Guide

Crack spread and refinery margins explained

Harbor Energy’s Gulf Coast refinery margin desk hedged spring driving-season exposure by shorting NYMEX WTI against a fixed notional of physical gasoline output. When WTI crude fell $4 per barrel on OPEC rhetoric but RBOB gasoline futures held firm, the desk’s “crude hedge” lost money on both legs: feedstock mark-to-market improved while product revenue assumptions collapsed. Weekly margin forecast error versus internal models averaged 340 basis points for six weeks. After rebuilding hedges around a 3-2-1 crack spread basket weighted to the refinery’s actual yield slate — and tying run-rate assumptions to EIA WPSR utilization by PADD — forecast error fell to 38 bps and hedge slippage on margin clips dropped from 22 to 5 basis points.

A crack spread is the price difference between refined petroleum products and crude oil input, expressed in dollars per barrel. It is the standard market proxy for gross refinery margin before operating costs, and it explains why refiners sometimes earn record profits when crude falls if gasoline and distillate prices stay elevated. Traders, airline fuel desks, and macro strategists watch cracks alongside inventory data and PPI energy pass-through. This guide covers crack taxonomy, futures-based calculation, seasonal patterns, links to refinery utilization, the Harbor Energy margin desk refactor, a technique decision table vs crude-only hedging, pitfalls, and a production checklist.

What crack spreads measure

Refineries buy crude and sell gasoline, diesel, jet fuel, and petrochemical feedstocks. The crack spread captures the spread between those output prices and crude input. It is not net profit — utilities, labor, maintenance turnarounds, and environmental compliance sit below the crack line — but it is the first-order signal of refinery economics and the primary hedge benchmark for merchant refiners.

Gross margin vs net margin

Gross refining margin (what cracks approximate) equals product revenue minus crude cost per barrel of throughput. Net margin subtracts variable and fixed operating costs, which run roughly $3–8 per barrel for efficient U.S. Gulf Coast plants but spike during turnarounds. Equity analysts quote cracks for quarter-ahead earnings; physical traders quote them for cargo and pipeline arbitrage.

Why cracks diverge from crude

Crude and products trade on different demand curves. A geopolitical risk premium in Brent may lift crude while U.S. gasoline stocks are comfortable, compressing the gasoline crack. Conversely, a refinery fire in PADD 3 can spike RBOB while WTI is flat, widening cracks. Inventory builds in the Weekly Petroleum Status Report often show product draws while crude builds — a classic crack-widening setup.

Crack spread formulas

Market participants standardize several crack definitions. Mixing them without conversion causes hedge mismatches.

3-2-1 crack spread

The 3-2-1 crack assumes three barrels of crude yield two barrels of gasoline and one barrel of distillate (heating oil / diesel proxy). Formula using futures prices:

3-2-1 crack = (2 × RBOB × 42 + 1 × HO × 42 − 3 × WTI) / 3

RBOB and heating oil (HO) NYMEX contracts quote in dollars per gallon; multiply by 42 gallons per barrel before combining. Divide by three to express margin per barrel of crude input. A 3-2-1 crack of $25 means the modeled product basket earns $25/barrel above crude cost before ops.

5-3-2 and custom yield slates

Complex refineries with heavy coking capacity use 5-3-2 (five barrels crude → three gasoline, two distillate) or plant-specific yields from assay tables. Harbor Energy’s refinery runs 52% gasoline, 34% distillate, 8% jet, 6% loss and petrochemical feed — their internal basket weights differ from textbook 3-2-1 by enough to matter at the 50–100 bps level.

Single-product cracks

Gasoline crack = RBOB × 42 − WTI. Distillate crack = HO × 42 − WTI. Single-product cracks isolate one output lane for seasonal trades: gasoline cracks peak in late spring ahead of Memorial Day driving demand; distillate cracks strengthen in autumn ahead of heating season and freight diesel demand.

Brent-based cracks

European and Asian refiners often crack against ICE Brent or Dubai rather than WTI. U.S. Gulf Coast exports price off Brent-linked cargoes; a widening Brent–WTI differential changes which crude leg belongs in the hedge even when product cracks look stable.

Seasonality, utilization, and inventory

Crack spreads are highly seasonal. Understanding the calendar prevents mistaking a structural shift for a one-week anomaly.

Driving season and gasoline

U.S. gasoline demand rises from April through August. Refiners ramp utilization in March–April; gasoline cracks typically widen before peak demand and compress after Labor Day when blenders switch to cheaper winter Reid vapor pressure specs. The EIA WPSR refinery utilization rate above 90% in May–July usually coincides with elevated gasoline cracks unless imports flood the coast.

Heating oil and distillate

Distillate cracks lead winter heating demand in the Northeast (PADD 1) and support trucking and rail diesel year-round. A cold winter forecast can widen HO cracks even when gasoline is soft. Jet fuel cracks correlate with distillate but diverge during air-travel shocks.

Turnarounds and utilization drops

Planned refinery maintenance in spring and fall reduces utilization for two to six weeks per unit. WPSR utilization falling 3+ percentage points week-on-week during turnaround season often widens cracks on the remaining running capacity — a supply shock, not weak demand. Confusing turnaround-driven utilization drops with demand destruction is a common macro error.

Inflation and PPI linkage

Gasoline and diesel feed household energy CPI and freight-sensitive PPI components with a two-to-six-week lag after crack moves. Macro desks pair crack monitors with inflation breakevens when refining tightness looks persistent rather than event-driven.

Harbor Energy margin desk refactor

Harbor Energy operates physical storage and a refinery margin hedging book for an affiliated Gulf Coast plant. The legacy workflow:

Hedge crude intake with flat WTI futures short vs expected runs.
Assume constant product crack from trailing 30-day average.
Ignore PADD-level utilization until WPSR headline crude moved 3+ million barrels.

In April 2025, WTI fell on OPEC+ guidance while RBOB held near summer highs on a gasoline draw streak. The crude short gained $4.1 million; unrealized product exposure lost $5.8 million as implied margins widened against an unhedged slate. Net: −$1.7 million on a week the refinery’s physical units printed record cash margin.

The refactor:

Yield-matched crack basket — daily 52/34/8/6 weights vs plant assay instead of textbook 3-2-1.
Simultaneous crack hedge — buy crack spread (long RBOB + HO, short WTI in ratio) for 70% of expected weekly throughput; crude-only leg for inventory timing only.
Utilization overlay — scale hedge notionals by WPSR PADD 3 utilization vs five-year band; reduce when turnarounds flagged in industry calendars.
Gasoline vs distillate season switch — April–September overweight gasoline crack; October–March overweight distillate by 15 points.

Metric	Before	After
Weekly margin forecast error (bps)	340	38
Hedge slippage per clip (bps)	22	5
Crude-only hedge P&L mismatch weeks	5 of 8	1 of 8
Gasoline season crack capture (%)	41%	78%

The desk still loses on one-off explosions and hurricane force majeure — cracks gap before futures reopen — but stopped systematically hedging the wrong risk factor.

Technique decision table

Approach	Best when	Weak when
Flat WTI crude hedge only	Inventory storage plays; pure crude directional book	Refinery margin exposure; product-driven earnings
Standard 3-2-1 crack spread	Quick refinery margin proxy; index products and ETFs	Plant yield slate diverges from 67/33 gasoline/distillate
Custom yield-weighted crack basket	Single-asset refiner hedging; physical run-rate match	Need simple cross-refinery comparables
Single-product gasoline or distillate crack	Seasonal lane trades; airline or trucking fuel hedges	Complex refineries with shifting yields
Crack + WPSR utilization overlay	Systematic margin forecasting; turnaround calendar	Geopolitical crude gaps dominate before stocks adjust
Refiner equity vs crack spread pairs	Relative value on merchant refiner names	Integrated majors with upstream offset

Common pitfalls

Forgetting the 42× gallon conversion — RBOB and HO quote per gallon; WTI quotes per barrel. Off-by-42 errors destroy hedge ratios.
Using WTI when crude slate is Brent-linked — Gulf Coast imports and exports increasingly price off Brent spreads.
Textbook 3-2-1 on a coker-heavy plant — yield mismatch of 5–15% is normal; customize weights.
Ignoring turnaround seasonality — utilization drops widen cracks; do not read as demand collapse.
Mixing RBOB with physical rack prices — futures crack differs from local rack minus pipeline crude by taxes and basis.
Single-week WPSR overfit — one gasoline draw does not guarantee sustained crack strength; use four-week trends.
Neglecting renewable diesel and bio mandates — RIN costs and RD capacity shift effective margins outside the futures crack.
Hedging crack without roll management — front-month RBOB vs WTI roll dates differ; calendar spreads bleed.

Production checklist

Document plant yield slate (gasoline, distillate, jet, loss) from latest assay.
Compute daily 3-2-1 and custom-weighted cracks from settled NYMEX prices.
Track gasoline and distillate single-product cracks separately by season.
Map WPSR PADD utilization to hedge notional scaling rules.
Flag turnaround windows in industry maintenance calendars.
Reconcile futures crack to physical rack minus crude basis monthly.
Monitor Brent–WTI differential for export parity shifts.
Set crack hedge ratio to 60–80% of expected throughput, not 100%.
Align RBOB and HO contract months with production timing lag.
Log RIN and bio mandate adjustments outside futures crack.
Stress-test margin model at ±$10 crack and ±$15 WTI shocks.
Review hedge P&L attribution weekly: crude leg vs product leg vs basis.

Key takeaways

Crack spreads measure gross refinery margin as product prices minus crude input — the right hedge benchmark when earnings move with refining spreads, not crude direction alone.
3-2-1 is the market standard but plant-specific yield weights matter for accurate hedging at the refinery level.
Gasoline and distillate cracks season differently; utilization and turnaround calendars explain many week-to-week moves in the WPSR.
Futures cracks require gallon-to-barrel conversion and careful contract roll alignment across RBOB, HO, and WTI.
Harbor Energy’s margin desk showed crude-only hedges can lose money in weeks when physical refinery cash margin hits records.