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What happens after a stock split? A month and a year later, every split since 2000
A year later the stock had on average done worse than from an ordinary day. A month after a split the stock stood higher in 53% of cases and a year later in 55%, against 59% and 73% from an ordinary day at the same companies. We counted 101 splits at 101 large US companies since 2000. The middle change in the year before the split was +32.6%.
The stock stood higher afterwards
What we counted
A stock split divides each share into several. The price per share falls by the same proportion, so the company is worth the same and your stake is unchanged: 100 shares at $200 become 200 shares at $100 in a 2-for-1 split. How a split works is in the lesson on stock splits. What is worth counting here is what the stock does next.
Since 2000 the 101 companies we follow have made 101 splits. We measure from the close on the first day at the new price and compare with the same companies from an ordinary trading day.
A month and a year later
| After | Higher after a split | Higher from an ordinary day |
|---|---|---|
| Large US companies, a month | 53% | 59% |
| Large US companies, a year | 55% | 73% |
| Without the year 2000, a month | 55% | 59% |
| Without the year 2000, a year | 66% | 75% |
| Stockholm's 30 companies, a month | 59% | 58% |
| Stockholm's 30 companies, a year | 63% | 73% |
After a month the stock stood higher after 53% of the splits, against 59% from an ordinary day. After a year it was 55% against 73%. The middle split was followed by a change of +0.7% after a month and +2.1% after a year.
The gap in that share after a month is −5.2 points, with a range of chance of −12.6 to +2.2, so it cannot be told apart from chance.
The gap in that share after a year is −17.8 points, with a range of chance of −34.3 to −1.2, so it can be told apart from chance.
The average after a month was +0.2% against +1.8%. The difference is −1.6 points and the range of chance −3.6 to +0.4. That includes zero, so it cannot be told apart from chance.
The average after a year was +2.4% against +23.8%. The difference is −21.4 points and the range of chance −36.3 to −6.6, so it can be told apart from chance.
In Stockholm the stock stood higher a year later after 63% of the splits, against 73%, and the average was +28.6% against +21.5%.
That average difference, +7.1 points with a range of −22.3 to +36.5, cannot be told apart from chance. Stockholm has only a few splits, so the range is wide.
The year before the split
In the year before the split the stock rose in 71 of 77 cases, and the middle change was +32.6%. From an ordinary day at the same companies the stock stood higher a year later in 73% of cases.
The gap in that share is +17.6 points, with a range of +10.7 to +24.6, outside the range of chance. So companies usually split when the price has already risen. That is why we cannot say the split itself does anything: it follows an unusually good year, and the year after is compared with all of the company's years.
The year 2000 weighs a lot
Of the 101 splits, 24 came in 2000, the year the dot-com bubble burst. Without that year the stock stood higher a year later after 66% of the splits, against 75%, and the average was +11.9% against +24.9%.
The average difference is −13.1 points with a range of −21.8 to −4.4, so it can be told apart from chance even without 2000.
The gap in that share is −8.4 points with a range of −17.8 to +1.1, and it cannot be told apart from chance.
Reverse splits
A reverse split merges several shares into one, so the price per share rises. Our list has 4: GE Aerospace (1-for-8, Aug 2, 2021), Duke Energy (1-for-3, Jul 3, 2012), Citigroup (1-for-10, May 9, 2011) and Intuitive Surgical (1-for-2, Jul 1, 2003). That is too few to count, so they are not in the numbers above.
Every split
Newest first. The latest is KLA's 10-for-1 on Jun 12, 2026. A single company can shift a lot by chance. What happened after the very largest falls is in the study of one-day falls, and how a split affects earnings per share is in the lesson on earnings per share.
| Company | Day | Split | A year later |
|---|---|---|---|
| KLA | 2026-06-12 | 10-for-1 | – |
| ServiceNow | 2025-12-18 | 5-for-1 | – |
| Netflix | 2025-11-17 | 10-for-1 | – |
| Palo Alto Networks | 2024-12-16 | 2-for-1 | −8.2% |
| Lam Research | 2024-10-03 | 10-for-1 | +74.8% |
| Broadcom | 2024-07-15 | 10-for-1 | +69.0% |
| Nvidia | 2024-06-10 | 10-for-1 | +19.1% |
| Walmart | 2024-02-26 | 3-for-1 | +64.3% |
| Palo Alto Networks | 2022-09-14 | 3-for-1 | +31.9% |
| Tesla | 2022-08-25 | 3-for-1 | −19.3% |
| Alphabet | 2022-07-18 | 20-for-1 | +11.9% |
| Amazon | 2022-06-06 | 20-for-1 | −2.9% |
| Intuitive Surgical | 2021-10-05 | 3-for-1 | −39.0% |
| Nvidia | 2021-07-20 | 4-for-1 | −4.3% |
| CSX | 2021-06-29 | 3-for-1 | −6.7% |
| NextEra Energy | 2020-10-27 | 4-for-1 | +14.4% |
| Tesla | 2020-08-31 | 5-for-1 | +47.6% |
| Apple | 2020-08-31 | 4-for-1 | +18.4% |
| Intuitive Surgical | 2017-10-06 | 3-for-1 | +45.6% |
| Intercontinental Exchange | 2016-11-04 | 5-for-1 | +25.6% |
| Nike | 2015-12-24 | 2-for-1 | −16.9% |
| Netflix | 2015-07-15 | 7-for-1 | −0.1% |
| Starbucks | 2015-04-09 | 2-for-1 | +28.9% |
| Visa | 2015-03-19 | 4-for-1 | +11.2% |
| Union Pacific | 2014-06-09 | 2-for-1 | −0.1% |
| Apple | 2014-06-09 | 7-for-1 | +38.4% |
| Alphabet | 2014-04-03 | 2-for-1 | −4.8% |
| Mastercard | 2014-01-22 | 10-for-1 | +1.9% |
| Salesforce | 2013-04-18 | 4-for-1 | +36.7% |
| Gilead Sciences | 2013-01-28 | 2-for-1 | +104.5% |
| Nike | 2012-12-26 | 2-for-1 | +54.4% |
| Coca-Cola | 2012-08-13 | 2-for-1 | +2.3% |
| CME Group | 2012-07-23 | 5-for-1 | +52.6% |
| CSX | 2011-06-16 | 3-for-1 | −6.1% |
| Danaher | 2010-06-14 | 2-for-1 | +29.7% |
| Berkshire Hathaway | 2010-01-21 | 50-for-1 | +11.0% |
| Union Pacific | 2008-05-29 | 2-for-1 | −37.2% |
| Deere | 2007-12-04 | 2-for-1 | −60.9% |
| Nvidia | 2007-09-11 | 3-for-2 | −68.7% |
| Gilead Sciences | 2007-06-25 | 2-for-1 | +40.8% |
| Nike | 2007-04-03 | 2-for-1 | +31.3% |
| CSX | 2006-08-16 | 2-for-1 | +34.0% |
| Wells Fargo | 2006-08-14 | 2-for-1 | 0.0% |
| Intuit | 2006-07-07 | 2-for-1 | +1.2% |
| Lowe's | 2006-07-03 | 2-for-1 | +1.8% |
| Nvidia | 2006-04-07 | 2-for-1 | −3.4% |
| Starbucks | 2005-10-24 | 2-for-1 | +37.0% |
| Caterpillar | 2005-07-14 | 2-for-1 | +37.9% |
| RTX | 2005-06-13 | 2-for-1 | +14.6% |
| CVS Health | 2005-06-07 | 2-for-1 | −1.4% |
| Elevance Health | 2005-06-01 | 2-for-1 | +9.7% |
| UnitedHealth Group | 2005-05-31 | 2-for-1 | −9.5% |
| Adobe | 2005-05-24 | 2-for-1 | −9.7% |
| Moody's | 2005-05-19 | 2-for-1 | +27.4% |
| S&P Global | 2005-05-18 | 2-for-1 | +18.8% |
| NextEra Energy | 2005-03-16 | 2-for-1 | +6.2% |
| Apple | 2005-02-28 | 2-for-1 | +52.7% |
| Chevron | 2004-09-13 | 2-for-1 | +28.1% |
| Gilead Sciences | 2004-09-07 | 2-for-1 | +25.5% |
| Bank of America | 2004-08-30 | 2-for-1 | +1.2% |
| QUALCOMM | 2004-08-16 | 2-for-1 | +19.7% |
| Procter & Gamble | 2004-06-21 | 2-for-1 | −0.4% |
| Danaher | 2004-05-21 | 2-for-1 | +20.8% |
| Netflix | 2004-02-12 | 2-for-1 | −70.1% |
| 3M | 2003-09-30 | 2-for-1 | +17.8% |
| Synopsys | 2003-09-24 | 2-for-1 | −51.7% |
| UnitedHealth Group | 2003-06-19 | 2-for-1 | +24.7% |
| Microsoft | 2003-02-18 | 2-for-1 | +8.2% |
| Applied Materials | 2002-04-17 | 2-for-1 | −48.6% |
| Gilead Sciences | 2002-03-08 | 2-for-1 | +4.6% |
| Nvidia | 2001-09-17 | 2-for-1 | −71.3% |
| Exxon Mobil | 2001-07-19 | 2-for-1 | −19.5% |
| Lowe's | 2001-07-02 | 2-for-1 | +20.7% |
| Johnson & Johnson | 2001-06-13 | 2-for-1 | +12.6% |
| Starbucks | 2001-04-30 | 2-for-1 | +17.1% |
| Gilead Sciences | 2001-02-22 | 2-for-1 | +134.8% |
| Duke Energy | 2001-01-29 | 2-for-1 | −5.3% |
| UnitedHealth Group | 2000-12-26 | 2-for-1 | +15.0% |
| Adobe | 2000-10-25 | 2-for-1 | −60.8% |
| Oracle | 2000-10-13 | 2-for-1 | −59.2% |
| Citigroup | 2000-08-28 | 4-for-3 | −19.2% |
| Vertex Pharmaceuticals | 2000-08-24 | 2-for-1 | −50.1% |
| AMD | 2000-08-22 | 2-for-1 | −57.9% |
| Intel | 2000-07-31 | 2-for-1 | −55.3% |
| Target | 2000-07-20 | 2-for-1 | +23.0% |
| Nvidia | 2000-06-27 | 2-for-1 | +27.5% |
| Apple | 2000-06-21 | 2-for-1 | −59.6% |
| JPMorgan Chase | 2000-06-12 | 3-for-2 | −6.2% |
| Charles Schwab | 2000-05-31 | 3-for-2 | −31.5% |
| Texas Instruments | 2000-05-23 | 2-for-1 | −38.0% |
| American Express | 2000-05-11 | 3-for-1 | −14.1% |
| GE Aerospace | 2000-05-08 | 3-for-1 | −4.5% |
| Micron Technology | 2000-05-02 | 2-for-1 | −31.3% |
| Cisco Systems | 2000-03-23 | 2-for-1 | −76.0% |
| Lam Research | 2000-03-17 | 3-for-1 | −50.5% |
| Applied Materials | 2000-03-16 | 2-for-1 | −49.7% |
| Analog Devices | 2000-03-16 | 2-for-1 | −49.9% |
| Morgan Stanley | 2000-01-27 | 2-for-1 | +23.3% |
| Oracle | 2000-01-19 | 2-for-1 | +18.4% |
| KLA | 2000-01-19 | 2-for-1 | −28.4% |
| Costco | 2000-01-14 | 2-for-1 | −11.2% |
35 of the companies have no split in our history, which is shorter for some of them.
How we counted
- 101 large US companies on our list, drawn from the S&P 500, from January 2000 or the company's first price to Nov 6, 2026, and for comparison the 30 companies in OMX Stockholm 30. The first split came on Jan 14, 2000.
- Companies that went bankrupt, were bought or left the exchange are missing. These are the largest companies today, so their ordinary day is unusually good too.
- The comparison is the same company's ordinary day, not the market. A comparison with the market over the same time can give a different answer.
- We measure from the close on the day of the split, and the year before stops at the close the day before. What happened on the day itself is not counted.
- Our price data also lists spin-offs as splits. We count only even ratios such as 2-for-1 and 3-for-2 and leave the rest out.
- Alphabet's two share classes split together and count once. Dates for older splits can be a few days off.
- A month is 21 trading days and a year 252. A split newer than that does not count in that column.
- An ordinary day is every trading day at the same company after the first 200. Each split weighs the same, so companies with many splits weigh more in the ordinary-day column too.
- The range of chance is 95% around the average difference. Companies count per year, because many splits come in the same year.
- Prices include dividends and splits. Companies are in the currency the stock trades in. Fees and tax are not counted.
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