ETF Overlap Analysis: How Much Do Two ETFs Share?

Two funds with different names can be largely the same investment. A world ETF and an S&P 500 ETF share the same handful of American technology companies at the top; add a technology sector fund and the concentration you were trying to spread gets worse, not better.

What we measure. For every company held by both funds we take the smaller of the two weights and add those up, then divide by the smaller of the two portfolios we have data for. The result is the share of capital that finances the same companies in both funds. We deliberately do not count how many holdings appear in both: that number sounds larger and says less, because the several hundred smallest positions of a world fund together barely move the needle.

What it does not tell you. Overlap is duplication, not risk. Two funds with no shared holding at all can still move almost identically — that is a question of correlation, not of composition. And a high overlap is not automatically a mistake: it depends on what the rest of the portfolio looks like.

Ready-made comparisons114
Highest overlap100 %
Lowest10 %

The largest duplications

Fund pairs across different indices, ranked by the share of capital financing the same companies in both.

ETF pairs by overlap
ComparisonOverlapshared holdings
SPYY vs XDWD90.1 %1141
EUNL vs IUSQ89.5 %1148
SPSA vs IUSQ84.1 %1404
SPYI vs IUSQ84.1 %1404
SPYM vs IS3N83.5 %1077
SWWD vs SPYI81.6 %1079
SPSA vs WIMI80.1 %1222
XDWD vs XD9U75.1 %485
SPYL vs SPPW73.1 %417
SXR8 vs SPPW73.1 %417
SPY5 vs SPPW73.1 %417
SPY5 vs XDWD72.9 %416
EUNL vs SXR872.6 %420
EUNL vs SPY572.5 %417
SPYL vs SPYY66.4 %417
SXR8 vs IUSQ65.4 %420
SPYL vs IUSQ65.3 %417
SPYI vs XD9U65 %482
SPYL vs SPYI64.3 %463
EXXT vs QDVE54.9 %34
WDSD vs SMC54.6 %190
WDSD vs XXSC54.6 %190
ZPRS vs SMC54.6 %190
ZPRS vs XXSC54.6 %190
EXXT vs XUIT54.2 %36

Compare indices instead of funds

To find out whether two investment ideas overlap, compare the indices — the fund wrapper does not change that.