SPY vs VOO vs VTI: 1.2 Effective Funds
Held in equal weight, SPY, VOO, VTI behave like 1.2 funds rather than 3. Every figure below is computed from the funds' current published holdings.
Three tickers, and the diversification of 1.2. Three funds sharing nothing would score 3.0; three identical funds score 1.0.
How the three compare
Where the duplication is
The combined figure above hides which pair is responsible. Each row is the overlap between two of the three, computed as Σ min(wA, wB).
| Pair | Overlap | |
|---|---|---|
| SPY vs VOO | 95.9% | |
| SPY vs VTI | 86.7% | |
| VOO vs VTI | 87.9% |
The most duplicated pair is SPY and VOO at 95.9%.
Held by all three
The ten largest of the positions that appear in SPY, VOO, VTI together — 86.7% of a portfolio split equally between them, by the same min-sum rule.
| Holding | Smallest of the three weights |
|---|---|
| NVDA | 6.33% |
| AAPL | 5.85% |
| MSFT | 3.81% |
| AMZN | 3.17% |
| GOOGL | 2.88% |
| AVGO | 2.46% |
| GOOG | 2.27% |
| MU | 1.75% |
| META | 1.70% |
| TSLA | 1.41% |
Frequently asked
How much do SPY, VOO, VTI overlap?
Held in equal weight, SPY, VOO, VTI behave like 1.2 funds rather than 3. SPY and VOO overlap 95.9%; SPY and VTI overlap 86.7%; VOO and VTI overlap 87.9%. Each figure is the sum of the smaller weight in each fund over every holding both own.
Which two of SPY, VOO, VTI are most alike?
SPY and VOO, at 95.9% by weight. That pair contributes most of the duplication in the combined figure above.
What does "1.2 Effective Funds" mean?
It is the number of genuinely independent funds this combination behaves like. Three funds sharing no holdings would score 3.0; three identical funds score 1.0. It is computed from the pairwise overlaps above, weighting each fund equally, and it is a measurement rather than a target — what counts as enough depends on what you were trying to do.
These are three funds. How many do you actually hold?
This page assumes an equal split between SPY, VOO, VTI. Paste your real holdings — every account, in the proportions you actually own them — for your own Effective Funds number, the companies underneath, and what else is duplicated. Free, no account, nothing stored.
X-ray my portfolio — free →Watch SPY vs VOO vs VTI
We re-read both funds’ published holdings every weeknight. Leave an address and we'll tell you when what's inside actually changes.
Not sending yet — email alerts are built but switched off, and you'll be among the first when they turn on. No spam, one-click unsubscribe.
Sources: issuer holdings files, SPY as of 2026-07-23, VOO as of 2026-06-30, VTI as of 2026-06-30. Weights are fractions of each fund. Diagnostics, not advice.