{"slug":"finra-margin-debt-statistics","qid":"worst_months","label":"Largest month-over-month declines in SPY month-end closes","post_title":"FINRA Margin Debt Statistics, Explained","post_url":"/blog/finra-margin-debt-statistics#q-worst_months","columns":["calendar_label","spy_change_pct"],"rows":[{"calendar_label":"Oct 2008","spy_change_pct":-16.74},{"calendar_label":"Mar 2020","spy_change_pct":-12.99},{"calendar_label":"Feb 2009","spy_change_pct":-10.53},{"calendar_label":"Sep 2022","spy_change_pct":-9.6},{"calendar_label":"Sep 2008","spy_change_pct":-9.32},{"calendar_label":"Dec 2018","spy_change_pct":-9.3},{"calendar_label":"Apr 2022","spy_change_pct":-8.77},{"calendar_label":"Jun 2008","spy_change_pct":-8.77},{"calendar_label":"Jun 2022","spy_change_pct":-8.63},{"calendar_label":"Jan 2009","spy_change_pct":-8.4}],"shape":"ranking","sql":"WITH daily AS\n(\n    SELECT\n        toDate(toTimeZone(window_start, 'America/New_York')) AS d,\n        argMax(close, window_start)                          AS px\n    FROM global_markets.delayed_stocks_minute_aggs\n    WHERE ticker = 'SPY'\n      AND window_start >= toDateTime('2006-01-01 00:00:00')\n      AND (toHour(toTimeZone(window_start, 'America/New_York')) * 60\n           + toMinute(toTimeZone(window_start, 'America/New_York'))) >= 570\n      AND (toHour(toTimeZone(window_start, 'America/New_York')) * 60\n           + toMinute(toTimeZone(window_start, 'America/New_York'))) < 960\n    GROUP BY d\n),\nmonth_close AS\n(\n    SELECT\n        toStartOfMonth(d)        AS m,\n        toFloat64(argMax(px, d)) AS close_px\n    FROM daily\n    GROUP BY m\n),\nchained AS\n(\n    SELECT\n        m,\n        close_px,\n        lagInFrame(close_px, 1) OVER (ORDER BY m ASC\n            ROWS BETWEEN 1 PRECEDING AND CURRENT ROW) AS prior_close\n    FROM month_close\n)\nSELECT\n    formatDateTime(m, '%b %Y')                   AS calendar_label,\n    round(100 * (close_px / prior_close - 1), 2) AS spy_change_pct\nFROM chained\nWHERE prior_close > 0\nORDER BY spy_change_pct ASC\nLIMIT 10","computed_at":"2026-08-22T04:06:29.242707+00:00","elapsed":7.66802956}