ABALX vs MDY: 1% overlap
American Funds American Balanced A and SPDR S&P MidCap 400 ETF Trust share 1.1% 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 — ABALX 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
ABALX and MDY hold 8 of the same securities. The ten contributing most to the overlap figure:
| Holding | in ABALX | in MDY | Δ |
|---|---|---|---|
| RGLD | 0.4% | 0.5% | 0.0% |
| USFD | 0.2% | 0.6% | 0.4% |
| ILMN | 0.2% | 0.8% | 0.7% |
| VNOM | 0.1% | 0.2% | 0.1% |
| ATI | 0.1% | 0.8% | 0.7% |
| MOH | 0.1% | 0.3% | 0.2% |
| CFR | 0.1% | 0.3% | 0.2% |
| MTN | 0.0% | 0.1% | 0.1% |
Where ABALX 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 | ABALX | MDY | Δ |
|---|---|---|---|
| Unclassified | 22.7% | 0.0% | +22.7pp |
| Industrials | 6.0% | 25.4% | −19.4pp |
| Treasuries | 12.3% | 0.0% | +12.3pp |
| Real Estate | 0.7% | 6.9% | −6.1pp |
| Financials | 8.9% | 14.8% | −5.9pp |
| Consumer Discretionary | 4.7% | 10.2% | −5.5pp |
| Materials | 1.9% | 5.4% | −3.6pp |
| Communication Services | 5.1% | 1.5% | +3.6pp |
Δ is ABALX 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
99.6% of ABALX by weight, held in no part of MDY.
95.3% of MDY by weight, held in no part of ABALX.
A large count with a small weight is the usual shape: the positions one fund adds are typically its smallest ones.
Concentration and cost
| ABALX | MDY | |
|---|---|---|
| Top 10 holdings | 36.3% | 7.6% |
| Positions held | 1,439 | 400 |
| Cost per $10,000 held, per year | $56 | $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 ABALX and MDY overlap?
ABALX and MDY overlap 1.1% by portfolio weight — largely distinct portfolios. They share 8 holdings. The figure comes from current issuer holdings files (ABALX as of 2026-03-31, MDY as of 2026-07-23).
How is the overlap between ABALX and MDY calculated?
As the sum of the smaller weight in each fund, over every holding both funds own: Σ min(wA, wB). If ABALX 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 ABALX and MDY?
That depends on your goals — we state facts, not advice. At 1.1% overlap, each fund still contributes meaningfully distinct exposure.
What does ABALX own that MDY doesn't?
ABALX holds 1,439 positions and MDY holds 400; 1,430 of ABALX's positions don't appear in MDY at all, and they are 99.6% of ABALX by weight.
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Related comparisons
Sources: issuer holdings files, ABALX as of 2026-03-31, MDY as of 2026-07-23. Weights are fractions of each fund. Diagnostics, not advice.