Every December session and how far its wash sale window reaches into the new year

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 2026-08-13, from Wash Sale Rule and Options: The 61-Day Window.

Rows × columns

22 × 4

Period covered

2025-12-01 to 2025-12-31

Computed

2026-08-13

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 2026-08-13, and the query below is what returned them.

WITH sessions AS
(
    SELECT DISTINCT date AS d
    FROM global_markets.stocks_daily_aggs
    WHERE ticker = 'SPY'
      AND date >= '2025-10-20'
      AND date <  '2026-02-10'
)
SELECT
    toString(sale.d)                                                    AS session_date,
    concat(formatDateTime(sale.d, '%b'), ' ', toString(toDayOfMonth(sale.d))) AS sold_on,
    countIf(s.d >= sale.d - 30 AND s.d <= sale.d + 30)                   AS sessions_in_window,
    greatest(dateDiff('day', toDate('2025-12-31'), sale.d + 30), 0)      AS window_days_in_new_year
FROM
(
    SELECT d
    FROM sessions
    WHERE d >= '2025-12-01'
      AND d <  '2026-01-01'
) AS sale
CROSS JOIN sessions AS s
GROUP BY sale.d
ORDER BY sale.d