FUBFX — Fidelity U.S. Bond Index Fund, Class F
Data updated: 2026-10-27
FUBFX — Fidelity U.S. Bond Index Fund, Class F. 0.03% expense ratio · since 2009 · Intermediate Core Bond. Holdings, fees, performance and SEC filings.
FUBFX Fund Overview
FUBFX — Fidelity U.S. Bond Index Fund, Class F is a US mutual fund managed by Fidelity Management & Research Company LLC, categorised as Intermediate Core Bond. FUBFX tracks the Bloomberg US Aggregate Bond Index. ABC INVEST provides holdings, performance, costs, cashflows, risk data, prospectus documents and SEC filings, sourced from SEC filings.
- Type: US mutual fund (index fund)
- Adviser: Fidelity Management & Research Company LLC
- Sub-advisers: FMR Investment Management (UK) Limited, Fidelity Management & Research (Hong Kong) Limited and Fidelity Management & Research (Japan) Limited
- Trust: Fidelity Salem Street Trust
- Category: Intermediate Core Bond
- Benchmark: Bloomberg US Aggregate Bond Index
- Inception date: September 24, 2009
- Assets under management: $69.50B
- Ticker: FUBFX
- SEC CIK: 0000035315
- SEC series ID: S000017676
- Share class ID: C000079295
- LEI: 5VUJ0DJSDOFYE2WQN531
About FUBFX
Fidelity U.S. Bond Index Fund (FUBFX) seeks to provide investment results that correspond to the aggregate price and interest performance of debt securities in the Bloomberg Barclays U.S. Aggregate Bond Index. It normally invests at least 80% of its assets in bonds included in that index, using statistical sampling based on duration, maturity, interest rate sensitivity, security structure, and credit quality to replicate its returns with a smaller number of securities. Its Class F shares, launched September 24, 2009, cost 0.03% a year.
FUBFX Holdings
Top 10 holdings of Fidelity U.S. Bond Index Fund by percentage of net assets, from the fund's latest SEC N-PORT filing.
| Holding | % of net assets |
|---|---|
| Ust Notes | 0.92% |
| Ust Notes | 0.84% |
| Fidelity Revere Street Trust | 0.84% |
| Ust Notes | 0.83% |
| Ust Notes | 0.75% |
| Ust Notes | 0.72% |
| Ust Notes | 0.72% |
| Fed Home Loan Mtg Corp. - Gold | 0.60% |
| Ust Notes | 0.59% |
| Ust Notes | 0.58% |
FUBFX Portfolio Allocation
Asset-class allocation of Fidelity U.S. Bond Index Fund by percentage of net assets, from the latest SEC N-PORT filing.
| Asset class | Allocation |
|---|---|
| Fixed Income | 74.1% |
| Securitized | 25.2% |
| Cash & Equivalents | 1.1% |
FUBFX Performance
Total returns for FUBFX through August 2026, from SEC filings.
| Period | Total return |
|---|---|
| YTD | -0.66% |
FUBFX Costs and Fees
FUBFX costs about $3 per $10,000 invested per year in fund expenses.
- Net expense ratio: 0.03%
- Gross expense ratio: 0.03%
- Portfolio turnover: 48%
- Brokerage commissions: 0.00 bps of average net assets (SEC N-CEN)
FUBFX Cashflows
Over the 12 months to 2026-08, Fidelity U.S. Bond Index Fund had net inflows of $4.92B, from monthly SEC N-PORT filings.
| Month | Net flow |
|---|---|
| 2026-08 | $676.94M |
| 2026-07 | $758.80M |
| 2026-06 | $184.37M |
| 2026-05 | $1.06B |
| 2026-04 | −$878.75M |
| 2026-03 | $67.26M |
FUBFX Debt Constituents
Largest debt holdings of Fidelity U.S. Bond Index Fund by percentage of net assets, from the latest SEC N-PORT filing.
| Debt holding | % of net assets |
|---|---|
| Ust Notes | 0.92% |
| Ust Notes | 0.84% |
| Ust Notes | 0.83% |
| Ust Notes | 0.75% |
| Ust Notes | 0.72% |
| Ust Notes | 0.72% |
| Ust Notes | 0.59% |
| Ust Notes | 0.58% |
| Ust Notes | 0.57% |
| Ust Notes | 0.57% |
FUBFX Prospectus and SEC Filings
Official Fidelity U.S. Bond Index Fund filings on SEC EDGAR — prospectus, portfolio holdings and annual reports.
- Prospectus (485BPOS) — filed 2026-10-27
- Prospectus (485BPOS) — filed 2025-10-27
- Prospectus (485BPOS) — filed 2024-10-25
- Portfolio holdings (N-PORT) — filed 2026-10-26
- Portfolio holdings (N-PORT) — filed 2026-07-24
- Portfolio holdings (N-PORT) — filed 2026-04-24
- Annual census (N-CEN) — filed 2025-11-12
- Annual census (N-CEN) — filed 2024-11-13
FUBFX Service Providers
Firms that manage, distribute, hold, administer and audit Fidelity U.S. Bond Index Fund, as reported on SEC Form N-CEN, fiscal year ending August 31, 2025.
- Adviser: Fidelity Management & Research Company LLC
- Sub-advisers: FMR Investment Management (UK) Limited, Fidelity Management & Research (Hong Kong) Limited and Fidelity Management & Research (Japan) Limited
- Distributor: Fidelity Distributors Company LLC
- Custodian: Bank of New York Mellon
- Transfer agent: Fidelity Investments Institutional Operations Company LLC
- Administrator: Fidelity Service Company
- Auditors: Deloitte & Touche LLP and PricewaterhouseCoopers LLP
- Securities lending agent: National Financial Services, LLC
Related Funds
Other Intermediate Core Bond funds tracked on ABC INVEST:
FUBFX: Frequently Asked Questions
What is the expense ratio of Fidelity U.S. Bond Index Fund (FUBFX)?
FUBFX has a net expense ratio of 0.03%, about $3 a year for every $10,000 invested. FUBFX fees and costs
What index does FUBFX track?
FUBFX is an index fund that tracks the Bloomberg US Aggregate Bond Index.
What are FUBFX's top holdings?
As of August 31, 2026, FUBFX held 10,603 positions. The largest are Ust Notes (0.92%), Ust Notes (0.84%), Fidelity Revere Street Trust (0.84%), Ust Notes (0.83%) and Ust Notes (0.75%). All FUBFX holdings
Can I download the full list of FUBFX holdings?
Yes. The complete FUBFX holdings list as of August 31, 2026 can be downloaded as a CSV file from the Holdings page: holding, ticker, FIGI, sector, country, asset type, shares, value and share of net assets, from the fund's SEC N-PORT filing. Download FUBFX holdings (CSV)
How large is FUBFX?
FUBFX manages $69.50B (SEC N-PORT, August 2026). Investors added a net $4.92B over the past 12 months.
Who manages FUBFX and when did it launch?
FUBFX is managed by Fidelity Management & Research Company LLC, with FMR Investment Management (UK) Limited, Fidelity Management & Research (Hong Kong) Limited and Fidelity Management & Research (Japan) Limited as sub-advisers. It is a series of Fidelity Salem Street Trust. It launched on September 24, 2009.
How does FUBFX compare with similar Intermediate Core Bond funds?
Among 260 Intermediate Core Bond funds with $100M+ in assets, FUBFX ranks #18 of 259 on net expense ratio (0.03%) and #6 of 260 by assets. The largest is Vanguard Total Bond Market Index Fund (BND). Compare FUBFX with BND
Where can I find FUBFX's prospectus and SEC filings?
FUBFX's latest prospectus (485BPOS) was filed October 27, 2026 and its latest N-PORT holdings report was filed October 26, 2026. All 54 filings are linked on ABC INVEST and on SEC EDGAR (series S000017676). FUBFX SEC filings
Data Sources
ABC INVEST compiles this page from public filings made to the U.S. Securities and Exchange Commission (SEC) through EDGAR: portfolio holdings and monthly cashflows from Form N-PORT, expenses and returns from fund prospectuses (Form 485BPOS) and the SEC DERA Risk/Return Summary data sets, and annual data from Form N-CEN.
For information only. Not investment advice: figures are as reported in SEC filings and may contain errors or be out of date. Past performance does not guarantee future results.