AULDX vs. AMRGX

Last updated Jun 4, 2026

AULDX (American Century Ultra Fund Class R6) and AMRGX (American Growth Fund Series One) are both Large Cap Growth Equities funds. Over the past 10 years, AULDX returned 18.69%/yr vs 12.23%/yr for AMRGX. Their correlation of 0.84 suggests significant overlap in exposure. AULDX charges 0.52%/yr vs 4.07%/yr for AMRGX.

Performance

AULDX vs. AMRGX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Century Ultra Fund Class R6 (AULDX) and American Growth Fund Series One (AMRGX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, AULDX achieves a 9.84% return, which is significantly lower than AMRGX's 18.37% return. Over the past 10 years, AULDX has outperformed AMRGX with an annualized return of 18.69%, while AMRGX has yielded a comparatively lower 12.23% annualized return.

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%

AMRGX

• 1D: 1.75%
• 1M: 7.84%
• YTD: 18.37%
• 6M: 16.83%
• 1Y: 37.84%
• 3Y*: 19.51%
• 5Y*: 10.60%
• 10Y*: 12.23%

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

AULDX vs. AMRGX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
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%
AMRGX American Growth Fund Series One	18.37%	11.18%	16.61%	24.38%	-19.93%	15.64%	18.65%	36.73%	-9.07%	13.37%

Correlation

The correlation between AULDX and AMRGX is 0.63, 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	0.63
Correlation (3Y) Calculated over the trailing 3-year period	0.75
Correlation (5Y) Calculated over the trailing 5-year period	0.81
Correlation (10Y) Calculated over the trailing 10-year period	0.83
Correlation (All Time) Calculated using the full available price history since Jan 3, 2014	0.84

Over the past year, the correlation between AULDX and AMRGX has dropped to 0.63 - well below their long-term average of 0.84, suggesting their price drivers have been diverging.

Return for Risk

AULDX vs. AMRGX — Risk / Return Rank

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

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

AMRGX

AMRGX Risk / Return Rank: 38
AMRGX Sharpe Ratio Rank: 27
AMRGX Sortino Ratio Rank: 29
AMRGX Omega Ratio Rank: 50
AMRGX Calmar Ratio Rank: 55
AMRGX Martin Ratio Rank: 29

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.

AULDX vs. AMRGX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Century Ultra Fund Class R6 (AULDX) and American Growth Fund Series One (AMRGX). 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.

	AULDX	AMRGX	Difference
Sharpe ratio: Return per unit of total volatility	1.65	1.47	+0.18
Sortino ratio: Return per unit of downside risk	2.26	2.23	+0.03
Omega ratio: Gain probability vs. loss probability	1.29	1.39	-0.10
Calmar ratio: Return relative to maximum drawdown	1.72	2.83	-1.11
Martin ratio: Return relative to average drawdown	6.07	6.90	-0.83
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

AULDX vs. AMRGX - Sharpe Ratio Comparison

The current AULDX Sharpe Ratio is 1.65, which is comparable to the AMRGX Sharpe Ratio of 1.47. The chart below compares the historical Sharpe Ratios of AULDX and AMRGX, 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

	AULDX	AMRGX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.65	1.47	+0.18
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.60	0.48	+0.12
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.85	0.57	+0.28
Sharpe Ratio (All Time) Calculated using the full available price history	0.78	0.12	+0.66

Drawdowns

AULDX vs. AMRGX - Drawdown Comparison

The maximum AULDX drawdown since its inception was -35.03%, smaller than the maximum AMRGX drawdown of -80.32%. Use the drawdown chart below to compare losses from any high point for AULDX and AMRGX.

Drawdown Indicators

	AULDX	AMRGX	Difference
Max Drawdown Largest peak-to-trough decline	-35.03%	-80.32%	+45.29%
Max Drawdown (1Y) Largest decline over 1 year	-15.60%	-13.98%	-1.62%
Max Drawdown (3Y) Largest decline over 3 years	-24.78%	-21.15%	-3.63%
Max Drawdown (5Y) Largest decline over 5 years	-35.03%	-35.42%	+0.39%
Max Drawdown (10Y) Largest decline over 10 years	-35.03%	-35.42%	+0.39%
Current Drawdown Current decline from peak	-0.38%	0.00%	-0.38%
Average Drawdown Average peak-to-trough decline	-6.19%	-40.25%	+34.06%
Ulcer Index Depth and duration of drawdowns from previous peaks	4.42%	5.66%	-1.24%

Volatility

AULDX vs. AMRGX - Volatility Comparison

The current volatility for American Century Ultra Fund Class R6 (AULDX) is 3.77%, while American Growth Fund Series One (AMRGX) has a volatility of 6.47%. This indicates that AULDX experiences smaller price fluctuations and is considered to be less risky than AMRGX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	AULDX	AMRGX	Difference
Volatility (1M) Calculated over the trailing 1-month period	3.77%	6.47%	-2.70%
Volatility (6M) Calculated over the trailing 6-month period	12.32%	24.98%	-12.66%
Volatility (1Y) Calculated over the trailing 1-year period	16.30%	26.89%	-10.59%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	22.57%	22.21%	+0.36%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	22.08%	21.50%	+0.58%

AULDX vs. AMRGX - Expense Ratio Comparison

AULDX has a 0.52% expense ratio, which is lower than AMRGX's 4.07% expense ratio.

Dividends

AULDX vs. AMRGX - Dividend Comparison

AULDX's dividend yield for the trailing twelve months is around 9.65%, less than AMRGX's 15.06% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
AMRGX American Growth Fund Series One	15.06%	17.82%	12.39%	8.17%	7.77%	12.21%	2.36%	0.00%	0.00%	0.00%	0.00%	0.00%
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%

Frequently Asked Questions

Can I hold both AULDX and AMRGX in my portfolio?

AULDX and AMRGX have a correlation of 0.63, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, AULDX or AMRGX?

AMRGX has higher volatility (6.47%) compared to AULDX (3.77%). In terms of maximum drawdown, AULDX dropped -35.03% vs AMRGX's -80.32%.

Which has better risk-adjusted returns?

AULDX currently has the higher Sharpe Ratio (1.65 vs 1.47), 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.