ITOT vs SPY: how much do they overlap?
iShares Core S&P Total U.S. Stock Market ETF (ITOT) · SPDR S&P 500 ETF Trust (SPY)
overlap by weight · 496 shared holdings
ITOT: 2470 holdings (as of 2026-03-31) · SPY: 504 holdings (as of 09-Jul-2026)
Note: the two funds' latest official filings have different dates, which can understate overlap slightly for funds tracking similar indexes.
High overlap
What this means
ITOT and SPY are largely the same portfolio. Holding both adds little diversification — most dollars end up in the same underlying stocks.
Overlap by weight sums the smaller of the two funds' weights for every stock they both hold — it answers "how much of my money is in the same stocks either way?" See methodology.
Top shared holdings
| Company | Ticker | in ITOT | in SPY |
|---|---|---|---|
| NVIDIA Corp. | NVDA | 6.69% | 7.57% |
| Apple, Inc. | AAPL | 5.88% | 7.16% |
| Microsoft Corp. | MSFT | 4.34% | 4.4% |
| Amazon.com, Inc. | AMZN | 3.21% | 3.73% |
| Alphabet, Inc. | GOOGL | 2.64% | 3.24% |
| Broadcom, Inc. | AVGO | 2.32% | 2.93% |
| Alphabet, Inc. | GOOG | 2.12% | 2.6% |
| Meta Platforms, Inc. | META | 1.98% | 2.14% |
| Tesla, Inc. | TSLA | 1.65% | 1.76% |
| Berkshire Hathaway, Inc. | BRK.B | 1.39% | 1.4% |
FAQ
How much do ITOT and SPY overlap?
ITOT and SPY have a 84.6% overlap by weight, sharing 496 holdings (out of 2470 in ITOT and 504 in SPY), based on official issuer holdings as of 2026-03-31.
What does 84.6% overlap mean?
ITOT and SPY are largely the same portfolio. Holding both adds little diversification — most dollars end up in the same underlying stocks.
Which stocks do ITOT and SPY both hold?
The largest shared positions are NVIDIA Corp., Apple, Inc., Microsoft Corp., Amazon.com, Inc., Alphabet, Inc.. The full list of top shared holdings with weights in each fund is shown on this page.