Stock Splits and Reverse Splits
A split multiplies share count and divides price by the same factor, changing nothing about the company's value — but the psychology, liquidity and index-fund mechanics around it are real.
A stock split takes every existing share and turns it into more shares, each proportionally cheaper, so the company's total value is unchanged. A 4-for-1 split turns one $800 share into four $200 shares; a shareholder who owned 10 shares worth $8,000 now owns 40 shares still worth $8,000. Nothing about assets, earnings or ownership percentage moved. A reverse split runs the same idea backward: a 1-for-10 reverse split turns ten $1 shares into one $10 share, again with total value unchanged.
If a split changes nothing economically, why do it? For a forward split, the usual reason is psychological and mechanical: a lower per-share price feels more accessible to retail investors, and it improves liquidity by increasing the number of shares available to trade in smaller lots, tightening bid-ask spreads. For a reverse split, the reason is almost always defensive: many exchanges require a minimum share price (commonly $1 on the Nasdaq) to stay listed, so a struggling stock trading at $0.30 might do a 1-for-20 reverse split to push its price to $6 and avoid delisting.
A split is a change in units, not in value — like re-quoting a distance in centimeters instead of meters. Any strategy or metric that treats a post-split price drop as a real decline (or a pre-split high share count as real dilution) is simply misreading the units.
A worked example
A stock closes at $1,200 before a 5-for-1 split. Post-split, the price opens at , i.e. $240, and a shareholder with 8 shares (worth $9,600) now holds 40 shares (still worth $9,600). Any historical price chart must apply a 5x adjustment factor to every price before the split date, or the chart shows a fake 80% crash on the split date — exactly the kind of artifact price adjustment exists to remove.
A reverse-split example: a stock at $0.40 does a 1-for-15 reverse split. Shares outstanding fall from 150m to 10m, and price rises to , i.e. $6.00. The company is worth exactly as much as before; only its optics with exchange listing rules have changed.
Reverse splits carry a stigma for good reason even though they are economically neutral: they are almost always a symptom of a stock that has already collapsed, not a cause of anything. Studies consistently find reverse-split stocks continue to underperform afterward — the split itself does nothing, but it correlates strongly with distress.
Related concepts
Practice in interviews
Further reading
- CRSP, Data Description Guide (adjustment factor methodology)