AIVSX vs MGK: 42% overlap
American Funds Investment Company of America A and Vanguard Mega Cap Growth ETF share 42.1% 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 — AIVSX as of 2026-03-31, 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 1.6. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
AIVSX and MGK hold 30 of the same securities. The ten contributing most to the overlap figure:
| Holding | in AIVSX | in MGK | Δ |
|---|---|---|---|
| NVDA | 6.5% | 13.2% | 6.7% |
| MSFT | 5.7% | 7.5% | 1.8% |
| AMZN | 4.7% | 4.4% | 0.3% |
| AVGO | 6.1% | 4.3% | 1.9% |
| LLY | 3.4% | 3.4% | 0.0% |
| META | 2.6% | 4.1% | 1.5% |
| GOOGL | 2.5% | 5.9% | 3.4% |
| AAPL | 2.2% | 12.1% | 9.9% |
| GOOG | 2.1% | 4.6% | 2.5% |
| AMAT | 1.3% | 1.1% | 0.2% |
Where AIVSX 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 | AIVSX | MGK | Δ |
|---|---|---|---|
| Information Technology | 29.2% | 58.6% | −29.5pp |
| Industrials | 11.8% | 2.6% | +9.2pp |
| Health Care | 11.2% | 4.9% | +6.4pp |
| Communication Services | 9.9% | 16.2% | −6.3pp |
| Consumer Staples | 6.4% | 0.4% | +6.0pp |
| Unclassified | 5.5% | 0.0% | +5.5pp |
| Financials | 8.2% | 4.0% | +4.2pp |
| Materials | 3.1% | 0.4% | +2.7pp |
Δ is AIVSX 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
53.6% of AIVSX by weight, held in no part of MGK.
18.5% of MGK by weight, held in no part of AIVSX.
A large count with a small weight is the usual shape: the positions one fund adds are typically its smallest ones.
Concentration and cost
| AIVSX | MGK | |
|---|---|---|
| Top 10 holdings | 39.5% | 63.5% |
| Positions held | 168 | 57 |
| Cost per $10,000 held, per year | $58 | $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 AIVSX and MGK overlap?
AIVSX and MGK overlap 42.1% by portfolio weight — moderate overlap. They share 30 holdings. The figure comes from current issuer holdings files (AIVSX as of 2026-03-31, MGK as of 2026-06-30).
How is the overlap between AIVSX and MGK calculated?
As the sum of the smaller weight in each fund, over every holding both funds own: Σ min(wA, wB). If AIVSX 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 AIVSX and MGK?
That depends on your goals — we state facts, not advice. At 42.1% overlap, each fund still contributes meaningfully distinct exposure.
What does AIVSX own that MGK doesn't?
AIVSX holds 168 positions and MGK holds 57; 138 of AIVSX's positions don't appear in MGK at all, and they are 53.6% of AIVSX by weight.
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Related comparisons
Sources: issuer holdings files, AIVSX as of 2026-03-31, MGK as of 2026-06-30. Weights are fractions of each fund. Diagnostics, not advice.