US Refineries Hit 98% Utilization as $75 Crack Spread Drives Gasoline Output to Summer Peak of 9.84 Million Barrels Per Day

US refineries processed crude at 98.0% of operable capacity for the week ending August 28, the highest summer utilization rate of 2026, according to the EIA Weekly Petroleum Status Report published September 2. Crude throughput reached 17.496 million barrels per day. Finished motor gasoline production climbed to 9.845 million barrels per day, both figures the strongest weekly readings since at least early July.

A $75 Per Barrel Crack Spread Signals Exceptional Refinery Margins

The 3-2-1 crack spread, a standard measure of refinery profitability, reached approximately $75 per barrel for the week ending August 28. The calculation uses EIA weekly spot prices: Gulf Coast conventional gasoline at $3.564 per gallon ($149.69 per barrel), and Gulf Coast ultra-low sulfur diesel at $4.274 per gallon ($179.51 per barrel). The week-average WTI Cushing spot price was $84.62 per barrel, per the same EIA dataset.

Applying the 3-2-1 formula, two parts gasoline plus one part diesel divided by three, minus crude, yields $75.01 per barrel. By Friday September 5, CME Group settled WTI at $91.48 per barrel, compressing the implied crack spread to roughly $68 per barrel as crude prices outpaced product markets. Both figures are more than twice the $25-to-$30 range that defined refinery margins through most of 2023 and 2024.

The EIA noted on September 4 that gasoline crack spreads at New York Harbor have averaged about $1 per gallon above comparable 2025 weeks since May. The 2025 crack spread peaked near 60 cents per gallon for the same period, making 2026 spreads roughly 2.5 times that prior peak. The EIA attributed the elevation to tight global gasoline supplies, including disruptions to Middle Eastern refined product exports linked to Hormuz shipping constraints.

Near-Capacity Operations Leave a 400,000-Barrel-Per-Day National Buffer

Running above 97% for multiple consecutive weeks compresses the maintenance window and removes flexibility for unplanned outages. The August 28 reading of 98.0% sits 3.7 percentage points above the 94.3% recorded for the comparable week ending August 29, 2025. Against estimated total operable capacity near 17.9 million barrels per day, only about 400,000 barrels per day of slack capacity remains nationally.

As our earlier analysis of IEA and OPEC demand projections noted, commercial crude stocks have remained broadly supported by domestic production at 13.862 million barrels per day. Those stocks stood at 424.5 million barrels as of August 28. Refineries drawing 17.496 million barrels per day consume crude faster than domestic output and net imports of 2.3 million barrels per day can sustain, pointing to gradual inventory erosion heading into the fourth quarter.

ExxonMobil Subsidiary Imperial Oil Captures Extra Margin on Western Canadian Select

Imperial Oil, 69.6% owned by ExxonMobil, operates the 191,000-barrel-per-day Strathcona refinery in Edmonton, Alberta, and the 85,000-barrel-per-day Sarnia refinery in Ontario. Both facilities process predominantly Alberta heavy crude priced at Western Canadian Select. WCS has traded at an approximately $14-to-$16 per barrel discount to WTI in recent sessions, per Argus Media crude oil assessments, reflecting heavy crude quality and pipeline transportation differentials.

That WCS discount accrues directly to refiners capable of running heavy feedstocks. A facility buying WCS near $70-to-$71 per barrel rather than WTI at $84.62 captures a $13-to-$14 per barrel cost saving that stacks on top of the prevailing $75 crack spread. This feedstock advantage consolidates inside ExxonMobil's integrated accounts through its 69.6% stake in Imperial Oil. Suncor Energy runs four refineries at Edmonton, Sarnia, Montreal, and Commerce City, Colorado, each with meaningful heavy crude capacity and equivalent WCS economics.

US Distillate Stocks Below Seasonal Range Ahead of Autumn Heating Demand

Distillate fuel oil stocks, covering diesel and heating oil, stood at 104.2 million barrels as of August 28, down from a July peak of 110.6 million barrels. In recent years, late-August US distillate stocks have ranged from 110 to 125 million barrels. Running 6 to 21 million barrels below that recent band adds a supply-scarcity premium to diesel prices, further supporting refinery margins even as throughput approaches physical limits.

Marathon Petroleum, the largest US refiner by capacity, and Valero Energy both operate major Gulf Coast complexes positioned to supply diesel exports to Latin America and Europe, where Middle Eastern distillate flows have been constrained. Both companies report fiscal third-quarter earnings in late October and early November, when the current high-margin environment will translate into reported results. With distillate stocks below seasonal norms and refinery utilization near its physical ceiling, the margin outlook for the downstream sector remains structurally firm entering October.