BIV vs MUB: 0% overlap
Vanguard Intermediate-Term Bond ETF and iShares National Muni Bond ETF 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 27 days apart — BIV as of 2026-06-30, the rest through 2026-07-27. 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
BIV and MUB hold 6 of the same securities. The ten contributing most to the overlap figure:
| Holding | in BIV | in MUB | Δ |
|---|---|---|---|
| 13063E | 0.0% | 1.2% | 1.2% |
| 88283L | 0.0% | 0.1% | 0.0% |
| 13063D | 0.0% | 2.7% | 2.7% |
| 64985S | 0.0% | 0.3% | 0.3% |
| 452252 | 0.0% | 0.6% | 0.6% |
| CASH | 0.3% | 0.0% | 0.3% |
Where BIV and MUB 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 | BIV | MUB | Δ |
|---|---|---|---|
| Treasuries | 55.9% | 0.0% | +55.9pp |
| State Tax-Backed | 0.0% | 30.5% | −30.4pp |
| Corporate — industrial & other | 20.2% | 0.0% | +20.2pp |
| Local Tax-Backed | 0.0% | 17.2% | −17.2pp |
| Financials | 14.3% | 0.0% | +14.3pp |
| Utilities | 3.9% | 16.7% | −12.8pp |
| School Districts | 0.0% | 10.1% | −10.1pp |
| Transportation | 0.0% | 10.0% | −10.0pp |
Δ is BIV minus MUB, 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
99.7% of BIV by weight, held in no part of MUB.
95.4% of MUB by weight, held in no part of BIV.
A large count with a small weight is the usual shape: the positions one fund adds are typically its smallest ones.
Concentration and cost
| BIV | MUB | |
|---|---|---|
| Top 10 holdings | 62.1% | 17.0% |
| Positions held | 854 | 970 |
| Cost per $10,000 held, per year | $3 | $5 |
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 BIV and MUB overlap?
BIV and MUB overlap 0.1% by portfolio weight — largely distinct portfolios. They share 6 holdings. The figure comes from current issuer holdings files (BIV as of 2026-06-30, MUB as of 2026-07-27).
How is the overlap between BIV and MUB calculated?
As the sum of the smaller weight in each fund, over every holding both funds own: Σ min(wA, wB). If BIV holds a stock at 6% and MUB 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 BIV and MUB?
That depends on your goals — we state facts, not advice. At 0.1% overlap, each fund still contributes meaningfully distinct exposure.
What does BIV own that MUB doesn't?
BIV holds 854 positions and MUB holds 970; 848 of BIV's positions don't appear in MUB at all, and they are 99.7% of BIV by weight.
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Related comparisons
Sources: issuer holdings files, BIV as of 2026-06-30, MUB as of 2026-07-27. Weights are fractions of each fund. Diagnostics, not advice.