WFBIX Performance — iShares U.S. Aggregate Bond Index Fund, Class K
Data updated: 2026-08-25
WFBIX returned +0.75% year to date and +3.72% over one year to Jun 2026. Annualised returns are +4.14% over 3 years and +0.10% over 5 years. The fund trailed its Core Bond category average: $100 invested three years ago grew to $113, against $120 for the category, and to $104 over one year, against $107. Volatility over the past three years was 5.53% a year. In the 12 months to Jun 2026 the fund took in a net $143.1M, and assets reached $3.27B.
WFBIX Growth of $100
What $100 invested in iShares U.S. Aggregate Bond Index Fund grew to, compounded from monthly returns reported on SEC Form N-PORT, against the Core Bond category average over the same months.
| Period | WFBIX | Category average |
|---|---|---|
| 1 year (Jul 2025 – Jun 2026) | $104 | $107 |
| 3 years (Jul 2023 – Jun 2026) | $113 | $120 |
| 5 years (Jul 2021 – Jun 2026) | $100 | $112 |
| Since data start (Jul 2019 – Jun 2026) | $109 | $126 |
WFBIX Trailing Returns
Total returns to Jun 2026, from SEC N-PORT.
| Period | Total return |
|---|---|
| YTD | +0.75% |
| 1 year | +3.72% |
| 3 years (annualised) | +4.14% |
| 5 years (annualised) | +0.10% |
WFBIX Annual Returns
Calendar-year total returns of iShares U.S. Aggregate Bond Index Fund, compounded from monthly SEC N-PORT returns. Partial years show the months covered.
| Year | Total return |
|---|---|
| 2026 (Jan–Jun) | +0.75% |
| 2025 | +7.13% |
| 2024 | +1.41% |
| 2023 | +5.59% |
| 2022 | −13.03% |
| 2021 | −1.79% |
| 2020 | +7.62% |
| 2019 (Jul–Dec) | +2.46% |
WFBIX Monthly Returns
Monthly total returns as reported on SEC Form N-PORT.
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2026 | +0.2% | +1.7% | −1.8% | +0.1% | +0.3% | +0.2% | — | — | — | — | — | — |
| 2025 | +0.5% | +2.2% | 0.0% | +0.4% | −0.7% | +1.5% | −0.3% | +1.2% | +1.1% | +0.7% | +0.6% | −0.3% |
| 2024 | 0.0% | −1.5% | +0.9% | −2.5% | +1.7% | +1.0% | +2.3% | +1.5% | +1.3% | −2.5% | +1.1% | −1.7% |
| 2023 | +3.3% | −2.5% | +2.5% | +0.6% | −1.1% | −0.4% | −0.1% | −0.6% | −2.5% | −1.6% | +4.4% | +3.7% |
| 2022 | −2.1% | −1.2% | −2.7% | −3.8% | +0.6% | −1.5% | +2.5% | −2.8% | −4.3% | −1.3% | +3.7% | −0.7% |
| 2021 | −0.8% | −1.5% | −1.2% | +0.7% | +0.2% | +0.8% | +1.1% | −0.1% | −0.9% | 0.0% | +0.3% | −0.4% |
| 2020 | +1.9% | +1.7% | −0.4% | +1.7% | +0.5% | +0.7% | +1.5% | −0.8% | −0.1% | −0.5% | +1.0% | +0.2% |
| 2019 | — | — | — | — | — | — | +0.3% | +2.6% | −0.5% | +0.2% | 0.0% | −0.1% |
WFBIX Risk
Risk measures from monthly returns over Jul 2023 – Jun 2026.
- 3-year volatility (annualised): 5.53%
- 3-year Sharpe ratio: -0.06 (vs 4.5% risk-free rate)
- Best month: +4.44% (Nov 2023)
- Worst month: −2.54% (Sep 2023)
WFBIX Fund Flows
Monthly money in and out of iShares U.S. Aggregate Bond Index Fund, from SEC Form N-PORT.
- 12-month net flow: $143.1M
- 12-month gross sales (incl. reinvestments): $1.8B
- Sales ÷ redemptions: 1.09×
| Month | Sales | Redemptions | Net flow |
|---|---|---|---|
| Jun 2026 | $98.1M | $510.2M | −$412.1M |
| May 2026 | $111.5M | $64.3M | $47.2M |
| Apr 2026 | $92.2M | $76.0M | $16.1M |
| Mar 2026 | $117.0M | $240.2M | −$123.2M |
| Feb 2026 | $85.0M | $75.4M | $9.7M |
| Jan 2026 | $135.9M | $103.4M | $32.5M |
| Dec 2025 | $264.7M | $86.6M | $178.1M |
| Nov 2025 | $113.9M | $87.3M | $26.6M |
| Oct 2025 | $118.5M | $138.0M | −$19.5M |
| Sep 2025 | $449.0M | $194.8M | $254.3M |
| Aug 2025 | $96.2M | $46.0M | $50.2M |
| Jul 2025 | $140.4M | $57.4M | $83.0M |
WFBIX Assets Under Management
Net assets of iShares U.S. Aggregate Bond Index Fund by report date, from SEC N-PORT filings.
| Report date | Net assets |
|---|---|
| 2026-06-30 | $3.27B |
| 2026-03-31 | $3.63B |
| 2025-12-31 | $3.75B |
| 2025-09-30 | $3.56B |
| 2025-06-30 | $3.14B |
| 2025-03-31 | $3.11B |
| 2024-12-31 | $3.02B |
| 2024-09-30 | $3.01B |
| 2024-06-30 | $2.79B |
| 2024-03-31 | $2.78B |
| 2023-12-31 | $2.61B |
| 2023-09-30 | $2.35B |
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.