IWM vs VO: 0% overlap
iShares Russell 2000 ETF and Vanguard Mid-Cap ETF share 0.2% of their portfolios by weight — computed as Σ min(wA, wB) over every holding both funds own.
You would hold two tickers and get the diversification of 2.0. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
IWM and VO hold 1 of the same securities. The ten contributing most to the overlap figure:
| Holding | in IWM | in VO | Δ |
|---|---|---|---|
| CASH | 0.2% | 0.5% | 0.3% |
Where IWM and VO differ
Sector weights as a share of each fund, ordered by the size of the gap rather than the size of the sector — two funds that overlap heavily still usually diverge somewhere.
| Sector | IWM | VO | Δ |
|---|---|---|---|
| Health Care | 19.9% | 7.8% | +12.1pp |
| Utilities | 3.0% | 8.4% | −5.3pp |
| Financials | 19.0% | 14.0% | +5.0pp |
| Industrials | 14.7% | 19.6% | −4.9pp |
| Information Technology | 12.8% | 16.1% | −3.3pp |
| Consumer Staples | 2.2% | 4.9% | −2.7pp |
| Energy | 6.1% | 7.3% | −1.2pp |
| Real Estate | 5.9% | 5.1% | +0.8pp |
Δ is IWM minus VO, in percentage points. Sector data is not published by every issuer, so “Unclassified” is a real category rather than a gap in the table.
What each fund holds alone
99.9% of IWM by weight, held in no part of VO.
99.5% of VO by weight, held in no part of IWM.
A large count with a small weight is the usual shape: the positions one fund adds are typically its smallest ones.
Concentration and cost
| IWM | VO | |
|---|---|---|
| Top 10 holdings | 3.3% | 9.5% |
| Positions held | 1,967 | 283 |
| Cost per $10,000 held, per year | $19 | $3 |
Cost is the expense ratio applied to $10,000; it excludes any brokerage commission, bid-ask spread or tax consequence. Figures are facts about the funds, not a suggestion about which to hold.
Frequently asked
How much do IWM and VO overlap?
IWM and VO overlap 0.2% by portfolio weight — largely distinct portfolios. They share 1 holdings. The figure comes from current issuer holdings files (IWM as of 2026-07-23, VO as of 2026-06-30).
How is the overlap between IWM and VO calculated?
As the sum of the smaller weight in each fund, over every holding both funds own: Σ min(wA, wB). If IWM holds a stock at 6% and VO holds the same stock at 4%, 4% counts as shared. The result is bounded between 0% and 100%, and it is computed after looking through any fund-of-funds to the underlying holdings.
Is it redundant to hold both IWM and VO?
That depends on your goals — we state facts, not advice. At 0.2% overlap, each fund still contributes meaningfully distinct exposure.
What does IWM own that VO doesn't?
IWM holds 1,967 positions and VO holds 283; 1,965 of IWM's positions don't appear in VO at all, and they are 99.9% of IWM by weight.
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Related comparisons
Sources: issuer holdings files, IWM as of 2026-07-23, VO as of 2026-06-30. Weights are fractions of each fund. Diagnostics, not advice.