ABALX vs FZROX: 29% overlap
American Funds American Balanced A and Fidelity ZERO Total Market Index share 28.5% of their portfolios by weight — computed as Σ min(wA, wB) over every holding both funds own.
Different holding dates. These holdings were published 30 days apart — ABALX as of 2026-03-31, the rest through 2026-04-30. 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 1.7. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
ABALX and FZROX hold 122 of the same securities. The ten contributing most to the overlap figure:
| Holding | in ABALX | in FZROX | Δ |
|---|---|---|---|
| AVGO | 3.4% | 2.8% | 0.5% |
| NVDA | 2.0% | 6.9% | 4.9% |
| MSFT | 2.0% | 4.3% | 2.3% |
| GOOGL | 1.7% | 3.2% | 1.5% |
| GOOG | 1.4% | 2.6% | 1.1% |
| LLY | 1.3% | 1.1% | 0.3% |
| MU | 1.3% | 0.8% | 0.4% |
| AMZN | 0.8% | 3.7% | 2.9% |
| V | 1.0% | 0.8% | 0.2% |
| META | 0.7% | 1.9% | 1.2% |
Where ABALX and FZROX 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 | FZROX | Δ |
|---|---|---|---|
| Unclassified | 22.7% | 3.8% | +18.9pp |
| Information Technology | 16.0% | 32.3% | −16.3pp |
| Treasuries | 12.3% | 0.0% | +12.3pp |
| Communication Services | 5.1% | 10.1% | −5.0pp |
| Consumer Discretionary | 4.7% | 9.6% | −4.9pp |
| Corporate — industrial & other | 3.6% | 0.0% | +3.6pp |
| Industrials | 6.0% | 9.2% | −3.2pp |
| Financials | 8.9% | 11.8% | −2.9pp |
Δ is ABALX minus FZROX, 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
54.5% of ABALX by weight, held in no part of FZROX.
43.7% of FZROX 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 | FZROX | |
|---|---|---|
| Top 10 holdings | 36.3% | 34.0% |
| Positions held | 1,439 | 2,685 |
| Cost per $10,000 held, per year | $56 | $0 |
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 FZROX overlap?
ABALX and FZROX overlap 28.5% by portfolio weight — moderate overlap. They share 122 holdings. The figure comes from current issuer holdings files (ABALX as of 2026-03-31, FZROX as of 2026-04-30).
How is the overlap between ABALX and FZROX 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 FZROX 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 FZROX?
That depends on your goals — we state facts, not advice. At 28.5% overlap, each fund still contributes meaningfully distinct exposure.
What does ABALX own that FZROX doesn't?
ABALX holds 1,439 positions and FZROX holds 2,685; 1,316 of ABALX's positions don't appear in FZROX at all, and they are 54.5% of ABALX by weight.
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Related comparisons
Sources: issuer holdings files, ABALX as of 2026-03-31, FZROX as of 2026-04-30. Weights are fractions of each fund. Diagnostics, not advice.