DIA vs VFIAX: 28% overlap
SPDR Dow Jones Industrial Average ETF and Vanguard 500 Index Admiral share 27.8% 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 1.7. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
DIA and VFIAX hold 30 of the same securities. The ten contributing most to the overlap figure:
| Holding | in DIA | in VFIAX | Δ |
|---|---|---|---|
| MSFT | 4.4% | 4.3% | 0.1% |
| AAPL | 3.7% | 6.6% | 2.9% |
| GOOGL | 3.6% | 3.2% | 0.4% |
| AMZN | 2.7% | 3.6% | 0.9% |
| NVDA | 2.4% | 7.5% | 5.1% |
| JPM | 4.0% | 1.3% | 2.8% |
| JNJ | 3.0% | 0.9% | 2.0% |
| V | 4.0% | 0.9% | 3.2% |
| WMT | 1.2% | 0.8% | 0.5% |
| CAT | 10.3% | 0.8% | 9.5% |
Where DIA 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 | DIA | VFIAX | Δ |
|---|---|---|---|
| Information Technology | 15.9% | 38.0% | −22.1pp |
| Financials | 28.6% | 11.6% | +17.1pp |
| Industrials | 17.5% | 8.9% | +8.5pp |
| Communication Services | 4.7% | 9.7% | −5.0pp |
| Health Care | 13.6% | 8.9% | +4.7pp |
| Utilities | 0.0% | 2.2% | −2.2pp |
| Real Estate | 0.0% | 1.8% | −1.8pp |
| Materials | 3.6% | 1.8% | +1.7pp |
Δ is DIA 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
0.0% of DIA by weight, held in no part of VFIAX.
63.3% of VFIAX by weight, held in no part of DIA.
A large count with a small weight is the usual shape: the positions one fund adds are typically its smallest ones.
Concentration and cost
| DIA | VFIAX | |
|---|---|---|
| Top 10 holdings | 56.2% | 36.4% |
| Positions held | 31 | 505 |
| Cost per $10,000 held, per year | $16 | $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 DIA and VFIAX overlap?
DIA and VFIAX overlap 27.8% by portfolio weight — moderate overlap. They share 30 holdings. The figure comes from current issuer holdings files (DIA as of 2026-07-23, VFIAX as of 2026-06-30).
How is the overlap between DIA and VFIAX calculated?
As the sum of the smaller weight in each fund, over every holding both funds own: Σ min(wA, wB). If DIA 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 DIA and VFIAX?
That depends on your goals — we state facts, not advice. At 27.8% overlap, each fund still contributes meaningfully distinct exposure.
What does DIA own that VFIAX doesn't?
DIA holds 31 positions and VFIAX holds 505; 0 of DIA's positions don't appear in VFIAX at all, and they are 0.0% of DIA by weight.
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Related comparisons
Sources: issuer holdings files, DIA as of 2026-07-23, VFIAX as of 2026-06-30. Weights are fractions of each fund. Diagnostics, not advice.