VANGUARD MORTGAGE-BACKED SECURITIES INDEX FUND
VANGUARD SCOTTSDALE FUNDS · Series S000026865 · 3 share classes
data updated 2026-08-10
Fund profile
As filed in the prospectus · 2026 Q2
Vanguard Mortgage-Backed Securities Index Fund (the Fund) seeks to track the performance of a market-weighted mortgage-backed securities index.
The fund tracks the Bloomberg U.S. MBS Float Adjusted Index using a sampling approach, holding a range of mortgage-backed securities issued by Ginnie Mae, Fannie Mae, and Freddie Mac that collectively approximate the index's risk factors and characteristics. Because the fund samples rather than holds all index constituents, its returns may diverge from the index.
| Share class | Expense ratio |
|---|---|
| VMBSX | 0.04% |
| VMBIX | 0.02% |
| VMBS | 0.03% |
Portfolio turnover 91.00% · as of 2026 Q2
Allocation
Asset groups · long / short shown separately, never netted · 2026 Q1
| Securitized | 97.80% |
| Cash & short-term | 4.57% |
Latest quarter
What changed since the fund's previous filing
Largest new: Ginnie Mae II Pool ×2, Fannie Mae or Freddie Mac ×6
Largest exited: Fannie Mae or Freddie Mac ×8
Return profile
Total return as filed — price change plus distributions reinvested · trailing figures to Feb 2026
| Share class | 1-year | 3-year | 5-year | Vol | Worst fall |
|---|---|---|---|---|---|
| — | — | — | — | — | |
| — | — | — | — | — | |
| — | — | — | — | — |
Debt profile
What this fund holds — value-weighted across its bond and securitized long positions · as of 2026-02-28
Share of the fund's debt by how its coupon behaves — the fact that decides whether a rate move reaches this portfolio at all.
| Fixed rate | 100.0% |
| Floating rate | 0.0% |
Share of the fund's debt value in each maturity band, shortest first.
| <1y | 3.5% |
| 1-3y | 0.1% |
| 3-5y | 0.1% |
| 5-10y | 2.3% |
| 10y+ | 94.1% |
Based on what filers reported; a filer that never reported a flag also reads as none.
Risk profile
Interest-rate and credit-spread sensitivity, both in years · as of 2026Q1
Most of this fund’s sensitivity is to interest rates, with credit spreads carrying nearly as much.
Where the loss would come from. The two shocks are the same size, so this is the balance of the fund's two sensitivities rather than a bet on one moving more.
| Interest rates | 56% |
| Credit spreads | 44% |
Filers report the impact of a 0.01% move only, so the total is our own scaling of that one number and overstates the loss on most bonds — read it as approximate, never as precise. The two sensitivities overlap rather than add up: they measure the same positions against different shocks, which is why the durations above are shown side by side and never summed.
Share of the fund's spread duration carried by each credit tier.
| Investment grade | +3.92 yr |
Share of duration at each point, shortest first. A positive figure loses value when spreads widen; a negative one offsets — a credit hedge.
| 3 mo | 0.04 yr | 1% |
| 1 yr | 0.56 yr | 11% |
| 5 yr | 1.35 yr | 28% |
| 10 yr | 2.30 yr | 47% |
| 30 yr | 0.64 yr | 13% |
| 3 mo | 0.03 yr | 1% |
| 1 yr | 0.42 yr | 11% |
| 5 yr | 1.08 yr | 28% |
| 10 yr | 1.88 yr | 48% |
| 30 yr | 0.51 yr | 13% |
The two bands measure the same positions against different shocks and do not add — a Treasury carries rate duration and no spread duration, a floating-rate credit the reverse. Rate tenors are also summed across every currency the fund discloses.
Show the numbers
| Tenor | Rate yrs | IG yrs | HY yrs | IG $/bp | HY $/bp |
|---|---|---|---|---|---|
| 3 mo | +0.04 | +0.03 | +0.00 | $51.9k | $0 |
| 1 yr | +0.56 | +0.42 | +0.00 | $712.5k | $0 |
| 5 yr | +1.35 | +1.08 | +0.00 | $1.83m | $0 |
| 10 yr | +2.30 | +1.88 | +0.00 | $3.18m | $0 |
| 30 yr | +0.64 | +0.51 | +0.00 | $858.4k | $0 |
Dollar change per 1bp of spread movement, as filed and sign-anchored. A blank cell was not filed; a zero was.
Holdings
By % of NAV · equity positions carry filed share counts · every resolvable issuer links to its company page
| Ticker | Issuer | %NAV | Value | Shares |
|---|---|---|---|---|
| — | Vanguard Cmt Funds-Vanguard Market Liquidity Fund | 4.57% | $774.22M | — |
| — | Ginnie Mae II Pool5.00% · due 2026-03-19 | 0.44% | $74.59M | — |
| — | Fannie Mae or Freddie Mac2.00% · due 2026-03-12 | 0.43% | $73.60M | — |
| — | Fannie Mae or Freddie Mac2.50% · due 2026-03-12 | 0.34% | $57.31M | — |
| — | Fannie Mae or Freddie Mac5.00% · due 2026-03-12 | 0.32% | $53.66M | — |
| — | Ginnie Mae II Pool5.00% · due 2056-02-20 | 0.29% | $49.31M | — |
| — | Freddie Mac Pool2.00% · due 2052-02-01 | 0.29% | $49.02M | — |
| — | Ginnie Mae II Pool5.00% · due 2054-11-20 | 0.28% | $46.67M | — |
| — | Freddie Mac Pool2.00% · due 2051-05-01 | 0.27% | $46.06M | — |
| — | Fannie Mae or Freddie Mac5.50% · due 2026-03-12 | 0.26% | $43.50M | — |
Top 10 positions are 7.49% of net assets, top 25 10.76%, across 8 issuers.
See more of this fund's book
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