etf overlap tool · moderate overlap
SPY vs DIA overlap
100.0% of DIA's money sits in companies SPY also holds; 30% of the two funds is the same money, spread over 30 companies both hold.
Holdings as of October 16, 2026 · source: SPDR (SPY), SPDR (DIA) · How we measured all 1,431 pairs
- same money
- same companies, extra weight
- only in this fund
Hold SPY and DIA with other funds or stocks? The free portfolio optimizer opens SPY and DIA beside the rest of what you own: the companies you hold twice, what the funds cost a year, and where the next deposit should go. No account.
The companies you would own twice
What only one of them gives you
GOOGALPHABET INC CL C2.43%
AVGOBROADCOM INC2.37%
LLYELI LILLY + CO1.52%
TSLATESLA INC1.51%
Every DIA holding is also in the other fund.
Where each fund puts its money
SPY and DIA: what people ask
How much do SPY and DIA overlap?
30% by weight, as of October 16, 2026: moderate overlap. 30 companies appear in both funds; they make up 40% of SPY and 100.0% of DIA.
Which stocks do SPY and DIA both hold?
The largest shared positions are MSFT, AAPL, GOOGL, AMZN and NVDA. Ranked by the smaller of the two weights, which is the part you would own twice.
Is it redundant to hold both SPY and DIA?
Out of every $100 split evenly between them, about $30 (half in each fund) buys identical positions. The rest is exposure only one of the two funds gives you: 474 names only in SPY, 0 only in DIA. Half in each behaves like 41 equally weighted stocks, against 44 for SPY alone and 22 for DIA alone. Whether that duplication is a problem depends on the mix you want; this is a description, not advice.
How is ETF overlap calculated here?
For every company held by both funds we take the smaller of its two weights and add them up. The weights come from the full holdings files SPDR publish, not a top-10 sample, and companies are matched by their ISIN so share classes stay apart. Sector overlap applies the same rule to the issuers' sector labels; "behaves like N equally weighted stocks" is one over the sum of the squared weights.
Weights come from each issuer's published holdings file and are matched company by company on their ISIN. Cash, futures and currency positions are left out. This page describes what the funds hold; it is not investment advice.