Stock Splits
A stock split increases share count and lowers price without changing company value. Learn how splits and reverse splits work, why they happen and the reaction.
A stock split divides each existing share into several new shares. In a 2 for 1 split, a shareholder with 100 shares at $300 ends up with 200 shares at $150. The total value is unchanged: the company is the same size, just sliced into more pieces. A reverse split does the opposite, combining shares into fewer, higher priced ones. Splits are pure accounting events, but they can still affect liquidity, investor perception, options and data, so traders need to understand them.
How a split works#
| Split | Shares after (from 100) | Price after (from $300) | Total value |
|---|---|---|---|
| 2 for 1 | 200 | $150 | $30,000 |
| 3 for 1 | 300 | $100 | $30,000 |
| 10 for 1 | 1,000 | $30 | $30,000 |
| 1 for 10 reverse | 10 | $3,000 | $30,000 |
Earnings per share, dividends per share and book value per share are all adjusted proportionally, so valuation ratios such as P/E do not change. See Net Income and EPS.
Why companies split their shares#
- Affordability and accessibility: lower prices make round lots more affordable, though fractional share trading has reduced this concern.
- Liquidity: more shares at lower prices can increase trading activity and narrow spreads.
- Options: lower share prices make option contracts (100 shares) more affordable for smaller investors.
- Index considerations: price weighted indices such as the Dow Jones Industrial Average are affected by share price levels. See What Is an Index?.
- Signalling: splits often follow strong price gains, so they can signal management confidence.
Recent high profile splits include Apple (4 for 1 in 2020), Tesla (5 for 1 in 2020 and 3 for 1 in 2022), Amazon and Alphabet (20 for 1 in 2022) and Nvidia (4 for 1 in 2021 and 10 for 1 in 2024).
Reverse splits#
Companies usually do reverse splits when their share price is very low, often to:
- Meet exchange listing rules, such as Nasdaq's and NYSE's requirements to stay above $1.
- Attract institutional investors who avoid very low priced stocks.
- Reduce the number of shares after heavy dilution.
Reverse splits are often seen as a negative sign, because they frequently come from struggling companies. Studies have found weak average performance after reverse splits, though results vary.
Market reactions#
Effects on options#
Exchanges adjust options for splits. In a 2 for 1 split, one call with a $200 strike typically becomes two calls with a $100 strike, keeping the position's value the same. For unusual split ratios, contracts may be adjusted to deliver a non standard number of shares. See How Options Work.
Effects on data and backtests#
Historical prices must be adjusted for splits, or charts will show false crashes and backtests will produce nonsense. Most data providers supply split adjusted prices, but traders should confirm. Raw unadjusted prices are needed when checking what actually traded on a given day. See Splits and Dividends in Price Data and Corporate Actions, Delistings and Rolls in Backtests.
Common mistakes#
- Thinking a split makes a stock cheaper in valuation terms.
- Using unadjusted data in backtests.
- Ignoring option adjustments around splits.
Frequently asked questions#
What is a stock split?#
A corporate action that increases the number of shares by dividing each share, lowering the share price proportionally without changing the company's value.
What is a reverse stock split?#
Combining several shares into one, which raises the share price and reduces share count, often to meet listing requirements.
Do stock splits increase value?#
Not directly. The company's total value stays the same, though splits can improve liquidity and sometimes coincide with positive investor sentiment.
Next, learn about companies combining in Mergers and Acquisitions.
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