AGG vs VTHRX: 30% overlap
iShares Core U.S. Aggregate Bond ETF and Vanguard Target Retirement 2030 share 29.8% 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 4 months apart — VTHRX as of 2026-03-31, the rest through 2026-07-23. 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 1.7. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
AGG and VTHRX hold 1,684 of the same securities. The ten contributing most to the overlap figure:
| Holding | in AGG | in VTHRX | Δ |
|---|---|---|---|
| UST-3-10Y | 21.0% | 6.0% | 15.0% |
| AGENCY-MBS | 24.1% | 5.7% | 18.3% |
| UST-0-3Y | 16.1% | 4.7% | 11.4% |
| UST-10Y+ | 9.3% | 2.9% | 6.5% |
| CASH | 2.7% | 1.9% | 0.8% |
| 46647P | 0.5% | 0.2% | 0.4% |
| 06051G | 0.5% | 0.1% | 0.4% |
| 459058 | 0.3% | 0.1% | 0.2% |
| 68389X | 0.3% | 0.1% | 0.2% |
| 023135 | 0.3% | 0.1% | 0.2% |
Where AGG and VTHRX 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 | VTHRX | Δ |
|---|---|---|---|
| Treasuries | 46.5% | 13.6% | +32.9pp |
| MBS Pass-Through | 24.1% | 5.7% | +18.3pp |
| Information Technology | 0.0% | 17.3% | −17.3pp |
| Unclassified | 0.0% | 13.3% | −13.3pp |
| Corporate — industrial & other | 14.3% | 4.4% | +9.9pp |
| Industrials | 0.0% | 6.9% | −6.9pp |
| Consumer Discretionary | 0.0% | 5.0% | −5.0pp |
| Health Care | 0.0% | 4.6% | −4.6pp |
Δ is AGG minus VTHRX, 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
0.4% of AGG by weight, held in no part of VTHRX.
69.7% of VTHRX 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 | VTHRX | |
|---|---|---|
| Top 10 holdings | 75.3% | 28.9% |
| Positions held | 1,864 | 7 |
| Cost per $10,000 held, per year | $3 | $8 |
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 VTHRX overlap?
AGG and VTHRX overlap 29.8% by portfolio weight — moderate overlap. They share 1,684 holdings. The figure comes from current issuer holdings files (AGG as of 2026-07-23, VTHRX as of 2026-03-31).
How is the overlap between AGG and VTHRX 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 VTHRX 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 VTHRX?
That depends on your goals — we state facts, not advice. At 29.8% overlap, each fund still contributes meaningfully distinct exposure.
What does AGG own that VTHRX doesn't?
AGG holds 1,864 positions and VTHRX holds 7; 179 of AGG's positions don't appear in VTHRX at all, and they are 0.4% of AGG by weight.
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Related comparisons
Sources: issuer holdings files, AGG as of 2026-07-23, VTHRX as of 2026-03-31. Weights are fractions of each fund. Diagnostics, not advice.