Trading sessions by day of the week, calendar year 2019

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 2026-08-08, from When Did the US Stock Market Start? 1792.

Rows × columns

7 × 3

Period covered

Friday to Wednesday

Computed

2026-08-08

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 2026-08-08, and the query below is what returned them.

SELECT
    formatDateTime(cal.day, '%W')   AS weekday,
    countIf(s.sessions > 0)         AS trading_days,
    count()                         AS calendar_days
FROM
(
    SELECT toDate('2019-01-01') + arrayJoin(range(365)) AS day
) AS cal
LEFT JOIN
(
    SELECT
        date     AS d,
        count()  AS sessions
    FROM global_markets.stocks_daily_aggs
    WHERE ticker = 'SPY'
      AND date >= '2019-01-01'
      AND date <  '2020-01-01'
    GROUP BY d
) AS s ON s.d = cal.day
GROUP BY weekday
ORDER BY min(toDayOfWeek(cal.day))