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What you will learn
- Identify which time and price observations are shown.
- Calculate the price change over two different intervals.
- Distinguish chart observations from dividends, your own return and a forecast.
Begin with the axes and the data
The horizontal axis shows four fictional observations, A to D. The vertical axis shows SEK per share and starts at zero. The points were chosen for the exercise, not taken from a company. Lines join the observations; we have no prices between them.
For a real chart, check the dates, currency and whether the observations are, for example, closing prices. More frequent observations may reveal movements a coarser chart hides. A chart of daily closing prices does not automatically show everything that happened within each day.
If the table does not fit, scroll it sideways.
| Observation | Price |
|---|---|
| A | SEK 80 |
| B | SEK 120 |
| C | SEK 100 |
| D | SEK 110 |
The same endpoint with different starting points
From A to D, price rises from SEK 80 to SEK 110. The change is (110 − 80) ÷ 80 × 100 = 37.5 percent. From B to D, it falls from SEK 120 to SEK 110: (110 − 120) ÷ 120 × 100, approximately −8.33 percent.
Both calculations are correct for their intervals. The data does not contradict itself. The starting point and value differ. State the full period when comparing two claims about performance; saying the share went up does not give enough information.
If the table does not fit, scroll it sideways.
| Interval | Start → end | Price change |
|---|---|---|
| A to D | SEK 80 → 110 | +37.5 % |
| B to D | SEK 120 → 110 | Approximately −8.33 % |
| C to D | SEK 100 → 110 | +10 % |
Check whether you are comparing the same thing
Two lines need the same interval and a comparable method to make a clear percentage-performance comparison. A higher price in SEK does not by itself mean that a share has performed better. That also depends on the price at the start of the comparison.
Ask whether the chart shows only price or also counts dividends. Check how a split affects older prices. Our fictional series shows price only, without dividends or a split. It should therefore not be presented as total return or as an actual result in your account.
State what the chart shows and what you do not know
Practise a checkable statement: between C and D, the displayed price rose from SEK 100 to SEK 110. Then record what you cannot determine from the line, such as why the change occurred or what the price will be after D.
Past results do not guarantee future results. Connect chart observations to questions rather than certain forecasts. Investiq's guide explains market data and practice with virtual money. This series works without an app account to help you practise a clear comparison.
- Check the start, end and observation frequency.
- Read the currency and scale on the price axis.
- State whether the graph shows price or a return measure.
- Separate an observed change from an explanation or forecast.
Try it yourself
Use the table: how does price change from B to C, and from A to C? Explain why the results differ despite the same endpoint.
Show the solution and explanation
B to C: approximately −16.67 percent. A to C: +25 percent.
(100 − 120) ÷ 120 × 100 ≈ −16.67. (100 − 80) ÷ 80 × 100 = 25. The ending price is the same, but the starting price and comparison base differ.
Check your understanding
Does the line tell us the prices between A and B?
Not in this exercise. We have only four observations. The straight connecting line is a way to draw them, not extra measured prices.
Can you read the future price after D from this chart?
No. It only shows the selected observations and supplies no future price.
Practise with virtual money
Try what you just learned in a practice portfolio with virtual money. You don't deposit any real money.
How the practice portfolio worksKeep learning and practising
More lessons on this topic
Prices, company events and currency
Sources and examples
The sources support the factual explanations. Calculations and exercises were created for this lesson. Amounts and price changes are invented unless stated otherwise.
This material is educational and does not recommend securities to buy. A simulated result does not guarantee a future result.
