SPYM vs VFIAX: 96% overlap
State Street SPDR Portfolio S&P 500 ETF and Vanguard 500 Index Admiral share 95.9% 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 1.0. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
SPYM and VFIAX hold 504 of the same securities. The ten contributing most to the overlap figure:
| Holding | in SPYM | in VFIAX | Δ |
|---|---|---|---|
| NVDA | 7.9% | 7.5% | 0.4% |
| AAPL | 7.4% | 6.6% | 0.8% |
| MSFT | 4.4% | 4.3% | 0.2% |
| AMZN | 3.6% | 3.6% | 0.0% |
| GOOGL | 2.9% | 3.2% | 0.3% |
| AVGO | 2.9% | 2.8% | 0.1% |
| GOOG | 2.4% | 2.6% | 0.2% |
| META | 2.1% | 1.9% | 0.2% |
| MU | 1.8% | 2.0% | 0.3% |
| LLY | 1.5% | 1.5% | 0.0% |
Where SPYM 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 | SPYM | VFIAX | Δ |
|---|---|---|---|
| Financials | 12.4% | 11.6% | +0.8pp |
| Consumer Discretionary | 8.7% | 9.3% | −0.6pp |
| Information Technology | 37.5% | 38.0% | −0.5pp |
| Energy | 3.4% | 3.0% | +0.4pp |
| Communication Services | 9.3% | 9.7% | −0.4pp |
| Health Care | 9.1% | 8.9% | +0.2pp |
| Cash and/or Derivatives | 0.1% | 0.2% | −0.2pp |
| Real Estate | 1.9% | 1.8% | +0.1pp |
Δ is SPYM 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 SPYM by weight, held in no part of VFIAX.
0.0% of VFIAX by weight, held in no part of SPYM.
A large count with a small weight is the usual shape: the positions one fund adds are typically its smallest ones.
Concentration and cost
| SPYM | VFIAX | |
|---|---|---|
| Top 10 holdings | 36.9% | 36.4% |
| Positions held | 507 | 505 |
| Cost per $10,000 held, per year | $2 | $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 SPYM and VFIAX overlap?
SPYM and VFIAX overlap 95.9% by portfolio weight — they are effectively the same fund. They share 504 holdings. The figure comes from current issuer holdings files (SPYM as of 2026-07-23, VFIAX as of 2026-06-30).
How is the overlap between SPYM and VFIAX calculated?
As the sum of the smaller weight in each fund, over every holding both funds own: Σ min(wA, wB). If SPYM 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 SPYM and VFIAX?
That depends on your goals — we state facts, not advice. At 95.9% overlap, most of what one fund holds, the other holds too. Expense ratios: SPYM 0.02% versus VFIAX 0.04%.
What does SPYM own that VFIAX doesn't?
SPYM holds 507 positions and VFIAX holds 505; 2 of SPYM's positions don't appear in VFIAX at all, and they are 0.0% of SPYM by weight.
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Related comparisons
Sources: issuer holdings files, SPYM as of 2026-07-23, VFIAX as of 2026-06-30. Weights are fractions of each fund. Diagnostics, not advice.