormuz traffic returns to normal by December 31? - Current price (probability): 17.50% - 7-day price change: -1.00% - 30-day price change: -16.00% - Total volume: $11,721,826 (USD notional) - Price range: 16.50% - 89.50% - Data points: 90 days
polymarket_related	OK	4.3s	2	Scanned 100 active Polymarket markets, kept 2 matches. keyword 'Strait of Hormuz': 2 markets \| keyword 'Hormuz transit': 0 markets \| keyword 'Iran ceasefire': 0 markets \| keyword 'Iran shipping': 0 markets
kalshi_related	OK	4.0s	1	1 related markets / summaries. keyword 'Hormuz': no matches \| keyword 'Iran ceasefire': no matches \| keyword 'Iran war': ok
claude_news	OK	25.8s	15	## Findings: Strait of Hormuz Traffic — Status as of Mid-September 2026 - Crisis origin & cause: Shipping traffic through the Strait of Hormuz has been largely blocked by Iran since 28 February 2026, when the United States and Israel launched an air war against Iran; in retaliation, the IRGC i
article_search	OK	46.6s	29	Fetched 29 unique articles across 5 queries (lookback=45d). 'Strait of Hormuz shipping traffic transit tankers': 10 articles \| 'Hormuz reopening ceasefire Iran shipping resumes': 10 articles \| 'IMF Portwatch Hormuz transit calls': 10 articles \| 'war risk insurance Gulf tankers Hormuz': 10 articles \|
gdelt_news	OK	59.7s	30	GDELT: 30 articles across 3 queries (lookback=30d). 'Strait of Hormuz shipping': 10 hits \| 'Hormuz tanker traffic': 10 hits \| 'Iran ceasefire Gulf shipping': 10 hits
wikipedia	OK	0.2s	4	Fetched 4 Wikipedia entries (0 missing pages).
code_execution	OK	40.4s	0	Model structure: P(normal by Dec 31 2026) = P(ceasefire/reopening by mid‑2026) × P(traffic recovers to threshold=60 \| ceasefire) + P(no ceasefire) × P(threshold crossed organically without formal resolution) Key parameters: - Baseline: 130 calls/day (midpoint of 120–140); threshold of 60 ≈

3. Evidence Brief Sonnet 5 · 7478 chars

# Current state IMF Portwatch's most recently reported 7‑day average transit count for Hormuz (data published ~2026-09-06) is roughly 5–10 ships/day, versus a pre-war baseline of ~85–140/day — this is far below the 60 threshold needed for "Yes." Multiple ceasefires/MOUs (April, June 2026) have collapsed into renewed Iranian attacks and mining, and as of September 2026 the strait remains functionally near-closed despite US mine-clearing and nascent Iran-Oman corridor talks. # Timeline of key events - 2026-02-28: US and Israel launch air war on Iran; IRGC blocks Hormuz, boards/attacks ships, lays mines (confirmed — Wikipedia). - 2026-04-xx: US-Iran ceasefire agreed; brief traffic uptick, still well below normal (confirmed — CRS/Congress.gov, Al Jazeera). - 2026-06-17 (approx): US-Iran MOU signed; strait reopens "toll-free" (confirmed — carraglobe.com). - 2026-07-08: Hostilities resume; Iran attacks shipping deemed non-compliant (confirmed — CNN, Congress.gov). - 2026-08-02: Trump pauses strikes; talks reportedly resume; oil prices drop on hope of reopening (confirmed — CNN). - 2026-08-06/07: Iran-Oman draft transit-route plan reported, restricting US/Israeli ships; under Iranian parliamentary review (reported — CNBC). - 2026-08-12: Traffic near 3-month low; ~13-ship 5-day average per Kpler, ~90% below pre-war baseline (confirmed — CNBC). - 2026-08-18: MOU expires; Trump says "no talks"; UAE-Iran direct shipping suspended (confirmed — CBC). - 2026-08-19: CNN reports Iran has lost significant operational control; Gulf states use dark-fleet/transponder-off tactics (reported — CNN). - 2026-08-25/27: US/CENTCOM confirm Hormuz shipping lanes cleared of mines; separately a tanker struck by projectile, one casualty (confirmed — NY Post/Moneycontrol; reported attack — CNBC). - 2026-08-27: Only ~5 confirmed crossings/day via Iran's unilateral designated route, down from 130+ pre-war (reported — CNBC, Al Jazeera "95% drop"). - Early-mid Sept 2026: Iran and Oman reach understanding on temporary joint maritime corridor; contingent on US lifting naval measures (reported — CBS News). - 2026-09-06/07: IMF Portwatch records ~6 transits; Iran warns US Gulf energy assets are "vulnerable" amid fresh clashes (confirmed data / reported tension — straits.live, SBS/AsiaOne). # Event Will IMF Portwatch's 7-day moving average of Hormuz "Arrivals of Ships" reach ≥60 on any date before Dec 31, 2026? # Outcomes to forecast - Yes (traffic ≥60 7-day avg by Dec 31, 2026) - No # Kalshi market anchor No kalshi_direct price was returned in this research pass (tool output absent). The closest cross-market anchor is this event's own Polymarket twin, priced at **17.5% YES**, down from ~89.5% high and down 16 points over 30 days — reflecting the repeated ceasefire collapses through July-August 2026. Treat Kalshi's own YES price (once retrieved) as the primary anchor; Polymarket suggests consensus is now firmly skeptical. # Sub-question answers 1. **Recent Portwatch average/trend**: ~5-10 transits/day as of early Sept 2026, down from a brief post-MOU uplift in June-July; trend has been declining/flat-to-low since the July 8 resumption of hostilities (claude_news, straits.live). 2. **Baseline vs. 60 threshold**: Pre-war baseline ~85-140/day (various sources; Kpler cites 130). 60 is ~43-70% of baseline — a substantial, not full, recovery. Lowest point during the crisis has been near-zero/single digits (e.g., "outbound transits drop to zero," Argus, Aug 25). 3. **Cause & ceasefire status**: Feb 28, 2026 US/Israel-Iran war triggered Iranian mining/blockade. Two ceasefire/MOU attempts (April, June) both collapsed (July 8 resumption). As of Sept 2026, no durable ceasefire; Iran-Oman temporary corridor talks are in progress but unconfirmed to be operational (CBS News, reported). 4. **Insurer/shipper behavior**: Gulf exporters (Saudi, UAE, Kuwait) are chartering VLCCs and using "dark fleet" tactics (transponders off) to route around Iranian threats via Oman; insurers remain cautious, premiums elevated; UAE suspended direct Iran shipping (CNN, CBC). No sign of confident mass return. 5. **Historical recovery precedent**: 1980s Tanker War never dropped below ~50% of baseline and rebounded quickly once fighting ended; 2019 Gulf attacks caused only shallow, brief dips. Red Sea/Houthi crisis (2023-25) is the more analogous case — traffic fell 50-70% and stayed depressed >12 months absent durable ceasefire, only partially recovering (~31/75 ships/day even by May 2026) (Wikipedia). 6. **Portwatch data continuity**: Data continues to publish with the standard ~1-week lag; no reported methodology break (straits.live). 7. **Sibling markets**: Sept 30, 2026 Hormuz-normal Polymarket twin is priced at just 1.1% YES (already near-certain No, reflecting closer deadline); Dec 31 twin at 17.5%. No direct Iran-ceasefire Kalshi market found. # Key facts (high-confidence) 1. [Wikipedia] War began 2026-02-28; strait blocked via IRGC mining/attacks since. 2. [CNBC 08-12] Traffic ~90% below 130/day pre-war baseline; ~13/day 5-day avg. 3. [Al Jazeera 08-27] July15-Aug23 average ~5 ships/day, ~95% below pre-war. 4. [CBS] Iran-Oman temporary corridor understanding reported early Sept 2026, contingent on US action. 5. [CENTCOM/NY Post] Mines cleared from shipping lanes by late Aug 2026, but attacks continued (tanker struck 08-26/27). # Cross-market signals - Polymarket (own market): 17.5% YES, down 16pts/30d, high volume ($11.7M) — clear "No"-leaning consensus, deteriorating. - Polymarket sibling (Sept 30 deadline): 1.1% YES — near-certain failure for the nearer deadline, suggesting market sees Dec 31 as only modestly more likely. - Kalshi: no direct data retrieved; no related Iran/Hormuz market found beyond unrelated Fed/soccer markets. # Analyst opinions and speculation - Pickering Energy Partners: Oman-route workaround "makes the most sense" for Gulf exporters bypassing Iranian tolls (CNN). - Kpler analysts: Iran has "lost significant control," but full normalization unlikely near-term given dark-fleet/politicized routing. - Code-execution model (speculative, not source-grounded in current data): estimates ~28-50% depending on current traffic level and ceasefire odds, but likely overstates current traffic (assumed 20-50/day) vs. actual reported ~5-10/day as of Sept 2026 — should be discounted. # Directional lean per outcome - **Yes**: Some support from mine-clearing progress, Iran-Oman corridor talks, Gulf states' active workarounds keeping some oil flowing (~9-15M bpd via various means). But traffic counts (not just oil volume) remain near record lows. - **No**: Dominant — repeated ceasefire failures (April, June), active mining/attacks through August, ~90-95% traffic collapse persisting 6+ months, insurer caution, and Polymarket pricing (17.5%) all point to "No" as heavily favored. # Gaps / unknowns - No confirmed Kalshi YES price captured in this research pass. - Unclear if Iran-Oman corridor, if operational, would register as "Arrivals of Ships" growth sufficient to hit 60. - No visibility into Sept-Dec 2026 data (research cuts off ~mid-Sept 2026); 3.5 months remain for a durable ceasefire to emerge. # Calibration anchors - Polymarket YES (this event): 17.5%, declining. - Polymarket sibling (Sept 30 deadline): 1.1% YES. - Historical precedent: Red Sea crisis stayed >50% depressed for over a year absent durable ceasefire — most analogous case argues against full-year recovery to 60/day threshold.

4. Forecasters Fable 5.1 + GPT-5.6 Sol · in parallel

claude-fable-5-1

58% conf

Yes	15%
No	85%

IMF Portwatch shows Hormuz transits at ~5–10/day as of early September 2026, roughly 90–95% below the pre-war baseline and an order of magnitude below the 60/day threshold, with two ceasefire/MOU attempts (April, June) having already collapsed into renewed attacks. Mine-clearing completion and Iran-Oman corridor talks provide a plausible path to recovery, and the 1980s Tanker War precedent shows traffic can rebound quickly once fighting durably stops, so a Yes is not negligible with ~3.5 months left. However, the more analogous Red Sea crisis shows shipping stays depressed for a year-plus absent a durable settlement, insurers remain cautious, and the Sept 30 sibling market at ~1% signals no near-term recovery underway. With no Kalshi price available, I anchor on the Polymarket twin at 17.5% YES (declining) and shade slightly lower given the persistently near-zero traffic and Iran's threats against Gulf energy assets.

gpt-5.6-sol

74% conf

Yes	17%
No	83%

Recent Portwatch traffic of roughly 5–10 ships/day is far below the 60 threshold and shows no sustained recovery since hostilities resumed in July. Repeated ceasefire failures, ongoing attacks, insurer caution, and the Red Sea precedent point toward No, while mine-clearing and Iran-Oman corridor talks preserve a limited path to Yes. With no Kalshi-direct price available, the best market anchor is Polymarket's 17.5% YES; the evidence broadly supports that skeptical consensus. Reaching a 60-ship seven-day average would likely require a durable settlement and rapid shipper return within the remaining 3.5 months.

5. Devil's Advocate Sonnet 5 · red-team critique

Both forecasters converge almost exactly on the Polymarket anchor (17.5%→15%/17%) without independently stress-testing whether that price itself is stale or reflects the same August-collapse dynamics rather than the Iran-Oman corridor news from early September, which postdates much of the price action described ("down 16 points over 30 days" ending ~Sept).

Neither forecast explicitly grapples with sub-question 5's strongest analog (Red Sea: traffic stayed >50% depressed for over a year even after some de-escalation) versus the weaker 1980s Tanker War analog they both cite for upside — they mention it but don't explain why they still assign ~15-17% rather than pushing toward the Red Sea-implied single digits.

Both treat the Sept 30 sibling market (1.1% YES) as merely "signals no near-term recovery" but don't use it to bound the Dec 31 estimate more rigorously — if near-zero probability of recovery in the next ~3 weeks, the incremental probability mass for the following 3 months needs an explicit "durable ceasefire forms + shippers return fast" compound estimate, which neither decomposes numerically.

Neither addresses the ambiguity flagged in the brief's "Gaps/unknowns": whether an operational Iran-Oman corridor would even register as "Arrivals of Ships" growth in Portwatch's methodology — this is a meaningful measurement-risk factor that could suppress Yes even if de facto trade normalizes.

Both forecasts ignore escalation tail risk in the other direction — Iran's Sept 6-7 warning that "US Gulf energy assets are vulnerable amid fresh clashes" suggests a plausible path to renewed/intensified conflict that could keep traffic even lower than 5-10/day, yet neither forecaster considers whether the No-side probability should be even more concentrated (e.g., 90%+) given this fresh escalation signal.

Forecaster 2's stated confidence (0.74) is notably higher than Forecaster 1's (0.58) despite nearly identical probability outputs and reasoning — this inconsistency in confidence calibration given essentially the same evidence base is unexplained and undermines the credibility of the confidence metric itself.

6. Aggregator Fable 5.1 · final calibrated forecast

14% (66% confidence)

Yes: 14% No: 86%

Portwatch transits sit at ~5–10/day in early September 2026, roughly an order of magnitude below the 60 threshold, after two ceasefire/MOU attempts collapsed and with fresh Iranian threats against Gulf energy assets. A Yes requires a compound path: a durable settlement forming within the next ~2.5 months (plausibly 25–30%) and then insurers/shippers returning fast enough to push the 7-day average above 60 before Dec 31 (perhaps 50–60% conditional), yielding roughly 13–17%. The Red Sea analog and the 1.1% Sept 30 sibling argue for shading below the high-volume Polymarket anchor of 17.5%, while mine-clearing completion and Iran-Oman corridor talks keep the tail from collapsing to single digits. I land slightly below both forecasters at 14% Yes, agreeing the critique's escalation and measurement-risk points warrant a modest downward shade but not a wholesale departure from the market consensus.

Pipeline Timing

Total pipeline time: 186.9s

Per-tool research timings shown in the Research section above.