SOXX vs SPYM: 18% overlap
iShares Semiconductor ETF and State Street SPDR Portfolio S&P 500 ETF share 18.3% 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 1.8. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
SOXX and SPYM hold 19 of the same securities. The ten contributing most to the overlap figure:
| Holding | in SOXX | in SPYM | Δ |
|---|---|---|---|
| NVDA | 8.3% | 7.9% | 0.3% |
| AVGO | 7.3% | 2.9% | 4.4% |
| MU | 8.5% | 1.8% | 6.8% |
| AMD | 8.7% | 1.4% | 7.4% |
| INTC | 5.3% | 0.7% | 4.5% |
| AMAT | 5.2% | 0.7% | 4.5% |
| LRCX | 4.2% | 0.6% | 3.6% |
| KLAC | 4.8% | 0.4% | 4.3% |
| TXN | 3.9% | 0.4% | 3.5% |
| ADI | 3.8% | 0.3% | 3.5% |
Where SOXX and SPYM 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 | SOXX | SPYM | Δ |
|---|---|---|---|
| Information Technology | 99.9% | 37.5% | +62.4pp |
| Financials | 0.0% | 12.4% | −12.4pp |
| Communication Services | 0.0% | 9.3% | −9.3pp |
| Health Care | 0.0% | 9.1% | −9.1pp |
| Industrials | 0.0% | 8.9% | −8.9pp |
| Consumer Discretionary | 0.0% | 8.7% | −8.7pp |
| Consumer Staples | 0.0% | 4.6% | −4.6pp |
| Energy | 0.0% | 3.4% | −3.4pp |
Δ is SOXX minus SPYM, 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
18.1% of SOXX by weight, held in no part of SPYM.
81.7% of SPYM by weight, held in no part of SOXX.
A large count with a small weight is the usual shape: the positions one fund adds are typically its smallest ones.
Concentration and cost
| SOXX | SPYM | |
|---|---|---|
| Top 10 holdings | 60.9% | 36.9% |
| Positions held | 32 | 507 |
| Cost per $10,000 held, per year | $34 | $2 |
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 SOXX and SPYM overlap?
SOXX and SPYM overlap 18.3% by portfolio weight — moderate overlap. They share 19 holdings. The figure comes from current issuer holdings files (SOXX as of 2026-07-23, SPYM as of 2026-07-23).
How is the overlap between SOXX and SPYM calculated?
As the sum of the smaller weight in each fund, over every holding both funds own: Σ min(wA, wB). If SOXX holds a stock at 6% and SPYM 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 SOXX and SPYM?
That depends on your goals — we state facts, not advice. At 18.3% overlap, each fund still contributes meaningfully distinct exposure.
What does SOXX own that SPYM doesn't?
SOXX holds 32 positions and SPYM holds 507; 12 of SOXX's positions don't appear in SPYM at all, and they are 18.1% of SOXX by weight.
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Related comparisons
Sources: issuer holdings files, SOXX as of 2026-07-23, SPYM as of 2026-07-23. Weights are fractions of each fund. Diagnostics, not advice.