BNDX vs SPY: 1% overlap
Vanguard Total International Bond ETF and SPDR S&P 500 ETF Trust share 0.7% of their portfolios by weight — computed as Σ min(wA, wB) over every holding both funds own.
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
BNDX and SPY hold 39 of the same securities. The ten contributing most to the overlap figure:
| Holding | in BNDX | in SPY | Δ |
|---|---|---|---|
| BAC | 0.1% | 0.6% | 0.5% |
| MS | 0.1% | 0.4% | 0.3% |
| JPM | 0.1% | 1.5% | 1.4% |
| Q | 0.0% | 0.0% | 0.0% |
| GS | 0.0% | 0.5% | 0.5% |
| MCD | 0.0% | 0.3% | 0.3% |
| CRH | 0.0% | 0.1% | 0.1% |
| MET | 0.0% | 0.1% | 0.0% |
| DLR | 0.0% | 0.1% | 0.1% |
| VZ | 0.0% | 0.3% | 0.3% |
Where BNDX and SPY 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 | BNDX | SPY | Δ |
|---|---|---|---|
| Unclassified | 88.4% | 0.0% | +88.4pp |
| Information Technology | 0.1% | 37.5% | −37.4pp |
| Financials | 2.0% | 12.4% | −10.4pp |
| Communication Services | 0.1% | 9.3% | −9.2pp |
| Health Care | 0.2% | 9.1% | −9.0pp |
| Industrials | 0.0% | 8.9% | −8.8pp |
| Consumer Discretionary | 0.2% | 8.8% | −8.5pp |
| Consumer Staples | 0.1% | 4.6% | −4.5pp |
Δ is BNDX minus SPY, 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
99.3% of BNDX by weight, held in no part of SPY.
76.8% of SPY by weight, held in no part of BNDX.
A large count with a small weight is the usual shape: the positions one fund adds are typically its smallest ones.
Concentration and cost
| BNDX | SPY | |
|---|---|---|
| Top 10 holdings | 24.4% | 36.9% |
| Positions held | 3,115 | 505 |
| Cost per $10,000 held, per year | $7 | $9 |
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 BNDX and SPY overlap?
BNDX and SPY overlap 0.7% by portfolio weight — largely distinct portfolios. They share 39 holdings. The figure comes from current issuer holdings files (BNDX as of 2026-06-30, SPY as of 2026-07-23).
How is the overlap between BNDX and SPY calculated?
As the sum of the smaller weight in each fund, over every holding both funds own: Σ min(wA, wB). If BNDX holds a stock at 6% and SPY 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 BNDX and SPY?
That depends on your goals — we state facts, not advice. At 0.7% overlap, each fund still contributes meaningfully distinct exposure.
What does BNDX own that SPY doesn't?
BNDX holds 3,115 positions and SPY holds 505; 3,076 of BNDX's positions don't appear in SPY at all, and they are 99.3% of BNDX by weight.
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Related comparisons
Sources: issuer holdings files, BNDX as of 2026-06-30, SPY as of 2026-07-23. Weights are fractions of each fund. Diagnostics, not advice.