The hindsight ceiling: SPY buy and hold, the same year without its biggest up days, and perfect one-day foresight
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 2026-07-31, from Look-Ahead Bias: The Backtest Killer.
| year | sessions | buy_and_hold_pct | without_big_up_days_pct | hindsight_ceiling_multiple |
|---|---|---|---|---|
| 2016 | 252 | 9.6 | -1.8 | 4.3 |
| 2017 | 251 | 19.4 | 19.4 | 2.2 |
| 2018 | 251 | -6.3 | -18.7 | 6.4 |
| 2019 | 252 | 28.8 | 22 | 4.2 |
| 2020 | 253 | 16.2 | -44.9 | 27.7 |
| 2021 | 252 | 27 | 21.5 | 4.9 |
| 2022 | 251 | -19.5 | -56.2 | 19.8 |
| 2023 | 250 | 24.3 | 21.5 | 5.1 |
| 2024 | 252 | 23.3 | 15.2 | 4.4 |
| 2025 | 250 | 16.4 | -6.6 | 6.3 |
- Rows × columns
- 10 × 5
- 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 |
|---|---|---|---|
year |
number | 2,016 to 2,025 | |
sessions |
number | 250 to 253 | |
buy_and_hold_pct |
number | -19.5 to 28.8 | percent |
without_big_up_days_pct |
number | -56.2 to 22 | percent |
hindsight_ceiling_multiple |
number | 2.2 to 27.7 |
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 bars AS (
SELECT date,
toFloat64(close) AS c,
any(toFloat64(close)) OVER (ORDER BY date ROWS BETWEEN 1 PRECEDING AND 1 PRECEDING) AS prev_c
FROM global_markets.stocks_daily_aggs
WHERE ticker = 'SPY'
AND date >= toDate('2015-12-01')
AND date <= toDate('2025-12-31')
),
rets AS (
SELECT toYear(date) AS year,
c / prev_c - 1 AS r
FROM bars
WHERE date >= toDate('2016-01-01')
AND prev_c > 0
)
SELECT year,
count() AS sessions,
round(100 * (exp(sum(log(1 + r))) - 1), 1) AS buy_and_hold_pct,
round(100 * (exp(sumIf(log(1 + r), r < 0.02)) - 1), 1) AS without_big_up_days_pct,
round(exp(sum(log(1 + abs(r)))), 1) AS hindsight_ceiling_multiple
FROM rets
GROUP BY year
ORDER BY year
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