IVV vs SPY vs VOO: 1.1 Effective Funds
Held in equal weight, IVV, SPY, VOO behave like 1.1 funds rather than 3. Every figure below is computed from the funds' current published holdings.
Three tickers, and the diversification of 1.1. 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 | |
|---|---|---|
| IVV vs SPY | 99.8% | |
| IVV vs VOO | 96.0% | |
| SPY vs VOO | 95.9% |
The most duplicated pair is IVV and SPY at 99.8%.
Held by all three
The ten largest of the positions that appear in IVV, SPY, VOO together — 95.8% of a portfolio split equally between them, by the same min-sum rule.
| Holding | Smallest of the three weights |
|---|---|
| NVDA | 7.51% |
| AAPL | 6.59% |
| MSFT | 4.30% |
| AMZN | 3.58% |
| GOOGL | 2.92% |
| AVGO | 2.77% |
| GOOG | 2.36% |
| META | 1.92% |
| MU | 1.75% |
| LLY | 1.47% |
Frequently asked
How much do IVV, SPY, VOO overlap?
Held in equal weight, IVV, SPY, VOO behave like 1.1 funds rather than 3. IVV and SPY overlap 99.8%; IVV and VOO overlap 96.0%; SPY and VOO overlap 95.9%. Each figure is the sum of the smaller weight in each fund over every holding both own.
Which two of IVV, SPY, VOO are most alike?
IVV and SPY, at 99.8% by weight. That pair contributes most of the duplication in the combined figure above.
What does "1.1 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 IVV, SPY, VOO. 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.
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Sources: issuer holdings files, IVV as of 2026-07-23, SPY as of 2026-07-23, VOO as of 2026-06-30. Weights are fractions of each fund. Diagnostics, not advice.