MRFOX vs. BIOPX

Last updated Jun 23, 2026

MRFOX (Marshfield Concentrated Opportunity Fund) and BIOPX (Baron Opportunity Fund) are both Large Cap Growth Equities funds. Over the past 10 years, MRFOX returned 15.90%/yr vs 22.22%/yr for BIOPX. A 0.55 correlation means they provide meaningful diversification when combined. MRFOX charges 1.05%/yr vs 1.31%/yr for BIOPX.

Performance

MRFOX vs. BIOPX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Marshfield Concentrated Opportunity Fund (MRFOX) and Baron Opportunity Fund (BIOPX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, MRFOX achieves a 1.40% return, which is significantly lower than BIOPX's 16.82% return. Over the past 10 years, MRFOX has underperformed BIOPX with an annualized return of 15.90%, while BIOPX has yielded a comparatively higher 22.22% annualized return.

MRFOX

• 1D: 0.06%
• 1M: -0.32%
• YTD: 1.40%
• 6M: 0.81%
• 1Y: 10.50%
• 3Y*: 13.67%
• 5Y*: 11.83%
• 10Y*: 15.90%

BIOPX

• 1D: 0.77%
• 1M: 9.55%
• YTD: 16.82%
• 6M: 15.41%
• 1Y: 35.79%
• 3Y*: 28.78%
• 5Y*: 11.36%
• 10Y*: 22.22%

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

MRFOX vs. BIOPX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
MRFOX Marshfield Concentrated Opportunity Fund	1.40%	10.05%	17.10%	17.68%	5.06%	17.71%	15.19%	36.26%	1.89%	25.92%
BIOPX Baron Opportunity Fund	16.82%	19.44%	39.87%	49.55%	-42.96%	11.90%	88.78%	40.34%	8.06%	40.58%

Correlation

The correlation between MRFOX and BIOPX is 0.17, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.17
Correlation (3Y) Calculated over the trailing 3-year period	0.35
Correlation (5Y) Calculated over the trailing 5-year period	0.49
Correlation (10Y) Calculated over the trailing 10-year period	0.54
Correlation (All Time) Calculated using the full available price history since Jan 4, 2016	0.55

Over the past year, the correlation between MRFOX and BIOPX has dropped to 0.17 - well below their long-term average of 0.55, suggesting their price drivers have been diverging.

Return for Risk

MRFOX vs. BIOPX — Risk / Return Rank

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

MRFOX

MRFOX Risk / Return Rank: 18
MRFOX Sharpe Ratio Rank: 17
MRFOX Sortino Ratio Rank: 18
MRFOX Omega Ratio Rank: 16
MRFOX Calmar Ratio Rank: 20
MRFOX Martin Ratio Rank: 19

BIOPX

BIOPX Risk / Return Rank: 41
BIOPX Sharpe Ratio Rank: 41
BIOPX Sortino Ratio Rank: 40
BIOPX Omega Ratio Rank: 40
BIOPX Calmar Ratio Rank: 46
BIOPX Martin Ratio Rank: 39

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.

MRFOX vs. BIOPX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Marshfield Concentrated Opportunity Fund (MRFOX) and Baron Opportunity Fund (BIOPX). 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.

	MRFOX	BIOPX	Difference
Sharpe ratio: Return per unit of total volatility	1.09	1.73	-0.64
Sortino ratio: Return per unit of downside risk	1.66	2.47	-0.81
Omega ratio: Gain probability vs. loss probability	1.19	1.31	-0.12
Calmar ratio: Return relative to maximum drawdown	1.53	2.47	-0.94
Martin ratio: Return relative to average drawdown	4.51	8.08	-3.57

MRFOX vs. BIOPX - Sharpe Ratio Comparison

The current MRFOX Sharpe Ratio is 1.09, which is lower than the BIOPX Sharpe Ratio of 1.73. The chart below compares the historical Sharpe Ratios of MRFOX and BIOPX, 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

MRFOX vs. BIOPX - Drawdown Comparison

The maximum MRFOX drawdown since its inception was -29.10%, smaller than the maximum BIOPX drawdown of -67.91%. Use the drawdown chart below to compare losses from any high point for MRFOX and BIOPX.

Drawdown Indicators

	MRFOX	BIOPX	Difference
Max Drawdown Largest peak-to-trough decline	-29.10%	-67.91%	+38.81%
Max Drawdown (1Y) Largest decline over 1 year	-7.03%	-14.16%	+7.13%
Max Drawdown (3Y) Largest decline over 3 years	-7.91%	-26.34%	+18.43%
Max Drawdown (5Y) Largest decline over 5 years	-12.98%	-51.45%	+38.47%
Max Drawdown (10Y) Largest decline over 10 years	-29.10%	-51.45%	+22.35%
Current Drawdown Current decline from peak	-1.05%	-1.44%	+0.39%
Average Drawdown Average peak-to-trough decline	-2.36%	-16.85%	+14.49%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.37%	4.31%	-1.94%

Volatility

MRFOX vs. BIOPX - Volatility Comparison

The current volatility for Marshfield Concentrated Opportunity Fund (MRFOX) is 2.91%, while Baron Opportunity Fund (BIOPX) has a volatility of 9.18%. This indicates that MRFOX experiences smaller price fluctuations and is considered to be less risky than BIOPX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	MRFOX	BIOPX	Difference
Volatility (1M) Calculated over the trailing 1-month period	2.91%	9.18%	-6.27%
Volatility (6M) Calculated over the trailing 6-month period	6.89%	14.64%	-7.75%
Volatility (1Y) Calculated over the trailing 1-year period	9.85%	20.15%	-10.30%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	12.08%	26.93%	-14.85%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	14.25%	24.99%	-10.74%

MRFOX vs. BIOPX - Expense Ratio Comparison

MRFOX has a 1.05% expense ratio, which is lower than BIOPX's 1.31% expense ratio.

Dividends

MRFOX vs. BIOPX - Dividend Comparison

MRFOX's dividend yield for the trailing twelve months is around 1.60%, less than BIOPX's 3.63% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
BIOPX Baron Opportunity Fund	3.63%	4.24%	4.95%	0.00%	0.00%	8.71%	6.96%	7.33%	5.29%	15.58%	13.52%	10.92%
MRFOX Marshfield Concentrated Opportunity Fund	1.60%	1.62%	4.59%	0.46%	0.35%	6.78%	2.68%	1.39%	1.94%	2.06%	0.60%	0.00%

Frequently Asked Questions

Can I hold both MRFOX and BIOPX in my portfolio?

MRFOX and BIOPX have a correlation of 0.17, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, MRFOX or BIOPX?

BIOPX has higher volatility (9.18%) compared to MRFOX (2.91%). In terms of maximum drawdown, MRFOX dropped -29.10% vs BIOPX's -67.91%.

Which has better risk-adjusted returns?

BIOPX currently has the higher Sharpe Ratio (1.73 vs 1.09), 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.