FMACX vs. MRFOX

Last updated Apr 2, 2026

Compare and contrast key facts about American Funds AMCAP Fund® Class F-3 (FMACX) and Marshfield Concentrated Opportunity Fund (MRFOX).

FMACX is managed by American Funds. It was launched on Aug 1, 2008. MRFOX is managed by Marshfield. It was launched on Dec 29, 2015.

Performance

FMACX vs. MRFOX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Funds AMCAP Fund® Class F-3 (FMACX) and Marshfield Concentrated Opportunity Fund (MRFOX). The values are adjusted to include any dividend payments, if applicable.

FMACX vs. MRFOX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
FMACX American Funds AMCAP Fund® Class F-3	-8.47%	18.07%	21.49%	31.48%	-28.43%	22.33%	21.81%	26.73%	-4.12%	18.35%
MRFOX Marshfield Concentrated Opportunity Fund	-2.97%	10.05%	17.10%	17.68%	5.06%	17.71%	15.19%	36.26%	1.89%	21.59%

Returns By Period

In the year-to-date period, FMACX achieves a -8.47% return, which is significantly lower than MRFOX's -2.97% return.

FMACX

• 1D: 3.72%
• 1M: -6.46%
• YTD: -8.47%
• 6M: -6.24%
• 1Y: 14.93%
• 3Y*: 16.16%
• 5Y*: 7.24%
• 10Y*: —

MRFOX

• 1D: 1.16%
• 1M: -4.29%
• YTD: -2.97%
• 6M: -3.36%
• 1Y: 3.66%
• 3Y*: 12.79%
• 5Y*: 10.99%
• 10Y*: 15.31%

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

FMACX vs. MRFOX - Expense Ratio Comparison

FMACX has a 0.34% expense ratio, which is lower than MRFOX's 1.05% expense ratio.

MRFOX

Marshfield Concentrated Opportunity Fund

FMACX

American Funds AMCAP Fund® Class F-3

Return for Risk

FMACX vs. MRFOX — Risk / Return Rank

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

FMACX

FMACX Risk / Return Rank: 33
FMACX Sharpe Ratio Rank: 29
FMACX Sortino Ratio Rank: 33
FMACX Omega Ratio Rank: 33
FMACX Calmar Ratio Rank: 34
FMACX Martin Ratio Rank: 36

MRFOX

MRFOX Risk / Return Rank: 14
MRFOX Sharpe Ratio Rank: 12
MRFOX Sortino Ratio Rank: 11
MRFOX Omega Ratio Rank: 10
MRFOX Calmar Ratio Rank: 21
MRFOX Martin Ratio Rank: 16

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.

FMACX vs. MRFOX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Funds AMCAP Fund® Class F-3 (FMACX) 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.

	FMACX	MRFOX	Difference
Sharpe ratio Return per unit of total volatility	0.79	0.33	+0.45
Sortino ratio Return per unit of downside risk	1.26	0.57	+0.69
Omega ratio Gain probability vs. loss probability	1.18	1.07	+0.11
Calmar ratio Return relative to maximum drawdown	1.09	0.68	+0.41
Martin ratio Return relative to average drawdown	4.38	1.75	+2.63
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

FMACX vs. MRFOX - Sharpe Ratio Comparison

The current FMACX Sharpe Ratio is 0.79, which is higher than the MRFOX Sharpe Ratio of 0.33. The chart below compares the historical Sharpe Ratios of FMACX 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

	FMACX	MRFOX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	0.79	0.33	+0.45
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.38	0.92	-0.54
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	—	1.07	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.59	1.06	-0.48

Correlation

The correlation between FMACX and MRFOX is 0.73, which is considered to be high. That indicates a strong positive relationship between their price movements. Having highly-correlated positions in a portfolio may signal a lack of diversification, potentially leading to increased risk during market downturns.

Dividends

FMACX vs. MRFOX - Dividend Comparison

FMACX's dividend yield for the trailing twelve months is around 9.41%, more than MRFOX's 1.67% yield.

	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016
FMACX American Funds AMCAP Fund® Class F-3	9.41%	8.62%	8.39%	3.80%	7.46%	4.50%	4.12%	5.16%	8.13%	5.64%	0.00%
MRFOX Marshfield Concentrated Opportunity Fund	1.67%	1.62%	4.59%	0.46%	0.35%	6.78%	2.68%	1.39%	1.94%	2.06%	0.60%

Drawdowns

FMACX vs. MRFOX - Drawdown Comparison

The maximum FMACX drawdown since its inception was -36.00%, which is greater than MRFOX's maximum drawdown of -29.10%. Use the drawdown chart below to compare losses from any high point for FMACX and MRFOX.

Drawdown Indicators

	FMACX	MRFOX	Difference
Max Drawdown Largest peak-to-trough decline	-36.00%	-29.10%	-6.90%
Max Drawdown (1Y) Largest decline over 1 year	-14.12%	-7.09%	-7.03%
Max Drawdown (5Y) Largest decline over 5 years	-36.00%	-12.98%	-23.02%
Max Drawdown (10Y) Largest decline over 10 years	—	-29.10%	—
Current Drawdown Current decline from peak	-10.93%	-5.32%	-5.61%
Average Drawdown Average peak-to-trough decline	-7.44%	-2.37%	-5.07%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.53%	2.77%	+0.76%

Volatility

FMACX vs. MRFOX - Volatility Comparison

American Funds AMCAP Fund® Class F-3 (FMACX) has a higher volatility of 6.72% compared to Marshfield Concentrated Opportunity Fund (MRFOX) at 3.04%. This indicates that FMACX'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

	FMACX	MRFOX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.72%	3.04%	+3.68%
Volatility (6M) Calculated over the trailing 6-month period	11.66%	7.08%	+4.58%
Volatility (1Y) Calculated over the trailing 1-year period	19.90%	11.83%	+8.07%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	19.19%	12.04%	+7.15%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	19.22%	14.29%	+4.93%