iShares U.S. Aggregate Bond Index Fund
Data updated: 2026-08-25
C000099166 — iShares U.S. Aggregate Bond Index Fund. United States Blend / Core Equity · $3.27B AUM. Holdings, fees, performance and SEC filings.
C000099166 Fund Overview
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: 3.4%
- SEC CIK: 0000893818
- SEC series ID: S000004270
- Share class ID: C000099166
C000099166 Investment Objective and Strategy
iShares U.S. Aggregate Bond Index Fund describes its objective and strategy as follows, from its latest prospectus filed with the SEC by BlackRock Funds III.
Investment objective
The investment objective of the iShares U.S. Aggregate Bond Index Fund (the Fund ), a series of BlackRock Funds III (the Trust ), is to seek to provide investment results that correspond to the total return performance of fixed-income securities in the aggregate, as represented by the Bloomberg U.S. Aggregate Bond Index (the Bloomberg U.S. Aggregate Index or the Underlying Index ).
Principal investment strategy
The Fund pursues its investment objective by seeking to match the total return performance of the Bloomberg U.S. Aggregate Index, which is composed of approximately 14,006 fixed-income securities. The fixed-income securities that comprise the Bloomberg U.S. Aggregate Index include U.S. Government securities and corporate bonds, as well as mortgage-backed securities, asset-backed securities and commercial mortgage-backed securities. All securities in the Bloomberg U.S. Aggregate Index are investment-grade. The Fund maintains a weighted average maturity consistent with that of the Bloomberg U.S. Aggregate Index, which generally ranges between 5 and 10 years. The Fund invests in a representative sample of these securities. Securities are selected for investment by the Fund in accordance with their relative proportion within the Bloomberg U.S.
Aggregate Index as well as based on credit quality, issuer sector, maturity structure, coupon rates and callability, among other factors. BFA, the investment adviser to the Master Portfolio in which the Fund invests, considers investments that provide substantially similar exposure to securities in the Bloomberg U.S. Aggregate Index to be investments comprising the Funds benchmark index. For example, the Fund may invest in mortgage dollar rolls and participate in to-be-announced (TBA) transactions on a regular basis to obtain exposure to mortgage-backed securities. The Fund is managed by determining which securities are to be purchased or sold to reflect, to the extent feasible, the investment characteristics of its benchmark index. Under normal circumstances, at least 90% of the value of the Funds assets, plus the amount of any borrowing for investment purposes, is invested in securities comprising the Bloomberg U.S.
Aggregate Index, which, for the Fund, are considered bonds. The Fund is a feeder fund that invests all of its assets in the Master Portfolio of MIP, which has the same investment objective and strategies as the Fund. All investments are made at the Master Portfolio level. This structure is sometimes called a master/feeder structure. The Funds investment results will correspond directly to the investment results of the Master Portfolio. For simplicity, the prospectus uses the name of the Fund or the term Fund (as applicable) to include the Master Portfolio.
C000099166 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% |
C000099166 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% |
C000099166 Performance
Total returns for C000099166 (as of 2026-10-01), from SEC filings.
| Period | Total return |
|---|---|
| YTD | 0.6% |
| 1 year | 3.4% |
| 3 years (annualised) | 3.8% |
| 5 years (annualised) | -0.2% |
C000099166 Risk Information
Risk metrics for C000099166, derived from monthly returns in SEC filings.
- 1-year volatility (annualised): 3.0%
C000099166 Costs and Fees
C000099166 costs about $35 per $10,000 invested per year in fund expenses.
- Net expense ratio: 0.35%
- Gross expense ratio: 0.35%
- Portfolio turnover: 93%
- Brokerage commissions: 0.00 bps of average net assets (SEC N-CEN)
C000099166 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 |
C000099166 Debt Constituents
No individual debt constituents are reported in iShares U.S. Aggregate Bond Index Fund's latest SEC N-PORT filing.
C000099166 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.