At-the-money SPY time decay accelerates near expiry (2026-07-13)
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 2026-07-15, from What Is Option Theta? Time Decay Explained.
| time_to_expiry | pct_of_price_per_day |
|---|---|
| 0-7 days | -19.3 |
| 8-30 days | -3.9 |
| 31-90 days | -1 |
| 90+ days | -0.2 |
- Rows × columns
- 4 × 2
- 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 |
|---|---|---|---|
time_to_expiry |
text | 4 distinct values (0-7 days, 31-90 days, 8-30 days…) | |
pct_of_price_per_day |
number | -19.3 to -0.2 | 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.
SELECT multiIf(days_to_expiry<=7,'0-7 days',days_to_expiry<=30,'8-30 days',
days_to_expiry<=90,'31-90 days','90+ days') AS time_to_expiry,
round(avg(theta/option_close)*100, 1) AS pct_of_price_per_day
FROM global_markets.options_greeks
WHERE date = '2026-07-13' AND underlying_symbol = 'SPY' AND abs(delta) BETWEEN 0.45 AND 0.55 AND option_close > 0.5
GROUP BY time_to_expiry ORDER BY min(days_to_expiry)
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