WFBIX — iShares U.S. Aggregate Bond Index Fund
Data updated: 2026-08-25
WFBIX — iShares U.S. Aggregate Bond Index Fund. United States Blend / Core Equity · $3.27B AUM. Holdings, fees, performance and SEC filings.
WFBIX Fund Overview
WFBIX — iShares U.S. Aggregate Bond Index Fund is a US mutual fund managed by BlackRock Funds III, categorised as United States Blend / Core Equity. ABC INVEST provides holdings, performance, costs, cashflows, risk data, prospectus documents and SEC filings, sourced from SEC filings.
- Type: US mutual fund
- Manager: BlackRock Funds III
- Category: United States Blend / Core Equity
- Assets under management: $3.27B
- 1-year return: 3.7%
- Ticker: WFBIX
- SEC CIK: 0000893818
- SEC series ID: S000004270
- Share class ID: C000011974
WFBIX Holdings
Top 1 holdings of iShares U.S. Aggregate Bond Index Fund by percentage of net assets, from the fund's latest SEC N-PORT filing.
| Holding | % of net assets |
|---|---|
| Master Investment Portfolio | 100.25% |
WFBIX Portfolio Allocation
Asset-class allocation of iShares U.S. Aggregate Bond Index Fund by percentage of net assets, from the latest SEC N-PORT filing.
| Asset class | Allocation |
|---|---|
| Equity | 100.3% |
WFBIX Performance
Total returns for WFBIX (as of 2026-09-01), from SEC filings.
| Period | Total return |
|---|---|
| YTD | 0.8% |
| 1 year | 3.7% |
| 3 years (annualised) | 4.1% |
| 5 years (annualised) | 0.1% |
WFBIX Risk Information
Risk metrics for WFBIX, derived from monthly returns in SEC filings.
- 1-year volatility (annualised): 3.2%
WFBIX Costs and Fees
WFBIX costs about $5 per $10,000 invested per year in fund expenses.
- Net expense ratio: 0.05%
- Gross expense ratio: 0.05%
- Portfolio turnover: 93%
- Brokerage commissions: 0.00 bps of average net assets (SEC N-CEN)
WFBIX Cashflows
Over the 12 months to 2026-06, iShares U.S. Aggregate Bond Index Fund had net inflows of $143.08M, from monthly SEC N-PORT filings.
| Month | Net flow |
|---|---|
| 2026-06 | −$412.09M |
| 2026-05 | $47.25M |
| 2026-04 | $16.15M |
| 2026-03 | −$123.23M |
| 2026-02 | $9.69M |
| 2026-01 | $32.53M |
WFBIX Debt Constituents
No individual debt constituents are reported in iShares U.S. Aggregate Bond Index Fund's latest SEC N-PORT filing.
WFBIX Prospectus and SEC Filings
Official iShares U.S. Aggregate Bond Index Fund filings on SEC EDGAR — prospectus, portfolio holdings and annual reports.
- Prospectus (485BPOS) — filed 2026-04-28
- Prospectus (485BPOS) — filed 2025-04-29
- Prospectus (485BPOS) — filed 2024-04-26
- Portfolio holdings (N-PORT) — filed 2026-08-25
- Portfolio holdings (N-PORT) — filed 2026-05-28
- Portfolio holdings (N-PORT) — filed 2026-02-24
- Annual census (N-CEN) — filed 2026-03-16
- Annual census (N-CEN) — filed 2025-03-17
Related Funds
Other United States Blend / Core Equity funds tracked on ABC INVEST:
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, annual data from Form N-CEN, and shareholder reports from Form N-CSR.