FZROX vs MGK: 45% overlap
Fidelity ZERO Total Market Index and Vanguard Mega Cap Growth ETF share 45.4% 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 2 months apart — FZROX as of 2026-04-30, the rest through 2026-06-30. 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 1.5. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
FZROX and MGK hold 55 of the same securities. The ten contributing most to the overlap figure:
| Holding | in FZROX | in MGK | Δ |
|---|---|---|---|
| NVDA | 6.9% | 13.2% | 6.3% |
| AAPL | 5.7% | 12.1% | 6.4% |
| MSFT | 4.3% | 7.5% | 3.1% |
| AMZN | 3.7% | 4.4% | 0.7% |
| GOOGL | 3.2% | 5.9% | 2.7% |
| AVGO | 2.8% | 4.3% | 1.4% |
| GOOG | 2.6% | 4.6% | 2.1% |
| META | 1.9% | 4.1% | 2.1% |
| TSLA | 1.5% | 3.9% | 2.4% |
| LLY | 1.1% | 3.4% | 2.3% |
Where FZROX and MGK 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 | MGK | Δ |
|---|---|---|---|
| Information Technology | 32.3% | 58.6% | −26.4pp |
| Financials | 11.8% | 4.0% | +7.9pp |
| Industrials | 9.2% | 2.6% | +6.6pp |
| Communication Services | 10.1% | 16.2% | −6.1pp |
| Consumer Staples | 4.6% | 0.4% | +4.2pp |
| Unclassified | 3.8% | 0.0% | +3.8pp |
| Health Care | 8.6% | 4.9% | +3.7pp |
| Energy | 3.5% | 0.0% | +3.5pp |
Δ is FZROX minus MGK, 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
54.8% of FZROX by weight, held in no part of MGK.
1.0% of MGK 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 | MGK | |
|---|---|---|
| Top 10 holdings | 34.0% | 63.5% |
| Positions held | 2,685 | 57 |
| Cost per $10,000 held, per year | $0 | $5 |
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 MGK overlap?
FZROX and MGK overlap 45.4% by portfolio weight — moderate overlap. They share 55 holdings. The figure comes from current issuer holdings files (FZROX as of 2026-04-30, MGK as of 2026-06-30).
How is the overlap between FZROX and MGK 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 MGK 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 MGK?
That depends on your goals — we state facts, not advice. At 45.4% overlap, each fund still contributes meaningfully distinct exposure.
What does FZROX own that MGK doesn't?
FZROX holds 2,685 positions and MGK holds 57; 2,629 of FZROX's positions don't appear in MGK at all, and they are 54.8% of FZROX by weight.
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Related comparisons
Sources: issuer holdings files, FZROX as of 2026-04-30, MGK as of 2026-06-30. Weights are fractions of each fund. Diagnostics, not advice.