Methodology
This page explains where FundMonkey's data comes from, how the metrics are calculated, and what the known limitations are. It's for users who want to understand what they're looking at rather than just take the numbers on trust.
Fund universe
FundMonkey covers UK retail open-ended investment funds (OEICs and unit trusts) and UK-listed ETFs available through major retail investment platforms. The universe is refreshed periodically; the exact size at any point in time is shown in the funds-pane header (e.g. "of 5,988 funds").
The dataset is filtered to exclude duplicate share classes where multiple share classes track the same underlying portfolio. Where multiple share classes exist, FundMonkey typically retains the one with the most representative cost basis and broadest retail availability.
Data sources
Performance data
Cumulative percentage returns over standard periods (3 months, 6 months, 1 year, 3 years, 5 years) are sourced from third-party fund data providers and platform aggregators. These figures are typically reported on a total return basis (including reinvested distributions) in GBP, and may be net of ongoing fund charges depending on the source.
Holdings data
Top holdings (typically the top 10 disclosed positions for each fund) are sourced from fund factsheets and managers' periodic disclosures. Holdings disclosures are point-in-time snapshots and can lag the actual portfolio by weeks or months, depending on each fund's disclosure schedule.
Sector classifications
Funds are mapped to Investment Association (IA) sectors where available, supplemented by issuer-provided categorisations for funds outside the IA framework. Sector boundaries are not always crisp and a fund's classification may shift if its mandate changes.
Active share
Active share is a measure of how much a fund's holdings differ from its benchmark index. It runs from 0% (identical to the index) to 100% (no overlap with the index).
Where wfund,i is the fund's weight in stock i and wbench,i is the benchmark's weight in stock i, summed across the union of holdings in both portfolios.
On FundMonkey, active share is calculated from the disclosed top-holdings list against an appropriate benchmark proxy for each fund's stated mandate. Because we don't have access to the full holdings of every fund (most disclose only top 10), the figure is an approximation based on disclosed positions, not a regulatory-grade calculation. It is most reliable for concentrated funds where the top 10 captures a large share of the portfolio.
Funds where active share could not be reliably calculated (e.g. because of insufficient holdings disclosure or no comparable benchmark) are flagged accordingly.
Aggregate top holdings ("combined top holdings")
The pie-chart icon in the funds pane computes a combined top-10 across whatever funds are currently displayed. It uses two independent rankings:
Equal-weighted
Treats each displayed fund as an equal-sized slice. For each stock:
Where N is the number of displayed funds that have holdings data available. Funds that don't hold the stock count as 0%, dragging the average down — this is what you'd actually own if you put equal money into all displayed funds.
Prevalence
Counts how many displayed funds hold each stock at all, regardless of weight:
For each stock, we also show the range of weights observed: the lowest and highest individual fund weight for that stock across all funds in the cohort. A narrow range (e.g. 2.5–3.8%) indicates consensus tracking; a wide range (e.g. 0.5–12.0%) suggests one or more funds have a concentrated conviction position.
Caveats
- Only the disclosed top holdings of each fund are visible; smaller positions are not in the aggregation
- Stock names are not normalised across data sources, so different listings of the same company (e.g. Class A vs Class C shares, or different ADR forms) may appear as distinct entries
- Multiple entries for the same name within a single fund (e.g. multiple share classes) are summed for weight but counted once for prevalence
Head-to-Head sector comparison
Head-to-Head mode lets you compare the average sector allocation of two performance cohorts — for example, funds returning >7% in the last year versus those returning <0%. Sector weights for each cohort are computed by averaging individual fund sector exposures across all funds in that cohort, treating each fund as equally weighted.
Cumulative performance
All percentage returns shown are cumulative over the stated period (not annualised), expressed in GBP, and aim to be on a total return basis. The exact reporting basis (gross or net of fees, distribution treatment) follows the source data provider's convention.
"Negative" filtering (< 0%) finds funds with a negative cumulative return over the selected period.
Update cadence
Different data types update on different cycles:
- Performance figures — refreshed periodically, typically not more than monthly
- Holdings data — refreshed when fund providers publish new disclosures, usually monthly or quarterly
- Fund universe and sector mappings — refreshed as needed when funds are launched, closed, merged, or recategorised
Figures shown on FundMonkey should be treated as indicative, not real-time. For decision-grade data, always consult the relevant fund factsheet or KIID directly.
Known limitations
- Disclosure lag — holdings shown reflect each fund's most recent disclosure, which can be weeks or months old.
- Top-N truncation — most funds disclose only their top 10 holdings; smaller positions are invisible.
- Currency — returns are in GBP. Funds with material non-GBP exposure may report differently in their own materials.
- Fee treatment — whether figures are gross or net of fund charges depends on the source. KIID-level figures are typically net of ongoing charges.
- Tax — nothing on FundMonkey accounts for any individual tax situation.
- Stock name normalisation — we do limited cleaning of holding names but cannot guarantee, for example, that "Microsoft" and "Microsoft Corp" are always merged.
- Active share — approximate, based on top-N disclosures rather than full portfolios.
How to read the UI
Funds table
Each row is one fund. The columns show fund name, active share, and cumulative performance over 3m / 6m / 1y / 3y / 5y. Click any column header to sort. Hover any row to see the fund's top holdings.
Performance filter pills
The pills (>3%, >5%, >7%, etc.) filter the table to funds whose return over the currently selected period exceeds the threshold. "< 0%" shows funds with negative returns. "ALL" clears the filter.
Sector filters
Click any sector chip to filter the table to funds in that sector. Multi-select mode lets you build a multi-sector cohort.
Toolbar buttons
- ⓘ Info — show/hide the legal disclaimer footer
- ☰ Sectors — show/hide the sector filter pane
- ☷ Multi-select — toggle multi-sector selection mode
- ★ Portfolio — show only your starred (tracked) funds
- ⇆ H2H — enter Head-to-Head comparison mode
Source attribution and accuracy
FundMonkey is not a primary data source. We aggregate and present data sourced from fund providers and third-party data aggregators, and we apply derived calculations on top of it. We make reasonable efforts to ensure accuracy but errors are possible at any stage — in the source data, in our ingestion, or in our calculations.
If you spot a number that looks wrong, please tell us: info@fundmonkey.co.uk
Changes to this methodology
This methodology will evolve as the service grows. We will update this page when material changes are made; the "Last updated" date at the top reflects the most recent revision.