Attribution analysis
Knowing that your portfolio returned 12% last year is useful. Knowing that 9 percentage points came from a single position, that currency moves erased 3 points, and that your fixed income sleeve contributed almost nothing: that is actionable. Attribution analysis is the process of decomposing portfolio returns into their sources, so you can make informed decisions rather than rely on aggregate figures that can be deeply misleading.
Why attribution matters
Without attribution, outperformance and underperformance are both opaque. A strong total return can mask dangerous concentration in one name. A disappointing return can hide a well-diversified strategy that was simply hit by an adverse currency move. Attribution cuts through the noise and answers the questions that matter: where did the return come from, and is the portfolio positioned the way you think it is?
Attribution as a rebalancing signal
Over time, positions that perform well grow as a share of the portfolio while laggards shrink, even if you have not changed a single holding. Attribution analysis makes this drift visible. When a single asset or asset class accounts for a disproportionate share of both returns and risk, it is often a sign that the portfolio has drifted away from its intended allocation. Reviewing attribution regularly provides a principled basis for rebalancing decisions: not arbitrary calendar-driven trimming, but targeted adjustments driven by what is actually driving the portfolio.
Attribution by asset
The most granular lens. IBviz shows the contribution of every individual position to the portfolio's total return, both in absolute terms and as a percentage. Top gainers and losers are surfaced immediately, and their contribution is broken down between price return and FX return so you can distinguish investment skill from currency luck. The historical top gainers and losers view lets you track how contribution has shifted over time and identify positions whose influence on the portfolio has grown beyond their intended weight.
Attribution by asset class
Aggregating contributions by asset class reveals which parts of the portfolio are pulling their weight. If equities are generating most of the return while fixed income and cash drag, that is a deliberate allocation worth confirming. If a small derivatives sleeve is dominating the P&L, that may call for a closer look at sizing. Asset-class attribution is particularly useful for multi-asset portfolios where the interaction between sleeves is as important as the performance of each sleeve in isolation.
Attribution by currency
For portfolios holding assets denominated in multiple currencies, FX moves can be a significant driver of returns, and one that is easy to overlook in aggregate figures. IBviz isolates the currency component of every position's P&L and aggregates it by currency, so you can see precisely how much of your return came from price appreciation and how much came from the EUR, USD, GBP, or JPY moving in your favour. This view is essential for understanding true economic exposure and for assessing whether hedging makes sense.
Contribution treemaps
IBviz visualizes attribution as interactive treemaps, where each position is represented by a rectangle sized by its weight in the portfolio and coloured by its contribution. The layout makes patterns that would be invisible in a table immediately obvious: large green blocks signal concentrated winners, clusters of small red blocks reveal broad-based underperformance. IBviz provides treemaps for the last day and the last month, giving you both a short-term and a medium-term attribution snapshot side by side.
Portfolio replay
Portfolio replay is an animated visualization that shows how your portfolio evolved over time: which positions grew, which shrank, how the composition shifted, and where returns concentrated. Rather than presenting a static snapshot, it plays back the portfolio's history as a moving picture, making it possible to observe in a single intuitive view what would take dozens of charts to convey statically.
Portfolio replay is particularly powerful for surfacing three things at once:
- Drivers: the positions and periods that generated the bulk of the return stand out visually as they grow and dominate the frame.
- Concentration: moments when the portfolio became heavily dependent on one or two positions are immediately visible as the layout collapses around those names.
- Correlation: positions that move together, rising and falling in sync across multiple periods, reveal hidden correlation that static correlation matrices can understate, especially during stress periods when correlations tend to spike.
Used alongside the treemaps and contribution charts, portfolio replay completes the attribution picture by adding the temporal dimension: not just where the return came from, but when, and how the portfolio's risk profile evolved along the way.