ACIIX vs. VOO

Last updated Jun 23, 2026

ACIIX (American Century Equity Income Fund Class I) and VOO (Vanguard S&P 500 ETF) are both funds - ACIIX is a Large Cap Value Equities fund managed by American Century, while VOO is a S&P 500 fund tracking the S&P 500 Index. Over the past 10 years, ACIIX returned 8.93%/yr vs 15.77%/yr for VOO. Their correlation of 0.84 suggests significant overlap in exposure. ACIIX charges 0.72%/yr vs 0.03%/yr for VOO.

Performance

ACIIX vs. VOO - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Century Equity Income Fund Class I (ACIIX) and Vanguard S&P 500 ETF (VOO). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, ACIIX achieves a 7.40% return, which is significantly lower than VOO's 9.75% return. Over the past 10 years, ACIIX has underperformed VOO with an annualized return of 8.93%, while VOO has yielded a comparatively higher 15.77% annualized return.

ACIIX

• 1D: -0.11%
• 1M: -0.07%
• YTD: 7.40%
• 6M: 6.90%
• 1Y: 16.79%
• 3Y*: 10.55%
• 5Y*: 7.82%
• 10Y*: 8.93%

VOO

• 1D: -0.29%
• 1M: 0.08%
• YTD: 9.75%
• 6M: 9.30%
• 1Y: 26.77%
• 3Y*: 21.36%
• 5Y*: 13.58%
• 10Y*: 15.77%

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

ACIIX vs. VOO - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
ACIIX American Century Equity Income Fund Class I	7.40%	12.05%	10.58%	4.25%	-2.96%	17.16%	1.19%	24.50%	-3.53%	13.69%
VOO Vanguard S&P 500 ETF	9.75%	17.82%	24.98%	26.32%	-18.17%	28.79%	18.32%	31.37%	-4.50%	21.77%

Correlation

The correlation between ACIIX and VOO is 0.47, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.47
Correlation (3Y) Calculated over the trailing 3-year period	0.55
Correlation (5Y) Calculated over the trailing 5-year period	0.70
Correlation (10Y) Calculated over the trailing 10-year period	0.78
Correlation (All Time) Calculated using the full available price history since Sep 9, 2010	0.84

Over the past year, the correlation between ACIIX and VOO has dropped to 0.47 - well below their long-term average of 0.84, suggesting their price drivers have been diverging.

Return for Risk

ACIIX vs. VOO — Risk / Return Rank

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

ACIIX

ACIIX Risk / Return Rank: 52
ACIIX Sharpe Ratio Rank: 54
ACIIX Sortino Ratio Rank: 62
ACIIX Omega Ratio Rank: 49
ACIIX Calmar Ratio Rank: 53
ACIIX Martin Ratio Rank: 43

VOO

VOO Risk / Return Rank: 68
VOO Sharpe Ratio Rank: 70
VOO Sortino Ratio Rank: 67
VOO Omega Ratio Rank: 69
VOO Calmar Ratio Rank: 63
VOO Martin Ratio Rank: 74

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.

ACIIX vs. VOO - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Century Equity Income Fund Class I (ACIIX) and Vanguard S&P 500 ETF (VOO). 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.

	ACIIX	VOO	Difference
Sharpe ratio: Return per unit of total volatility	2.00	2.17	-0.17
Sortino ratio: Return per unit of downside risk	3.01	2.93	+0.08
Omega ratio: Gain probability vs. loss probability	1.35	1.39	-0.04
Calmar ratio: Return relative to maximum drawdown	2.67	3.02	-0.35
Martin ratio: Return relative to average drawdown	8.69	13.58	-4.89

ACIIX vs. VOO - Sharpe Ratio Comparison

The current ACIIX Sharpe Ratio is 2.00, which is comparable to the VOO Sharpe Ratio of 2.17. The chart below compares the historical Sharpe Ratios of ACIIX and VOO, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

Drawdowns

ACIIX vs. VOO - Drawdown Comparison

The maximum ACIIX drawdown since its inception was -39.16%, which is greater than VOO's maximum drawdown of -33.99%. Use the drawdown chart below to compare losses from any high point for ACIIX and VOO.

Drawdown Indicators

	ACIIX	VOO	Difference
Max Drawdown Largest peak-to-trough decline	-39.16%	-33.99%	-5.17%
Max Drawdown (1Y) Largest decline over 1 year	-6.38%	-8.90%	+2.52%
Max Drawdown (3Y) Largest decline over 3 years	-10.15%	-18.69%	+8.54%
Max Drawdown (5Y) Largest decline over 5 years	-13.49%	-24.52%	+11.03%
Max Drawdown (10Y) Largest decline over 10 years	-32.76%	-33.99%	+1.23%
Current Drawdown Current decline from peak	-1.44%	-1.74%	+0.30%
Average Drawdown Average peak-to-trough decline	-5.24%	-3.68%	-1.56%
Ulcer Index Depth and duration of drawdowns from previous peaks	1.95%	1.98%	-0.03%

Volatility

ACIIX vs. VOO - Volatility Comparison

The current volatility for American Century Equity Income Fund Class I (ACIIX) is 2.57%, while Vanguard S&P 500 ETF (VOO) has a volatility of 4.60%. This indicates that ACIIX experiences smaller price fluctuations and is considered to be less risky than VOO based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	ACIIX	VOO	Difference
Volatility (1M) Calculated over the trailing 1-month period	2.57%	4.60%	-2.03%
Volatility (6M) Calculated over the trailing 6-month period	6.22%	9.73%	-3.51%
Volatility (1Y) Calculated over the trailing 1-year period	8.50%	12.39%	-3.89%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	10.77%	16.90%	-6.13%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	13.39%	18.05%	-4.66%

ACIIX vs. VOO - Expense Ratio Comparison

ACIIX has a 0.72% expense ratio, which is higher than VOO's 0.03% expense ratio.

Dividends

ACIIX vs. VOO - Dividend Comparison

ACIIX's dividend yield for the trailing twelve months is around 10.86%, more than VOO's 1.04% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
ACIIX American Century Equity Income Fund Class I	10.86%	10.55%	11.71%	8.21%	8.96%	7.02%	2.18%	7.57%	9.05%	12.14%	8.08%	10.72%
VOO Vanguard S&P 500 ETF	1.04%	1.13%	1.24%	1.46%	1.69%	1.25%	1.54%	1.88%	2.06%	1.78%	2.02%	2.10%

Frequently Asked Questions

Can I hold both ACIIX and VOO in my portfolio?

ACIIX and VOO have a correlation of 0.47, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, ACIIX or VOO?

VOO has higher volatility (4.60%) compared to ACIIX (2.57%). In terms of maximum drawdown, ACIIX dropped -39.16% vs VOO's -33.99%.

Which has better risk-adjusted returns?

VOO currently has the higher Sharpe Ratio (2.17 vs 2.00), 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.