AIVSX vs MDY: 0% overlap
American Funds Investment Company of America A and SPDR S&P MidCap 400 ETF Trust share 0.1% 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 4 months apart — AIVSX as of 2026-03-31, 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 2.0. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
AIVSX and MDY hold 1 of the same securities. The ten contributing most to the overlap figure:
| Holding | in AIVSX | in MDY | Δ |
|---|---|---|---|
| XPO | 0.1% | 0.7% | 0.6% |
Where AIVSX and MDY 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 | MDY | Δ |
|---|---|---|---|
| Information Technology | 29.2% | 13.8% | +15.3pp |
| Industrials | 11.8% | 25.4% | −13.5pp |
| Communication Services | 9.9% | 1.5% | +8.4pp |
| Financials | 8.2% | 14.8% | −6.7pp |
| Real Estate | 0.8% | 6.9% | −6.1pp |
| Unclassified | 5.5% | 0.0% | +5.5pp |
| Consumer Staples | 6.4% | 3.1% | +3.3pp |
| Energy | 1.9% | 4.9% | −3.0pp |
Δ is AIVSX minus MDY, 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
100.2% of AIVSX by weight, held in no part of MDY.
98.2% of MDY 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 | MDY | |
|---|---|---|
| Top 10 holdings | 39.5% | 7.6% |
| Positions held | 168 | 400 |
| Cost per $10,000 held, per year | $58 | $23 |
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 MDY overlap?
AIVSX and MDY overlap 0.1% by portfolio weight — largely distinct portfolios. They share 1 holdings. The figure comes from current issuer holdings files (AIVSX as of 2026-03-31, MDY as of 2026-07-23).
How is the overlap between AIVSX and MDY 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 MDY 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 MDY?
That depends on your goals — we state facts, not advice. At 0.1% overlap, each fund still contributes meaningfully distinct exposure.
What does AIVSX own that MDY doesn't?
AIVSX holds 168 positions and MDY holds 400; 167 of AIVSX's positions don't appear in MDY at all, and they are 100.2% of AIVSX by weight.
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Related comparisons
Sources: issuer holdings files, AIVSX as of 2026-03-31, MDY as of 2026-07-23. Weights are fractions of each fund. Diagnostics, not advice.