Twenty checks are not needed if the first few essentials are missing: identity, date, price field and reconciliation. This guide keeps the exchange, dated legs and historical-data boundary visible so the quoted relationship can be checked.
Identify every column
Save venue, vendor ticker, product root, month code, year and field with the source file. Confirm that an MWE Minneapolis observation is not a CME KFP/HRS price. Keep the source’s Last and settlement fields distinct and record the timezone or trade date used. A downloaded file with a plausible header can still contain a mislabeled column or a blank contract.
Compare the vendor’s first and last date to the exchange listing and your intended analysis window. An October 2025 observation in a December 2026 contract is historical, not the December 2026 market close.
Normalize without inventing
Parse Bloomberg fractional glyphs into quarter-cent values, preserve the associated row date and reject nonpositive placeholders. Check duplicates on contract and date, off-tick values, weekend anomalies and observations dated beyond a contract’s life. A correction tab should replace only the columns it actually fixes; do not overwrite an unrelated verified series.
Reconcile each imported contract with the cleaned source by row count, date range and every date-price pair. If a provider later adds daily closes, compare several overlapping dates before approving its exact dated ticker. Keep the historical source immutable while resolving disagreements.
Guard every derived result
A calendar requires two same-day legs; a butterfly requires three; an intermarket pair requires the two correct venues and matched dates. Count how many dates and seasons remain after the join. Separate normalized chart shape from raw-dollar P&L, and show the as-of date wherever a “current” metric appears.
If fresh Minneapolis prices cannot be verified, keep the historical studies available and suppress the current spread, ranking and opportunity card. A visible gap is more useful than a polished but synthetic price.
See the dated contracts behind the formula
Explore matched historical Minneapolis prices, individual years and the selected date window. The dataset has no verified current MGE spread.
Open MGE Historical Research →Primary sources
Exchange and USDA sources establish product definitions and context. Recheck the current rules and dates before using a contract.
Continue this series
Educational historical research, not investment advice. Futures and multi-leg spreads involve substantial loss, execution and delivery risk. Historical results do not guarantee future outcomes. Imported Minneapolis prices stop on 24 October 2025; current quotes and margin must be verified independently.