Will US crude oil inventories (excl. SPR) fall below 400M barrels by September 2026?
The Condition
Strait of Hormuz sustained disruption (>50% traffic reduction for 14+ days) before June 30, 2026
Our Ensemble Estimates
Given Hormuz sustained disruption: Will US crude oil inventories (excl. SPR) fall below 400M barrels by September 2026?
Given Hormuz reopens: Will US crude oil inventories (excl. SPR) fall below 400M barrels by September 2026?
Causal Effect
A sustained Hormuz disruption increases the probability of US crude inventories breaching 400M barrels from 8% to 52% — a +44pp causal effect. The mechanism is a 1-2 mbpd net supply gap creating export arbitrage pull on US light-sweet crude, with SPR authorization timing as the critical swing variable. Without disruption, normal seasonal draws leave inventories well above threshold.
Why This Matters
Tests whether a sustained Hormuz disruption draws down US commercial crude inventories to critically low levels. The US is near-energy-self-sufficient but oil is globally priced — a sustained global supply gap of 1.0-2.5 mbpd would incentivize exports of US light-sweet crude to fill the medium-sour shortfall, draining domestic inventories. SPR at 415M barrels is a potential release valve but politically constrained. Current commercial inventories are approximately 430-440M barrels. The grade mismatch ($2-5/bbl effective premium for lost medium-sour barrels) further incentivizes US crude exports.
Resolution Criteria
EIA Weekly Petroleum Status Report shows US crude oil inventories excluding SPR below 400 million barrels for any weekly reporting date between March 1 and September 30, 2026
Source Analysis
Deliverable offsets without SPR total only 1.5-2.5 mbpd against a base case disruption of 3-5 mbpd; the Hormuz paradox means OPEC+ spare capacity is trapped behind the disrupted chokepoint