Fidelity Flex U.S. Bond Index Fund
Fidelity Salem Street Trust · 1 share class
Fund classification
Classified from what the fund holds · as of 2026 Q2
Fidelity Flex U.S. Bond Index Fund is a U.S. bond index fund that tracks the Bloomberg U.S. Aggregate Bond Index.
- Asset class
- Bonds
- Region
- United States
- Management
- Index (passive)
- Fund type
- Open-end fund
- Credit quality
- Investment grade
- Rate sensitivity
- Intermediate duration
Fund profile
As filed in the prospectus · 2025 Q4
Fidelity Flex U.S. Bond Index Fund seeks to provide investment results that correspond to the aggregate price and interest performance of the debt securities in the Bloomberg U.S. Aggregate Bond Index.
The fund uses statistical sampling to track the Bloomberg U.S. Aggregate Bond Index, holding a smaller number of securities selected to replicate the index's returns across duration, maturity, interest rate sensitivity, structure, and credit quality. Because the fund samples rather than holds all index constituents, its returns may diverge from the index. The fund may use derivatives including swaps, options, and futures to adjust risk exposure.
| Share class | Expense ratio |
|---|---|
| FIBUX | 0.00% |
Portfolio turnover 68.00% · as of 2025 Q4
Allocation
Asset groups · long / short shown separately, never netted · 2026 Q2
| Bonds | 75.29% |
| Securitized | 24.56% |
| Cash & short-term | 1.66% |
| Stocks | 0.01% |
Sector allocation
The same holdings as Allocation above, grouped by market sector instead of asset type · as of 2026 Q2
| Government | 46.9% |
| Securitized | 25.1% |
| Financials | 6.2% |
| Other | 4.2% |
| 12 smaller | 17.6% |
Government, Securitized and Cash are non-corporate buckets; International is foreign holdings we don’t sector-classify, and Other is the residual (held funds, unresolved names).
Latest quarter
What changed since the fund's previous filing
Largest new: UST NOTES ×6, UNITED STATES TREASURY BOND ×2
Largest exited: UST NOTES ×6, GNMA II GTD PASS THRU CTF MULTIPLE ISSUER, FNMA/FHLG TBA ISSUER
Return profile
Total return as filed — price change plus distributions reinvested · trailing figures to Apr 2026
May 2026 has been filed since the trailing figures were struck, so it is not in the table above or the curve — every figure here shares one cut-off, which is what makes them comparable with other funds.
Debt profile
What this fund holds — value-weighted across its bond and securitized long positions · as of 2026-05-31
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 | 95.3% |
| Floating rate | 4.7% |
Share of the fund's debt value in each maturity band, shortest first.
| <1y | 2.9% |
| 1-3y | 21.2% |
| 3-5y | 15.3% |
| 5-10y | 18.3% |
| 10y+ | 42.4% |
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 2026Q2
More of this fund’s sensitivity sits in credit spreads than in interest rates — a rate rally that comes with a credit selloff works against it.
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.
| Credit spreads | 50% |
| Interest rates | 50% |
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 | +5.86 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 | 0.01 yr | 0% |
| 1 yr | 0.54 yr | 9% |
| 5 yr | 1.44 yr | 25% |
| 10 yr | 2.05 yr | 35% |
| 30 yr | 1.76 yr | 30% |
| 3 mo | 0.14 yr | 2% |
| 1 yr | 0.92 yr | 16% |
| 5 yr | 1.83 yr | 31% |
| 10 yr | 2.04 yr | 35% |
| 30 yr | 0.93 yr | 16% |
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 | +0.01 | +0.14 | +0.00 | $55.4k | $0 |
| 1 yr | +0.54 | +0.92 | +0.00 | $369.6k | $0 |
| 5 yr | +1.44 | +1.83 | +0.00 | $738.5k | $0 |
| 10 yr | +2.05 | +2.04 | +0.00 | $819.9k | $0 |
| 30 yr | +1.76 | +0.93 | +0.00 | $375.8k | $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 |
|---|---|---|---|---|
| — | Fidelity Revere Street Trust | 1.66% | $66.68M | — |
| — | UST NOTES4.13% · due 2036-02-15 | 1.16% | $46.69M | — |
| — | UST NOTES3.50% · due 2029-01-15 | 0.95% | $38.32M | — |
| — | UST NOTES3.88% · due 2027-05-31 | 0.94% | $37.74M | — |
| — | UST NOTES3.63% · due 2027-08-31 | 0.89% | $35.85M | — |
| — | UNITED STATES TREASURY BOND4.50% · due 2044-02-15 | 0.82% | $33.18M | — |
| — | UST NOTES3.50% · due 2028-10-15 | 0.81% | $32.73M | — |
| — | UST NOTES3.88% · due 2029-04-15 | 0.81% | $32.65M | — |
| — | UST NOTES4.00% · due 2027-12-15 | 0.80% | $32.35M | — |
| — | UNITED STATES TREASURY BOND4.63% · due 2046-02-15 | 0.78% | $31.30M | — |
Top 10 positions are 9.62% of net assets, top 25 18.43%, across 890 issuers.
See more of this fund's book
More positions with filed share counts, and the quarter-over-quarter change list rather than the largest few — free with an account, no card required.
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