Share of SPY session volume printed in the opening minute, third Friday vs other Fridays
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 2026-08-16, from When Is SQ Day for Nikkei 225 Options?.
| month | month_label | third_friday_pct | other_friday_pct |
|---|---|---|---|
| 2025-08-01 | Aug 2025 | 1.33 | 0.95 |
| 2025-09-01 | Sep 2025 | 1.89 | 1.07 |
| 2025-10-01 | Oct 2025 | 1.7 | 0.92 |
| 2025-11-01 | Nov 2025 | 1.14 | 1.44 |
| 2025-12-01 | Dec 2025 | 1.26 | 1.23 |
| 2026-01-01 | Jan 2026 | 1.31 | 1.31 |
| 2026-02-01 | Feb 2026 | 0.81 | 1.34 |
| 2026-03-01 | Mar 2026 | 0.6 | 0.96 |
| 2026-04-01 | Apr 2026 | 1.45 | 1.71 |
| 2026-05-01 | May 2026 | 1.44 | 1.25 |
| 2026-07-01 | Jul 2026 | 1.67 | 1.13 |
- Rows × columns
- 11 × 4
- 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 |
|---|---|---|---|
month |
date | 2025-08-01 to 2026-07-01 | |
month_label |
text | 11 distinct values (Apr 2026, Aug 2025, Dec 2025…) | |
third_friday_pct |
number | 0.6 to 1.89 | percent |
other_friday_pct |
number | 0.92 to 1.71 | percent |
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.
Run it yourself
This is the exact query behind the result above. Change a ticker, a date or a column and run it against the warehouse — no account, no key. The no-signup tier is smaller than the one this page was computed on; a query that reaches past it comes back saying which plan runs it.
WITH per_session AS
(
SELECT
toDate(toTimeZone(window_start, 'America/New_York')) AS session_date,
sumIf(toFloat64(volume), et_minute = 570) AS opening_minute_volume,
sumIf(toFloat64(volume), et_minute >= 570 AND et_minute < 960) AS session_volume,
countIf(et_minute >= 570 AND et_minute < 960) AS session_minutes
FROM
(
SELECT
window_start,
volume,
toHour(toTimeZone(window_start, 'America/New_York')) * 60
+ toMinute(toTimeZone(window_start, 'America/New_York')) AS et_minute
FROM global_markets.delayed_stocks_minute_aggs
WHERE ticker = 'SPY'
AND window_start >= '2025-08-01'
AND window_start < '2026-08-01'
)
GROUP BY session_date
HAVING session_volume > 0 AND session_minutes > 300
)
SELECT
toString(toStartOfMonth(session_date)) AS month,
formatDateTime(toStartOfMonth(session_date), '%b %Y') AS month_label,
round(100 * avgIf(opening_minute_volume / session_volume,
toDayOfMonth(session_date) BETWEEN 15 AND 21), 2) AS third_friday_pct,
round(100 * avgIf(opening_minute_volume / session_volume,
toDayOfMonth(session_date) NOT BETWEEN 15 AND 21), 2) AS other_friday_pct
FROM per_session
WHERE toDayOfWeek(session_date) = 5
GROUP BY month, month_label
HAVING countIf(toDayOfMonth(session_date) BETWEEN 15 AND 21) > 0
AND countIf(toDayOfMonth(session_date) NOT BETWEEN 15 AND 21) > 0
ORDER BY month
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