IJH vs SPY: how much do they really overlap?
IJH (iShares Core S&P Mid-Cap ETF, tracking the S&P MidCap 400) and SPY (SPDR S&P 500 ETF Trust, tracking the S&P 500) overlap by roughly 0% by weight. 0 of IJH's top 10 holdings also appear in SPY. A 50/50 blend of the two behaves like about 203 equally-weighted bets (diversification grade A). In short, the two funds hold almost none of the same securities — they are complementary, not redundant.
The same companies, in both funds
These 0 holdings appear in both IJH and SPY. The weight columns show how much of each fund each name represents.
| Holding | in IJH | in SPY |
|---|
Only in IJH
iShares Core S&P Mid-Cap ETF — US mid-cap. Its biggest holdings that SPY doesn’t have:
| TWLO TWILIO INC CLASS A | 0.86% |
| CRS CARPENTER TECHNOLOGY CORP | 0.84% |
| MKSI MKS | 0.82% |
| CW CURTISS WRIGHT CORP | 0.77% |
| NVT NVENT ELECTRIC PLC | 0.75% |
| ENTG ENTEGRIS INC | 0.75% |
| ATI ATI INC | 0.74% |
| ILMN ILLUMINA INC | 0.73% |
Only in SPY
SPDR S&P 500 ETF Trust — US large-cap. Its biggest holdings that IJH doesn’t have:
| NVDA NVIDIA Corporation | 7.38% |
| AAPL Apple Inc. | 6.47% |
| MSFT Microsoft Corporation | 4.28% |
| AMZN Amazon.com, Inc. | 3.68% |
| GOOGL Alphabet Inc. | 3.24% |
| AVGO Broadcom Inc. | 2.76% |
| GOOG Alphabet Inc. | 2.60% |
| MU Micron Technology, Inc. | 2.02% |
So — essentially different. Should you hold both?
IJH and SPY hold almost none of the same securities — they are complementary, not redundant. Held together they genuinely broaden your exposure — a 50/50 blend reaches ~203 effective positions (grade A), because they hold largely different securities.
Holdings as of — IJH: 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 50); the diffuse long tail barely moves the math.
See this for YOUR whole portfolio, free →IJH vs SPY — FAQ
- How much do IJH and SPY overlap?
- IJH and SPY overlap by approximately 0% measured by portfolio weight — that is the share of the smaller fund's holdings (by weight) that also sit inside the other. 0 of IJH's 10 largest holdings are also held by SPY. They share 0 of their listed top holdings in total.
- Is it redundant to hold both IJH and SPY?
- Because they hold almost none of the same securities — they are complementary, not redundant, holding both is not redundant — each fund covers largely different holdings, so together they broaden your exposure. A 50/50 blend has an effective 203 positions and a A diversification grade.
- What does SPY hold that IJH doesn't?
- SPY's largest holdings that IJH doesn't hold include NVDA, AAPL, MSFT, AMZN, GOOGL. Its category is US large-cap, versus IJH's US mid-cap.
- Which is more concentrated, IJH or SPY?
- IJH's top 10 holdings are 27% of its listed weight; SPY's are 71%. The more concentrated fund leans harder on its largest names.