Each slice on the pie chart can vary in thickness. Over time, certain investments will outperform others, causing their ‘Actual Weight’ (shown in blue) to exceed their ‘Target Weight’ (shown in grey). As a result, outperforming slices will expand on the chart, while underperforming will shrink.
Let’s consider a stock with a 30% ‘Target Weight’. This investment has performed exceptionally compared to others in the pie, so its ‘Actual Weight’ is now 35.98%. We refer to this as an "overweight" slice. Conversely, if the actual value falls below the target value, it is considered an "underweight" slice.