Portfolio overlap: holdings and calculation methodology
Published
Research retrieved and calculated 27 October 2026. All three issuer holdings datasets are dated 23 October 2026. These are fresh research supplements, the frozen Rogha directory and holdings release remain unchanged. Anonymous fund codes are used in the article; company names and benchmark names are retained where needed to explain the findings.
Selection and official sources
A · iShares Core MSCI World UCITS ETF USD (Acc) · IE00B4L5Y983. Issuer page; live CSV holdings; dated public issuer feed. Positive equity rows: 1248; their original disclosed weight totals 99.53943%. CSV and precise feed were reconciled within per-row rounding tolerances.
B · iShares Core S&P 500 UCITS ETF USD (Acc) · IE00B5BMR087. Issuer page; live CSV holdings; dated public issuer feed. Positive equity rows: 503; their original disclosed weight totals 99.86996%. CSV and precise feed were reconciled within per-row rounding tolerances.
C · iShares Nasdaq 100 UCITS ETF USD (Acc) · IE00B53SZB19. Issuer page; live CSV holdings; dated public issuer feed. Positive equity rows: 101; their original disclosed weight totals 99.96437%. CSV and precise feed were reconciled within per-row rounding tolerances.
Same-provider selection keeps field definitions and data format consistent; it is not a provider recommendation or an exhaustive ETF sample. A is developed-world large/mid-cap exposure, not all-country. Current CSV links may change. The dated public feed has precise weights and ISINs; retained internal files and hashes support the calculation. Source data are not offered here as a public raw-data download.
How the weights were calculated
Retain rows labelled Equity with positive holdingPercent. Exclude cash, money-market funds, collateral/margins, futures, FX and zero/non-positive equity rows. For each fund, divide each retained weight by the sum of retained equity weights and multiply by 100. Combine as 0.8 × A plus 0.2 × B or C, matching exact ISINs. These are 80/20 allocations to normalised equity sleeves, not an exact NAV-level investment in the unadjusted funds. Futures are not assigned zero economic exposure; their exposure is outside this equity-only exercise.
Country uses the issuer’s countryOfRisk classification consistently. It is not ISIN domicile, exchange location or company revenue. Sector uses sectorName; this is not a look-through measure of AI revenue. Positive equity rows count disclosed securities, not index members. Duplicate ISIN entries are aggregated.
Company consolidation explicitly combines Alphabet A/C, ASML ordinary/ADR, News Corp A/B, Atlas Copco A/B, HEICO common/A and Lindt’s two securities. Other names are kept separate; no ultimate-parent consolidation of separately listed subsidiaries is assumed. The company mapping is recorded in the retained internal calculations. ASML’s ADR is a new security relative to A, but not a newly represented company. This is why new-security and new-company weights differ.
Top-ten-company concentration is the sum of the ten largest consolidated company weights in each portfolio, with that list reselected for each combination. New-security exposure in the addition is the weight of ISINs absent from A; multiply by 0.2 for their weight in the mix. New-company exposure instead checks the explicit company keys. Zero-valued lines do not count as existing positive exposure.
Two different overlap questions
A versus B: 442 shared ISINs. The weight of B invested in securities also held by A is 98.83873%. Symmetric weighted overlap, sum of min(weight A, weight B) across the combined ISIN universe, is 71.08945%. These metrics answer different questions: shared names can carry substantially different weights. Their complements are not measures of independent risk or diversification.
A versus C: 97 shared ISINs. The weight of C invested in securities also held by A is 98.36566%. Symmetric weighted overlap, sum of min(weight A, weight C) across the combined ISIN universe, is 39.27836%. These metrics answer different questions: shared names can carry substantially different weights. Their complements are not measures of independent risk or diversification.
Validation and interpretation
All dated feeds assert 20261023. All retained positive equity positions have ISINs. Each normalised fund and combined portfolio sums to 100% within numerical tolerance. The latest CSV has the same date and corroborates precise feed weights to its two-decimal rounding, aggregating duplicate ticker/name records solely for that cross-check. Ticker collisions across companies are not used for matching.
Full source SHA-256 hashes, row counts, original totals, excluded classes and outputs are recorded in the internal results and source ledger. No raw constituent files are bundled into the reader-facing article. No NAV total-return history, volatility, correlations, drawdowns, future returns, currency hedge effects, transaction costs or individual tax outcomes were calculated. Small differences from issuer headline exposure figures can arise because this exercise normalises positive equities and excludes other assets.
Current-market context
Microsoft Investor Relations, read 27 October, schedules FY27 Q1 results for 28 October 2026. The article uses that verified upcoming event to explain repeated company exposure, without predicting results or relying on unsourced intraday market moves. Other earnings dates, market prices and rate decisions are not needed for the calculations.
Read the related global-benchmark and active/passive explainers for more context.