FXAIX vs SOXX: 14% overlap
Fidelity 500 Index and iShares Semiconductor ETF share 14.2% 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 5 months apart — FXAIX as of 2026-02-28, 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 1.9. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
FXAIX and SOXX hold 17 of the same securities. The ten contributing most to the overlap figure:
| Holding | in FXAIX | in SOXX | Δ |
|---|---|---|---|
| NVDA | 7.3% | 8.3% | 0.9% |
| AVGO | 2.6% | 7.3% | 4.8% |
| MU | 0.8% | 8.5% | 7.7% |
| AMD | 0.6% | 8.7% | 8.2% |
| AMAT | 0.5% | 5.2% | 4.7% |
| LRCX | 0.5% | 4.2% | 3.7% |
| INTC | 0.3% | 5.3% | 4.9% |
| KLAC | 0.3% | 4.8% | 4.4% |
| TXN | 0.3% | 3.9% | 3.6% |
| ADI | 0.3% | 3.8% | 3.5% |
Where FXAIX and SOXX 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 | FXAIX | SOXX | Δ |
|---|---|---|---|
| Information Technology | 31.8% | 99.9% | −68.1pp |
| Financials | 12.0% | 0.0% | +12.0pp |
| Communication Services | 10.5% | 0.0% | +10.5pp |
| Consumer Discretionary | 9.7% | 0.0% | +9.7pp |
| Health Care | 9.6% | 0.0% | +9.6pp |
| Industrials | 8.3% | 0.0% | +8.3pp |
| Consumer Staples | 5.4% | 0.0% | +5.4pp |
| Energy | 3.4% | 0.0% | +3.4pp |
Δ is FXAIX minus SOXX, 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
85.8% of FXAIX by weight, held in no part of SOXX.
26.0% of SOXX by weight, held in no part of FXAIX.
A large count with a small weight is the usual shape: the positions one fund adds are typically its smallest ones.
Concentration and cost
| FXAIX | SOXX | |
|---|---|---|
| Top 10 holdings | 36.4% | 60.9% |
| Positions held | 506 | 32 |
| Cost per $10,000 held, per year | $1 | $34 |
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 FXAIX and SOXX overlap?
FXAIX and SOXX overlap 14.2% by portfolio weight — largely distinct portfolios. They share 17 holdings. The figure comes from current issuer holdings files (FXAIX as of 2026-02-28, SOXX as of 2026-07-23).
How is the overlap between FXAIX and SOXX calculated?
As the sum of the smaller weight in each fund, over every holding both funds own: Σ min(wA, wB). If FXAIX holds a stock at 6% and SOXX 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 FXAIX and SOXX?
That depends on your goals — we state facts, not advice. At 14.2% overlap, each fund still contributes meaningfully distinct exposure.
What does FXAIX own that SOXX doesn't?
FXAIX holds 506 positions and SOXX holds 32; 488 of FXAIX's positions don't appear in SOXX at all, and they are 85.8% of FXAIX by weight.
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Related comparisons
Sources: issuer holdings files, FXAIX as of 2026-02-28, SOXX as of 2026-07-23. Weights are fractions of each fund. Diagnostics, not advice.