Quality arbitrage exploits price differences between commodity grades. By blending, upgrading, or processing commodities, traders can transform lower-value inputs into higher-value outputs. This requires technical knowledge, infrastructure, and operational capability.
Quality Dimensions
Crude Oil Quality
Parameter
Description
Impact
API Gravity
Density measure (higher = lighter)
Lighter yields more gasoline
Sulfur Content
Sweet (<0.5%) vs Sour (>0.5%)
Lower sulfur = premium
TAN
Total Acid Number
High TAN needs special refinery
Pour Point
Temperature at which oil stops flowing
Cold weather handling
Metals
Nickel, vanadium content
Refinery catalyst poisoning
Crude Oil Classification
Class
API
Sulfur
Examples
Premium/Discount
Light Sweet
>35°
<0.5%
Brent, Bonny Light
Highest
Medium Sour
25-35°
0.5-2%
Arab Light, Mars
Middle
Heavy Sour
<25°
>2%
Maya, Boscan
Lowest
Metals Quality
Metal
Key Specs
Premium/Discount
Copper
99.99% (Grade A)
LME deliverable
Copper
99.90% (off-grade)
Discount to LME
Aluminum
P1020A (99.7%+)
LME deliverable
Zinc
SHG (99.995%)
LME deliverable
Agricultural Quality
Commodity
Key Specs
Impact
Wheat
Protein content
Higher protein = premium
Corn
Moisture, damage
Lower moisture = premium
Soybeans
Oil/protein content
Crush yield
Sugar
ICUMSA color, pol
Lower ICUMSA = premium
Blending Strategies
Basic Blending Math
BLENDING FORMULA
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For any parameter that blends linearly:
Blend Value = (A% × Value_A) + (B% × Value_B)
EXAMPLE: API Gravity Blending
Light crude: 40° API, 60%
Heavy crude: 25° API, 40%
Blend API = (0.60 × 40) + (0.40 × 25)
= 24 + 10
= 34° API
Non-Linear Blending
Some parameters don’t blend linearly:
VISCOSITY BLENDING
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Viscosity blends on a log scale:
ln(μ_blend) = Σ(xi × ln(μi))
Where:
μ = viscosity
x = volume fraction
This means:
Adding small amounts of light crude
significantly reduces blend viscosity
Blending Optimization
BLENDING OPTIMIZATION PROBLEM
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OBJECTIVE: Maximize value
INPUTS:
Light Sweet: $78/bbl (unlimited)
Medium Sour: $72/bbl (unlimited)
Heavy Sour: $65/bbl (unlimited)
TARGET OUTPUT:
Medium blend meeting spec:
- API: 32-35°
- Sulfur: <1.5%
OUTPUT VALUE:
Target market: $76/bbl
CONSTRAINTS:
- Tank capacity: 500,000 bbl
- Must meet specs
SOLUTION (linear programming):
Light: 30% @ $78 = $23.40
Medium: 50% @ $72 = $36.00
Heavy: 20% @ $65 = $13.00
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Input cost: $72.40/bbl
Blending cost: $0.50/bbl
Total cost: $72.90/bbl
Sale: $76.00/bbl
Margin: $3.10/bbl
Quality Arbitrage Types
Type 1: Grade Blending
CRUDE OIL GRADE BLENDING
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MARKET OBSERVATION:
Refinery needs: Medium sour crude (32° API, 1.5% S)
Available grades:
Bonny Light (40° API, 0.1% S): $80/bbl
Arab Heavy (28° API, 2.8% S): $66/bbl
BLEND DESIGN:
Target: 32° API, 1.5% sulfur
Ratio calculation (API):
0.40x + 0.28(1-x) = 0.32
x = 0.33 (33% light, 67% heavy)
Check sulfur:
(0.33 × 0.1%) + (0.67 × 2.8%) = 1.91%
Too high! Adjust ratio.
Iterate to: 40% light, 60% heavy
API: (0.40 × 40) + (0.60 × 28) = 32.8° ✓
Sulfur: (0.40 × 0.1) + (0.60 × 2.8) = 1.72%
Close enough with quality tolerance ✓
ECONOMICS:
Input: (0.40 × $80) + (0.60 × $66) = $71.60/bbl
Blending: $0.50/bbl
Total: $72.10/bbl
Market price: $75/bbl
Margin: $2.90/bbl
Type 2: Quality Upgrading
COPPER CONCENTRATE UPGRADING
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STARTING MATERIAL:
Copper concentrate: 25% Cu, $100 TC/RC discount
PROCESS:
Smelting (third-party tolling):
Cost: $80/MT of copper produced
OUTPUT:
Copper cathode: 99.99% Cu (LME Grade A)
ECONOMICS:
Concentrate: LME - $100 TC/RC
Smelting: $80/MT Cu produced
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Cost basis: LME - $20
Sell: LME (Grade A)
Margin: $20/MT Cu
On 10,000 MT Cu (40,000 MT concentrate):
Profit: $200,000
Type 3: Contamination Arbitrage
OFF-SPEC FUEL ARBITRAGE
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SCENARIO:
Contaminated diesel cargo rejected by buyer
Off-spec parameter: Sulfur 55 ppm (spec: max 50 ppm)
Discount: $15/MT
SOLUTION OPTIONS:
Option A: Re-blend
Mix with ultra-low sulfur diesel (10 ppm)
Ratio: 80% contaminated + 20% ULSD
Result: (0.80 × 55) + (0.20 × 10) = 46 ppm ✓
Cost: ULSD premium $20/MT × 20% = $4/MT
Margin: $15 - $4 - $1 blending = $10/MT
Option B: Downgrade market
Sell to market accepting 500 ppm
Discount vs original market: $50/MT
Loss: $35/MT additional
Margin: Negative
DECISION: Re-blend (Option A)
Type 4: Regional Specification Arbitrage
SPECIFICATION ARBITRAGE
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OBSERVATION:
US market: Requires 87 octane gasoline
European market: Requires 95 octane gasoline
Octane premium: ~$0.05/gallon per point
OPPORTUNITY:
Europe produces 95 octane (excess supply)
US needs 87 octane (deficit)
TRADE:
Buy European 95 octane (at discount due to surplus)