AGG vs BND: 94% overlap
iShares Core U.S. Aggregate Bond ETF and Vanguard Total Bond Market ETF share 93.8% 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 1.1. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
AGG and BND hold 1,670 of the same securities. The ten contributing most to the overlap figure:
| Holding | in AGG | in BND | Δ |
|---|---|---|---|
| UST-3-10Y | 21.1% | 21.4% | 0.4% |
| AGENCY-MBS | 23.7% | 20.2% | 3.5% |
| UST-0-3Y | 16.1% | 17.1% | 1.0% |
| UST-10Y+ | 9.6% | 9.9% | 0.3% |
| CASH | 2.8% | 0.9% | 1.9% |
| 46647P | 0.5% | 0.5% | 0.0% |
| 06051G | 0.5% | 0.5% | 0.1% |
| 023135 | 0.3% | 0.3% | 0.0% |
| 459058 | 0.3% | 0.4% | 0.1% |
| 68389X | 0.3% | 0.4% | 0.0% |
Where AGG and BND 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 | BND | Δ |
|---|---|---|---|
| MBS Pass-Through | 23.7% | 20.2% | +3.5pp |
| Cash & Other | -2.0% | 0.0% | −2.0pp |
| Cash and/or Derivatives | 2.8% | 0.9% | +1.9pp |
| Treasuries | 46.8% | 48.5% | −1.7pp |
| Unclassified | 0.0% | 0.6% | −0.6pp |
| Supranational | 0.9% | 1.4% | −0.5pp |
| Corporate — industrial & other | 14.2% | 14.6% | −0.3pp |
| CMBS | 0.7% | 0.4% | +0.3pp |
Δ is AGG minus BND, 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
0.5% of AGG by weight, held in no part of BND.
0.7% of BND 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 | BND | |
|---|---|---|
| Top 10 holdings | 75.2% | 71.6% |
| Positions held | 1,860 | 2,030 |
| 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 BND overlap?
AGG and BND overlap 93.8% by portfolio weight — they are effectively the same fund. They share 1,670 holdings. The figure comes from current issuer holdings files (AGG as of 2026-10-22, BND as of 2026-09-30).
How is the overlap between AGG and BND 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 BND 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 BND?
That depends on your goals — we state facts, not advice. At 93.8% overlap, most of what one fund holds, the other holds too. Expense ratios: AGG 0.03% versus BND 0.03%.
What does AGG own that BND doesn't?
AGG holds 1,860 positions and BND holds 2,030; 189 of AGG's positions don't appear in BND at all, and they are 0.5% of AGG by weight.
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Related comparisons
Sources: issuer holdings files, AGG as of 2026-10-22, BND as of 2026-09-30. Weights are fractions of each fund. Diagnostics, not advice.