IN PLAIN ENGLISH
Value-weighted price return for each sector (or currency) you hold, over the selected timeframe, with each group's contribution to the whole-portfolio return.
WHY IT HELPS
Separates which parts of the portfolio drove the result from which parts merely moved, so a big percentage move in a tiny position is not mistaken for a big effect.
HOW IT'S CALCULATED
Each holding's start price is its previous close for the 1 day timeframe, otherwise the closest price in its history to the start date; both prices are converted to portfolio currency, and GBP holdings are checked for a pence versus pounds mismatch. A group's return is the sum of its holdings' value change divided by the sum of their start values — weighted by position size, not an average of the per-holding percentages. Weight is the group's current value over total current value. Contribution in percentage points is the group's value change divided by total current value, so the contributions of all groups add up to the portfolio return. Holdings with no usable start price are excluded rather than counted as flat. A fund's return can't be divided among the sectors it holds, so funds are grouped together as Fund.
Educational content only. It is not personal financial advice.