Crude oil inventories at Cushing, Oklahoma fell below 20 million barrels during the week ending June 19 and remained there through the week ending July 10.
The drawdown represents roughly 26 percent of the hub’s 76 million barrel working storage capacity, marking the lowest Cushing has run since October 2014.
Cushing is the physical delivery point for West Texas Intermediate futures, the most actively traded oil contract in the world and the benchmark for U.S. oil prices.
The drawdown coincided with disruptions to Middle East oil flows following the Strait of Hormuz crisis, which increased demand for U.S. crude exports significantly.
As global buyers turned toward American barrels, Cushing stocks fell for eight straight weeks by mid-June, dropping from roughly 29 million barrels in early May at a pace of about 800,000 barrels a week.
Nationally, total U.S. commercial crude inventories sat at roughly 409.7 million barrels as of mid-July, about 4 percent below the five-year average.
The Energy Information Administration published a public explainer on July 16 addressing a technical point that suddenly carried significant market weight: storage tanks cannot be emptied to zero under normal operating conditions.
Every tank requires a minimum volume, called a tank bottom, to keep pump suction effective and pipeline connections functioning, meaning not all reported barrels are actually deliverable to market.
The EIA drew a specific distinction between reported inventory and deliverable supply, saying it is reviewing pilot study results aimed at pinning down actual minimum working levels at individual storage facilities.
That distinction matters for anyone reading the weekly inventory numbers as a straightforward gauge of available supply, since reported figures may overstate how much crude could respond to a sudden disruption.
The clearest sign of market stress showed up in the spread between Brent and West Texas Intermediate, which under ordinary conditions sees WTI trading at a discount because Cushing is landlocked.
The five-day rolling average of the Brent-WTI spread turned negative from June 18 to June 24, and again from July 2 to July 8, meaning WTI at Cushing was actually trading above Brent crude.
That was the narrowest the spread had been since January 2022, reflecting buyers competing hard for crude sitting at a hub that increasingly could not spare it.
The week ending July 17 brought national commercial crude inventories up 2.0 million barrels to 411.7 million, a headline build that traders read as broadly bearish for prices.
However, Cushing itself told a different story, with stocks at the hub falling another 700,000 barrels that same week to roughly 19.4 million barrels, meaning the national build occurred entirely elsewhere in the system.
For anyone with contracts, hedges, or storage arrangements priced off WTI at Cushing, the inventory report is no longer a routine weekly data point given current conditions.