VBIIX vs. WFBIX
VBIIX (Vanguard Intermediate-Term Bond Index Fund) and WFBIX (iShares U.S. Aggregate Bond Index Fund) are both Intermediate Core Bond funds. Over the past 10 years, VBIIX returned 1.77%/yr vs 1.96%/yr for WFBIX. Their correlation of 0.90 suggests significant overlap in exposure. VBIIX charges 0.15%/yr vs 0.05%/yr for WFBIX.
Performance
VBIIX vs. WFBIX - Performance Comparison
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Returns By Period
In the year-to-date period, VBIIX achieves a -0.09% return, which is significantly lower than WFBIX's 0.43% return. Over the past 10 years, VBIIX has underperformed WFBIX with an annualized return of 1.77%, while WFBIX has yielded a comparatively higher 1.96% annualized return.
VBIIX
- 1D
- 0.00%
- 1M
- 0.36%
- YTD
- -0.09%
- 6M
- -0.31%
- 1Y
- 4.97%
- 3Y*
- 4.06%
- 5Y*
- 0.16%
- 10Y*
- 1.77%
WFBIX
- 1D
- 0.00%
- 1M
- 0.45%
- YTD
- 0.43%
- 6M
- 0.32%
- 1Y
- 5.35%
- 3Y*
- 5.33%
- 5Y*
- 0.99%
- 10Y*
- 1.96%
VBIIX vs. WFBIX - Yearly Performance Comparison
| 2026 (YTD) | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | |
|---|---|---|---|---|---|---|---|---|---|---|
VBIIX Vanguard Intermediate-Term Bond Index Fund | -0.09% | 8.12% | 1.44% | 5.67% | -13.34% | -2.73% | 9.72% | 10.11% | -0.24% | 3.78% |
WFBIX iShares U.S. Aggregate Bond Index Fund | 0.43% | 7.16% | 1.43% | 9.65% | -13.03% | -1.79% | 7.40% | 8.72% | -0.08% | 3.39% |
Correlation
The correlation between VBIIX and WFBIX is 0.95 - these two move nearly in lockstep. At this level, holding both provides almost no diversification benefit. If you already own one, adding the other does little to reduce portfolio risk.
| Correlation | |
|---|---|
Correlation (1Y) Calculated over the trailing 1-year period | 0.95 |
Correlation (3Y) Calculated over the trailing 3-year period | 0.95 |
Correlation (5Y) Calculated over the trailing 5-year period | 0.96 |
Correlation (10Y) Calculated over the trailing 10-year period | 0.92 |
Correlation (All Time) Calculated using the full available price history since Mar 1, 1994 | 0.90 |
The correlation between VBIIX and WFBIX has been stable across timeframes, ranging from 0.90 to 0.96 - a consistent structural relationship.
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Return for Risk
VBIIX vs. WFBIX — Risk / Return Rank
VBIIX
WFBIX
VBIIX vs. WFBIX - Risk-Adjusted Trends Comparison
This table presents a comparison of risk-adjusted performance metrics for Vanguard Intermediate-Term Bond Index Fund (VBIIX) and iShares U.S. Aggregate Bond Index Fund (WFBIX). Risk-adjusted metrics are performance indicators that assess an investment's returns in relation to its risk, enabling a more accurate comparison of different investment options.
| VBIIX | WFBIX | Difference | |
|---|---|---|---|
| Sharpe ratioReturn per unit of total volatility | -0.16 | ||
| Sortino ratioReturn per unit of downside risk | -0.24 | ||
| Omega ratioGain probability vs. loss probability | 1.21 | 1.25 | -0.04 |
| Calmar ratioReturn relative to maximum drawdown | 1.45 | 1.78 | -0.33 |
| Martin ratioReturn relative to average drawdown | 4.39 | 5.34 | -0.95 |
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month. | |||
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Sharpe Ratios by Period
| VBIIX | WFBIX | Difference | |
|---|---|---|---|
Sharpe Ratio (1Y)Calculated over the trailing 1-year period | 1.19 | 1.36 | -0.16 |
Sharpe Ratio (5Y)Calculated over the trailing 5-year period | 0.03 | 0.16 | -0.13 |
Sharpe Ratio (10Y)Calculated over the trailing 10-year period | 0.33 | 0.38 | -0.05 |
Sharpe Ratio (All Time)Calculated using the full available price history | 0.83 | 0.94 | -0.11 |
Drawdowns
VBIIX vs. WFBIX - Drawdown Comparison
The maximum VBIIX drawdown since its inception was -19.32%, roughly equal to the maximum WFBIX drawdown of -18.68%. Use the drawdown chart below to compare losses from any high point for VBIIX and WFBIX.
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Drawdown Indicators
| VBIIX | WFBIX | Difference | |
|---|---|---|---|
Max DrawdownLargest peak-to-trough decline | -19.32% | -18.68% | -0.64% |
Max Drawdown (1Y)Largest decline over 1 year | -3.44% | -3.02% | -0.42% |
Max Drawdown (3Y)Largest decline over 3 years | -6.07% | -6.09% | +0.02% |
Max Drawdown (5Y)Largest decline over 5 years | -18.93% | -17.84% | -1.09% |
Max Drawdown (10Y)Largest decline over 10 years | -19.32% | -18.68% | -0.64% |
Current DrawdownCurrent decline from peak | -2.39% | -1.50% | -0.89% |
Average DrawdownAverage peak-to-trough decline | -2.98% | -2.26% | -0.72% |
Ulcer IndexDepth and duration of drawdowns from previous peaks | 1.14% | 1.00% | +0.14% |
Volatility
VBIIX vs. WFBIX - Volatility Comparison
Vanguard Intermediate-Term Bond Index Fund (VBIIX) has a higher volatility of 1.44% compared to iShares U.S. Aggregate Bond Index Fund (WFBIX) at 1.34%. This indicates that VBIIX's price experiences larger fluctuations and is considered to be riskier than WFBIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.
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Volatility by Period
| VBIIX | WFBIX | Difference | |
|---|---|---|---|
Volatility (1M)Calculated over the trailing 1-month period | 1.44% | 1.34% | +0.10% |
Volatility (6M)Calculated over the trailing 6-month period | 3.01% | 2.83% | +0.18% |
Volatility (1Y)Calculated over the trailing 1-year period | 4.19% | 3.97% | +0.22% |
Volatility (5Y)Calculated over the trailing 5-year period, annualized | 6.38% | 6.40% | -0.02% |
Volatility (10Y)Calculated over the trailing 10-year period, annualized | 5.36% | 5.17% | +0.19% |
VBIIX vs. WFBIX - Expense Ratio Comparison
VBIIX has a 0.15% expense ratio, which is higher than WFBIX's 0.05% expense ratio. However, both funds are considered low-cost compared to the broader market, where average expense ratios usually range from 0.3% to 0.9%.
Dividends
VBIIX vs. WFBIX - Dividend Comparison
VBIIX's dividend yield for the trailing twelve months is around 4.12%, more than WFBIX's 3.91% yield.
| Position | TTM | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
VBIIX Vanguard Intermediate-Term Bond Index Fund | 4.12% | 3.61% | 3.71% | 2.72% | 2.30% | 2.99% | 2.85% | 2.66% | 2.78% | 2.66% | 2.98% | 3.02% |
WFBIX iShares U.S. Aggregate Bond Index Fund | 3.91% | 3.78% | 3.68% | 6.82% | 2.60% | 2.04% | 2.43% | 2.88% | 2.71% | 2.24% | 2.25% | 2.20% |
Frequently Asked Questions
With a correlation of 0.95, VBIIX and WFBIX move almost identically. Holding both adds very little diversification - you're essentially doubling your position in the same market segment. Choosing one is usually more capital-efficient.
VBIIX has higher volatility (1.44%) compared to WFBIX (1.34%). In terms of maximum drawdown, VBIIX dropped -19.32% vs WFBIX's -18.68%.
WFBIX currently has the higher Sharpe Ratio (1.36 vs 1.19), meaning it's delivered slightly more return per unit of risk over the trailing 12 months. However, this ranking shifts over time - use the Risk/Return Score above for a more comprehensive view that combines Sharpe, Sortino, and other measures used by quantitative funds.
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