US Strategic Petroleum Reserve Hits Four-Decade Low as Brent Climbs Back Toward $100
With the SPR at its lowest since 1983 and the US-Iran peace deal broken, J.P. Morgan's June warning about depleted global buffers is now visible in prices.
ICE Brent crude front-month was trading at $99.54 a barrel on Monday (2026-09-21), climbing back through the $90s after a brief peace deal between the United States and Iran pushed it below $80 in late June. The recovery reflects the inventory reality that J.P. Morgan analysts laid out in June: available global supply buffers were never large enough to absorb a prolonged Strait of Hormuz closure, and strategic reserves have now been drawn down to levels not seen in decades.5,8
The US Strategic Petroleum Reserve bore the sharpest depletion. By mid-July (2026-07-15), it had fallen to 316 million barrels, its lowest level since 1983, down from 414 million barrels at the conflict's outset, according to Foreign Policy citing J.P. Morgan estimates. That is a 98-million-barrel draw in roughly four months. The reserve was built after the 1973 crisis precisely to buffer supply shocks from flowing directly into prices; at 316 million barrels, it has lost about a quarter of its pre-conflict capacity.8
J.P. Morgan's June report described the broader shock plainly: "despite the relative calm in broader markets, the physical supply shock itself has been immense," with supply losses from the Strait's closure "severe and intensified." Around 13 million barrels per day were estimated to have been removed from global supply during peak disruption, according to oilprice.com.2,3
The global storage cushion compounded the strain. When Iran first closed the strait, the world held about 8.4 billion barrels in storage — elevated after two years of oversupply. But J.P. Morgan estimated only around 800 million of those barrels were accessible without pushing critical infrastructure into stress. Against that ceiling, total oil losses were already estimated at roughly 1 billion barrels by mid-May, according to peakoil.com — more than double the IEA's entire planned emergency release of 400 million barrels. The IEA itself reported that governments and industry had released 164 million barrels as of May 8 (2026-05-08) at a record pace, warning of "rapidly shrinking buffers."8,1
Markets initially treated Hormuz's closure as temporary. Brent surged from $72 in late February to above $118 in March, then fell back below $80 by late June as the peace deal reopened shipping lanes, according to JPMorgan data cited by AOL Finance. Every major bank that published forecasts revised hard in both directions within weeks. That deal has since collapsed. Foreign Policy reported on July 21 (2026-07-21) that the US-Iran agreement had broken down, with prices rising again.5,8
The demand response has been slower than the supply disruption warrants. Energy Aspects, in an analysis sent to Rigzone on May 28 (2026-05-28), found its high-frequency data showed "limited consumer demand response to higher oil prices," with strong backwardation and rapid destocking exaggerating fears of destruction. J.P. Morgan analysts noted the distinction between forgone activity and structural substitution matters enormously: "the macro signal is materially different" depending on which is driving any apparent demand reduction. They drew a parallel to 1973, asking whether the current shock would force an analogous efficiency shift. Their answer was "possibly yes," but they cautioned the adjustment path may differ markedly from five decades ago.2
EIA data released on Wednesday June 17 (2026-06-17) showed US commercial crude inventories drew by 8.3 million barrels, the latest in a series of drawdowns analysts warned could sustain elevated prices even as diplomatic pressure eased.4 By early July (2026-07-07), oilprice.com reported analysts had briefly shifted to an oversupply narrative as tankers left the Persian Gulf in greater numbers than the preceding three months, with importing nations warned of a "wave" of crude. That mood reversed sharply. On Monday July 13 (2026-07-13), Brent futures were up 3.5% at $78.68 a barrel after renewed US-Iran military tensions escalated over the weekend, having earlier climbed close to 5%, according to Yahoo Finance.6,7
Saudi Arabia rerouted 5 million barrels a day through its Red Sea terminal and the UAE boosted exports through alternate routes, according to J.P. Morgan, providing partial offsets to the strait's closure. Brent at $99.54 sits roughly $19 below the March peak. But with the SPR at 316 million barrels — its leanest since 1983 — and commercial stocks still drawing, the US enters any renewed closure with materially less shock-absorbing capacity than it held at the conflict's start. Rebuilding that reserve to prior levels, even at sustained drawdown rates reversed, would take years, and no diplomatic calendar currently in view sets a timeline for that.8