VTAPX vs. ACITX

Last updated Jun 4, 2026

VTAPX (Vanguard Short-Term Inflation-Protected Securities Index Fund Admiral Shares) and ACITX (American Century Inflation-Adjusted Bond Fund) are both Inflation-Protected Bonds funds. Over the past 10 years, VTAPX returned 3.13%/yr vs 2.66%/yr for ACITX. A 0.79 correlation means they provide meaningful diversification when combined. VTAPX charges 0.06%/yr vs 0.46%/yr for ACITX.

Performance

VTAPX vs. ACITX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Vanguard Short-Term Inflation-Protected Securities Index Fund Admiral Shares (VTAPX) and American Century Inflation-Adjusted Bond Fund (ACITX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, VTAPX achieves a 2.05% return, which is significantly higher than ACITX's 1.70% return. Over the past 10 years, VTAPX has outperformed ACITX with an annualized return of 3.13%, while ACITX has yielded a comparatively lower 2.66% annualized return.

VTAPX

• 1D: 0.00%
• 1M: 0.04%
• YTD: 2.05%
• 6M: 2.04%
• 1Y: 4.69%
• 3Y*: 5.23%
• 5Y*: 3.38%
• 10Y*: 3.13%

ACITX

• 1D: 0.00%
• 1M: 0.09%
• YTD: 1.70%
• 6M: 1.24%
• 1Y: 5.14%
• 3Y*: 3.75%
• 5Y*: 0.92%
• 10Y*: 2.66%

*Multi-year figures are annualized to reflect compound growth (CAGR)

VTAPX vs. ACITX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
VTAPX Vanguard Short-Term Inflation-Protected Securities Index Fund Admiral Shares	2.05%	6.03%	4.73%	4.59%	-2.84%	5.26%	4.97%	4.85%	0.53%	0.82%
ACITX American Century Inflation-Adjusted Bond Fund	1.70%	6.68%	1.68%	3.17%	-12.37%	6.38%	10.28%	7.85%	-1.21%	4.47%

Correlation

The correlation between VTAPX and ACITX is 0.73, 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	0.73
Correlation (3Y) Calculated over the trailing 3-year period	0.81
Correlation (5Y) Calculated over the trailing 5-year period	0.82
Correlation (10Y) Calculated over the trailing 10-year period	0.79
Correlation (All Time) Calculated using the full available price history since Jan 3, 2013	0.79

The correlation between VTAPX and ACITX has been stable across timeframes, ranging from 0.73 to 0.82 - a consistent structural relationship.

Return for Risk

VTAPX vs. ACITX — Risk / Return Rank

Compare risk-adjusted metric ranks to identify better-performing investments over the past 12 months.

VTAPX

VTAPX Risk / Return Rank: 94
VTAPX Sharpe Ratio Rank: 91
VTAPX Sortino Ratio Rank: 95
VTAPX Omega Ratio Rank: 90
VTAPX Calmar Ratio Rank: 96
VTAPX Martin Ratio Rank: 97

ACITX

ACITX Risk / Return Rank: 34
ACITX Sharpe Ratio Rank: 30
ACITX Sortino Ratio Rank: 34
ACITX Omega Ratio Rank: 30
ACITX Calmar Ratio Rank: 43
ACITX Martin Ratio Rank: 36

The rank (0–100) shows how this investment's returns compare to the risk taken. Higher = better. Based on the past 12 months of data, combining Sharpe, Sortino, and other metrics used by quantitative funds and institutional investors.

VTAPX vs. ACITX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Vanguard Short-Term Inflation-Protected Securities Index Fund Admiral Shares (VTAPX) and American Century Inflation-Adjusted Bond Fund (ACITX). 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.

	VTAPX	ACITX	Difference
Sharpe ratio: Return per unit of total volatility	3.03	1.57	+1.47
Sortino ratio: Return per unit of downside risk	5.02	2.41	+2.61
Omega ratio: Gain probability vs. loss probability	1.65	1.29	+0.36
Calmar ratio: Return relative to maximum drawdown	6.45	2.47	+3.97
Martin ratio: Return relative to average drawdown	25.59	7.88	+17.71
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

VTAPX vs. ACITX - Sharpe Ratio Comparison

The current VTAPX Sharpe Ratio is 3.03, which is higher than the ACITX Sharpe Ratio of 1.57. The chart below compares the historical Sharpe Ratios of VTAPX and ACITX, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

Sharpe Ratios by Period

	VTAPX	ACITX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	3.03	1.57	+1.47
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	1.27	0.15	+1.12
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	1.41	0.49	+0.92
Sharpe Ratio (All Time) Calculated using the full available price history	1.07	0.76	+0.31

Drawdowns

VTAPX vs. ACITX - Drawdown Comparison

The maximum VTAPX drawdown since its inception was -5.33%, smaller than the maximum ACITX drawdown of -15.50%. Use the drawdown chart below to compare losses from any high point for VTAPX and ACITX.

Drawdown Indicators

	VTAPX	ACITX	Difference
Max Drawdown Largest peak-to-trough decline	-5.33%	-15.50%	+10.17%
Max Drawdown (1Y) Largest decline over 1 year	-0.72%	-2.05%	+1.33%
Max Drawdown (3Y) Largest decline over 3 years	-0.92%	-5.08%	+4.16%
Max Drawdown (5Y) Largest decline over 5 years	-5.33%	-15.50%	+10.17%
Max Drawdown (10Y) Largest decline over 10 years	-5.33%	-15.50%	+10.17%
Current Drawdown Current decline from peak	-0.04%	-0.88%	+0.84%
Average Drawdown Average peak-to-trough decline	-1.03%	-3.24%	+2.21%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.18%	0.64%	-0.46%

Volatility

VTAPX vs. ACITX - Volatility Comparison

The current volatility for Vanguard Short-Term Inflation-Protected Securities Index Fund Admiral Shares (VTAPX) is 0.57%, while American Century Inflation-Adjusted Bond Fund (ACITX) has a volatility of 0.85%. This indicates that VTAPX experiences smaller price fluctuations and is considered to be less risky than ACITX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	VTAPX	ACITX	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.57%	0.85%	-0.28%
Volatility (6M) Calculated over the trailing 6-month period	1.11%	2.20%	-1.09%
Volatility (1Y) Calculated over the trailing 1-year period	1.52%	3.24%	-1.72%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	2.67%	6.14%	-3.47%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	2.23%	5.50%	-3.27%

VTAPX vs. ACITX - Expense Ratio Comparison

VTAPX has a 0.06% expense ratio, which is lower than ACITX's 0.46% expense ratio.

Dividends

VTAPX vs. ACITX - Dividend Comparison

VTAPX's dividend yield for the trailing twelve months is around 3.55%, less than ACITX's 4.23% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
ACITX American Century Inflation-Adjusted Bond Fund	4.23%	4.30%	2.19%	4.44%	7.34%	4.47%	1.16%	2.45%	4.31%	3.47%	2.27%	0.99%
VTAPX Vanguard Short-Term Inflation-Protected Securities Index Fund Admiral Shares	3.55%	3.78%	2.68%	2.84%	6.82%	4.67%	1.19%	1.94%	2.45%	1.52%	0.76%	0.00%

Frequently Asked Questions

Can I hold both VTAPX and ACITX in my portfolio?

VTAPX and ACITX have a correlation of 0.73, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, VTAPX or ACITX?

ACITX has higher volatility (0.85%) compared to VTAPX (0.57%). In terms of maximum drawdown, VTAPX dropped -5.33% vs ACITX's -15.50%.

Which has better risk-adjusted returns?

VTAPX currently has the higher Sharpe Ratio (3.03 vs 1.57), 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.