ACFOX vs. FUMIX

Last updated Jun 24, 2026

ACFOX (American Century Investments Focused Dynamic Growth Fund) and FUMIX (Fidelity SAI U.S. Momentum Index Fund) are both Large Cap Growth Equities funds. Over the past 5 years, ACFOX returned 8.89%/yr vs 17.37%/yr for FUMIX. Their correlation of 0.82 suggests significant overlap in exposure. ACFOX charges 0.85%/yr vs 0.11%/yr for FUMIX.

Performance

ACFOX vs. FUMIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Century Investments Focused Dynamic Growth Fund (ACFOX) and Fidelity SAI U.S. Momentum Index Fund (FUMIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, ACFOX achieves a 3.87% return, which is significantly lower than FUMIX's 32.63% return.

ACFOX

• 1D: -1.92%
• 1M: -3.93%
• YTD: 3.87%
• 6M: 1.69%
• 1Y: 25.58%
• 3Y*: 25.25%
• 5Y*: 8.89%
• 10Y*: 19.36%

FUMIX

• 1D: 1.37%
• 1M: 9.64%
• YTD: 32.63%
• 6M: 30.51%
• 1Y: 40.33%
• 3Y*: 33.62%
• 5Y*: 17.37%
• 10Y*: —

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

ACFOX vs. FUMIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
ACFOX American Century Investments Focused Dynamic Growth Fund	3.87%	20.51%	43.30%	35.66%	-36.32%	7.08%	73.31%	32.30%	6.51%	26.40%
FUMIX Fidelity SAI U.S. Momentum Index Fund	32.63%	17.01%	33.39%	14.67%	-15.79%	22.56%	29.92%	24.16%	-1.41%	22.71%

Correlation

The correlation between ACFOX and FUMIX is 0.76, 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	0.76
Correlation (3Y) Calculated over the trailing 3-year period	0.81
Correlation (5Y) Calculated over the trailing 5-year period	0.79
Correlation (All Time) Calculated using the full available price history since Feb 9, 2017	0.82

The correlation between ACFOX and FUMIX has been stable across timeframes, ranging from 0.76 to 0.82 - a consistent structural relationship.

Return for Risk

ACFOX vs. FUMIX — Risk / Return Rank

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

ACFOX

ACFOX Risk / Return Rank: 24
ACFOX Sharpe Ratio Rank: 26
ACFOX Sortino Ratio Rank: 23
ACFOX Omega Ratio Rank: 24
ACFOX Calmar Ratio Rank: 23
ACFOX Martin Ratio Rank: 25

FUMIX

FUMIX Risk / Return Rank: 78
FUMIX Sharpe Ratio Rank: 75
FUMIX Sortino Ratio Rank: 68
FUMIX Omega Ratio Rank: 68
FUMIX Calmar Ratio Rank: 86
FUMIX Martin Ratio Rank: 92

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.

ACFOX vs. FUMIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Century Investments Focused Dynamic Growth Fund (ACFOX) and Fidelity SAI U.S. Momentum Index Fund (FUMIX). 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.

	ACFOX	FUMIX	Difference
Sharpe ratio: Return per unit of total volatility	1.36	2.31	-0.96
Sortino ratio: Return per unit of downside risk	1.87	3.13	-1.26
Omega ratio: Gain probability vs. loss probability	1.24	1.42	-0.18
Calmar ratio: Return relative to maximum drawdown	1.65	3.89	-2.24
Martin ratio: Return relative to average drawdown	5.63	17.44	-11.81

ACFOX vs. FUMIX - Sharpe Ratio Comparison

The current ACFOX Sharpe Ratio is 1.36, which is lower than the FUMIX Sharpe Ratio of 2.31. The chart below compares the historical Sharpe Ratios of ACFOX and FUMIX, 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

ACFOX vs. FUMIX - Drawdown Comparison

The maximum ACFOX drawdown since its inception was -58.92%, which is greater than FUMIX's maximum drawdown of -33.36%. Use the drawdown chart below to compare losses from any high point for ACFOX and FUMIX.

Drawdown Indicators

	ACFOX	FUMIX	Difference
Max Drawdown Largest peak-to-trough decline	-58.92%	-33.36%	-25.56%
Max Drawdown (1Y) Largest decline over 1 year	-16.52%	-10.99%	-5.53%
Max Drawdown (3Y) Largest decline over 3 years	-27.03%	-19.90%	-7.13%
Max Drawdown (5Y) Largest decline over 5 years	-43.77%	-27.66%	-16.11%
Max Drawdown (10Y) Largest decline over 10 years	-43.77%	—	—
Current Drawdown Current decline from peak	-5.96%	0.00%	-5.96%
Average Drawdown Average peak-to-trough decline	-14.68%	-6.29%	-8.39%
Ulcer Index Depth and duration of drawdowns from previous peaks	4.82%	2.44%	+2.38%

Volatility

ACFOX vs. FUMIX - Volatility Comparison

American Century Investments Focused Dynamic Growth Fund (ACFOX) and Fidelity SAI U.S. Momentum Index Fund (FUMIX) have volatilities of 7.93% and 7.70%, respectively, indicating that both stocks experience similar levels of price fluctuations. This suggests that the risk associated with both stocks, as measured by volatility, is nearly the same. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	ACFOX	FUMIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	7.93%	7.70%	+0.23%
Volatility (6M) Calculated over the trailing 6-month period	16.14%	16.10%	+0.04%
Volatility (1Y) Calculated over the trailing 1-year period	20.10%	18.50%	+1.60%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	25.46%	21.38%	+4.08%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	23.92%	21.83%	+2.09%

ACFOX vs. FUMIX - Expense Ratio Comparison

ACFOX has a 0.85% expense ratio, which is higher than FUMIX's 0.11% expense ratio.

Dividends

ACFOX vs. FUMIX - Dividend Comparison

ACFOX's dividend yield for the trailing twelve months is around 7.27%, more than FUMIX's 2.09% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
ACFOX American Century Investments Focused Dynamic Growth Fund	7.27%	7.56%	0.00%	0.00%	0.00%	2.48%	0.62%	0.00%	0.00%	0.00%	1.15%	1.33%
FUMIX Fidelity SAI U.S. Momentum Index Fund	2.09%	2.77%	5.89%	18.09%	2.10%	20.67%	8.68%	2.09%	3.84%	0.88%	0.00%	0.00%

Frequently Asked Questions

Can I hold both ACFOX and FUMIX in my portfolio?

ACFOX and FUMIX have a correlation of 0.76, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, ACFOX or FUMIX?

ACFOX has higher volatility (7.93%) compared to FUMIX (7.70%). In terms of maximum drawdown, ACFOX dropped -58.92% vs FUMIX's -33.36%.

Which has better risk-adjusted returns?

FUMIX currently has the higher Sharpe Ratio (2.31 vs 1.36), 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.