SPY vs VTIAX: 1% overlap
SPDR S&P 500 ETF Trust and Vanguard Total International Stock Index Admiral share 0.8% 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 2.0. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
SPY and VTIAX hold 57 of the same securities. The ten contributing most to the overlap figure:
| Holding | in SPY | in VTIAX | Δ |
|---|---|---|---|
| PRU | 0.1% | 0.1% | 0.0% |
| ROP | 0.1% | 0.6% | 0.6% |
| ALL | 0.1% | 0.1% | 0.1% |
| DTE | 0.0% | 0.2% | 0.2% |
| MRK | 0.5% | 0.0% | 0.5% |
| HBAN | 0.1% | 0.0% | 0.0% |
| PPL | 0.0% | 0.1% | 0.0% |
| DG | 0.0% | 0.2% | 0.1% |
| EQT | 0.1% | 0.0% | 0.0% |
| EL | 0.0% | 0.1% | 0.1% |
Where SPY and VTIAX 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 | SPY | VTIAX | Δ |
|---|---|---|---|
| Information Technology | 37.5% | 20.9% | +16.6pp |
| Unclassified | 0.0% | 9.1% | −9.1pp |
| Financials | 12.4% | 19.7% | −7.3pp |
| Communication Services | 9.3% | 3.3% | +6.0pp |
| Industrials | 8.9% | 13.8% | −4.9pp |
| Health Care | 9.1% | 5.3% | +3.8pp |
| Materials | 1.8% | 5.2% | −3.4pp |
| Cash and/or Derivatives | 0.0% | 2.5% | −2.5pp |
Δ is SPY minus VTIAX, 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
95.2% of SPY by weight, held in no part of VTIAX.
98.1% of VTIAX by weight, held in no part of SPY.
A large count with a small weight is the usual shape: the positions one fund adds are typically its smallest ones.
Concentration and cost
| SPY | VTIAX | |
|---|---|---|
| Top 10 holdings | 36.9% | 16.3% |
| Positions held | 505 | 8,453 |
| Cost per $10,000 held, per year | $9 | $9 |
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 SPY and VTIAX overlap?
SPY and VTIAX overlap 0.8% by portfolio weight — largely distinct portfolios. They share 57 holdings. The figure comes from current issuer holdings files (SPY as of 2026-07-23, VTIAX as of 2026-06-30).
How is the overlap between SPY and VTIAX calculated?
As the sum of the smaller weight in each fund, over every holding both funds own: Σ min(wA, wB). If SPY holds a stock at 6% and VTIAX 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 SPY and VTIAX?
That depends on your goals — we state facts, not advice. At 0.8% overlap, each fund still contributes meaningfully distinct exposure.
What does SPY own that VTIAX doesn't?
SPY holds 505 positions and VTIAX holds 8,453; 447 of SPY's positions don't appear in VTIAX at all, and they are 95.2% of SPY by weight.
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Related comparisons
Sources: issuer holdings files, SPY as of 2026-07-23, VTIAX as of 2026-06-30. Weights are fractions of each fund. Diagnostics, not advice.