Stock split
💰 CapitalShares are divided, lowering the per-share price.
Typical size
1-5% on announcement
Timeframe
Announcement pop; drift into the effective date
Evidence
5 logged events
Why it moves the price
Economically it changes nothing. It works, when it works, through sentiment and accessibility — a lower share price widens the retail buyer base and signals management confidence.
What separates a good call from a naive one
The move happens on the *announcement*, not the split date, and it is pure psychology — there is no fundamental change. Splits cluster near price peaks because companies split after big runs, so beware chasing.
Measured impact
Every logged event is measured against real closing prices: the move from the close before the event, compared with the S&P 500 over the same window.
Next day
+8.68%
- Median
- +8.03%
- Moved up
- 100% of 5
- vs S&P 500
- +8.30%
After 1 week
+14.44%
- Median
- +9.93%
- Moved up
- 100% of 5
- vs S&P 500
- +14.06%
After 1 month
+11.35%
- Median
- +13.29%
- Moved up
- 60% of 5
- vs S&P 500
- +12.18%
The logged evidence agrees with the textbook expectation. Based on 5 measured events.
The evidence (5)
Every row is a real event, measured against actual closing prices.
| Date | Stock | What happened | Next day | 1 week | 1 month | vs S&P |
|---|---|---|---|---|---|---|
| May 23, 2024 | NVDA | 10-for-1 stock split announced with Q1 results Announced after the close on May 22, together with strong results. | +9.32% | +16.38% | +24.39% | +10.05% |
| Mar 28, 2022 | TSLA | Company says it will seek shareholder approval for a stock split Pure announcement effect — no results released that day. | +8.03% | +7.32% | -13.28% | +7.32% |
| Mar 10, 2022 | AMZN | 20-for-1 split and a $10B buyback announced Announced after the close on Mar 9. | +5.41% | +9.93% | +13.29% | +5.86% |
| Feb 2, 2022 | GOOGL | 20-for-1 stock split announced with Q4 results Announced after the close on Feb 1. | +7.52% | +1.28% | -2.72% | +6.55% |
| Aug 12, 2020 | TSLA | 5-for-1 stock split announced Announced after the close on Aug 11. | +13.12% | +37.30% | +35.09% | +11.73% |
Measured from historical closing prices. Past reactions do not guarantee future ones. Not financial advice.