Historical prices change because data providers adjust them for corporate actions such as splits, bonus issues, and dividends, so that the past series stays comparable with today. The raw price that traded on a given day does not change, but the adjusted series everyone charts is recalculated each time a new corporate action occurs. This is why the same historical close can look different depending on when and where you pull it.
Key takeaways
- The actual price that traded on a past date never changes; what changes is the adjusted series that most charts and datasets display.
- Splits and bonus issues increase the share count, so past prices are scaled down to keep the chart continuous and avoid a fake gap.
- Dividend adjustments lower past prices slightly to reflect the cash that left the company, producing a total-return style series.
- Because adjustments are reapplied whenever a new corporate action happens, a historical dataset is restated over time rather than fixed forever.
- Two providers can show different historical prices for the same day simply because one adjusts for dividends and the other does not.
Does the actual traded price ever change?
No. The price at which a share actually changed hands on a given day is a matter of record on the NSE or BSE, and that number is fixed forever. If a stock closed at 2,000 rupees on a Tuesday, it closed at 2,000 rupees.
What changes is the adjusted historical series that almost every chart, screener, and dataset displays. That series is a recalculated version of the raw prices, designed to stay comparable with the present. When you notice that a past close looks different today than it did a year ago, you are not seeing a rewritten record. You are seeing the effect of adjustment.
Why do splits and bonus issues force past prices down?
A Stock Split divides each share into more shares. A split that turns each share into two would turn one 2,000 rupee share into two 1,000 rupee shares. Nothing about the company's value changed, only the number of pieces it is divided into. A Bonus Issue works similarly: existing holders receive extra shares for free, so the price per share falls in proportion.
If a data provider left the raw prices alone, the chart would show a sudden vertical drop from 2,000 to 1,000 on the split date, which looks like a fifty percent crash that never happened. To prevent this false gap, providers scale every price before the split down by the same ratio. The whole history is multiplied by an adjustment factor so the line stays continuous and percentage returns remain honest.
Open the history view on Artha Terminal to inspect a consistent, corporate-action-adjusted price series and see how past values are calculated.
How do dividends change the historical series?
When a company pays a Dividend, cash leaves the business and goes to shareholders. On the Ex-Dividend Date, the share price typically opens lower by roughly the dividend amount, because a buyer from that day no longer receives the payout. That drop is not a loss of value, it is value being handed out.
An adjusted, or total-return, series accounts for this by nudging all prices before the ex-date down slightly, so the reinvested value of past dividends is reflected in the line. This is why a dividend-adjusted chart of a steady payer such as a large index constituent can sit noticeably below its unadjusted twin over many years. Neither is wrong; they answer different questions. The unadjusted line shows price alone, while the adjusted line shows what a holder who reinvested every payout actually experienced.
Why does a historical dataset get restated?
Adjustment is not a one-time event. Every adjustment factor is calculated relative to the present, so each new corporate action reaches back and rescales the entire prior history again. A split announced this month changes the adjusted value of a price from five years ago.
This is why the same historical figure can differ between two pulls of the same dataset, or between two providers. One may adjust only for splits and bonuses, another may also fold in dividends, and a third may show raw unadjusted prices. None is lying. They are applying different, defensible conventions. This is the same mechanism behind Why market cap differs, where the same underlying facts produce different published numbers depending on method.
How should you read an adjusted chart without being misled?
First, know which series you are looking at. If you are comparing a stock's price today with a headline it made at an all-time high years ago, the adjusted chart may show a lower past peak than the number quoted in old news, because the old number was unadjusted. Both can be correct.
Second, use adjusted data for measuring returns and raw data for reconstructing what a headline said on the day. Mixing them causes confusion. On Artha Terminal, the stock page and the price OHLC history are built on a consistent adjustment convention, so the trend you see reflects genuine performance rather than a phantom gap on a split date. If a past value ever looks surprising, you can ask Ask Warren why it differs from a figure you saw elsewhere, and it will explain the corporate action behind the change.