{"slug":"what-is-option-theta","qid":"theta_dte","label":"At-the-money SPY time decay accelerates near expiry (2026-07-13)","post_title":"What Is Option Theta? Time Decay Explained","post_url":"/blog/what-is-option-theta#q-theta_dte","columns":["time_to_expiry","pct_of_price_per_day"],"rows":[{"time_to_expiry":"0-7 days","pct_of_price_per_day":-19.3},{"time_to_expiry":"8-30 days","pct_of_price_per_day":-3.9},{"time_to_expiry":"31-90 days","pct_of_price_per_day":-1},{"time_to_expiry":"90+ days","pct_of_price_per_day":-0.2}],"shape":"series","sql":"SELECT multiIf(days_to_expiry<=7,'0-7 days',days_to_expiry<=30,'8-30 days',\n               days_to_expiry<=90,'31-90 days','90+ days') AS time_to_expiry,\n       round(avg(theta/option_close)*100, 1) AS pct_of_price_per_day\nFROM global_markets.options_greeks\nWHERE date = '2026-07-13' AND underlying_symbol = 'SPY' AND abs(delta) BETWEEN 0.45 AND 0.55 AND option_close > 0.5\nGROUP BY time_to_expiry ORDER BY min(days_to_expiry)","computed_at":"2026-07-15T06:07:50.585622+00:00","elapsed":0.001845578}