Does a Stock Go Up After a Split?

A stock split multiplies a company's share count and divides its price by the same factor, so a $600 stock that splits 3-for-1 becomes three $200 shares worth exactly what they were. Does the stock then go up? On the median it has, a little, but by less than the market. Across hundreds of forward splits from 2016 to 2025, the typical stock trailed the S&P 500 in the three months after it split, in every period measured. The larger price move came before the split, not after.

What a split does, and what it does not

The mechanics are value-neutral. A forward split lowers the price and raises the share count in equal measure, and nothing about the business changes overnight. Two separate things get folded into the idea of a "split pop": the run-up that precedes a split, and whatever the stock does afterward. This study measures the second directly, off the split's execution date, and keeps it apart from the first. The announcement date, where academic work has found a small reaction, comes weeks earlier and is already in the price by the execution date measured here.

The run-up comes before the split

The best-known recent splits show the shape, each measured over the six months into its split and the three months out of it.

WITH
cohort AS (
    SELECT ticker, max(execution_date) AS ex,
           argMax(concat(toString(split_to), '-for-', toString(split_from)), execution_date) AS ratio
    FROM global_markets.stocks_splits
    WHERE ticker IN ('NVDA', 'AVGO', 'NFLX', 'AMZN', 'GOOGL', 'AAPL', 'TSLA')
      AND split_to >= 2 * split_from
      AND adjustment_type IN ('forward_split', 'stock_dividend')
      AND execution_date >= '2020-01-01' AND execution_date <= '2026-01-31'
    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 >= '2019-06-01 00:00:00' AND window_start < '2026-07-14 00:00:00'
      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 sd, prices AS sp FROM series WHERE ticker = 'SPY')
SELECT c.ticker AS ticker,
       c.ratio AS ratio,
       toString(c.ex) AS ex_date,
       round((s.prices[indexOf(s.days, c.ex) - 1] / s.prices[indexOf(s.days, c.ex) - 1 - 126] - 1) * 100, 1) AS run_up_before_pct,
       round((s.prices[indexOf(s.days, c.ex) + 63] / s.prices[indexOf(s.days, c.ex)] - 1) * 100, 1) AS after_3mo_pct,
       round((spy.sp[indexOf(spy.sd, c.ex) + 63] / spy.sp[indexOf(spy.sd, c.ex)] - 1) * 100, 1) AS spy_3mo_pct
FROM cohort c INNER JOIN series s ON s.ticker = c.ticker CROSS JOIN spy
WHERE indexOf(s.days, c.ex) > 130 AND length(s.prices) >= indexOf(s.days, c.ex) + 63
ORDER BY run_up_before_pct DESC

NVDA climbed 165.6% in the six months before its 10-for-1 split, and AAPL rose 67%. The run-up is not universal: AMZN, GOOGL, and NFLX went into their splits with six-month returns of -28.8%, -21%, and -6.6%. What almost none of the seven did was outrun the market afterward. NVDA returned -11.2% in the three months after its split against the S&P 500's 2.5%, and most of the group trailed the index over the same stretch.

Does a stock go up after a split? The record says less than the market

Seven names prove nothing, so here is every liquid forward split from 2016 through 2025 (a share split of 2-for-1 or larger, priced above $30 going in), grouped into three periods. For each, the median stock's three-month return after the split sits beside the S&P 500's over the identical windows.

WITH
cohort AS (
    SELECT ticker, min(execution_date) AS ex
    FROM global_markets.stocks_splits
    WHERE adjustment_type IN ('forward_split', 'stock_dividend') AND split_to >= 2 * split_from
      AND execution_date >= '2016-01-01' AND execution_date <= '2025-12-31' AND ticker != 'SPCX'
    GROUP BY ticker, execution_date
),
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 >= '2015-06-01 00:00:00' AND window_start < '2026-02-01 00:00:00'
      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 sd, prices AS sp FROM series WHERE ticker = 'SPY'),
fwd AS (
    SELECT ex,
        (prices[i0 - 1] / prices[i0 - 1 - 126] - 1) * 100 AS run_up,
        (prices[i0 + 63] / prices[i0] - 1) * 100 AS ret,
        (sp[j0 + 63] / sp[j0] - 1) * 100 AS spy_ret
    FROM (
        SELECT c.ex AS ex, indexOf(s.days, c.ex) AS i0, indexOf(spy.sd, c.ex) AS j0,
               s.prices AS prices, spy.sp AS sp
        FROM cohort c INNER JOIN series s ON s.ticker = c.ticker CROSS JOIN spy
    )
    WHERE i0 > 130 AND length(prices) >= i0 + 63 AND prices[i0] > 0 AND prices[i0 - 1] >= 30
)
SELECT multiIf(toYear(ex) <= 2019, '2016-2019', toYear(ex) <= 2023, '2020-2023', '2024-2025') AS period,
    count() AS splits,
    round(median(run_up), 1) AS median_runup_before_pct,
    round(median(ret), 1) AS median_after_3mo_pct,
    round(median(spy_ret), 1) AS median_spy_3mo_pct,
    round(median(ret - spy_ret), 1) AS median_gap_vs_spy_pct,
    round(100.0 * countIf(ret > spy_ret) / count(), 0) AS pct_beat_spy
FROM fwd GROUP BY period ORDER BY period

The three periods tell one story. In 2016-2019 the median split stock returned 1.8% in the three months after execution, against the S&P 500's 3.8%. In 2020-2023 it was 1% against 4.9%. In 2024-2025, 0% against 3.3%. Flat to modestly higher each time, and below the index each time. Fewer than half the splits beat the market in any window, between 37% and 41%. The run-up beforehand was the larger move throughout, a median of 10.6% to 17.1%.

Why "stocks always go up after a split" does not hold up

A split changes the share count and the price by the same factor and nothing else, so any edge afterward would have to come from the kind of company that splits, not from the split. Splitting companies are prior winners by construction, and in the data that group did not extend its lead once it split: in every period since 2016 the median trailed the market over the following quarter. The reverse split, which happens to falling stocks, is followed by more weakness on average. The two together point the same way. What a stock did before a split has not carried into a market-beating return after it.

FAQ

Does a stock go up after a stock split?

On the median it has risen slightly, but by less than the market. Across liquid forward splits from 2016 to 2025 the median stock returned between 0% and 1.8% in the next three months, trailing the S&P 500 in every period, and fewer than half beat the index.

Should I buy a stock before or after it splits?

The split itself has offered no edge. The larger price move came before it, a median run-up of as much as 17.1%, and the return afterward trailed the market in every period since 2016. A split does not change what a share is worth.

Why do stocks often rise before a split?

A stock reaches a high enough price to consider splitting only after it has appreciated, so a run-up tends to precede a split by construction. Boards commonly announce a split after a strong stretch to bring the per-share price down.

Do stock splits create value?

No. A forward split multiplies the shares and divides the price by the same factor, leaving the company's market value and each holder's stake unchanged. It is a change of units, not of worth.

Which big stocks have split recently?

NVDA (10-for-1), AAPL, and the other names in the panel above all split in recent years. Most had run up beforehand, and most trailed the S&P 500 in the three months after splitting.

Every panel above is a stored, inspectable query. Open the SQL under any chart to audit it, or run the same before-and-after test on any split in the record on the Strasmore terminal.