AGTHX vs MGK: 45% overlap
American Funds Growth Fund of America A and Vanguard Mega Cap Growth ETF share 45.3% 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 4 months apart — AGTHX as of 2026-02-28, 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
AGTHX and MGK hold 42 of the same securities. The ten contributing most to the overlap figure:
| Holding | in AGTHX | in MGK | Δ |
|---|---|---|---|
| NVDA | 6.1% | 13.2% | 7.2% |
| AVGO | 4.3% | 4.3% | 0.0% |
| META | 4.2% | 4.1% | 0.2% |
| MSFT | 4.0% | 7.5% | 3.4% |
| LLY | 3.3% | 3.4% | 0.1% |
| GOOG | 2.9% | 4.6% | 1.7% |
| GOOGL | 2.9% | 5.9% | 3.0% |
| AMZN | 2.9% | 4.4% | 1.6% |
| TSLA | 2.6% | 3.9% | 1.3% |
| AAPL | 1.8% | 12.1% | 10.3% |
Where AGTHX 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 | AGTHX | MGK | Δ |
|---|---|---|---|
| Information Technology | 30.6% | 58.6% | −28.1pp |
| Unclassified | 7.6% | 0.0% | +7.6pp |
| Industrials | 9.8% | 2.6% | +7.2pp |
| Health Care | 11.0% | 4.9% | +6.1pp |
| Communication Services | 13.2% | 16.2% | −3.0pp |
| Financials | 6.5% | 4.0% | +2.6pp |
| Consumer Staples | 2.4% | 0.4% | +2.0pp |
| Energy | 1.9% | 0.0% | +1.9pp |
Δ is AGTHX 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
50.4% of AGTHX by weight, held in no part of MGK.
8.0% of MGK by weight, held in no part of AGTHX.
A large count with a small weight is the usual shape: the positions one fund adds are typically its smallest ones.
Concentration and cost
| AGTHX | MGK | |
|---|---|---|
| Top 10 holdings | 36.7% | 63.5% |
| Positions held | 309 | 57 |
| Cost per $10,000 held, per year | $61 | $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 AGTHX and MGK overlap?
AGTHX and MGK overlap 45.3% by portfolio weight — moderate overlap. They share 42 holdings. The figure comes from current issuer holdings files (AGTHX as of 2026-02-28, MGK as of 2026-06-30).
How is the overlap between AGTHX and MGK calculated?
As the sum of the smaller weight in each fund, over every holding both funds own: Σ min(wA, wB). If AGTHX 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 AGTHX and MGK?
That depends on your goals — we state facts, not advice. At 45.3% overlap, each fund still contributes meaningfully distinct exposure.
What does AGTHX own that MGK doesn't?
AGTHX holds 309 positions and MGK holds 57; 266 of AGTHX's positions don't appear in MGK at all, and they are 50.4% of AGTHX by weight.
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Related comparisons
Sources: issuer holdings files, AGTHX as of 2026-02-28, MGK as of 2026-06-30. Weights are fractions of each fund. Diagnostics, not advice.