PDFDX vs. RYOIX

Last updated Jun 4, 2026

PDFDX (Perkins Discovery Fund) and RYOIX (Rydex Biotechnology Fund) are both Health & Biotech Equities funds. Over the past 10 years, PDFDX returned 9.82%/yr vs 8.43%/yr for RYOIX. A 0.56 correlation means they provide meaningful diversification when combined. PDFDX charges 2.50%/yr vs 1.36%/yr for RYOIX.

Performance

PDFDX vs. RYOIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Perkins Discovery Fund (PDFDX) and Rydex Biotechnology Fund (RYOIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, PDFDX achieves a 1.98% return, which is significantly lower than RYOIX's 3.07% return. Over the past 10 years, PDFDX has outperformed RYOIX with an annualized return of 9.82%, while RYOIX has yielded a comparatively lower 8.43% annualized return.

PDFDX

• 1D: -0.19%
• 1M: 5.46%
• YTD: 1.98%
• 6M: 2.97%
• 1Y: 31.05%
• 3Y*: 8.77%
• 5Y*: -4.76%
• 10Y*: 9.82%

RYOIX

• 1D: -2.50%
• 1M: -0.87%
• YTD: 3.07%
• 6M: 1.44%
• 1Y: 37.64%
• 3Y*: 12.67%
• 5Y*: 4.98%
• 10Y*: 8.43%

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

PDFDX vs. RYOIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
PDFDX Perkins Discovery Fund	1.98%	9.94%	19.19%	10.77%	-39.93%	2.11%	62.16%	15.01%	22.19%	11.58%
RYOIX Rydex Biotechnology Fund	3.07%	30.62%	-0.95%	6.06%	-13.04%	2.05%	21.94%	30.69%	-8.94%	29.68%

Correlation

The correlation between PDFDX and RYOIX is 0.51, 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	0.51
Correlation (3Y) Calculated over the trailing 3-year period	0.59
Correlation (5Y) Calculated over the trailing 5-year period	0.70
Correlation (10Y) Calculated over the trailing 10-year period	0.69
Correlation (All Time) Calculated using the full available price history since Jan 5, 1999	0.56

The correlation between PDFDX and RYOIX shifts across timeframes, from 0.51 (1 year) to 0.70 (5 years), reflecting how their relationship changes across market environments.

Return for Risk

PDFDX vs. RYOIX — Risk / Return Rank

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

PDFDX

PDFDX Risk / Return Rank: 19
PDFDX Sharpe Ratio Rank: 20
PDFDX Sortino Ratio Rank: 22
PDFDX Omega Ratio Rank: 18
PDFDX Calmar Ratio Rank: 18
PDFDX Martin Ratio Rank: 15

RYOIX

RYOIX Risk / Return Rank: 62
RYOIX Sharpe Ratio Rank: 47
RYOIX Sortino Ratio Rank: 48
RYOIX Omega Ratio Rank: 40
RYOIX Calmar Ratio Rank: 90
RYOIX Martin Ratio Rank: 86

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.

PDFDX vs. RYOIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Perkins Discovery Fund (PDFDX) and Rydex Biotechnology Fund (RYOIX). 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.

	PDFDX	RYOIX	Difference
Sharpe ratio: Return per unit of total volatility	1.29	2.02	-0.73
Sortino ratio: Return per unit of downside risk	2.00	2.93	-0.93
Omega ratio: Gain probability vs. loss probability	1.22	1.34	-0.12
Calmar ratio: Return relative to maximum drawdown	1.52	4.63	-3.11
Martin ratio: Return relative to average drawdown	4.28	16.65	-12.36
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

PDFDX vs. RYOIX - Sharpe Ratio Comparison

The current PDFDX Sharpe Ratio is 1.29, which is lower than the RYOIX Sharpe Ratio of 2.02. The chart below compares the historical Sharpe Ratios of PDFDX and RYOIX, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

Sharpe Ratios by Period

	PDFDX	RYOIX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.29	2.02	-0.73
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	-0.16	0.24	-0.40
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.34	0.36	-0.02
Sharpe Ratio (All Time) Calculated using the full available price history	0.38	0.36	+0.02

Drawdowns

PDFDX vs. RYOIX - Drawdown Comparison

The maximum PDFDX drawdown since its inception was -67.44%, smaller than the maximum RYOIX drawdown of -74.43%. Use the drawdown chart below to compare losses from any high point for PDFDX and RYOIX.

Drawdown Indicators

	PDFDX	RYOIX	Difference
Max Drawdown Largest peak-to-trough decline	-67.44%	-74.43%	+6.99%
Max Drawdown (1Y) Largest decline over 1 year	-22.11%	-8.43%	-13.68%
Max Drawdown (3Y) Largest decline over 3 years	-31.75%	-23.47%	-8.28%
Max Drawdown (5Y) Largest decline over 5 years	-59.95%	-33.66%	-26.29%
Max Drawdown (10Y) Largest decline over 10 years	-62.70%	-33.66%	-29.04%
Current Drawdown Current decline from peak	-34.65%	-4.48%	-30.17%
Average Drawdown Average peak-to-trough decline	-25.72%	-27.64%	+1.92%
Ulcer Index Depth and duration of drawdowns from previous peaks	7.80%	2.34%	+5.46%

Volatility

PDFDX vs. RYOIX - Volatility Comparison

Perkins Discovery Fund (PDFDX) and Rydex Biotechnology Fund (RYOIX) have volatilities of 6.50% and 6.58%, 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

	PDFDX	RYOIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.50%	6.58%	-0.08%
Volatility (6M) Calculated over the trailing 6-month period	18.09%	14.84%	+3.25%
Volatility (1Y) Calculated over the trailing 1-year period	26.02%	19.35%	+6.67%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	29.80%	21.22%	+8.58%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	28.96%	23.23%	+5.73%

PDFDX vs. RYOIX - Expense Ratio Comparison

PDFDX has a 2.50% expense ratio, which is higher than RYOIX's 1.36% expense ratio.

Dividends

PDFDX vs. RYOIX - Dividend Comparison

PDFDX's dividend yield for the trailing twelve months is around 9.60%, less than RYOIX's 12.19% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
PDFDX Perkins Discovery Fund	9.60%	4.25%	0.00%	0.00%	1.78%	31.11%	1.71%	0.00%	0.58%	0.00%	0.00%	0.00%
RYOIX Rydex Biotechnology Fund	12.19%	12.57%	14.61%	0.00%	1.29%	19.39%	7.28%	8.58%	14.11%	5.38%	0.00%	1.45%

Frequently Asked Questions

Can I hold both PDFDX and RYOIX in my portfolio?

PDFDX and RYOIX have a correlation of 0.51, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, PDFDX or RYOIX?

RYOIX has higher volatility (6.58%) compared to PDFDX (6.50%). In terms of maximum drawdown, PDFDX dropped -67.44% vs RYOIX's -74.43%.

Which has better risk-adjusted returns?

RYOIX currently has the higher Sharpe Ratio (2.02 vs 1.29), 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.