BND vs VBIAX: 21% overlap
Vanguard Total Bond Market ETF and Vanguard Balanced Index Admiral share 21.1% 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 — VBIAX 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 1.8. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
BND and VBIAX hold 1,895 of the same securities. The ten contributing most to the overlap figure:
| Holding | in BND | in VBIAX | Δ |
|---|---|---|---|
| AGENCY-MBS | 20.3% | 8.1% | 12.3% |
| CASH | 1.1% | 1.8% | 0.7% |
| 46647P | 0.6% | 0.2% | 0.3% |
| 06051G | 0.5% | 0.2% | 0.3% |
| 459058 | 0.4% | 0.1% | 0.2% |
| 68389X | 0.3% | 0.1% | 0.2% |
| 61747Y | 0.2% | 0.1% | 0.1% |
| 95000U | 0.3% | 0.1% | 0.1% |
| 298785 | 0.3% | 0.1% | 0.2% |
| 38141G | 0.3% | 0.1% | 0.2% |
Where BND and VBIAX 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 | BND | VBIAX | Δ |
|---|---|---|---|
| Unclassified | 0.7% | 55.1% | −54.4pp |
| Treasuries | 48.2% | 19.1% | +29.0pp |
| MBS Pass-Through | 20.3% | 8.1% | +12.3pp |
| Corporate — industrial & other | 14.6% | 5.8% | +8.9pp |
| Financials | 7.9% | 3.6% | +4.3pp |
| Utilities | 2.6% | 1.2% | +1.4pp |
| Health Care | 0.0% | 1.2% | −1.2pp |
| Information Technology | 0.0% | 1.0% | −1.0pp |
Δ is BND minus VBIAX, 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
48.6% of BND by weight, held in no part of VBIAX.
79.0% of VBIAX by weight, held in no part of BND.
A large count with a small weight is the usual shape: the positions one fund adds are typically its smallest ones.
Concentration and cost
| BND | VBIAX | |
|---|---|---|
| Top 10 holdings | 71.7% | 45.2% |
| Positions held | 2,047 | 5,119 |
| Cost per $10,000 held, per year | $3 | $7 |
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 BND and VBIAX overlap?
BND and VBIAX overlap 21.1% by portfolio weight — moderate overlap. They share 1,895 holdings. The figure comes from current issuer holdings files (BND as of 2026-06-30, VBIAX as of 2026-03-31).
How is the overlap between BND and VBIAX calculated?
As the sum of the smaller weight in each fund, over every holding both funds own: Σ min(wA, wB). If BND holds a stock at 6% and VBIAX 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 BND and VBIAX?
That depends on your goals — we state facts, not advice. At 21.1% overlap, each fund still contributes meaningfully distinct exposure.
What does BND own that VBIAX doesn't?
BND holds 2,047 positions and VBIAX holds 5,119; 152 of BND's positions don't appear in VBIAX at all, and they are 48.6% of BND by weight.
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Related comparisons
Sources: issuer holdings files, BND as of 2026-06-30, VBIAX as of 2026-03-31. Weights are fractions of each fund. Diagnostics, not advice.