FXAIX vs ITOT: 82% overlap
Fidelity 500 Index and iShares Core S&P Total U.S. Stock Market ETF share 82.0% of their portfolios by weight — computed as Σ min(wA, wB) over every holding both funds own.
Different holding dates. These holdings were published about 5 months apart — FXAIX as of 2026-02-28, the rest through 2026-07-23. Each fund is compared using its most recent file, so any trading in between shows up as a difference.
You would hold two tickers and get the diversification of 1.2. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
FXAIX and ITOT hold 471 of the same securities. The ten contributing most to the overlap figure:
| Holding | in FXAIX | in ITOT | Δ |
|---|---|---|---|
| NVDA | 7.3% | 7.0% | 0.3% |
| AAPL | 6.6% | 6.6% | 0.1% |
| MSFT | 5.0% | 3.9% | 1.0% |
| AMZN | 3.5% | 3.2% | 0.3% |
| GOOGL | 3.1% | 2.6% | 0.5% |
| AVGO | 2.6% | 2.6% | 0.0% |
| GOOG | 2.5% | 2.1% | 0.4% |
| META | 2.4% | 1.8% | 0.6% |
| LLY | 1.4% | 1.3% | 0.1% |
| JPM | 1.4% | 1.3% | 0.1% |
Where FXAIX and ITOT differ
Sector weights as a share of each fund, ordered by the size of the gap rather than the size of the sector — two funds that overlap heavily still usually diverge somewhere.
| Sector | FXAIX | ITOT | Δ |
|---|---|---|---|
| Information Technology | 31.8% | 35.2% | −3.4pp |
| Unclassified | 3.3% | 0.0% | +3.3pp |
| Industrials | 8.3% | 10.1% | −1.8pp |
| Communication Services | 10.5% | 8.7% | +1.8pp |
| Consumer Staples | 5.4% | 4.4% | +0.9pp |
| Consumer Discretionary | 9.7% | 8.8% | +0.9pp |
| Financials | 12.0% | 12.7% | −0.7pp |
| Materials | 1.5% | 2.1% | −0.6pp |
Δ is FXAIX minus ITOT, in percentage points. Sector data is not published by every issuer, so “Unclassified” is a real category rather than a gap in the table.
What each fund holds alone
3.3% of FXAIX by weight, held in no part of ITOT.
14.8% of ITOT by weight, held in no part of FXAIX.
A large count with a small weight is the usual shape: the positions one fund adds are typically its smallest ones.
Concentration and cost
| FXAIX | ITOT | |
|---|---|---|
| Top 10 holdings | 36.4% | 32.7% |
| Positions held | 506 | 2,440 |
| Cost per $10,000 held, per year | $1 | $3 |
Cost is the expense ratio applied to $10,000; it excludes any brokerage commission, bid-ask spread or tax consequence. Figures are facts about the funds, not a suggestion about which to hold.
Frequently asked
How much do FXAIX and ITOT overlap?
FXAIX and ITOT overlap 82.0% by portfolio weight — substantial duplication if you hold both. They share 471 holdings. The figure comes from current issuer holdings files (FXAIX as of 2026-02-28, ITOT as of 2026-07-23).
How is the overlap between FXAIX and ITOT calculated?
As the sum of the smaller weight in each fund, over every holding both funds own: Σ min(wA, wB). If FXAIX holds a stock at 6% and ITOT holds the same stock at 4%, 4% counts as shared. The result is bounded between 0% and 100%, and it is computed after looking through any fund-of-funds to the underlying holdings.
Is it redundant to hold both FXAIX and ITOT?
That depends on your goals — we state facts, not advice. At 82.0% overlap, most of what one fund holds, the other holds too. Expense ratios: FXAIX 0.01% versus ITOT 0.03%.
What does FXAIX own that ITOT doesn't?
FXAIX holds 506 positions and ITOT holds 2,440; 34 of FXAIX's positions don't appear in ITOT at all, and they are 3.3% of FXAIX by weight.
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Related comparisons
Sources: issuer holdings files, FXAIX as of 2026-02-28, ITOT as of 2026-07-23. Weights are fractions of each fund. Diagnostics, not advice.