ACFOX vs. MRFOX

Last updated Apr 1, 2026

Compare and contrast key facts about American Century Investments Focused Dynamic Growth Fund (ACFOX) and Marshfield Concentrated Opportunity Fund (MRFOX).

ACFOX is managed by American Century. It was launched on May 31, 2006. MRFOX is managed by Marshfield. It was launched on Dec 29, 2015.

Performance

ACFOX vs. MRFOX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Century Investments Focused Dynamic Growth Fund (ACFOX) and Marshfield Concentrated Opportunity Fund (MRFOX). The values are adjusted to include any dividend payments, if applicable.

ACFOX vs. MRFOX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
ACFOX American Century Investments Focused Dynamic Growth Fund	-14.41%	20.51%	43.30%	35.66%	-36.32%	7.08%	73.31%	32.30%	6.51%	34.55%
MRFOX Marshfield Concentrated Opportunity Fund	-4.08%	10.05%	17.10%	17.68%	5.06%	17.71%	15.19%	36.26%	1.89%	25.92%

Returns By Period

In the year-to-date period, ACFOX achieves a -14.41% return, which is significantly lower than MRFOX's -4.08% return. Over the past 10 years, ACFOX has outperformed MRFOX with an annualized return of 16.85%, while MRFOX has yielded a comparatively lower 15.18% annualized return.

ACFOX

• 1D: -0.86%
• 1M: -8.88%
• YTD: -14.41%
• 6M: -10.23%
• 1Y: 19.65%
• 3Y*: 21.09%
• 5Y*: 6.51%
• 10Y*: 16.85%

MRFOX

• 1D: 0.67%
• 1M: -5.13%
• YTD: -4.08%
• 6M: -4.60%
• 1Y: 2.70%
• 3Y*: 12.36%
• 5Y*: 10.91%
• 10Y*: 15.18%

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

ACFOX vs. MRFOX - Expense Ratio Comparison

ACFOX has a 0.85% expense ratio, which is lower than MRFOX's 1.05% expense ratio.

MRFOX

Marshfield Concentrated Opportunity Fund

ACFOX

American Century Investments Focused Dynamic Growth Fund

Return for Risk

ACFOX vs. MRFOX — Risk / Return Rank

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

ACFOX

ACFOX Risk / Return Rank: 36
ACFOX Sharpe Ratio Rank: 35
ACFOX Sortino Ratio Rank: 42
ACFOX Omega Ratio Rank: 36
ACFOX Calmar Ratio Rank: 35
ACFOX Martin Ratio Rank: 32

MRFOX

MRFOX Risk / Return Rank: 12
MRFOX Sharpe Ratio Rank: 13
MRFOX Sortino Ratio Rank: 13
MRFOX Omega Ratio Rank: 11
MRFOX Calmar Ratio Rank: 12
MRFOX Martin Ratio Rank: 11

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. MRFOX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Century Investments Focused Dynamic Growth Fund (ACFOX) and Marshfield Concentrated Opportunity Fund (MRFOX). 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.

	ACFOX	MRFOX	Difference
Sharpe ratio Return per unit of total volatility	0.77	0.31	+0.45
Sortino ratio Return per unit of downside risk	1.26	0.54	+0.71
Omega ratio Gain probability vs. loss probability	1.17	1.07	+0.10
Calmar ratio Return relative to maximum drawdown	0.94	0.31	+0.63
Martin ratio Return relative to average drawdown	3.40	0.80	+2.61
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

ACFOX vs. MRFOX - Sharpe Ratio Comparison

The current ACFOX Sharpe Ratio is 0.77, which is higher than the MRFOX Sharpe Ratio of 0.31. The chart below compares the historical Sharpe Ratios of ACFOX and MRFOX, offering insights into how both investments have performed under varying market conditions. These values are calculated using daily returns over the previous 12 months.

Sharpe Ratios by Period

	ACFOX	MRFOX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	0.77	0.31	+0.45
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.26	0.91	-0.65
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.71	1.07	-0.35
Sharpe Ratio (All Time) Calculated using the full available price history	0.52	1.05	-0.53

Correlation

The correlation between ACFOX and MRFOX is 0.60, which is considered to be moderate. This suggests that the two assets have some degree of positive relationship in their price movements. Moderate correlation can be acceptable for portfolio diversification, offering a balance between risk and potential returns.

Dividends

ACFOX vs. MRFOX - Dividend Comparison

ACFOX's dividend yield for the trailing twelve months is around 8.83%, more than MRFOX's 1.69% yield.

	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
ACFOX American Century Investments Focused Dynamic Growth Fund	8.83%	7.56%	0.00%	0.00%	0.00%	2.48%	0.62%	0.00%	0.00%	0.00%	1.15%	1.33%
MRFOX Marshfield Concentrated Opportunity Fund	1.69%	1.62%	4.59%	0.46%	0.35%	6.78%	2.68%	1.39%	1.94%	2.06%	0.60%	0.00%

Drawdowns

ACFOX vs. MRFOX - Drawdown Comparison

The maximum ACFOX drawdown since its inception was -58.92%, which is greater than MRFOX's maximum drawdown of -29.10%. Use the drawdown chart below to compare losses from any high point for ACFOX and MRFOX.

Drawdown Indicators

	ACFOX	MRFOX	Difference
Max Drawdown Largest peak-to-trough decline	-58.92%	-29.10%	-29.82%
Max Drawdown (1Y) Largest decline over 1 year	-16.52%	-7.09%	-9.43%
Max Drawdown (5Y) Largest decline over 5 years	-43.77%	-12.98%	-30.79%
Max Drawdown (10Y) Largest decline over 10 years	-43.77%	-29.10%	-14.67%
Current Drawdown Current decline from peak	-16.52%	-6.40%	-10.12%
Average Drawdown Average peak-to-trough decline	-14.81%	-2.37%	-12.44%
Ulcer Index Depth and duration of drawdowns from previous peaks	4.56%	2.75%	+1.81%

Volatility

ACFOX vs. MRFOX - Volatility Comparison

American Century Investments Focused Dynamic Growth Fund (ACFOX) has a higher volatility of 6.86% compared to Marshfield Concentrated Opportunity Fund (MRFOX) at 2.74%. This indicates that ACFOX's price experiences larger fluctuations and is considered to be riskier than MRFOX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	ACFOX	MRFOX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.86%	2.74%	+4.12%
Volatility (6M) Calculated over the trailing 6-month period	14.48%	7.00%	+7.48%
Volatility (1Y) Calculated over the trailing 1-year period	24.83%	11.79%	+13.04%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	25.20%	12.04%	+13.16%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	23.67%	14.29%	+9.38%