Glossary · Fund structure
Holdings overlap
The share of two funds’ portfolios that consists of the same underlying holdings at the same weights.
Two funds with different names, managers and objectives can hold substantially the same companies. Overlap quantifies that: it sums the smaller of the two weights for every holding they share.
High overlap means combining the funds diversifies less than the count of funds suggests — the same underlying exposure is being paid for twice.
Overlap is only as complete as the holdings data behind it. Where only top-10 holdings are published, the figure describes the overlap among those, and this site labels it as such rather than presenting it as full-portfolio overlap.
How we calculate it
Σ min(weight A, weight B) over the holdings both funds publish. Where a fund publishes only part of its portfolio, a second figure divides by the smaller of the two funds’ disclosed weights.
The full method, with a worked exampleOn Fundology: Compare two funds’ holdings
Related terms
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Definitions describe how a term is used on Fundology. This is information, not advice.