DIA vs SPY: how much do they really overlap?
DIA (SPDR Dow Jones Industrial Average ETF, tracking the Dow Jones Industrial Average) and SPY (SPDR S&P 500 ETF Trust, tracking the S&P 500) overlap by roughly 38% by weight. 4 of DIA'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 9 holdings appear in both DIA and SPY. The weight columns show how much of each fund each name represents.
| Holding | in DIA | in SPY |
|---|---|---|
| MSFT Microsoft Corporation | 4.20% | 4.28% |
| GOOGL Alphabet Inc. | 4.03% | 3.24% |
| AAPL Apple Inc. | 3.21% | 6.47% |
| AMZN Amazon.com, Inc. | 2.73% | 3.68% |
| NVDA NVIDIA Corporation | 2.22% | 7.38% |
| JPM JPMorgan Chase & Co. | 3.75% | 1.38% |
| JNJ Johnson & Johnson | 2.94% | 0.97% |
| V Visa Inc. | 3.89% | 0.89% |
| CAT Caterpillar Inc. | 11.76% | 0.74% |
Only in DIA
SPDR Dow Jones Industrial Average ETF — US blue-chip (Dow 30). Its biggest holdings that SPY doesn’t have:
| GS The Goldman Sachs Group, Inc. | 11.61% |
| UNH UnitedHealth Group Incorporated | 4.78% |
| AMGN Amgen Inc. | 4.10% |
| HD The Home Depot, Inc. | 3.99% |
| SHW The Sherwin-Williams Company | 3.92% |
| AXP American Express Company | 3.88% |
| TRV The Travelers Companies, Inc. | 3.78% |
| IBM International Business Machines Corporation | 3.16% |
Only in SPY
SPDR S&P 500 ETF Trust — US large-cap. Its biggest holdings that DIA doesn’t have:
| AVGO Broadcom Inc. | 2.76% |
| GOOG Alphabet Inc. | 2.60% |
| MU Micron Technology, Inc. | 2.02% |
| META Meta Platforms, Inc. | 1.93% |
| TSLA Tesla, Inc. | 1.81% |
| LLY Eli Lilly and Company | 1.52% |
| BRK.B Berkshire Hathaway Inc. | 1.42% |
| AMD Advanced Micro Devices, Inc. | 1.38% |
So — partly overlapping. Should you hold both?
DIA 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 — DIA: Jun 29, 2026 (State Street Global Advisors); SPY: Jun 29, 2026 (State Street Global Advisors). Refreshed monthly. Overlap is measured across each fund’s largest holdings (top 25); the diffuse long tail barely moves the math.
See this for YOUR whole portfolio, free →DIA vs SPY — FAQ
- How much do DIA and SPY overlap?
- DIA and SPY overlap by approximately 38% measured by portfolio weight — that is the share of the smaller fund's holdings (by weight) that also sit inside the other. 4 of DIA's 10 largest holdings are also held by SPY. They share 9 of their listed top holdings in total.
- Is it redundant to hold both DIA 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 (MSFT) 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 DIA doesn't?
- SPY's largest holdings that DIA doesn't hold include AVGO, GOOG, MU, META, TSLA. Its category is US large-cap, versus DIA's US blue-chip (Dow 30).
- Which is more concentrated, DIA or SPY?
- DIA's top 10 holdings are 59% of its listed weight; SPY's are 71%. The more concentrated fund leans harder on its largest names.