Guardfolio Research · ETF Overlap
ITOT vs SPY Overlap: 35.2% of Weight in Shared Holdings
ITOT (iShares Core S&P Total US Stock Market) and SPY (SPDR S&P 500) overlap by 35.2% of weight through 10 shared top-10 holdings — including NVDA, AAPL, MSFT, AMZN, GOOGL. Here is exactly which stocks duplicate, the sector picture, and whether holding both concentrates or diversifies your portfolio.
Overlap Summary
Bottom line
ITOT and SPY overlap heavily — 35.2% of weight sits in the same 10 top-10 names. Owning both stacks the same mega-cap bets rather than spreading risk.
The Data
Exactly which stocks ITOT and SPY share
The table below shows every holding that appears in both funds' top 10, with each fund's weight and the shared (minimum) weight that counts toward overlap.
| Holding | ITOT weight | SPY weight | Shared (min) |
|---|---|---|---|
| NVIDIA Corp. (NVDA) | 7.91% | 7.84% | 7.84% |
| Apple Inc. (AAPL) | 6.04% | 6.44% | 6.04% |
| Microsoft Corp. (MSFT) | 4.20% | 4.89% | 4.20% |
| Amazon.com, Inc. (AMZN) | 3.60% | 4.19% | 3.60% |
| Alphabet Inc. (GOOGL) | 3.22% | 3.62% | 3.22% |
| Broadcom Inc. (AVGO) | 2.88% | 3.20% | 2.88% |
| Alphabet Inc. (GOOG) | 2.57% | 2.89% | 2.57% |
| Meta Platforms, Inc. (META) | 1.87% | 2.16% | 1.87% |
| Tesla, Inc. (TSLA) | 1.72% | 1.74% | 1.72% |
| Berkshire Hathaway Inc. (BRK.B) | 1.23% | 1.40% | 1.23% |
| Total shared top-10 weight | 35.2% | 38.4% | 35.2% |
Weights are approximate, based on the most recent quarterly holdings. The 35.2% figure is the sum of the lesser of each fund's weight per shared holding (the conservative top-10 method).
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Sector Picture
ITOT vs SPY: sector exposure side by side
Two funds can share few holdings yet still concentrate the same sectors. Here is how the top sectors compare (94.0% combined sector overlap).
| Sector | ITOT | SPY |
|---|---|---|
| Technology | 32.2% | 33.1% |
| Financial Services | 12.8% | 12.2% |
| Consumer Discretionary | 10.5% | 10.4% |
| Healthcare | 9.1% | 9.3% |
| Industrials | 9.6% | 8.6% |
| Communication Services | 7.6% | 8.2% |
The Verdict
Should you hold both ITOT and SPY?
ITOT and SPY overlap heavily — 35.2% of weight sits in the same 10 top-10 names. Owning both stacks the same mega-cap bets rather than spreading risk. You are also paying two expense ratios for largely the same exposure. Treat this pair as one position, not two.
FAQ
ITOT vs SPY overlap: common questions
How much do ITOT and SPY overlap?
ITOT (iShares Core S&P Total US Stock Market) and SPY (SPDR S&P 500) overlap by approximately 35.2% of weight based on their top-10 holdings, with 94.0% sector overlap. They share 10 top-10 holdings: NVDA, AAPL, MSFT, AMZN, GOOGL, AVGO, GOOG, META, TSLA, BRK.B.
What stocks do ITOT and SPY both hold?
Both ITOT and SPY hold NVIDIA Corp (NVDA), Apple Inc (AAPL), Microsoft Corp (MSFT), Amazon (AMZN), Alphabet Inc (GOOGL), Broadcom Inc (AVGO), Alphabet Inc (GOOG), Meta Platforms (META) among their top positions. These shared names account for the 35.2% weight overlap.
Is it worth holding both ITOT and SPY?
ITOT and SPY overlap heavily — 35.2% of weight sits in the same 10 top-10 names. Owning both stacks the same mega-cap bets rather than spreading risk. You are also paying two expense ratios for largely the same exposure. Treat this pair as one position, not two.
What is the difference between ITOT and SPY?
ITOT is a total US market fund (US Total Market, 0.03% expense ratio) and SPY is an S&P 500 fund (US Large-Cap Blend, 0.09% expense ratio). ITOT's top 10 is 35.2% of the fund; SPY's is 38.4%.
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