VAIPX vs. APOIX
VAIPX (Vanguard Inflation-Protected Securities Fund Admiral Shares) and APOIX (American Century Short Duration Inflation Protection Bond Fund Investor Class) are both Inflation-Protected Bonds funds. Over the past 10 years, VAIPX returned 2.64%/yr vs 3.13%/yr for APOIX. Their correlation of 0.81 suggests significant overlap in exposure. VAIPX charges 0.10%/yr vs 0.57%/yr for APOIX.
Performance
VAIPX vs. APOIX - Performance Comparison
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Returns By Period
In the year-to-date period, VAIPX achieves a 1.65% return, which is significantly lower than APOIX's 2.02% return. Over the past 10 years, VAIPX has underperformed APOIX with an annualized return of 2.64%, while APOIX has yielded a comparatively higher 3.13% annualized return.
VAIPX
- 1D
- 0.00%
- 1M
- 0.13%
- YTD
- 1.65%
- 6M
- 1.27%
- 1Y
- 5.31%
- 3Y*
- 4.04%
- 5Y*
- 1.17%
- 10Y*
- 2.64%
APOIX
- 1D
- 0.00%
- 1M
- -0.00%
- YTD
- 2.02%
- 6M
- 1.90%
- 1Y
- 4.51%
- 3Y*
- 4.85%
- 5Y*
- 2.96%
- 10Y*
- 3.13%
VAIPX vs. APOIX - Yearly Performance Comparison
| 2026 (YTD) | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | |
|---|---|---|---|---|---|---|---|---|---|---|
VAIPX Vanguard Inflation-Protected Securities Fund Admiral Shares | 1.65% | 6.87% | 1.85% | 3.83% | -11.92% | 5.69% | 10.96% | 8.16% | -1.39% | 2.91% |
APOIX American Century Short Duration Inflation Protection Bond Fund Investor Class | 2.02% | 5.95% | 4.15% | 3.82% | -3.89% | 6.30% | 5.06% | 4.77% | 1.81% | 0.73% |
Correlation
The correlation between VAIPX and APOIX is 0.71, which is moderate. They share some common price drivers but move independently often enough to provide real diversification benefit when combined.
| Correlation | |
|---|---|
Correlation (1Y) Calculated over the trailing 1-year period | 0.71 |
Correlation (3Y) Calculated over the trailing 3-year period | 0.81 |
Correlation (5Y) Calculated over the trailing 5-year period | 0.81 |
Correlation (10Y) Calculated over the trailing 10-year period | 0.77 |
Correlation (All Time) Calculated using the full available price history since Jun 13, 2005 | 0.81 |
The correlation between VAIPX and APOIX shifts across timeframes, from 0.71 (1 year) to 0.81 (all time), reflecting how their relationship changes across market environments.
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Return for Risk
VAIPX vs. APOIX — Risk / Return Rank
VAIPX
APOIX
VAIPX vs. APOIX - Risk-Adjusted Trends Comparison
This table presents a comparison of risk-adjusted performance metrics for Vanguard Inflation-Protected Securities Fund Admiral Shares (VAIPX) and American Century Short Duration Inflation Protection Bond Fund Investor Class (APOIX). 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.
| VAIPX | APOIX | Difference | |
|---|---|---|---|
| Sharpe ratioReturn per unit of total volatility | -0.91 | ||
| Sortino ratioReturn per unit of downside risk | -1.65 | ||
| Omega ratioGain probability vs. loss probability | 1.28 | 1.51 | -0.23 |
| Calmar ratioReturn relative to maximum drawdown | 2.53 | 5.81 | -3.28 |
| Martin ratioReturn relative to average drawdown | 8.02 | 19.09 | -11.07 |
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
| VAIPX | APOIX | Difference | |
|---|---|---|---|
Sharpe Ratio (1Y)Calculated over the trailing 1-year period | 1.54 | 2.45 | -0.91 |
Sharpe Ratio (5Y)Calculated over the trailing 5-year period | 0.20 | 0.90 | -0.70 |
Sharpe Ratio (10Y)Calculated over the trailing 10-year period | 0.50 | 1.10 | -0.60 |
Sharpe Ratio (All Time)Calculated using the full available price history | 0.52 | 0.72 | -0.20 |
Drawdowns
VAIPX vs. APOIX - Drawdown Comparison
The maximum VAIPX drawdown since its inception was -15.04%, roughly equal to the maximum APOIX drawdown of -14.54%. Use the drawdown chart below to compare losses from any high point for VAIPX and APOIX.
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Drawdown Indicators
| VAIPX | APOIX | Difference | |
|---|---|---|---|
Max DrawdownLargest peak-to-trough decline | -15.04% | -14.54% | -0.50% |
Max Drawdown (1Y)Largest decline over 1 year | -2.05% | -0.76% | -1.29% |
Max Drawdown (3Y)Largest decline over 3 years | -4.52% | -1.42% | -3.10% |
Max Drawdown (5Y)Largest decline over 5 years | -14.40% | -6.58% | -7.82% |
Max Drawdown (10Y)Largest decline over 10 years | -14.40% | -6.58% | -7.82% |
Current DrawdownCurrent decline from peak | -0.09% | -0.00% | -0.09% |
Average DrawdownAverage peak-to-trough decline | -3.81% | -1.99% | -1.82% |
Ulcer IndexDepth and duration of drawdowns from previous peaks | 0.65% | 0.23% | +0.42% |
Volatility
VAIPX vs. APOIX - Volatility Comparison
Vanguard Inflation-Protected Securities Fund Admiral Shares (VAIPX) has a higher volatility of 0.97% compared to American Century Short Duration Inflation Protection Bond Fund Investor Class (APOIX) at 0.51%. This indicates that VAIPX's price experiences larger fluctuations and is considered to be riskier than APOIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.
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Volatility by Period
| VAIPX | APOIX | Difference | |
|---|---|---|---|
Volatility (1M)Calculated over the trailing 1-month period | 0.97% | 0.51% | +0.46% |
Volatility (6M)Calculated over the trailing 6-month period | 2.32% | 1.25% | +1.07% |
Volatility (1Y)Calculated over the trailing 1-year period | 3.38% | 1.81% | +1.57% |
Volatility (5Y)Calculated over the trailing 5-year period, annualized | 5.99% | 3.31% | +2.68% |
Volatility (10Y)Calculated over the trailing 10-year period, annualized | 5.32% | 2.85% | +2.47% |
VAIPX vs. APOIX - Expense Ratio Comparison
VAIPX has a 0.10% expense ratio, which is lower than APOIX's 0.57% expense ratio.
Dividends
VAIPX vs. APOIX - Dividend Comparison
VAIPX's dividend yield for the trailing twelve months is around 4.49%, more than APOIX's 3.91% yield.
| Position | TTM | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
APOIX American Century Short Duration Inflation Protection Bond Fund Investor Class | 3.91% | 3.99% | 2.31% | 2.78% | 5.63% | 3.92% | 0.81% | 1.69% | 3.99% | 1.52% | 0.42% | 0.00% |
VAIPX Vanguard Inflation-Protected Securities Fund Admiral Shares | 4.49% | 4.74% | 4.17% | 4.31% | 8.45% | 5.13% | 1.38% | 2.29% | 3.12% | 2.41% | 3.49% | 0.88% |
Frequently Asked Questions
VAIPX and APOIX have a correlation of 0.71, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.
VAIPX has higher volatility (0.97%) compared to APOIX (0.51%). In terms of maximum drawdown, VAIPX dropped -15.04% vs APOIX's -14.54%.
APOIX currently has the higher Sharpe Ratio (2.45 vs 1.54), 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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