The 2010 Flash Crash, Minute by Minute

On May 6, 2010, the US stock market fell roughly nine percent in minutes and recovered most of it almost as fast — the Flash Crash, the strangest half hour in modern market-structure history. It remains the canonical demonstration of what happens when liquidity — not value — disappears. The minute tape preserves all of it. Every number is a stored query; expand any panel for the SQL.

The day, on one row

WITH
    (
        SELECT argMaxIf(toFloat64(close), window_start, (toHour(toTimeZone(window_start, 'America/New_York')) * 60 + toMinute(toTimeZone(window_start, 'America/New_York'))) BETWEEN 570 AND 959)
        FROM global_markets.delayed_stocks_minute_aggs
        WHERE ticker = 'SPY'
          AND window_start >= toDateTime('2010-05-05 00:00:00') AND window_start < toDateTime('2010-05-06 04:00:00')
    ) AS prior_rth_close
SELECT
    round(prior_rth_close, 2) AS prior_close,
    round(toFloat64(argMinIf(open, window_start, (toHour(toTimeZone(window_start, 'America/New_York')) * 60 + toMinute(toTimeZone(window_start, 'America/New_York'))) BETWEEN 570 AND 959)), 2) AS rth_open,
    round((toFloat64(argMinIf(open, window_start, (toHour(toTimeZone(window_start, 'America/New_York')) * 60 + toMinute(toTimeZone(window_start, 'America/New_York'))) BETWEEN 570 AND 959)) / prior_rth_close - 1) * 100, 1) AS gap_pct,
    round(minIf(toFloat64(low), (toHour(toTimeZone(window_start, 'America/New_York')) * 60 + toMinute(toTimeZone(window_start, 'America/New_York'))) BETWEEN 570 AND 959), 2) AS rth_low,
    formatDateTime(toTimeZone(argMinIf(window_start, (toFloat64(low), toInt64(toUnixTimestamp(window_start))), (toHour(toTimeZone(window_start, 'America/New_York')) * 60 + toMinute(toTimeZone(window_start, 'America/New_York'))) BETWEEN 570 AND 959), 'America/New_York'), '%H:%i') AS low_et,
    round(maxIf(toFloat64(high), (toHour(toTimeZone(window_start, 'America/New_York')) * 60 + toMinute(toTimeZone(window_start, 'America/New_York'))) BETWEEN 570 AND 959), 2) AS rth_high,
    round(toFloat64(argMaxIf(close, window_start, (toHour(toTimeZone(window_start, 'America/New_York')) * 60 + toMinute(toTimeZone(window_start, 'America/New_York'))) BETWEEN 570 AND 959)), 2) AS rth_close,
    round((toFloat64(argMaxIf(close, window_start, (toHour(toTimeZone(window_start, 'America/New_York')) * 60 + toMinute(toTimeZone(window_start, 'America/New_York'))) BETWEEN 570 AND 959)) / prior_rth_close - 1) * 100, 1) AS day_change_pct,
    round((minIf(toFloat64(low), (toHour(toTimeZone(window_start, 'America/New_York')) * 60 + toMinute(toTimeZone(window_start, 'America/New_York'))) BETWEEN 570 AND 959) / prior_rth_close - 1) * 100, 1) AS low_vs_prior_pct,
    round(toFloat64(sum(volume)) / 1e6, 1) AS day_shares_m,
    countIf((toHour(toTimeZone(window_start, 'America/New_York')) * 60 + toMinute(toTimeZone(window_start, 'America/New_York'))) BETWEEN 570 AND 959) AS rth_minute_bars
FROM global_markets.delayed_stocks_minute_aggs
WHERE ticker = 'SPY'
  AND window_start >= toDateTime('2010-05-06 04:00:00') AND window_start < toDateTime('2010-05-06 23:59:00')

The day was already nervous — a Greek-debt headline tape all morning — and SPY drifted lower from its $116.26 open. Then, in the mid-afternoon, the floor vanished: the day's low of $105 printed at 14:45 ET, -10.1% below the prior close. By the bell SPY had clawed back to $112.88 — -3.4% on the day, an enormous fall by any standard, and yet far above the bottom of the air pocket. Volume: 639.9 million shares, one of the heaviest SPY sessions of its era.

Thirty-six minutes, half-hour by half-hour

SELECT
    formatDateTime(toStartOfInterval(toTimeZone(window_start, 'America/New_York'), INTERVAL 30 MINUTE), '%H:%i') AS et_time,
    round(toFloat64(argMax(close, window_start)), 2) AS bucket_close,
    round(min(toFloat64(low)), 2) AS bucket_low,
    round(toFloat64(sum(volume)) / 1e6, 1) AS shares_m
FROM global_markets.delayed_stocks_minute_aggs
WHERE ticker = 'SPY'
  AND window_start >= toDateTime('2010-05-06 04:00:00') AND window_start < toDateTime('2010-05-06 23:59:00')
  AND (toHour(toTimeZone(window_start, 'America/New_York')) * 60 + toMinute(toTimeZone(window_start, 'America/New_York'))) BETWEEN 570 AND 959
GROUP BY et_time
ORDER BY et_time

The 14:30 bucket carries the crash: its low of $105 sits far below its close of $111.79 — the market went down and came back inside a single half-hour bucket. During those minutes, quotes in individual stocks went absurd: household names printed at a penny and at $100,000 as market-maker placeholder quotes ("stub quotes") became the only bids and offers left. Those prints were later canceled by the exchanges; the index tape above survived as the honest record.

Where the selling was sharpest

SELECT
    formatDateTime(toTimeZone(window_start, 'America/New_York'), '%H:%i') AS et_minute,
    round(toFloat64(open), 2) AS minute_open,
    round(toFloat64(low), 2) AS minute_low,
    round(toFloat64(open) - toFloat64(low), 2) AS drop_within_minute_usd,
    round(toFloat64(volume) / 1e6, 2) AS shares_m
FROM global_markets.delayed_stocks_minute_aggs
WHERE ticker = 'SPY'
  AND window_start >= toDateTime('2010-05-06 18:00:00') AND window_start < toDateTime('2010-05-06 19:30:00')
ORDER BY drop_within_minute_usd DESC
LIMIT 5

The single worst minute dropped $5.72 from its open to its low — at 14:49 ET, on 4.98 million shares in sixty seconds. The regulatory post-mortem attributed the cascade to a large automated sell program interacting with fleeing high-frequency liquidity; what the tape itself shows is simpler and more durable: prices need standing buyers, and for half an hour there weren't any. This is the strongest argument ever recorded for understanding what a market order does — every stop-loss that triggered in that window became a market order hunting for bids that did not exist. The NBBO is a market's heartbeat, and that afternoon it flatlined.

What it felt like at the retail screen

For anyone watching a brokerage screen that afternoon, the numbers stopped making sense: blue-chip stocks flashing prices down eighty and ninety percent, ETFs quoted at pennies, then everything snapping back before a coffee cooled. Orders placed into the chaos filled at those absurd prints — the exchanges later canceled trades more than 60% away from pre-crash prices, an arbitrary line that made whole only the most extreme victims. Anyone whose stop-loss sold at 30% below value kept their fill. That asymmetry — canceled at 61%, honored at 59% — did more to teach retail traders about order types than any pamphlet ever printed.

What changed afterward

The flash crash produced the modern circuit-breaker regime: single-stock Limit Up/Limit Down bands and revised market-wide halts, machinery visible in later crises (March 2020's halts are its direct descendants). Stub quotes were banned; clearly-erroneous-trade rules were formalized. The market structure you trade today was substantially drafted in the aftermath of those thirty-six minutes.

Flash crash FAQ

What caused the 2010 flash crash?

The official SEC/CFTC report described a large automated E-mini sell program executing into thin liquidity, with high-frequency intermediaries first amplifying volume and then withdrawing. The tape's version: liquidity evaporated, and prices fell to wherever the next resting bid happened to be — sometimes a penny.

How far did the market fall in the flash crash?

SPY's low printed -10.1% below the prior close at 14:45 ET, and the index recovered most of that within the following half hour, closing -3.4% down.

Could a flash crash happen again?

Smaller versions have — individual symbols hit LULD halts routinely, and mini flash events recur. The 2010-scale market-wide version has so far been contained by the halt machinery it inspired. The honest answer is that the structural ingredient — liquidity that can withdraw in milliseconds — is permanent.

Every panel above is a stored, versioned query over the historical tape — expand the SQL to see each measurement. Want to feel this day instead of reading it? It is one of the playable scenarios in the Strasmore Labs trading simulator.