VBLLX vs. PBDIX
VBLLX (Vanguard Long-Term Bond Index Fund Institutional Shares) and PBDIX (T. Rowe Price QM U.S. Bond Index Fund) are both Total Bond Market funds. Over the past 10 years, VBLLX returned 0.08%/yr vs 2.05%/yr for PBDIX. Their correlation of 0.90 means they have usually moved in the same direction. VBLLX charges 0.05%/yr vs 0.23%/yr for PBDIX.
Performance
VBLLX vs. PBDIX - Performance Comparison
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Returns By Period
In the year-to-date period, VBLLX achieves a -3.40% return, which is significantly lower than PBDIX's -0.77% return. Over the past 10 years, VBLLX has underperformed PBDIX with an annualized return of 0.08%, while PBDIX has yielded a comparatively higher 2.05% annualized return.
VBLLX
- 1D
- -0.50%
- 1M
- -3.76%
- 6M
- -3.24%
- YTD
- -3.40%
- 1Y
- -1.14%
- 3Y*
- 1.12%
- 5Y*
- -5.26%
- 10Y*
- 0.08%
- ALL TIME*
- 3.79%
PBDIX
- 1D
- -0.32%
- 1M
- -1.57%
- 6M
- -0.72%
- YTD
- -0.77%
- 1Y
- 1.84%
- 3Y*
- 5.67%
- 5Y*
- 0.72%
- 10Y*
- 2.05%
- ALL TIME*
- 3.88%
Liquidity Comparison
| Position | Avg. Volume Value (2W) | Avg. Volume Value (1M) | Avg. Volume Value (3M) |
|---|---|---|---|
| $0.00 | $0.00 | $0.00 | |
| $0.00 | $0.00 | $0.00 |
VBLLX vs. PBDIX - Yearly Performance Comparison
| 2026 (YTD) | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | |
|---|---|---|---|---|---|---|---|---|---|---|
VBLLX Vanguard Long-Term Bond Index Fund Institutional Shares | -3.40% | 6.60% | -4.12% | 7.13% | -27.20% | -3.08% | 16.27% | 19.15% | -4.71% | 10.89% |
PBDIX T. Rowe Price QM U.S. Bond Index Fund | -0.77% | 8.29% | 4.75% | 8.62% | -14.24% | -1.45% | 8.17% | 8.69% | -0.01% | 3.83% |
Correlation
The correlation between VBLLX and PBDIX is 0.89, meaning they have usually moved in the same direction, including during past declines.
| Correlation | |
|---|---|
Correlation (1Y) Focuses on recent behavior, but can change the most. | 0.89 |
Correlation (3Y) Balances recent behavior with more history. | 0.90 |
Correlation (5Y) Shows whether the relationship held over a longer period. | 0.92 |
Correlation (10Y) Provides a long-term view across more market conditions. | 0.91 |
Correlation (All Time) Calculated using the full available price history since Jan 31, 2006 | 0.90 |
The correlation between VBLLX and PBDIX has been stable across timeframes, ranging from 0.89 to 0.92 - a consistent structural relationship.
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Return for Risk
VBLLX vs. PBDIX — Risk / Return Rank
VBLLX
PBDIX
VBLLX vs. PBDIX - Risk-Adjusted Trends Comparison
This table presents a comparison of risk-adjusted performance metrics for Vanguard Long-Term Bond Index Fund Institutional Shares (VBLLX) and T. Rowe Price QM U.S. Bond Index Fund (PBDIX). 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.
| VBLLX | PBDIX | Difference | |
|---|---|---|---|
| Sharpe ratioReturn per unit of total volatility | -0.65 | ||
| Sortino ratioReturn per unit of downside risk | -0.93 | ||
| Omega ratioGain probability vs. loss probability | 1.00 | 1.11 | -0.11 |
| Calmar ratioReturn relative to maximum drawdown | -0.02 | 0.90 | -0.92 |
| Martin ratioReturn relative to average drawdown | -0.04 | 2.29 | -2.32 |
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Drawdowns
VBLLX vs. PBDIX - Drawdown Comparison
The maximum VBLLX drawdown since its inception was -38.42%, which is greater than PBDIX's maximum drawdown of -19.20%. Use the drawdown chart below to compare losses from any high point for VBLLX and PBDIX.
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Drawdown Indicators
| VBLLX | PBDIX | Difference | |
|---|---|---|---|
Max DrawdownLargest peak-to-trough decline | -38.42% | -19.20% | -19.22% |
Max Drawdown (1Y)Largest decline over 1 year | -6.35% | -2.94% | -3.41% |
Max Drawdown (3Y)Largest decline over 3 years | -11.55% | -4.87% | -6.68% |
Max Drawdown (5Y)Largest decline over 5 years | -36.29% | -19.01% | -17.28% |
Max Drawdown (10Y)Largest decline over 10 years | -38.42% | -19.20% | -19.22% |
Current DrawdownCurrent decline from peak | -27.42% | -2.55% | -24.87% |
Average DrawdownAverage peak-to-trough decline | -9.33% | -2.16% | -7.17% |
Ulcer IndexDepth and duration of drawdowns from previous peaks | 2.71% | 1.15% | +1.56% |
Volatility
VBLLX vs. PBDIX - Volatility Comparison
Vanguard Long-Term Bond Index Fund Institutional Shares (VBLLX) has a higher volatility of 2.07% compared to T. Rowe Price QM U.S. Bond Index Fund (PBDIX) at 1.03%. This indicates that VBLLX's price experiences larger fluctuations and is considered to be riskier than PBDIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.
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Volatility by Period
| VBLLX | PBDIX | Difference | |
|---|---|---|---|
Volatility (1M)Calculated over the trailing 1-month period | 2.07% | 1.03% | +1.04% |
Volatility (6M)Calculated over the trailing 6-month period | 6.06% | 3.25% | +2.81% |
Volatility (1Y)Calculated over the trailing 1-year period | 7.89% | 4.15% | +3.74% |
Volatility (5Y)Calculated over the trailing 5-year period, annualized | 12.82% | 6.12% | +6.70% |
Volatility (10Y)Calculated over the trailing 10-year period, annualized | 11.55% | 5.03% | +6.52% |
VBLLX vs. PBDIX - Expense Ratio Comparison
VBLLX has a 0.05% expense ratio, which is lower than PBDIX's 0.23% expense ratio. Despite the difference, both funds are considered low-cost compared to the broader market, where average expense ratios usually range from 0.3% to 0.9%.
Dividends
VBLLX vs. PBDIX - Dividend Comparison
VBLLX's dividend yield for the trailing twelve months is around 4.57%, more than PBDIX's 4.34% yield.
| Position | TTM | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
PBDIX T. Rowe Price QM U.S. Bond Index Fund | 4.34% | 5.19% | 7.21% | 6.39% | 2.01% | 1.84% | 3.59% | 3.18% | 2.94% | 2.75% | 2.82% | 2.99% |
VBLLX Vanguard Long-Term Bond Index Fund Institutional Shares | 4.57% | 4.66% | 4.64% | 3.75% | 4.16% | 2.89% | 5.84% | 3.62% | 3.82% | 3.69% | 4.19% | 4.98% |
Frequently Asked Questions
VBLLX and PBDIX have a correlation of 0.89, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.
VBLLX has higher volatility (2.07%) compared to PBDIX (1.03%). In terms of maximum drawdown, VBLLX dropped -38.42% vs PBDIX's -19.20%.
PBDIX currently has the higher Sharpe Ratio (0.64 vs -0.01), 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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