etf overlap tool · nearly the same fund
VOO vs SPY overlap
97% of VOO and SPY is the same money, spread over 501 companies both funds hold.
Holdings as of September 30, 2026 · source: Vanguard (VOO), SPDR (SPY) · How we measured all 1,431 pairs
- same money
- same companies, extra weight
- only in this fund
Swapping one for the other to harvest a loss? In our study of 32 tax-loss harvesting ETF pairs, VOO and SPY correlated 0.9999 over the 261 weeks to October 16, 2026 and were never more than 1 point apart in a week; over the year to that date, VOO returned 0.08 points more than SPY. IRS Publication 550 sets no test for when two ETFs are “substantially identical” under the wash-sale rule: it says to consider “all the facts and circumstances in your particular case,” so no correlation figure settles the question.
Hold VOO and SPY with other funds or stocks? The free portfolio optimizer opens VOO and SPY 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
GOOGAlphabet Inc2.45%2.43%
What only one of them gives you
CTVACorteva Inc0.08%Where each fund puts its money
VOO and SPY: what people ask
Is SPY the same as VOO?
Nearly: 97% of the money in VOO and SPY sits in the same companies at the same weights, as of September 30, 2026. The other 3.4% is weight differences, plus 4 names only in VOO and 3 only in SPY.
How much do VOO and SPY overlap?
97% by weight, as of September 30, 2026: nearly the same fund. 501 companies appear in both funds; they make up 99.8% of VOO and 99.8% of SPY.
Which stocks do VOO and SPY both hold?
The largest shared positions are NVDA, AAPL, MSFT, AMZN and GOOGL. Ranked by the smaller of the two weights, which is the part you would own twice.
Is it redundant to hold both VOO and SPY?
Out of every $100 split evenly between them, about $97 (half in each fund) buys identical positions. The rest is exposure only one of the two funds gives you: 4 names only in VOO, 3 only in SPY. Half in each behaves like 44 equally weighted stocks, against 43 for VOO alone and 44 for SPY 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 Vanguard and 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.