Every quarterly witching session since September 2024: market-wide share volume vs. the month's other sessions
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 2026-08-10, from What Is Triple Witching? Volume & Volatility.
| witching_session | witching_shares_b | other_days_median_b | times_median | gap_to_next_heaviest |
|---|---|---|---|---|
| 2024-09-20 | 13.6 | 10.1 | 1.34 | 1.97 |
| 2024-12-20 | 16.1 | 13.1 | 1.23 | -1.37 |
| 2025-03-21 | 13.9 | 14.3 | 0.97 | -4.03 |
| 2025-06-20 | 16.2 | 15.8 | 1.02 | -7.24 |
| 2025-09-19 | 20.2 | 16.7 | 1.21 | 1.37 |
| 2025-12-19 | 18 | 14.5 | 1.24 | 1.15 |
| 2026-03-20 | 19.9 | 18.9 | 1.05 | -3.14 |
| 2026-06-18 | 26.7 | 20.1 | 1.33 | 1.15 |
- Rows × columns
- 8 × 5
- Period covered
- to
- Computed
- Completeness
- No missing values
- Source
- US exchange, SIP and OPRA market data
- Licence
- Strasmore terms · free, no signup
What each column holds
| Column | Type | Range | Notes |
|---|---|---|---|
witching_session |
date | 2024-09-20 to 2026-06-18 | |
witching_shares_b |
number | 13.6 to 26.7 | count |
other_days_median_b |
number | 10.1 to 20.1 | |
times_median |
number | 0.97 to 1.34 | |
gap_to_next_heaviest |
number | -7.24 to 1.97 |
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 , and the query below is what returned them.
the exact SQL behind every number
WITH daily AS (
SELECT toDate(toTimeZone(window_start, 'America/New_York')) AS day,
sum(toFloat64(volume)) / 1e9 AS shares_b
FROM global_markets.delayed_stocks_minute_aggs
WHERE window_start >= '2024-09-01 04:00:00'
AND window_start < '2026-07-01 04:00:00'
AND toMonth(toTimeZone(window_start, 'America/New_York')) IN (3, 6, 9, 12)
GROUP BY day
),
witching AS (
SELECT toStartOfMonth(day) AS m,
maxIf(day, day <= addDays(toStartOfMonth(day),
((5 - toDayOfWeek(toStartOfMonth(day)) + 7) % 7) + 14)) AS witching_day
FROM daily
GROUP BY m
)
SELECT toString(w.witching_day) AS witching_session,
round(anyIf(d.shares_b, d.day = w.witching_day), 1) AS witching_shares_b,
round(quantileDeterministicIf(0.5)(d.shares_b, cityHash64(toString(d.day)), d.day != w.witching_day), 1) AS other_days_median_b,
round(anyIf(d.shares_b, d.day = w.witching_day)
/ quantileDeterministicIf(0.5)(d.shares_b, cityHash64(toString(d.day)), d.day != w.witching_day), 2) AS times_median,
round(anyIf(d.shares_b, d.day = w.witching_day) - maxIf(d.shares_b, d.day != w.witching_day), 2) AS gap_to_next_heaviest
FROM daily AS d
INNER JOIN witching AS w ON toStartOfMonth(d.day) = w.m
GROUP BY w.witching_day
HAVING countIf(d.day != w.witching_day) > 0
ORDER BY w.witching_day
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