SOXX vs SPY: how much do they really overlap?
SOXX (iShares Semiconductor ETF, tracking the NYSE Semiconductor) and SPY (SPDR S&P 500 ETF Trust, tracking the S&P 500) overlap by roughly 31% by weight. 7 of SOXX's top 10 holdings also appear in SPY. A 50/50 blend of the two behaves like about 45 equally-weighted bets (diversification grade B). In short, the two funds share a meaningful core of the same megacaps, but each also brings real exposure the other lacks.
The same companies, in both funds
These 7 holdings appear in both SOXX and SPY. The weight columns show how much of each fund each name represents.
| Holding | in SOXX | in SPY |
|---|---|---|
| NVDA NVIDIA CORP | 6.81% | 7.38% |
| AVGO BROADCOM INC | 6.08% | 2.76% |
| MU MICRON TECHNOLOGY INC | 8.54% | 2.02% |
| AMD ADVANCED MICRO DEVICES INC | 8.09% | 1.38% |
| INTC INTEL CORPORATION | 6.33% | 0.97% |
| AMAT APPLIED MATERIAL INC | 5.77% | 0.86% |
| LRCX LAM RESEARCH CORP | 4.89% | 0.80% |
Only in SOXX
iShares Semiconductor ETF — semiconductors. Its biggest holdings that SPY doesn’t have:
| KLAC KLA CORP | 5.64% |
| MRVL MARVELL TECHNOLOGY INC | 4.88% |
| TSM TAIWAN SEMICONDUCTOR MANUFACTURING | 4.26% |
| TXN TEXAS INSTRUMENT INC | 3.50% |
| ADI ANALOG DEVICES INC | 3.45% |
| TER TERADYNE INC | 3.36% |
| NXPI NXP SEMICONDUCTORS NV | 3.14% |
| ALAB ASTERA LABS INC | 3.02% |
Only in SPY
SPDR S&P 500 ETF Trust — US large-cap. Its biggest holdings that SOXX doesn’t have:
| AAPL Apple Inc. | 6.47% |
| MSFT Microsoft Corporation | 4.28% |
| AMZN Amazon.com, Inc. | 3.68% |
| GOOGL Alphabet Inc. | 3.24% |
| GOOG Alphabet Inc. | 2.60% |
| META Meta Platforms, Inc. | 1.93% |
| TSLA Tesla, Inc. | 1.81% |
| LLY Eli Lilly and Company | 1.52% |
So — partly overlapping. Should you hold both?
SOXX and SPY share a meaningful core of the same megacaps, but each also brings real exposure the other lacks. Held together they keep a shared megacap core but each still pulls in exposure the other lacks, so a 50/50 blend spreads to ~45 effective positions (grade B).
Holdings as of — SOXX: Jun 30, 2026 (iShares (BlackRock)); SPY: Jun 29, 2026 (State Street Global Advisors). Refreshed monthly. Overlap is measured across each fund’s largest holdings (top 33); the diffuse long tail barely moves the math.
See this for YOUR whole portfolio, free →SOXX vs SPY — FAQ
- How much do SOXX and SPY overlap?
- SOXX and SPY overlap by approximately 31% measured by portfolio weight — that is the share of the smaller fund's holdings (by weight) that also sit inside the other. 7 of SOXX's 10 largest holdings are also held by SPY. They share 7 of their listed top holdings in total.
- Is it redundant to hold both SOXX and SPY?
- Because they share a meaningful core of the same megacaps, but each also brings real exposure the other lacks, holding both is partly redundant: you double up on a shared core (NVDA) while each fund still adds distinct exposure. A 50/50 blend has an effective 45 positions and a B diversification grade.
- What does SPY hold that SOXX doesn't?
- SPY's largest holdings that SOXX doesn't hold include AAPL, MSFT, AMZN, GOOGL, GOOG. Its category is US large-cap, versus SOXX's semiconductors.
- Which is more concentrated, SOXX or SPY?
- SOXX's top 10 holdings are 61% of its listed weight; SPY's are 71%. The more concentrated fund leans harder on its largest names.