How Rule 605 Preflight works

Clear, repeatable calculations.

RegPreflight independently recalculates the Rule 605(a)(2) OES summary metrics from the published Rule 605(a)(1) detailed aggregates when the required detailed fields are populated and a complete month-specific S&P 500 classification is supplied.

What this review covers

RegPreflight checks the finished reporting output. It does not verify the completeness of source orders or independently validate source timestamps, NBBO inputs, market data, or upstream inclusion decisions.

A passing result means the submitted reports passed RegPreflight's checks and the recalculated OES values matched within the documented review limits.

Bucket mapping

  • Summary M maps to detailed order type MXXNN.
  • Summary ML maps to detailed order type LYNNN.
  • Detailed lot-size flags are aggregated together.
  • Summary size 199999 aggregates detailed size buckets 0, 250, 1000, 5000, 10000, 20000, and 50000.
  • Summary size 200000 maps only to detailed size 200000.
  • S&P grouping uses membership applicable on the first day of the reporting month.
  • Reporter code, Designated Participant, and report month must align between the summary and detailed data used in the calculation.

All 12 OES formulas

OES fieldRegPreflight formulaDetailed inputs
AvgOrderQtyΣF10 / ΣF88, 10
AvgOrderSizeΣF9 / ΣF88, 9
ExctdOrderMidPtAvgΣ((F12+F13)×F32) / Σ(F12+F13)12, 13, 32
PctExctdAtQuotOrBetterΣ(F37+F40) / Σ(F12+F13)12, 13, 37, 40
PctExctdPIΣF37 / Σ(F12+F13)12, 13, 37
WghtdAvgPctPI[Σ(F37×F38)−Σ(F42×F43)] / Σ((F12+F13)×F32)12, 13, 32, 37, 38, 42, 43
AvgEffctvSprdPctΣ((F12+F13)×F34) / Σ((F12+F13)×F32)12, 13, 32, 34
AvgPctQuotSprdΣ((F12+F13)×F33) / Σ((F12+F13)×F32)12, 13, 32, 33
AvgEFQPct100 × Σ((F12+F13)×F34) / Σ((F12+F13)×F33)12, 13, 33, 34
AvgRealSprdPct15secΣ((F12+F13)×F26) / Σ((F12+F13)×F32)12, 13, 26, 32
AvgRealSprdPct1minΣ((F12+F13)×F28) / Σ((F12+F13)×F32)12, 13, 28, 32
WghtdAvgExctnTime[Σ(F37×F39)+Σ(F40×F41)+Σ(F42×F44)] / Σ(F12+F13)12, 13, 37, 39, 40, 41, 42, 44

Rounding and precision

For 11 OES metrics, RegPreflight uses a base review tolerance of 0.0001. This is a product review control, not an SEC compliance threshold.

AvgEFQPct is handled differently because it is a ratio of aggregate effective spread to aggregate quoted spread. Both components are reconstructed from detailed values published to at most six decimal places. RegPreflight derives a publication-rounding envelope from that input precision and treats a published value as consistent only when it falls inside the mathematically possible range.

References