BULIX vs. AIOIX

Last updated Jun 4, 2026

BULIX (American Century Utilities Fund) and AIOIX (American Century International Opportunities Fund) are both mutual funds - BULIX is a Utilities Equities fund managed by American Century, while AIOIX is a Foreign Small & Mid Cap Equities fund managed by American Century. Over the past 10 years, BULIX returned 6.86%/yr vs 8.30%/yr for AIOIX. At a 0.45 correlation, their price movements are largely independent. BULIX charges 0.65%/yr vs 1.48%/yr for AIOIX.

Performance

BULIX vs. AIOIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Century Utilities Fund (BULIX) and American Century International Opportunities Fund (AIOIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, BULIX achieves a 4.40% return, which is significantly lower than AIOIX's 15.88% return. Over the past 10 years, BULIX has underperformed AIOIX with an annualized return of 6.86%, while AIOIX has yielded a comparatively higher 8.30% annualized return.

BULIX

• 1D: 1.70%
• 1M: -5.06%
• YTD: 4.40%
• 6M: 2.91%
• 1Y: 10.79%
• 3Y*: 15.11%
• 5Y*: 8.21%
• 10Y*: 6.86%

AIOIX

• 1D: -0.15%
• 1M: 2.46%
• YTD: 15.88%
• 6M: 18.09%
• 1Y: 32.80%
• 3Y*: 15.62%
• 5Y*: 2.92%
• 10Y*: 8.30%

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

BULIX vs. AIOIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
BULIX American Century Utilities Fund	4.40%	16.76%	24.32%	-7.51%	-4.37%	13.77%	-2.38%	19.94%	1.82%	0.59%
AIOIX American Century International Opportunities Fund	15.88%	29.62%	1.31%	8.63%	-30.19%	5.79%	31.07%	28.95%	-22.19%	45.09%

Correlation

The correlation between BULIX and AIOIX is 0.24, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.24
Correlation (3Y) Calculated over the trailing 3-year period	0.33
Correlation (5Y) Calculated over the trailing 5-year period	0.39
Correlation (10Y) Calculated over the trailing 10-year period	0.35
Correlation (All Time) Calculated using the full available price history since Jan 3, 2002	0.45

Over the past year, the correlation between BULIX and AIOIX has dropped to 0.24 - well below their long-term average of 0.45, suggesting their price drivers have been diverging.

Return for Risk

BULIX vs. AIOIX — Risk / Return Rank

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

BULIX

BULIX Risk / Return Rank: 11
BULIX Sharpe Ratio Rank: 10
BULIX Sortino Ratio Rank: 9
BULIX Omega Ratio Rank: 10
BULIX Calmar Ratio Rank: 13
BULIX Martin Ratio Rank: 10

AIOIX

AIOIX Risk / Return Rank: 37
AIOIX Sharpe Ratio Rank: 35
AIOIX Sortino Ratio Rank: 32
AIOIX Omega Ratio Rank: 34
AIOIX Calmar Ratio Rank: 37
AIOIX Martin Ratio Rank: 44

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.

BULIX vs. AIOIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Century Utilities Fund (BULIX) and American Century International Opportunities Fund (AIOIX). 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.

	BULIX	AIOIX	Difference
Sharpe ratio: Return per unit of total volatility	0.81	1.73	-0.91
Sortino ratio: Return per unit of downside risk	1.17	2.36	-1.19
Omega ratio: Gain probability vs. loss probability	1.15	1.31	-0.16
Calmar ratio: Return relative to maximum drawdown	1.26	2.32	-1.06
Martin ratio: Return relative to average drawdown	3.11	9.33	-6.22
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

BULIX vs. AIOIX - Sharpe Ratio Comparison

The current BULIX Sharpe Ratio is 0.81, which is lower than the AIOIX Sharpe Ratio of 1.73. The chart below compares the historical Sharpe Ratios of BULIX and AIOIX, 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

	BULIX	AIOIX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	0.81	1.73	-0.91
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.49	0.16	+0.34
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.38	0.44	-0.06
Sharpe Ratio (All Time) Calculated using the full available price history	0.45	0.55	-0.09

Drawdowns

BULIX vs. AIOIX - Drawdown Comparison

The maximum BULIX drawdown since its inception was -55.21%, smaller than the maximum AIOIX drawdown of -66.16%. Use the drawdown chart below to compare losses from any high point for BULIX and AIOIX.

Drawdown Indicators

	BULIX	AIOIX	Difference
Max Drawdown Largest peak-to-trough decline	-55.21%	-66.16%	+10.95%
Max Drawdown (1Y) Largest decline over 1 year	-8.93%	-14.00%	+5.07%
Max Drawdown (3Y) Largest decline over 3 years	-16.54%	-18.46%	+1.92%
Max Drawdown (5Y) Largest decline over 5 years	-24.56%	-41.19%	+16.63%
Max Drawdown (10Y) Largest decline over 10 years	-33.86%	-41.19%	+7.33%
Current Drawdown Current decline from peak	-7.38%	-1.86%	-5.52%
Average Drawdown Average peak-to-trough decline	-10.03%	-16.02%	+5.99%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.61%	3.47%	+0.14%

Volatility

BULIX vs. AIOIX - Volatility Comparison

The current volatility for American Century Utilities Fund (BULIX) is 5.15%, while American Century International Opportunities Fund (AIOIX) has a volatility of 6.73%. This indicates that BULIX experiences smaller price fluctuations and is considered to be less risky than AIOIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	BULIX	AIOIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	5.15%	6.73%	-1.58%
Volatility (6M) Calculated over the trailing 6-month period	11.14%	16.02%	-4.88%
Volatility (1Y) Calculated over the trailing 1-year period	13.85%	18.86%	-5.01%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	16.71%	18.91%	-2.20%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	18.05%	18.95%	-0.90%

BULIX vs. AIOIX - Expense Ratio Comparison

BULIX has a 0.65% expense ratio, which is lower than AIOIX's 1.48% expense ratio.

Dividends

BULIX vs. AIOIX - Dividend Comparison

BULIX's dividend yield for the trailing twelve months is around 10.93%, more than AIOIX's 0.24% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
AIOIX American Century International Opportunities Fund	0.24%	0.27%	0.32%	0.23%	0.00%	17.80%	3.18%	0.92%	5.28%	9.09%	0.04%	7.15%
BULIX American Century Utilities Fund	10.93%	11.60%	2.36%	2.65%	7.78%	7.50%	7.55%	2.97%	6.91%	7.70%	6.99%	5.87%

Frequently Asked Questions

Can I hold both BULIX and AIOIX in my portfolio?

BULIX and AIOIX have a correlation of 0.24, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, BULIX or AIOIX?

AIOIX has higher volatility (6.73%) compared to BULIX (5.15%). In terms of maximum drawdown, BULIX dropped -55.21% vs AIOIX's -66.16%.

Which has better risk-adjusted returns?

AIOIX currently has the higher Sharpe Ratio (1.73 vs 0.81), 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.