What happened next: median move after a reverse split vs. SPY, splits executed 4-9 months ago

WITH cohort AS (
    SELECT ticker, min(execution_date) AS ex
    FROM global_markets.stocks_splits
    WHERE adjustment_type = 'reverse_split'
      AND execution_date >= today() - INTERVAL 270 DAY
      AND execution_date <= today() - INTERVAL 120 DAY
      AND ticker != 'SPCX'
    GROUP BY ticker
),
bars AS (
    SELECT ticker,
           toDate(toTimeZone(window_start, 'America/New_York')) AS d,
           toFloat64(argMax(close, window_start)) AS px
    FROM global_markets.delayed_stocks_minute_aggs
    WHERE (ticker IN (SELECT ticker FROM cohort) OR ticker = 'SPY')
      AND window_start >= today() - INTERVAL 275 DAY
      AND (toHour(toTimeZone(window_start, 'America/New_York')) * 60
           + toMinute(toTimeZone(window_start, 'America/New_York'))) BETWEEN 570 AND 959
    GROUP BY ticker, d
),
series AS (
    SELECT ticker,
           arrayMap(x -> x.1, arraySort(x -> x.1, groupArray((d, px)))) AS days,
           arrayMap(x -> x.2, arraySort(x -> x.1, groupArray((d, px)))) AS prices
    FROM bars
    GROUP BY ticker
),
spy AS (
    SELECT days AS spy_days, prices AS spy_prices
    FROM series
    WHERE ticker = 'SPY'
),
horizons AS (SELECT arrayJoin([5, 21, 63]) AS h),
fwd AS (
    SELECT c.ticker AS ticker,
           h.h AS h,
           indexOf(s.days, c.ex) AS i0,
           indexOf(spy.spy_days, c.ex) AS j0,
           (s.prices[i0 + h.h] / s.prices[i0] - 1) * 100 AS ret,
           (spy.spy_prices[j0 + h.h] / spy.spy_prices[j0] - 1) * 100 AS spy_ret
    FROM cohort AS c
    INNER JOIN series AS s ON s.ticker = c.ticker
    CROSS JOIN horizons AS h
    CROSS JOIN spy AS spy
    WHERE i0 > 0
      AND j0 > 0
      AND length(s.prices) >= i0 + h.h
      AND s.prices[i0] > 0
)
SELECT multiIf(h = 5, '1 week after (5 sessions)',
               h = 21, '1 month after (21 sessions)',
               '3 months after (63 sessions)') AS horizon,
       count() AS splits_measured,
       round(quantileDeterministic(0.5)(ret, cityHash64(ticker)), 1) AS median_stock_pct,
       round(abs(quantileDeterministic(0.5)(ret, cityHash64(ticker))), 1) AS median_stock_pct_abs,
       round(quantileDeterministic(0.5)(spy_ret, cityHash64(ticker)), 1) AS median_spy_pct,
       round(quantileDeterministic(0.5)(ret, cityHash64(ticker))
             - quantileDeterministic(0.5)(spy_ret, cityHash64(ticker)), 1) AS median_gap_pct,
       round(100.0 * countIf(ret < 0) / count(), 1) AS pct_below_split_day
FROM fwd
GROUP BY h
ORDER BY h