ETF Overlap
Does your ETF portfolio
have overlaps?
Calculate the overlap between your UCITS ETFs. Identify redundancies, compare TER and AUM, and build a more diversified portfolio.
e.g. VWCE, CSPX, IWDA, EIMI…
Investor guides
All guides →TER and Tracking Difference: the real cost of your ETF
The TER displayed on the KID is not the real cost of your ETF. The Tracking Difference — the gap between the ETF's return and its index — is the only metric that measures what you truly pay. For some ETFs, the listed TER is 0.20% but the TD is negative: the ETF outperforms its index.
Physical vs synthetic ETF replication: what difference does it make?
WPEA physically replicates the MSCI World while CW8 does so synthetically via a swap — yet both track the same index with a tiny gap. Understanding the difference lets you assess counterparty risk and explains why synthetic ETFs qualify for the French PEA.
Frequently asked questions about ETF Overlap
What is ETF Overlap?
ETF Overlap is the share of holdings two ETFs have in common, weighted by their respective allocations. A high overlap means both funds expose you to a very similar portfolio, so holding both adds little diversification.
Why calculate the overlap between two ETFs?
To measure the actual diversification between two ETFs. Combining several funds exposed to the same securities (notably US tech giants like Apple, Microsoft, NVIDIA) means duplicating part of the portfolio. Calculating ETF Overlap reveals this redundancy and quantifies the share that is genuinely distinct between the two exposures.
How does ETF Overlap calculate the overlap?
Our calculator uses the min-weight formula: for each security held by both ETFs, we keep the minimum weight between A and B, then sum. Example: Apple at 5% in CW8 and 4.8% in EWLD contributes 4.8% to the overlap. The final result ranges from 0% (no common holdings) to 100% (identical composition).
What overlap percentage is considered high?
ETF Overlap classifies the result into four tiers: under 15% (complementary), 15 to 40% (lightly redundant), 40 to 70% (partially redundant), over 70% (highly redundant). Above 70%, holding both ETFs adds only marginal diversification.
Do an MSCI World ETF and an S&P 500 ETF overlap?
Yes, significantly. The S&P 500 represents about 70% of the MSCI World market cap, which includes the same 500 large-cap US companies plus the rest of developed markets. The overlap between an MSCI World ETF and an S&P 500 ETF typically exceeds 65%, making them largely redundant.
How does the tool handle PEA-eligible synthetic ETFs?
Synthetic (swap-based) ETFs eligible for the French PEA, such as CW8, DCAM or PE500, do not physically hold the securities of their underlying index. ETF Overlap resolves each synthetic to its physical proxy tracking the same index, then compares the proxy's holdings. The result reflects real economic exposure, not the legal composition of the fund.
How does overlap evolve with the number of ETFs held?
Mathematically, the more ETFs accumulated on close geographies or indices (World, Europe, USA), the higher the probability of overlap. A portfolio combining several ETFs covering the same developed markets often shows a high cumulative overlap. ETF Overlap measures this level before and after each addition to track how diversification evolves.
Is ETF Overlap the only criterion to look at when comparing two ETFs?
No. When two ETFs show high overlap, other criteria come into play to differentiate them: TER (fees), AUM (size, liquidity), tax wrapper eligibility (PEA, life insurance), replication method (physical or synthetic), and trading currency. Our ETF profile displays these criteria side by side.