POGRX vs. RCKSX

Last updated Aug 1, 2026

POGRX (PRIMECAP Odyssey Growth Fund) and RCKSX (Rock Oak Core Growth Fund) are both Large Cap Blend Equities funds. Over the past 10 years, POGRX returned 16.41%/yr vs 11.23%/yr for RCKSX. Their correlation of 0.87 means they have usually moved in the same direction. POGRX charges 0.66%/yr vs 1.25%/yr for RCKSX.

Performance

POGRX vs. RCKSX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in PRIMECAP Odyssey Growth Fund (POGRX) and Rock Oak Core Growth Fund (RCKSX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, POGRX achieves a 22.85% return, which is significantly higher than RCKSX's 20.84% return. Over the past 10 years, POGRX has outperformed RCKSX with an annualized return of 16.41%, while RCKSX has yielded a comparatively lower 11.23% annualized return.

POGRX

• 1D: 3.85%
• 1M: -4.02%
• 6M: 16.81%
• YTD: 22.85%
• 1Y: 52.22%
• 3Y*: 25.37%
• 5Y*: 14.97%
• 10Y*: 16.41%
• ALL TIME*: 12.96%

RCKSX

• 1D: 0.49%
• 1M: 1.77%
• 6M: 14.90%
• YTD: 20.84%
• 1Y: 26.97%
• 3Y*: 19.18%
• 5Y*: 8.92%
• 10Y*: 11.23%
• ALL TIME*: 8.00%

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

Liquidity Comparison

Position	Avg. Volume Value (2W)	Avg. Volume Value (1M)	Avg. Volume Value (3M)
POGRX PRIMECAP Odyssey Growth Fund	$0.00	$0.00	$0.00
RCKSX Rock Oak Core Growth Fund	$0.00	$0.00	$0.00

POGRX vs. RCKSX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
POGRX PRIMECAP Odyssey Growth Fund	22.85%	32.99%	13.09%	23.85%	-14.61%	18.81%	17.05%	23.98%	-4.56%	32.07%
RCKSX Rock Oak Core Growth Fund	20.84%	12.99%	15.12%	15.57%	-18.09%	9.96%	13.75%	19.05%	-2.14%	22.69%

Correlation

The correlation between POGRX and RCKSX is 0.53, which is moderate. They have sometimes moved together and sometimes differently, sharing some price drivers without tracking each other closely.

	Correlation
Correlation (1Y) Focuses on recent behavior, but can change the most.	0.53
Correlation (3Y) Balances recent behavior with more history.	0.69
Correlation (5Y) Shows whether the relationship held over a longer period.	0.78
Correlation (10Y) Provides a long-term view across more market conditions.	0.84
Correlation (All Time) Calculated using the full available price history since Jan 3, 2005	0.87

Over the past year, the correlation between POGRX and RCKSX has dropped to 0.53 - well below their long-term average of 0.87, suggesting their price drivers have been diverging.

Return for Risk

POGRX vs. RCKSX — Risk / Return Rank

Compare historical risk-adjusted metric ranks over the past 12 months.

POGRX

POGRX Risk / Return Rank: 89
POGRX Sharpe Ratio Rank: 91
POGRX Sortino Ratio Rank: 87
POGRX Omega Ratio Rank: 84
POGRX Calmar Ratio Rank: 91
POGRX Martin Ratio Rank: 91

RCKSX

RCKSX Risk / Return Rank: 89
RCKSX Sharpe Ratio Rank: 87
RCKSX Sortino Ratio Rank: 85
RCKSX Omega Ratio Rank: 80
RCKSX Calmar Ratio Rank: 98
RCKSX Martin Ratio Rank: 97

The rank (0–100) uses a weighted average of the Sharpe, Sortino, Omega, Calmar, and Martin percentile ranks for the trailing 12 months. Higher means stronger historical risk-adjusted performance within the peer group.

POGRX vs. RCKSX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for PRIMECAP Odyssey Growth Fund (POGRX) and Rock Oak Core Growth Fund (RCKSX). 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.

	POGRX	RCKSX	Difference
Sharpe ratio: Return per unit of total volatility	2.30	2.14	+0.16
Sortino ratio: Return per unit of downside risk	3.13	3.07	+0.07
Omega ratio: Gain probability vs. loss probability	1.40	1.36	+0.04
Calmar ratio: Return relative to maximum drawdown	3.40	5.87	-2.47
Martin ratio: Return relative to average drawdown	12.40	19.20	-6.79

POGRX vs. RCKSX - Sharpe Ratio Comparison

The current POGRX Sharpe Ratio is 2.30, which is comparable to the RCKSX Sharpe Ratio of 2.14. The chart below compares the historical Sharpe Ratios of POGRX and RCKSX, 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

POGRX vs. RCKSX - Drawdown Comparison

The maximum POGRX drawdown since its inception was -51.63%, smaller than the maximum RCKSX drawdown of -57.88%. Use the drawdown chart below to compare losses from any high point for POGRX and RCKSX.

Drawdown Indicators

	POGRX	RCKSX	Difference
Max Drawdown Largest peak-to-trough decline	-51.63%	-57.88%	+6.25%
Max Drawdown (1Y) Largest decline over 1 year	-14.40%	-4.14%	-10.26%
Max Drawdown (3Y) Largest decline over 3 years	-22.13%	-18.22%	-3.91%
Max Drawdown (5Y) Largest decline over 5 years	-26.85%	-22.54%	-4.31%
Max Drawdown (10Y) Largest decline over 10 years	-35.29%	-33.10%	-2.19%
Current Drawdown Current decline from peak	-8.22%	-0.28%	-7.94%
Average Drawdown Average peak-to-trough decline	-7.11%	-9.44%	+2.33%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.95%	1.28%	+2.67%

Volatility

POGRX vs. RCKSX - Volatility Comparison

PRIMECAP Odyssey Growth Fund (POGRX) has a higher volatility of 7.59% compared to Rock Oak Core Growth Fund (RCKSX) at 2.54%. This indicates that POGRX's price experiences larger fluctuations and is considered to be riskier than RCKSX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	POGRX	RCKSX	Difference
Volatility (1M) Calculated over the trailing 1-month period	7.59%	2.54%	+5.05%
Volatility (6M) Calculated over the trailing 6-month period	18.17%	7.57%	+10.60%
Volatility (1Y) Calculated over the trailing 1-year period	21.29%	11.36%	+9.93%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	20.21%	15.57%	+4.64%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	20.66%	17.39%	+3.27%

POGRX vs. RCKSX - Expense Ratio Comparison

POGRX has a 0.66% expense ratio, which is lower than RCKSX's 1.25% expense ratio.

Dividends

POGRX vs. RCKSX - Dividend Comparison

POGRX's dividend yield for the trailing twelve months is around 20.26%, more than RCKSX's 5.18% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
POGRX PRIMECAP Odyssey Growth Fund	20.26%	24.89%	20.79%	13.28%	12.36%	13.68%	12.50%	5.13%	2.45%	1.54%	5.83%	1.29%
RCKSX Rock Oak Core Growth Fund	5.18%	6.26%	0.47%	0.71%	1.00%	4.31%	16.56%	3.18%	0.59%	5.91%	0.70%	3.21%

Frequently Asked Questions

Can I hold both POGRX and RCKSX in my portfolio?

POGRX and RCKSX have a correlation of 0.53, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, POGRX or RCKSX?

POGRX has higher volatility (7.59%) compared to RCKSX (2.54%). In terms of maximum drawdown, POGRX dropped -51.63% vs RCKSX's -57.88%.

Which has better risk-adjusted returns?

POGRX currently has the higher Sharpe Ratio (2.30 vs 2.14), 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.