SPY vs SWTSX: 84% overlap
SPDR S&P 500 ETF Trust and Schwab Total Stock Market Index share 84.3% of their portfolios by weight — computed as Σ min(wA, wB) over every holding both funds own.
Different holding dates. These holdings were published about 3 months apart — SWTSX as of 2026-04-30, the rest through 2026-07-23. Each fund is compared using its most recent file, so any trading in between shows up as a difference.
You would hold two tickers and get the diversification of 1.2. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
SPY and SWTSX hold 469 of the same securities. The ten contributing most to the overlap figure:
| Holding | in SPY | in SWTSX | Δ |
|---|---|---|---|
| NVDA | 7.9% | 6.9% | 1.0% |
| AAPL | 7.4% | 5.7% | 1.7% |
| MSFT | 4.4% | 4.3% | 0.1% |
| AMZN | 3.6% | 3.7% | 0.1% |
| 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% |
| TSLA | 1.4% | 1.5% | 0.1% |
| BRK-B | 1.4% | 1.2% | 0.2% |
Where SPY and SWTSX 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 | SWTSX | Δ |
|---|---|---|---|
| Information Technology | 37.5% | 32.3% | +5.2pp |
| Unclassified | 0.0% | 3.4% | −3.4pp |
| Consumer Discretionary | 8.8% | 9.6% | −0.8pp |
| Communication Services | 9.3% | 10.1% | −0.8pp |
| Industrials | 8.9% | 9.4% | −0.5pp |
| Financials | 12.4% | 11.9% | +0.5pp |
| Health Care | 9.1% | 8.7% | +0.5pp |
| Real Estate | 1.9% | 2.3% | −0.4pp |
Δ is SPY minus SWTSX, 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
3.0% of SPY by weight, held in no part of SWTSX.
13.8% of SWTSX 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 | SWTSX | |
|---|---|---|
| Top 10 holdings | 36.9% | 33.9% |
| Positions held | 505 | 2,939 |
| Cost per $10,000 held, per year | $9 | $3 |
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 SWTSX overlap?
SPY and SWTSX overlap 84.3% by portfolio weight — substantial duplication if you hold both. They share 469 holdings. The figure comes from current issuer holdings files (SPY as of 2026-07-23, SWTSX as of 2026-04-30).
How is the overlap between SPY and SWTSX 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 SWTSX 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 SWTSX?
That depends on your goals — we state facts, not advice. At 84.3% overlap, most of what one fund holds, the other holds too. Expense ratios: SPY 0.09% versus SWTSX 0.03%.
What does SPY own that SWTSX doesn't?
SPY holds 505 positions and SWTSX holds 2,939; 35 of SPY's positions don't appear in SWTSX at all, and they are 3.0% of SPY by weight.
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Related comparisons
Sources: issuer holdings files, SPY as of 2026-07-23, SWTSX as of 2026-04-30. Weights are fractions of each fund. Diagnostics, not advice.