RYGRX vs. AULDX

Last updated Jun 4, 2026

RYGRX (Rydex S&P 500 Pure Growth Fund) and AULDX (American Century Ultra Fund Class R6) are both Large Cap Growth Equities funds. Over the past 10 years, RYGRX returned 13.20%/yr vs 18.69%/yr for AULDX. Their correlation of 0.88 suggests significant overlap in exposure. RYGRX charges 2.26%/yr vs 0.52%/yr for AULDX.

Performance

RYGRX vs. AULDX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Rydex S&P 500 Pure Growth Fund (RYGRX) and American Century Ultra Fund Class R6 (AULDX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, RYGRX achieves a 30.14% return, which is significantly higher than AULDX's 9.84% return. Over the past 10 years, RYGRX has underperformed AULDX with an annualized return of 13.20%, while AULDX has yielded a comparatively higher 18.69% annualized return.

RYGRX

• 1D: 0.92%
• 1M: 11.15%
• YTD: 30.14%
• 6M: 30.55%
• 1Y: 37.82%
• 3Y*: 25.67%
• 5Y*: 11.07%
• 10Y*: 13.20%

AULDX

• 1D: -0.38%
• 1M: 6.26%
• YTD: 9.84%
• 6M: 8.20%
• 1Y: 26.07%
• 3Y*: 22.37%
• 5Y*: 13.43%
• 10Y*: 18.69%

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

RYGRX vs. AULDX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
RYGRX Rydex S&P 500 Pure Growth Fund	30.14%	11.00%	25.73%	5.80%	-28.71%	26.61%	26.34%	34.13%	-6.28%	23.74%
AULDX American Century Ultra Fund Class R6	9.84%	13.05%	29.99%	43.86%	-32.15%	23.89%	50.31%	35.23%	1.04%	32.36%

Correlation

The correlation between RYGRX and AULDX is 0.75, 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	0.75
Correlation (3Y) Calculated over the trailing 3-year period	0.78
Correlation (5Y) Calculated over the trailing 5-year period	0.84
Correlation (10Y) Calculated over the trailing 10-year period	0.87
Correlation (All Time) Calculated using the full available price history since Jan 3, 2014	0.88

The correlation between RYGRX and AULDX shifts across timeframes, from 0.75 (1 year) to 0.88 (all time), reflecting how their relationship changes across market environments.

Return for Risk

RYGRX vs. AULDX — Risk / Return Rank

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

RYGRX

RYGRX Risk / Return Rank: 55
RYGRX Sharpe Ratio Rank: 46
RYGRX Sortino Ratio Rank: 42
RYGRX Omega Ratio Rank: 41
RYGRX Calmar Ratio Rank: 78
RYGRX Martin Ratio Rank: 71

AULDX

AULDX Risk / Return Rank: 28
AULDX Sharpe Ratio Rank: 33
AULDX Sortino Ratio Rank: 29
AULDX Omega Ratio Rank: 30
AULDX Calmar Ratio Rank: 22
AULDX Martin Ratio Rank: 25

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.

RYGRX vs. AULDX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Rydex S&P 500 Pure Growth Fund (RYGRX) and American Century Ultra Fund Class R6 (AULDX). 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.

	RYGRX	AULDX	Difference
Sharpe ratio: Return per unit of total volatility	2.00	1.65	+0.35
Sortino ratio: Return per unit of downside risk	2.70	2.26	+0.44
Omega ratio: Gain probability vs. loss probability	1.35	1.29	+0.06
Calmar ratio: Return relative to maximum drawdown	3.53	1.72	+1.81
Martin ratio: Return relative to average drawdown	13.56	6.07	+7.48
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

RYGRX vs. AULDX - Sharpe Ratio Comparison

The current RYGRX Sharpe Ratio is 2.00, which is comparable to the AULDX Sharpe Ratio of 1.65. The chart below compares the historical Sharpe Ratios of RYGRX and AULDX, 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

	RYGRX	AULDX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	2.00	1.65	+0.35
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.47	0.60	-0.12
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.58	0.85	-0.27
Sharpe Ratio (All Time) Calculated using the full available price history	0.44	0.78	-0.34

Drawdowns

RYGRX vs. AULDX - Drawdown Comparison

The maximum RYGRX drawdown since its inception was -54.22%, which is greater than AULDX's maximum drawdown of -35.03%. Use the drawdown chart below to compare losses from any high point for RYGRX and AULDX.

Drawdown Indicators

	RYGRX	AULDX	Difference
Max Drawdown Largest peak-to-trough decline	-54.22%	-35.03%	-19.19%
Max Drawdown (1Y) Largest decline over 1 year	-11.17%	-15.60%	+4.43%
Max Drawdown (3Y) Largest decline over 3 years	-24.95%	-24.78%	-0.17%
Max Drawdown (5Y) Largest decline over 5 years	-36.57%	-35.03%	-1.54%
Max Drawdown (10Y) Largest decline over 10 years	-36.63%	-35.03%	-1.60%
Current Drawdown Current decline from peak	0.00%	-0.38%	+0.38%
Average Drawdown Average peak-to-trough decline	-9.41%	-6.19%	-3.22%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.91%	4.42%	-1.51%

Volatility

RYGRX vs. AULDX - Volatility Comparison

Rydex S&P 500 Pure Growth Fund (RYGRX) has a higher volatility of 6.39% compared to American Century Ultra Fund Class R6 (AULDX) at 3.77%. This indicates that RYGRX's price experiences larger fluctuations and is considered to be riskier than AULDX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	RYGRX	AULDX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.39%	3.77%	+2.62%
Volatility (6M) Calculated over the trailing 6-month period	16.30%	12.32%	+3.98%
Volatility (1Y) Calculated over the trailing 1-year period	19.71%	16.30%	+3.41%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	23.50%	22.57%	+0.93%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	22.88%	22.08%	+0.80%

RYGRX vs. AULDX - Expense Ratio Comparison

RYGRX has a 2.26% expense ratio, which is higher than AULDX's 0.52% expense ratio.

Dividends

RYGRX vs. AULDX - Dividend Comparison

RYGRX's dividend yield for the trailing twelve months is around 3.91%, less than AULDX's 9.65% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
AULDX American Century Ultra Fund Class R6	9.65%	10.60%	3.32%	5.68%	6.97%	6.42%	2.67%	4.18%	7.94%	6.19%	4.45%	5.06%
RYGRX Rydex S&P 500 Pure Growth Fund	3.91%	5.09%	0.00%	0.00%	0.00%	2.81%	4.43%	12.10%	7.15%	6.26%	0.05%	2.96%

Frequently Asked Questions

Can I hold both RYGRX and AULDX in my portfolio?

RYGRX and AULDX have a correlation of 0.75, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, RYGRX or AULDX?

RYGRX has higher volatility (6.39%) compared to AULDX (3.77%). In terms of maximum drawdown, RYGRX dropped -54.22% vs AULDX's -35.03%.

Which has better risk-adjusted returns?

RYGRX currently has the higher Sharpe Ratio (2.00 vs 1.65), 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.