VB vs VFIAX: 3% overlap
Vanguard Small-Cap ETF and Vanguard 500 Index Admiral share 3.4% 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
VB and VFIAX hold 131 of the same securities. The ten contributing most to the overlap figure:
| Holding | in VB | in VFIAX | Δ |
|---|---|---|---|
| CASH | 1.7% | 0.2% | 1.5% |
| FLEX | 0.4% | 0.1% | 0.3% |
| JBL | 0.5% | 0.1% | 0.4% |
| EME | 0.4% | 0.1% | 0.4% |
| Q | 0.2% | 0.1% | 0.2% |
| EQT | 0.2% | 0.1% | 0.1% |
| STLD | 0.2% | 0.0% | 0.1% |
| NRG | 0.4% | 0.0% | 0.3% |
| CNC | 0.2% | 0.0% | 0.1% |
| TPR | 0.4% | 0.0% | 0.3% |
Where VB and VFIAX 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 | VB | VFIAX | Δ |
|---|---|---|---|
| Information Technology | 16.1% | 38.0% | −21.9pp |
| Industrials | 21.0% | 8.9% | +12.1pp |
| Communication Services | 3.0% | 9.7% | −6.7pp |
| Real Estate | 7.1% | 1.8% | +5.3pp |
| Materials | 5.3% | 1.8% | +3.5pp |
| Health Care | 11.9% | 8.9% | +3.0pp |
| Cash and/or Derivatives | 1.7% | 0.2% | +1.5pp |
| Financials | 12.7% | 11.6% | +1.1pp |
Δ is VB minus VFIAX, 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
76.9% of VB by weight, held in no part of VFIAX.
96.6% of VFIAX by weight, held in no part of VB.
A large count with a small weight is the usual shape: the positions one fund adds are typically its smallest ones.
Concentration and cost
| VB | VFIAX | |
|---|---|---|
| Top 10 holdings | 5.6% | 36.4% |
| Positions held | 1,308 | 505 |
| Cost per $10,000 held, per year | $3 | $4 |
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 VB and VFIAX overlap?
VB and VFIAX overlap 3.4% by portfolio weight — largely distinct portfolios. They share 131 holdings. The figure comes from current issuer holdings files (VB as of 2026-06-30, VFIAX as of 2026-06-30).
How is the overlap between VB and VFIAX calculated?
As the sum of the smaller weight in each fund, over every holding both funds own: Σ min(wA, wB). If VB holds a stock at 6% and VFIAX 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 VB and VFIAX?
That depends on your goals — we state facts, not advice. At 3.4% overlap, each fund still contributes meaningfully distinct exposure.
What does VB own that VFIAX doesn't?
VB holds 1,308 positions and VFIAX holds 505; 1,177 of VB's positions don't appear in VFIAX at all, and they are 76.9% of VB by weight.
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Related comparisons
Sources: issuer holdings files, VB as of 2026-06-30, VFIAX as of 2026-06-30. Weights are fractions of each fund. Diagnostics, not advice.