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.
| session_date | sold_on | sessions_in_window | window_days_in_new_year |
|---|---|---|---|
| 2025-12-01 | Dec 1 | 41 | 0 |
| 2025-12-02 | Dec 2 | 41 | 1 |
| 2025-12-03 | Dec 3 | 42 | 2 |
| 2025-12-04 | Dec 4 | 41 | 3 |
| 2025-12-05 | Dec 5 | 40 | 4 |
| 2025-12-08 | Dec 8 | 40 | 7 |
| 2025-12-09 | Dec 9 | 41 | 8 |
| 2025-12-10 | Dec 10 | 42 | 9 |
| 2025-12-11 | Dec 11 | 41 | 10 |
| 2025-12-12 | Dec 12 | 40 | 11 |
| 2025-12-15 | Dec 15 | 40 | 14 |
| 2025-12-16 | Dec 16 | 41 | 15 |
| 2025-12-17 | Dec 17 | 42 | 16 |
| 2025-12-18 | Dec 18 | 41 | 17 |
| 2025-12-19 | Dec 19 | 40 | 18 |
| 2025-12-22 | Dec 22 | 39 | 21 |
| 2025-12-23 | Dec 23 | 40 | 22 |
| 2025-12-24 | Dec 24 | 41 | 23 |
| 2025-12-26 | Dec 26 | 39 | 25 |
| 2025-12-29 | Dec 29 | 40 | 28 |
| 2025-12-30 | Dec 30 | 41 | 29 |
| 2025-12-31 | Dec 31 | 42 | 30 |
- Rows × columns
- 22 × 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 |
|---|---|---|---|
session_date |
date | 2025-12-01 to 2025-12-31 | |
sold_on |
text | 22 distinct values (Dec 1, Dec 10, Dec 11…) | |
sessions_in_window |
number | 39 to 42 | |
window_days_in_new_year |
number | 0 to 30 |
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 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
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