Look at the window around the number
A fictional fund rises from 100 to 120 in one year, then falls to 96 in the next. The first year shows a 20% gain; the second shows a 20% loss. Across both years, the result is a 4% loss, not zero. The starting base changes between the calculations.
An advertisement that displays only the first year tells a true but incomplete story. A longer chart can also mislead if its start date happens to follow a deep decline. Ask why the selected period was used and what happened outside it.
Identify what kind of performance is shown
Actual historical results, modelled results and back-tests are different forms of evidence. A back-test applies rules to past data; it does not show that an investor actually followed those rules with real transactions under those conditions. An illustrative projection describes assumptions rather than an observed outcome.
The SEC's performance-claims bulletin distinguishes these presentations and warns about selective periods. When reading a chart, write its status next to the number. That simple label helps prevent a hypothetical line from being remembered later as a realised track record.
Ask what the figure leaves out
Check whether returns include distributions, fees and relevant taxes, and whether the currency matches the intended comparison. A benchmark without product charges and a fund result after charges are different measurements. They may still be useful together, but the difference must be visible.
Also consider changes to the fund or strategy. A name can remain while management, mandate or implementation changes. Historical data may describe a different approach from the one currently offered. Read the accompanying notes instead of assuming continuity from the chart alone.
Past results can help describe how an investment behaved during a particular period. They cannot set a minimum future return, guarantee recovery after a loss or establish suitability for a reader's goal. Use them as one piece of context alongside the actual holdings, costs, risks and money's purpose. If a decision depends on the next period repeating the best period on the chart, the assumption deserves to be written down explicitly and questioned.
