PREFX vs. AMRGX

Last updated Jun 25, 2026

PREFX (T. Rowe Price Tax-Efficient Equity Fund) and AMRGX (American Growth Fund Series One) are both Large Cap Growth Equities funds. Over the past 10 years, PREFX returned 16.66%/yr vs 12.67%/yr for AMRGX. Their correlation of 0.86 suggests significant overlap in exposure. PREFX charges 0.76%/yr vs 4.07%/yr for AMRGX.

Performance

PREFX vs. AMRGX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in T. Rowe Price Tax-Efficient Equity Fund (PREFX) 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, PREFX achieves a 2.50% return, which is significantly lower than AMRGX's 17.93% return. Over the past 10 years, PREFX has outperformed AMRGX with an annualized return of 16.66%, while AMRGX has yielded a comparatively lower 12.67% annualized return.

PREFX

• 1D: -1.95%
• 1M: -3.14%
• YTD: 2.50%
• 6M: 0.89%
• 1Y: 14.16%
• 3Y*: 21.05%
• 5Y*: 10.40%
• 10Y*: 16.66%

AMRGX

• 1D: -2.41%
• 1M: 2.80%
• YTD: 17.93%
• 6M: 15.90%
• 1Y: 35.19%
• 3Y*: 19.71%
• 5Y*: 10.31%
• 10Y*: 12.67%

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

PREFX vs. AMRGX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
PREFX T. Rowe Price Tax-Efficient Equity Fund	2.50%	16.30%	32.37%	36.98%	-30.52%	22.19%	35.32%	36.59%	-0.46%	28.80%
AMRGX American Growth Fund Series One	17.93%	11.18%	16.61%	24.38%	-19.93%	15.64%	18.65%	36.73%	-9.07%	13.37%

Correlation

The correlation between PREFX and AMRGX is 0.64, 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	0.64
Correlation (3Y) Calculated over the trailing 3-year period	0.75
Correlation (5Y) Calculated over the trailing 5-year period	0.82
Correlation (10Y) Calculated over the trailing 10-year period	0.85
Correlation (All Time) Calculated using the full available price history since Jan 2, 2001	0.86

Over the past year, the correlation between PREFX and AMRGX has dropped to 0.64 - well below their long-term average of 0.86, suggesting their price drivers have been diverging.

Return for Risk

PREFX vs. AMRGX — Risk / Return Rank

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

PREFX

PREFX Risk / Return Rank: 14
PREFX Sharpe Ratio Rank: 15
PREFX Sortino Ratio Rank: 15
PREFX Omega Ratio Rank: 15
PREFX Calmar Ratio Rank: 12
PREFX Martin Ratio Rank: 13

AMRGX

AMRGX Risk / Return Rank: 38
AMRGX Sharpe Ratio Rank: 27
AMRGX Sortino Ratio Rank: 29
AMRGX Omega Ratio Rank: 48
AMRGX Calmar Ratio Rank: 55
AMRGX Martin Ratio Rank: 30

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.

PREFX vs. AMRGX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for T. Rowe Price Tax-Efficient Equity Fund (PREFX) 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.

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.

	PREFX	AMRGX	Difference
Sharpe ratio: Return per unit of total volatility	1.00	1.34	-0.34
Sortino ratio: Return per unit of downside risk	1.46	2.04	-0.58
Omega ratio: Gain probability vs. loss probability	1.18	1.34	-0.16
Calmar ratio: Return relative to maximum drawdown	1.01	2.66	-1.65
Martin ratio: Return relative to average drawdown	3.36	6.47	-3.11

PREFX vs. AMRGX - Sharpe Ratio Comparison

The current PREFX Sharpe Ratio is 1.00, which is comparable to the AMRGX Sharpe Ratio of 1.34. The chart below compares the historical Sharpe Ratios of PREFX 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.

Drawdowns

PREFX vs. AMRGX - Drawdown Comparison

The maximum PREFX drawdown since its inception was -56.70%, smaller than the maximum AMRGX drawdown of -80.32%. Use the drawdown chart below to compare losses from any high point for PREFX and AMRGX.

Drawdown Indicators

	PREFX	AMRGX	Difference
Max Drawdown Largest peak-to-trough decline	-56.70%	-80.32%	+23.62%
Max Drawdown (1Y) Largest decline over 1 year	-16.18%	-13.98%	-2.20%
Max Drawdown (3Y) Largest decline over 3 years	-23.06%	-21.15%	-1.91%
Max Drawdown (5Y) Largest decline over 5 years	-35.95%	-35.42%	-0.53%
Max Drawdown (10Y) Largest decline over 10 years	-35.95%	-35.42%	-0.53%
Current Drawdown Current decline from peak	-5.90%	-2.41%	-3.49%
Average Drawdown Average peak-to-trough decline	-10.25%	-40.17%	+29.92%
Ulcer Index Depth and duration of drawdowns from previous peaks	4.80%	5.70%	-0.90%

Volatility

PREFX vs. AMRGX - Volatility Comparison

The current volatility for T. Rowe Price Tax-Efficient Equity Fund (PREFX) is 6.51%, while American Growth Fund Series One (AMRGX) has a volatility of 8.47%. This indicates that PREFX 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

	PREFX	AMRGX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.51%	8.47%	-1.96%
Volatility (6M) Calculated over the trailing 6-month period	13.50%	16.11%	-2.61%
Volatility (1Y) Calculated over the trailing 1-year period	16.48%	27.85%	-11.37%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	21.79%	22.45%	-0.66%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	21.29%	21.58%	-0.29%

PREFX vs. AMRGX - Expense Ratio Comparison

PREFX has a 0.76% expense ratio, which is lower than AMRGX's 4.07% expense ratio.

Dividends

PREFX vs. AMRGX - Dividend Comparison

PREFX has not paid dividends to shareholders, while AMRGX's dividend yield for the trailing twelve months is around 15.11%.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
AMRGX American Growth Fund Series One	15.11%	17.82%	12.39%	8.17%	7.77%	12.21%	2.36%	0.00%	0.00%	0.00%	0.00%	0.00%
PREFX T. Rowe Price Tax-Efficient Equity Fund	0.00%	0.00%	0.85%	0.61%	0.88%	2.09%	1.98%	0.94%	1.36%	2.82%	0.22%	0.55%

Frequently Asked Questions

Can I hold both PREFX and AMRGX in my portfolio?

PREFX and AMRGX have a correlation of 0.64, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, PREFX or AMRGX?

AMRGX has higher volatility (8.47%) compared to PREFX (6.51%). In terms of maximum drawdown, PREFX dropped -56.70% vs AMRGX's -80.32%.

Which has better risk-adjusted returns?

AMRGX currently has the higher Sharpe Ratio (1.34 vs 1.00), 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.