Bid Ask and Mid
Separate executable sides from the midpoint used for analysis.
Begin with the executable market object.
Bid is where a buyer stands, ask is where a seller stands and mid is only their arithmetic centre. The spread is a cost and a liquidity signal.
Separate executable sides from the midpoint used for analysis.
Make the quote arithmetic explicit.
Notation and units
Decimal rates and volatilities, year-fraction time and continuous compounding unless stated otherwise.
Record venue, timestamp, and convention.
The venue, timestamp, executable side and data status are part of every market observation.
Midpoints and derived probabilities are analytical coordinates, not guaranteed executable levels.
Licensing, freshness and resolution rules determine how the observation may be used.
“An unstated convention is a future reconciliation break.”— THEQUANTBATEMAN
Distinguish observation from inference.
Quote validation, transaction-cost estimates, marking policy and model-versus-market comparisons.
Ask what can actually be traded or hedged.
Start from the executable side and timestamp. Derived Foundations signals are only as reliable as the market state and resolution convention beneath them.
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