Effective dates by weekday: US-listed splits, 2021 to mid-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 2026-08-05, from When Does a Stock Split Take Effect?.

Rows × columns

5 × 3

Period covered

Friday to Wednesday

Computed

2026-08-05

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 2026-08-05, and the query below is what returned them.

WITH s AS (
    SELECT ticker,
           execution_date,
           toFloat64(max(split_to)) / toFloat64(max(split_from)) AS ratio
    FROM global_markets.stocks_splits
    WHERE execution_date >= toDate('2021-01-01')
      AND execution_date <= toDate('2026-07-31')
      AND split_to > 0
      AND split_from > 0
    GROUP BY ticker, execution_date
)
SELECT multiIf(toDayOfWeek(execution_date) = 1, 'Monday',
               toDayOfWeek(execution_date) = 2, 'Tuesday',
               toDayOfWeek(execution_date) = 3, 'Wednesday',
               toDayOfWeek(execution_date) = 4, 'Thursday',
               'Friday') AS weekday,
       countIf(ratio >= 1.25) AS forward_splits,
       countIf(ratio < 1) AS reverse_splits
FROM s
WHERE toDayOfWeek(execution_date) <= 5
GROUP BY weekday
ORDER BY forward_splits DESC, weekday