A Stock Split Doesn't Change What You Own. So Why Does the Price Still Move?
6 min read
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6 min read
In June 2024, Nvidia investors logged in one morning and saw ten shares in their account for every one they had the day before. The price per share had dropped to a tenth of what it was. Nothing about the money they had invested changed. Yet the stock kept climbing for months afterward, and headlines kept calling the split a reason why.
That is the puzzle of a stock split: an action that, on paper, changes nothing about what you own, followed by a price that often moves anyway. Here is what actually happens in the math, and what is really driving the price move next to it.
A stock split takes each share you own and divides it into a set number of smaller shares, without changing the total value of your holding. A 1:5 split turns 1 share into 5, at one-fifth the price each. A 10-for-1 split, like Nvidia's, turns 1 share into 10, at one-tenth the price each.
Unilever Indonesia (UNVR) ran a 1:5 split effective 2 January 2020. An investor holding shares worth Rp42,000 each the day before ended up with five times as many shares, each worth Rp8,400, according to a worked example published by Ajaib.
| Before split | After split | |
|---|---|---|
| Shares held | 100 | 500 |
| Price per share | Rp42,000 | Rp8,400 |
| Total value | Rp4,200,000 | Rp4,200,000 |
The total in the last row does not move. That is the entire mechanical effect of a split: more shares, each worth proportionally less, same total value, same percentage of the company owned. Market capitalization, the company's total share price multiplied by its total share count, is identical the moment before and the moment after.
Bank Central Asia (BBCA) ran the same kind of 1:5 split on 13 October 2021. The stock closed its first split-adjusted trading day at Rp7,500, reported by Bisnis.com, a level that lines up with roughly a fifth of its pre-split price. Nothing about Bank Central Asia's business, revenue or profit changed that day.
Nvidia's 10-for-1 split took effect after the close on 7 June 2024, cutting the share price from about $1,208.88 to $120.88, reported by Forbes. By June 2026, Yahoo Finance reported the stock had climbed more than 67% since that split, adding close to $2 trillion in market capitalization.
Here is the catch: that rise is not evidence the split itself created value. Nvidia's fiscal 2025 revenue reached roughly $130.5 billion, up 114% year over year, with data center revenue up 142% as demand for AI chips surged. The company's underlying business grew enormously over that period. A split that happened on one specific week in the middle of that growth is not what moved the price. It is easy to mix up "the stock split, then the price rose" with "the split caused the price to rise." They happened in the same story, not in a cause-and-effect relationship.
Even once you strip out cases like Nvidia, where the company's own growth explains almost everything, research on stock splits still finds a real, if smaller, pattern. A widely cited study by finance researchers Ikenberry, Rankine and Stice examined 1,275 two-for-one stock splits and found the announcement of a split was followed by an average excess return (the stock's return above what the broader market did over the same period) of 3.38%, then a further 7.93% in the year after, and 12.15% over three years.
Researchers call this an underreaction: the market does not immediately price in the full information content of a split announcement, so the price keeps drifting upward for months afterward. The likely reason is not the split mechanics themselves. It is what a split signals. Companies generally only split when management is confident enough in near-term performance to make the stock more accessible to a wider pool of buyers. The split itself is a side effect of that confidence, not the cause of the later price move.
Liquidity is how easily a stock can be bought or sold without moving its price much. Splits are often framed as a way to boost liquidity by making shares "more affordable," attracting more buyers.
The research here is genuinely mixed. Some studies find the number of trades and quotes increases meaningfully after a split, while other measures like total daily trading volume show no significant change. Findings on how long any liquidity gain lasts also disagree: some research finds the effect fades within months and liquidity settles back near, or even below, pre-split levels. There is no single, settled number to quote here, so treat "splits always boost liquidity" as an oversimplification rather than a fact.
A stock split is not a signal to act on by itself, and it is not evidence that a stock is now a better or worse holding than it was the day before. The two things worth separating in your own thinking:
If a company you hold announces a split, the useful question is not "should I buy before the price gets cheaper," since the price per share falling tells you nothing about whether the shares are cheap or expensive relative to the business behind them. The useful question is the one you should already be asking regardless of any split: is the underlying business still performing the way you expected when you bought in.
Before reacting to any stock split news, look at what actually happened to the price and the underlying business, not just the headline ratio. NetWort's asset pages show a stock's full price history, including how it actually moved around past corporate actions like Nvidia's own June 2024 split, so you can see the real pattern instead of the story around it. For an IDX example, Bank Central Asia's own asset page shows the same for its 2021 split.