VBILX vs. WFBIX
VBILX (Vanguard Intermediate-Term Bond Index Fund Admiral Shares) and WFBIX (iShares U.S. Aggregate Bond Index Fund) are both Intermediate Core Bond funds. Over the past 10 years, VBILX returned 1.79%/yr vs 1.87%/yr for WFBIX. Their correlation of 0.91 suggests significant overlap in exposure. VBILX charges 0.06%/yr vs 0.05%/yr for WFBIX.
Performance
VBILX vs. WFBIX - Performance Comparison
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Returns By Period
In the year-to-date period, VBILX achieves a -0.53% return, which is significantly lower than WFBIX's 0.10% return. Both investments have delivered pretty close results over the past 10 years, with VBILX having a 1.79% annualized return and WFBIX not far ahead at 1.87%.
VBILX
- 1D
- -0.29%
- 1M
- 0.47%
- YTD
- -0.53%
- 6M
- -0.08%
- 1Y
- 3.75%
- 3Y*
- 4.34%
- 5Y*
- 0.09%
- 10Y*
- 1.79%
WFBIX
- 1D
- -0.33%
- 1M
- 0.56%
- YTD
- 0.10%
- 6M
- 0.42%
- 1Y
- 4.19%
- 3Y*
- 5.22%
- 5Y*
- 0.77%
- 10Y*
- 1.87%
VBILX vs. WFBIX - Yearly Performance Comparison
| 2026 (YTD) | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | |
|---|---|---|---|---|---|---|---|---|---|---|
VBILX Vanguard Intermediate-Term Bond Index Fund Admiral Shares | -0.53% | 8.57% | 1.54% | 6.09% | -13.59% | -2.36% | 9.82% | 10.20% | -0.15% | 3.86% |
WFBIX iShares U.S. Aggregate Bond Index Fund | 0.10% | 7.16% | 1.43% | 9.65% | -13.03% | -1.79% | 7.40% | 8.72% | -0.08% | 3.39% |
Correlation
The correlation between VBILX 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 Nov 12, 2001 | 0.91 |
The correlation between VBILX and WFBIX has been stable across timeframes, ranging from 0.91 to 0.96 - a consistent structural relationship.
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Return for Risk
VBILX vs. WFBIX — Risk / Return Rank
VBILX
WFBIX
VBILX vs. WFBIX - Risk-Adjusted Trends Comparison
This table presents a comparison of risk-adjusted performance metrics for Vanguard Intermediate-Term Bond Index Fund Admiral Shares (VBILX) 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.
Values are calculated on a 1-year rolling basis and updated daily. Risk-adjusted metrics are more stable over longer periods — use the period switch above to explore them.
| VBILX | WFBIX | Difference | |
|---|---|---|---|
| Sharpe ratioReturn per unit of total volatility | -0.15 | ||
| Sortino ratioReturn per unit of downside risk | -0.21 | ||
| Omega ratioGain probability vs. loss probability | 1.17 | 1.20 | -0.03 |
| Calmar ratioReturn relative to maximum drawdown | 1.19 | 1.47 | -0.28 |
| Martin ratioReturn relative to average drawdown | 3.31 | 4.11 | -0.81 |
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Drawdowns
VBILX vs. WFBIX - Drawdown Comparison
The maximum VBILX drawdown since its inception was -19.26%, roughly equal to the maximum WFBIX drawdown of -18.68%. Use the drawdown chart below to compare losses from any high point for VBILX and WFBIX.
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Drawdown Indicators
| VBILX | WFBIX | Difference | |
|---|---|---|---|
Max DrawdownLargest peak-to-trough decline | -19.26% | -18.68% | -0.58% |
Max Drawdown (1Y)Largest decline over 1 year | -3.43% | -3.02% | -0.41% |
Max Drawdown (3Y)Largest decline over 3 years | -6.05% | -6.09% | +0.04% |
Max Drawdown (5Y)Largest decline over 5 years | -19.15% | -17.84% | -1.31% |
Max Drawdown (10Y)Largest decline over 10 years | -19.26% | -18.68% | -0.58% |
Current DrawdownCurrent decline from peak | -2.31% | -1.82% | -0.49% |
Average DrawdownAverage peak-to-trough decline | -3.15% | -2.26% | -0.89% |
Ulcer IndexDepth and duration of drawdowns from previous peaks | 1.23% | 1.08% | +0.15% |
Volatility
VBILX vs. WFBIX - Volatility Comparison
Vanguard Intermediate-Term Bond Index Fund Admiral Shares (VBILX) has a higher volatility of 1.33% compared to iShares U.S. Aggregate Bond Index Fund (WFBIX) at 1.17%. This indicates that VBILX'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
| VBILX | WFBIX | Difference | |
|---|---|---|---|
Volatility (1M)Calculated over the trailing 1-month period | 1.33% | 1.17% | +0.16% |
Volatility (6M)Calculated over the trailing 6-month period | 3.12% | 2.89% | +0.23% |
Volatility (1Y)Calculated over the trailing 1-year period | 4.15% | 3.93% | +0.22% |
Volatility (5Y)Calculated over the trailing 5-year period, annualized | 6.39% | 6.41% | -0.02% |
Volatility (10Y)Calculated over the trailing 10-year period, annualized | 5.37% | 5.18% | +0.19% |
VBILX vs. WFBIX - Expense Ratio Comparison
VBILX has a 0.06% 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
VBILX vs. WFBIX - Dividend Comparison
VBILX's dividend yield for the trailing twelve months is around 4.23%, more than WFBIX's 3.92% yield.
| Position | TTM | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
VBILX Vanguard Intermediate-Term Bond Index Fund Admiral Shares | 4.23% | 4.01% | 3.80% | 3.09% | 1.99% | 3.39% | 2.94% | 2.73% | 2.87% | 2.73% | 3.06% | 3.09% |
WFBIX iShares U.S. Aggregate Bond Index Fund | 3.92% | 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, VBILX 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.
VBILX has higher volatility (1.33%) compared to WFBIX (1.17%). In terms of maximum drawdown, VBILX dropped -19.26% vs WFBIX's -18.68%.
WFBIX currently has the higher Sharpe Ratio (1.13 vs 0.98), 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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