AGG vs BIV: 45% overlap
iShares Core U.S. Aggregate Bond ETF and Vanguard Intermediate-Term Bond ETF share 44.9% 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 1.6. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
AGG and BIV hold 843 of the same securities. The ten contributing most to the overlap figure:
| Holding | in AGG | in BIV | Δ |
|---|---|---|---|
| UST-3-10Y | 21.0% | 55.9% | 34.9% |
| 46647P | 0.5% | 1.1% | 0.6% |
| 06051G | 0.5% | 0.9% | 0.4% |
| 38141G | 0.3% | 0.6% | 0.3% |
| AGENCY-MBS | 24.1% | 0.3% | 23.8% |
| 68389X | 0.3% | 0.5% | 0.1% |
| 023135 | 0.3% | 0.4% | 0.0% |
| 459058 | 0.3% | 0.4% | 0.1% |
| 95000U | 0.3% | 0.6% | 0.3% |
| 404280 | 0.3% | 0.6% | 0.3% |
Where AGG and BIV 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 | AGG | BIV | Δ |
|---|---|---|---|
| MBS Pass-Through | 24.1% | 0.3% | +23.8pp |
| Treasuries | 46.5% | 55.9% | −9.5pp |
| Financials | 8.0% | 14.3% | −6.3pp |
| Corporate — industrial & other | 14.3% | 20.2% | −5.9pp |
| Cash and/or Derivatives | 2.9% | 0.3% | +2.6pp |
| Cash & Other | -2.3% | 0.0% | −2.3pp |
| Utilities | 2.6% | 3.9% | −1.3pp |
| Supranational | 0.9% | 1.8% | −0.9pp |
Δ is AGG minus BIV, 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
29.8% of AGG by weight, held in no part of BIV.
0.2% of BIV by weight, held in no part of AGG.
A large count with a small weight is the usual shape: the positions one fund adds are typically its smallest ones.
Concentration and cost
| AGG | BIV | |
|---|---|---|
| Top 10 holdings | 75.5% | 62.1% |
| Positions held | 1,865 | 854 |
| Cost per $10,000 held, per year | $3 | $3 |
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 AGG and BIV overlap?
AGG and BIV overlap 44.9% by portfolio weight — moderate overlap. They share 843 holdings. The figure comes from current issuer holdings files (AGG as of 2026-07-27, BIV as of 2026-06-30).
How is the overlap between AGG and BIV calculated?
As the sum of the smaller weight in each fund, over every holding both funds own: Σ min(wA, wB). If AGG holds a stock at 6% and BIV 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 AGG and BIV?
That depends on your goals — we state facts, not advice. At 44.9% overlap, each fund still contributes meaningfully distinct exposure.
What does AGG own that BIV doesn't?
AGG holds 1,865 positions and BIV holds 854; 1,021 of AGG's positions don't appear in BIV at all, and they are 29.8% of AGG by weight.
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Related comparisons
Sources: issuer holdings files, AGG as of 2026-07-27, BIV as of 2026-06-30. Weights are fractions of each fund. Diagnostics, not advice.