Trading sessions vs calendar days, twelve months through June 2026

Answered against 22 years of US equities and 12 years of US options data and published with the query that produced it. This result is stored as of 2026-08-01, from When Do Mutual Fund Trades Settle?.

Rows × columns

12 × 4

Period covered

2025-07 to 2026-06

Computed

2026-08-01

Completeness

No missing values

Source

US exchange, SIP and OPRA market data

Licence

Strasmore terms · free, no signup

Formats

JSON · CSV · the SQL below

What each column holds

Computed from Strasmore's warehouse of US exchange, SIP and OPRA market data. Equity prices are delayed; options greeks and implied volatility are end-of-day. This result is stored, not recomputed on load — it is exactly the numbers that were returned on 2026-08-01, and the query below is what returned them.

WITH sessions AS (
    SELECT DISTINCT toDate(toTimeZone(window_start, 'America/New_York')) AS session_date
    FROM global_markets.delayed_stocks_minute_aggs
    WHERE ticker = 'SPY'
      AND toDate(toTimeZone(window_start, 'America/New_York')) BETWEEN toDate('2025-07-01') AND toDate('2026-06-30')
      AND (toHour(toTimeZone(window_start, 'America/New_York')) * 60
           + toMinute(toTimeZone(window_start, 'America/New_York'))) BETWEEN 570 AND 959
)
SELECT formatDateTime(toStartOfMonth(session_date), '%Y-%m') AS month,
       formatDateTimeInJodaSyntax(toStartOfMonth(session_date), 'MMMM yyyy') AS month_label,
       count() AS trading_sessions,
       toDayOfMonth(toLastDayOfMonth(session_date)) AS calendar_days
FROM sessions
GROUP BY month, month_label, calendar_days
ORDER BY month