Mills Assessed Rack Clearing (MARC) Price

Methodology & Specifications Guide — Version 2026.04

MARC Prices are transaction clearing prices that reflect the true market-tradeable value of unbranded wholesale fuel at a given terminal city, at a given time, for a given product specification. They are constructed to incorporate both buy-side and sell-side pricing evidence, weighted by transaction type, price type, and volume.

MARC Prices are not a simple statistical calculation on wholesale posted prices. They are not a “low” (minimum posted price), not a “high” (maximum posted price), and not a simple arithmetic average. They are assessed values that synthesize multiple layers of market evidence into a single price that reflects where a willing buyer and willing seller would transact in an arm’s-length transaction at the time of assessment.

Three-Dimensional Weighting

Transaction Type. Executed trades are the highest-priority evidence of market value. Firm bids and offers rank second. Posted prices, which are seller-determined and do not require buyer agreement, rank below direct market interaction.

Price Type. NET prices (reflecting actual cash settlement terms) are weighted over GROSS prices (list prices before discounts), ensuring the assessment captures the operationally relevant price level at which physical product changes hands.

Volume. Larger-volume transactions and indications carry proportionally more influence, reflecting the market-making significance of institutional-scale activity.

Input Hierarchy

Priority 1 — Traded Actuals

Executed trades between buyers and sellers at the assessed terminal location. These represent the most direct evidence of market value. Traded actuals include transactions reported by market participants, observed through electronic trading platforms, or confirmed through broker activity. The price, volume, transaction terms, and counterparty type of each trade are considered in determining the assessed value.

Priority 2 — Bid/Offer Actuals

Firm bids and offers observed at the assessed terminal location. These provide transparent indications of market-clearing levels in the absence of executed trades. A firm bid represents the price at which a buyer has committed to purchase, while a firm offer represents the price at which a seller has committed to sell. The bid-offer spread, the directionality of movement, and the counterparty type are all considered.

Priority 3 — Geographic Derived

When direct trading activity or firm bids and offers are insufficient at a given terminal city, observed rack market activity from neighboring terminals within the same supply corridor or PADD region is considered, adjusted for known logistics, supply, and demand differentials between markets. Geographic proxy relationships are based on physical supply routes, pipeline connectivity, and historical price correlation analysis, and are reviewed periodically and updated as supply infrastructure or market dynamics change.

Priority 4 — Price Chain Derived

When direct physical market inputs are insufficient, derived estimates from other points in the fuel price chain establish a theoretical anchor for the assessment.

Retail-Derived: Derived from average retail fuel prices for a defined geographic region as reported by third-party retail price sources. Federal, state, and local excise and sales taxes are deducted from the retail reference price. Expected downstream margins, including retail dealer margin and supply chain margins, are estimated and removed to approximate a rack-equivalent value. Because true supplier and buyer margin structures are not fully observable, a small degree of editorial judgment is applied to reflect market variability and capture a reasonable range of potential rack outcomes.

Futures-Derived: Futures-derived inputs are not intended to replace retail observations but to provide directional guidance during periods when retail price data is limited or reported intermittently. Front-month NYMEX RBOB (gasoline) and NYMEX ULSD (diesel) futures contracts are monitored as indicators of short-term price momentum in physical markets. Both the direction (increase or decrease) and the magnitude (classified as low, medium, or high) of futures price movements are considered. Momentum signals are then used to infer whether rack-level prices are likely to adjust upward, downward, or remain stable in subsequent assessment periods.

Assessment Process

Data collection. All available market evidence is gathered for the terminal city and product specification: traded actuals, bid/offer levels, posted prices, geographic proxy observations, and price chain indicators.
Classification & weighting. Each data point is classified by transaction type, price type, and volume, and weighted according to the input hierarchy.
Cross-referencing. Terminal-level observations are cross-referenced against spot market conditions, futures movements, and neighboring terminal activity to identify and resolve anomalies, outliers, or stale data.
Assessment determination. The assessed clearing price is determined based on the weight of evidence, with higher-priority inputs exerting the strongest influence.
Quality control. Each assessment is reviewed for consistency with historical levels, related terminal prices, and prevailing market conditions before publication.

Editorial Judgment

In markets where data is limited, conflicting, or ambiguous, editorial judgment informed by market knowledge, historical patterns, supply/demand fundamentals, and input from market participants is applied. This judgment is not arbitrary — it is constrained by the assessed value’s required consistency with observable market evidence and the broader price chain.

Corrections

If a published MARC Price is determined to contain an error after publication, a correction is issued as promptly as practicable. Corrections are clearly identified and timestamped, disclosing both the original and corrected values.

MARC Prices are assessments of market-clearing levels at a point in time and should not be construed as guaranteed transaction prices. Actual transaction prices may differ due to counterparty-specific terms, credit conditions, volume commitments, or delivery logistics. MARC Prices do not include branded product premiums. For the complete MARC Price Methodology and Specifications Guide (2026.04), sign up or email support@millsprice.io.