In a stock split, a company multiplies its share count and divides the price by the same factor. In a 4-for-1 split, one share worth 400 becomes four shares worth 100. Your stake is identical before and after.
The pizza analogy that actually works
Cutting a pizza into eight slices instead of four does not give you more pizza. A split is the same: the company's market capitalisation, revenue, profit and your percentage ownership are all unchanged. Nothing about the business happened.
So why do splits move the price?
Because of what a split signals, not what it does. Companies split after the price has risen a long way, and boards usually only do it when they are comfortable the price will stay up there. The split is therefore a quiet confidence signal — and it attracts attention, which brings buyers.
There is also a practical accessibility argument, though it has weakened considerably now that most brokers offer fractional shares. When you can buy 0.03 of a share, a high share price stops being a barrier at all.
Reverse splits are a different animal
A reverse split does the opposite — ten shares at 0.50 become one share at 5. The mechanics are just as neutral, but the motivation rarely is. Companies do this to escape the minimum-price rules that would get them delisted from an exchange. A reverse split does not cause trouble, but it very often advertises it.
When a split genuinely matters
- Index eligibility. Some indices are price-weighted rather than market-cap-weighted, so a split changes a company's weight in them.
- Options trading. Contract sizes and strikes are adjusted, which matters if you hold them.
- Your own psychology. If a lower headline price tempts you to buy something you had already rejected at the higher price, the split has changed your behaviour without changing the investment. That is worth noticing.
Summary
Treat a split as news about sentiment, not about value. If a company was not worth owning at 400, it is not worth owning at 100 either — it is exactly the same company.