Diesel Stocks at a Five-Year Low, and the Funds Are Barely Long: September 2026
Key takeaways
- In the EIA week ending 18 September 2026, US distillate stocks were 107.4 million barrels, 8.6% below the 5-year average for that week and level with the lowest reading for that week in the five years the band covers. ULSD stocks were 10.0% below.
- The diesel crack, NY Harbor ULSD against WTI, was $113.88 a barrel on 22 September. A year earlier it was $36.43. It first closed above $100 on 17 August 2026.
- Managed Money was net long only 13,468 NY Harbor ULSD contracts on the COT report for 15 September, less than a third of the 41,206 it held in July 2025.
- Gasoline is the opposite case. Stocks are also at the floor of their band, but Managed Money is crowded long RBOB, with a COT Index of 82.
- Energy Radar reports each of these readings. It does not combine them into a forecast, because no crossed combination of positioning and inventory has enough history behind it to publish one.
Introduction
Two weekly releases describe the US refined products market. The EIA's Weekly Petroleum Status Report, out on Wednesday, counts the barrels. The CFTC's Commitments of Traders report, out on Friday, shows who holds the futures. Read one without the other and you get half the picture.
This September the two halves disagree more than usual. Diesel is the tighter of the two main products by almost every physical measure, and it is the one speculators are least interested in. Gasoline is less tight, and it is the one they have crowded into.
This note sets out what Energy Radar shows for diesel and gasoline this week, where the numbers come from, and what they do not say. It describes data. It does not forecast prices.
The Barrels: Distillate at the Bottom of Its Band
Energy Radar compares every stock series with its own 5-year seasonal band: the range that series has occupied in the same calendar week over the last five years, including this one. A reading at the base of the band is the lowest for that week in that window.
EIA data for the week ending 18 September 2026:
| Series | Level | vs 5-year average | Band position | Week change |
|---|---|---|---|---|
| Distillate stocks | 107.4 million bbl | -8.6% | At the base | -0.4 million |
| ULSD stocks | 96.4 million bbl | -10.0% | At the base | -0.6 million |
| Distillate days of supply | 29.5 days | -6.7% | At the base | -0.4 days |
| Gasoline stocks | 206.0 million bbl | -4.2% | At the base | -1.7 million |
| Gasoline days of supply | 23.5 days | -4.5% | At the base | unchanged |
| Commercial crude stocks | 426.4 million bbl | +1.5% | Inside | +3.0 million |
Four of the six rows are at the floor of their band in the same week. Crude itself is not. Commercial crude stocks rose 3.0 million barrels and sit inside their band, and Cushing crossed back above its own 5-year average. The squeeze is in the products, not in the crude that makes them.
The flows explain part of it:
- Refinery utilisation fell to 94.0%, down 2.8 points on the week, and refiner crude input dropped by 519,000 barrels a day. September is when refiners begin autumn maintenance, so fewer barrels of new product were made.
- Distillate product supplied rose to 3.98 million barrels a day, up 474,000 on the week. Product supplied is the EIA's measure of what left primary storage for use.
- Distillate exports fell to 1.33 million barrels a day, down 283,000. Lower exports kept more diesel at home and stocks still fell.
Jet fuel stocks, at 45.5 million barrels, are 5.0% above their 5-year average and inside the band. Propane, at 107.9 million, is 10.2% above average and above its band. The tightness is specific to diesel and gasoline, not to every product.
The Price of Tightness: The Diesel Crack
A crack spread is what a refiner earns turning a barrel of crude into a product. Energy Radar calculates it from EIA daily spot prices: the NY Harbor ULSD price in dollars a gallon, multiplied by 42 gallons, minus WTI at Cushing.
On 22 September 2026, ULSD was $5.007 a gallon and WTI $96.41 a barrel, a crack of $113.88.
| Date | ULSD ($/gal) | WTI ($/bbl) | Diesel crack ($/bbl) |
|---|---|---|---|
| 15 September 2025 | 2.383 | 63.66 | 36.43 |
| 17 August 2026 | 4.532 | 86.04 | 104.30 (first close above $100) |
| 16 September 2026 | 5.365 | 103.62 | 121.71 (high of the series) |
| 22 September 2026 | 5.007 | 96.41 | 113.88 |
The crack has closed above $100 on 20 days, all of them since 17 August. Against the 284 daily readings Energy Radar holds, which go back to August 2025, the current value sits at the 98th percentile. That window is about a year, so this is a statement about the last year, not about history. The panel says so itself and does not publish the crack as a measured base rate: the sample is too small.
The gasoline crack is high too, at $52.73 and the 89th percentile of the same window, but it peaked at $63.56 on 28 August and has come down since. The diesel crack is still close to its high.
The Positioning: Crowded Where It Is Less Tight
Managed Money net positions on the COT report for Tuesday 15 September 2026, from the CFTC Disaggregated report:
| Contract | Net long | COT Index (3 years) | Z-score (52 weeks) | Energy Radar reads |
|---|---|---|---|---|
| NY Harbor ULSD | 13,468 | 68.5 | -0.21 | Net long leaning |
| RBOB gasoline | 83,217 | 82.1 | +1.02 | Crowded long |
| WTI crude (NYMEX) | 136,768 | 48.4 | +1.05 | Net short leaning |
Diesel: a small long, and shrinking
The ULSD long is small in absolute terms and has been falling. It was 20,985 contracts on 1 September and 13,468 two weeks later, the smallest since 4 August. The 2026 high was 24,325 on 3 February. In July 2025 it was 41,206. Managed Money holds 35,414 contracts long against 21,946 short, so there is a real short book on the other side of a very tight physical market.
The COT Index and the z-score disagree here, and it is worth seeing why. The COT Index of 68.5 ranks the position against the last three years, which include a net short of 46,823 in December 2024, so almost any long ranks above the middle. The z-score of -0.21 compares it with the last 52 weeks, which contain larger longs, so the same position reads slightly below average. Our COT Index guide covers how much the lookback window changes the answer.
This is not new behaviour for diesel. During the 2022 diesel squeeze, between March and November of that year, the Managed Money net long ranged from 8,809 to 31,423 contracts. Diesel tightness has rarely been expressed as a large speculative long in this contract. Some of it goes to Europe instead: in ICE gasoil, the European diesel contract, Managed Money was net long 94,666 contracts on the same report, a COT Index of 87.6.
Gasoline: the crowd is here
Managed Money was net long 92,926 RBOB contracts on 8 September, the largest since 2 December 2025, with a COT Index of 92.3. A week later it had eased to 83,217, still a COT Index of 82 and in Energy Radar's crowded long zone.
So speculators are long the product whose crack has already come off its high, and light in the product whose crack has not. That is a description of where positions sit. It is not evidence that either group is right.
Crude: in the middle
WTI Managed Money is net long 136,768 contracts, a COT Index of 48. Energy Radar reads that as net short leaning, because the index is below 50, even though the position is a net long. The index measures where the position sits in its own three-year range, not which side of zero it is on.
What Energy Radar Does Not Say
It does not cross the two axes into a call. Every combination of positioning state and inventory state, crowded long with stocks below band for example, has fewer than 30 independent observations in the history available. That is below our publication bar, so the panel names both readings and stops there.
It does not treat low stocks as bullish. We tested fourteen relationships between a stock series' band position and the price over the following eight weeks. Most did not clear the bar, and the two that did ran opposite to the textbook: stocks above the band preceded higher prices, not lower. None of the relationships that cleared applies to this week's readings. The Energy Radar guide sets out the full test.
It does not forecast winter. Distillate stocks usually draw into the heating season, which is exactly why a reading at the base of the band in September draws attention. Whether that ends in higher prices, more imports, lower exports or simply a rebuild after maintenance is not something the data can tell you in advance.
What to Watch Next
- Refinery runs after maintenance. If utilisation recovers in October and distillate stocks start to build, the band position improves from the supply side.
- Distillate exports. They fell this week. A rebound while stocks are this low would tighten the domestic balance further.
- The crack's direction, not its level. A crack that holds above $100 while stocks rebuild is a different situation from one that falls as stocks rebuild.
- Whether Managed Money follows the physical market into diesel, or keeps its exposure in gasoline. The next COT report, for Tuesday 22 September, is published on Friday 25 September.
Where COTInsight Fits
- Energy Radar (Ultimate) puts all of this on one screen for WTI, natural gas, RBOB gasoline and NY Harbor ULSD: 33 EIA series on the oil panel, each against its own 5-year band, the cracks with their percentile, and the COT Index for each contract's own positioning. It publishes a measured base rate only where one clears the publication bar, and says so when none does.
- Pro includes 10 years of weekly COT history and CSV export, enough to put this ULSD position next to 2022 yourself.
- Ultimate adds the full archive, PDF reports, weekly AI commentary, the REST API and historical outcome statistics for each contract's own positioning readings.
- The COTInsight TradingView indicator (Ultimate) plots the same COT Index, z-score and regime under the price chart, so the RBOB crowding and the ULSD gap are visible where you already watch the crack.
See pricing or open the dashboard.
Frequently Asked Questions
How low are US distillate stocks in September 2026?
In the EIA week ending 18 September 2026, distillate stocks were 107.4 million barrels, 8.6% below the 5-year average for that week and level with the lowest reading for that week in the five-year window. ULSD stocks, a subset, were 96.4 million barrels, 10.0% below average.
What is the diesel crack spread right now?
On 22 September 2026, NY Harbor ULSD at $5.007 a gallon against WTI at $96.41 gave a crack of $113.88 a barrel, near the $121.71 high of 16 September. A year earlier it was $36.43. These are EIA daily spot prices.
Are hedge funds long diesel futures?
Only lightly. Managed Money was net long 13,468 NY Harbor ULSD contracts on the 15 September 2026 COT report, down from 20,985 two weeks earlier and far below the 41,206 of July 2025.
Why is gasoline "crowded long" when diesel is tighter?
Energy Radar reads each contract's own positioning. Managed Money holds 83,217 RBOB contracts net long, a COT Index of 82, which is in the crowded zone. The ULSD position ranks at 68 on the same scale. The two contracts are positioned independently, whatever the physical market is doing.
Do low inventories mean prices will rise?
Not reliably. In our tests, stocks sitting below their 5-year band did not produce a measured relationship with later prices strong enough to publish. This note is descriptive and is not investment advice.
Summary
In the EIA week ending 18 September 2026, US distillate, ULSD and gasoline stocks all sat at the base of their 5-year seasonal bands, while crude stocks were comfortably inside theirs. The diesel crack was $113.88 a barrel on 22 September, up from $36.43 a year earlier and at the 98th percentile of the last year's daily readings. On the 15 September COT report, Managed Money was net long only 13,468 ULSD contracts, the smallest since early August, but crowded long in RBOB gasoline at a COT Index of 82. Energy Radar shows both sides and does not combine them into a forecast, because the history needed to measure that combination does not exist. Data: EIA Weekly Petroleum Status Report and daily spot prices; CFTC Commitments of Traders. Not investment advice.