FZROX vs ITOT: 90% overlap
Fidelity ZERO Total Market Index and iShares Core S&P Total U.S. Stock Market ETF share 90.1% 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 3 months apart — FZROX as of 2026-04-30, 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 1.1. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
FZROX and ITOT hold 2,218 of the same securities. The ten contributing most to the overlap figure:
| Holding | in FZROX | in ITOT | Δ |
|---|---|---|---|
| NVDA | 6.9% | 7.0% | 0.1% |
| AAPL | 5.7% | 6.6% | 0.9% |
| MSFT | 4.3% | 3.9% | 0.4% |
| AMZN | 3.7% | 3.2% | 0.5% |
| GOOGL | 3.2% | 2.6% | 0.6% |
| AVGO | 2.8% | 2.6% | 0.3% |
| GOOG | 2.6% | 2.1% | 0.5% |
| META | 1.9% | 1.8% | 0.1% |
| TSLA | 1.5% | 1.2% | 0.3% |
| BRK-B | 1.2% | 1.3% | 0.0% |
Where FZROX 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 | FZROX | ITOT | Δ |
|---|---|---|---|
| Unclassified | 3.8% | 0.0% | +3.8pp |
| Information Technology | 32.3% | 35.2% | −2.9pp |
| Communication Services | 10.1% | 8.7% | +1.4pp |
| Health Care | 8.6% | 9.7% | −1.1pp |
| Industrials | 9.2% | 10.1% | −1.0pp |
| Financials | 11.8% | 12.7% | −0.9pp |
| Consumer Discretionary | 9.6% | 8.8% | +0.8pp |
| Materials | 1.6% | 2.1% | −0.5pp |
Δ is FZROX 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
3.9% of FZROX by weight, held in no part of ITOT.
3.7% of ITOT by weight, held in no part of FZROX.
A large count with a small weight is the usual shape: the positions one fund adds are typically its smallest ones.
Concentration and cost
| FZROX | ITOT | |
|---|---|---|
| Top 10 holdings | 34.0% | 32.7% |
| Positions held | 2,685 | 2,440 |
| Cost per $10,000 held, per year | $0 | $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 FZROX and ITOT overlap?
FZROX and ITOT overlap 90.1% by portfolio weight — they are effectively the same fund. They share 2,218 holdings. The figure comes from current issuer holdings files (FZROX as of 2026-04-30, ITOT as of 2026-07-23).
How is the overlap between FZROX and ITOT calculated?
As the sum of the smaller weight in each fund, over every holding both funds own: Σ min(wA, wB). If FZROX 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 FZROX and ITOT?
That depends on your goals — we state facts, not advice. At 90.1% overlap, most of what one fund holds, the other holds too. Expense ratios: FZROX 0.00% versus ITOT 0.03%.
What does FZROX own that ITOT doesn't?
FZROX holds 2,685 positions and ITOT holds 2,440; 466 of FZROX's positions don't appear in ITOT at all, and they are 3.9% of FZROX by weight.
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Sources: issuer holdings files, FZROX as of 2026-04-30, ITOT as of 2026-07-23. Weights are fractions of each fund. Diagnostics, not advice.