IWB vs VB Overlap
IWB is an equity ETF from IShares, while VB is a small-cap U.S. equity ETF from Vanguard. IWB and VB show limited overlap, with an estimated weighted overlap of 8.32%. They share 543 holdings in the loaded dataset, led by SNDK, FIX, and CIEN.
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Quick Answer
IWB is an equity ETF from IShares, while VB is a small-cap U.S. equity ETF from Vanguard. IWB and VB show limited overlap, with an estimated weighted overlap of 8.32%. They share 543 holdings in the loaded dataset, led by SNDK, FIX, and CIEN.
- 8.32% weighted overlap across 543 shared holdings.
- The top three shared holdings explain 3.52% of the measured overlap.
- IWB and VB are closer in breadth than a broad-vs-niche ETF pair.
- The overlap is mostly explained by the top shared positions rather than sector labels alone.
- Holding both can still add materially different exposure.
Data Freshness
- IWB holdings
- Mar 12, 2026
- VB holdings
- Mar 12, 2026
- Overlap computed
- Mar 15, 2026
- Data source
- Financial Modeling Prep
Review the methodology for the overlap formula and refresh policy.
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About These ETFs
What Stands Out In This Comparison
What This Means
IWB is an equity ETF from IShares, while VB is a small-cap U.S. equity ETF from Vanguard. IWB and VB do not own much of the same portfolio weight. That usually means you are combining different parts of the market, with only a small amount of duplication through names like SNDK, FIX, and CIEN.
How They Differ
IWB is an equity ETF from IShares, while VB is a small-cap U.S. equity ETF from Vanguard. Neither fund clearly dominates on breadth, so the practical difference is more about weighting, index construction, and cost. VB has the lower expense ratio, while IWB charges more for its exposure.
What Drives The Overlap
The overlap is driven by a relatively small set of large shared positions. The top three shared holdings account for 3.52% of the score, which means the result is heavily influenced by the biggest common weights rather than a long tail of tiny positions.
When One May Fit Better
Because IWB and VB are closer in breadth, the better fit usually comes down to index methodology, issuer preference, and cost. VB has the lower expense ratio, while IWB charges more for its exposure.
Overlap Driver Snapshot
Concentration
The top three shared holdings explain 3.52% of the full overlap score.
That helps show whether the score comes from a handful of giant shared positions or from a broader mix of common holdings.
Shared Sector Tilt
Sector tags are not consistently available for the biggest shared positions in this dataset, so this comparison leans more on the specific holdings than on sector labels.
Top Shared Holdings
These are the holdings contributing the most to the overlap score between IWB and VB.
| Holding | Name | IWB Wt. | VB Wt. | Overlap |
|---|---|---|---|---|
| SNDK | SANDISK CORP | 0.14% | 1.06% | 0.14% |
| FIX | COMFORT SYSTEMS USA INC | 0.08% | 0.54% | 0.08% |
| CIEN | CIENA CORP | 0.08% | 0.47% | 0.08% |
| LITE | LUMENTUM HOLDINGS INC | 0.08% | 0.37% | 0.08% |
| TER | TERADYNE INC | 0.08% | 0.25% | 0.08% |
| COHR | COHERENT CORP | 0.07% | 0.44% | 0.07% |
| EQT | EQT CORP | 0.06% | 0.24% | 0.06% |
| EME | EMCOR GROUP INC | 0.05% | 0.43% | 0.05% |
| NRG | NRG ENERGY INC | 0.05% | 0.39% | 0.05% |
| TPR | TAPESTRY INC | 0.05% | 0.34% | 0.05% |
Why These ETFs Overlap
IWB is an equity ETF from IShares, while VB is a small-cap U.S. equity ETF from Vanguard. The overlap exists because both funds allocate meaningful weight to the same holdings. In this dataset, the biggest shared drivers are SNDK, FIX, and CIEN, which appear in both portfolios and push the overlap score higher.
Holding both IWB and VB can make sense if you want exposure to different sleeves of the market. The overlap is small enough that both funds may still improve diversification.
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Frequently Asked Questions About IWB and VB
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How Overlap Is Calculated
A straightforward approach used by portfolio analysts.
For every stock that appears in both ETFs, we take the smaller of the two weights. Adding up all those minimums gives the total overlap percentage. A score of 100% means the two ETFs hold the exact same stocks in the same proportions.
Want the full explanation? Read the methodology page.