STMGX vs. TRSSX

Last updated Jun 24, 2026

STMGX (American Beacon Stephens Mid-Cap Growth Fund) and TRSSX (T. Rowe Price Institutional Small Cap Stock Fund) are both mutual funds - STMGX is a Mid Cap Growth Equities fund managed by American Beacon, while TRSSX is a Small Cap Growth Equities fund managed by T. Rowe Price. Over the past 10 years, STMGX returned 14.17%/yr vs 12.40%/yr for TRSSX. Their correlation of 0.89 suggests significant overlap in exposure. STMGX charges 1.14%/yr vs 0.66%/yr for TRSSX.

Performance

STMGX vs. TRSSX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Beacon Stephens Mid-Cap Growth Fund (STMGX) and T. Rowe Price Institutional Small Cap Stock Fund (TRSSX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, STMGX achieves a 10.83% return, which is significantly lower than TRSSX's 16.00% return. Over the past 10 years, STMGX has outperformed TRSSX with an annualized return of 14.17%, while TRSSX has yielded a comparatively lower 12.40% annualized return.

STMGX

• 1D: 0.04%
• 1M: 4.11%
• YTD: 10.83%
• 6M: 9.00%
• 1Y: 18.29%
• 3Y*: 16.40%
• 5Y*: 6.18%
• 10Y*: 14.17%

TRSSX

• 1D: 0.50%
• 1M: 4.74%
• YTD: 16.00%
• 6M: 13.48%
• 1Y: 26.95%
• 3Y*: 15.77%
• 5Y*: 5.32%
• 10Y*: 12.40%

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

STMGX vs. TRSSX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
STMGX American Beacon Stephens Mid-Cap Growth Fund	10.83%	12.98%	13.16%	25.22%	-28.31%	12.29%	39.82%	31.31%	1.71%	27.97%
TRSSX T. Rowe Price Institutional Small Cap Stock Fund	16.00%	8.21%	10.93%	17.65%	-23.36%	16.81%	25.07%	33.96%	-3.07%	15.41%

Correlation

The correlation between STMGX and TRSSX is 0.80, 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	0.80
Correlation (3Y) Calculated over the trailing 3-year period	0.80
Correlation (5Y) Calculated over the trailing 5-year period	0.86
Correlation (10Y) Calculated over the trailing 10-year period	0.85
Correlation (All Time) Calculated using the full available price history since Feb 2, 2006	0.89

The correlation between STMGX and TRSSX has been stable across timeframes, ranging from 0.80 to 0.89 - a consistent structural relationship.

Return for Risk

STMGX vs. TRSSX — Risk / Return Rank

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

STMGX

STMGX Risk / Return Rank: 22
STMGX Sharpe Ratio Rank: 19
STMGX Sortino Ratio Rank: 19
STMGX Omega Ratio Rank: 16
STMGX Calmar Ratio Rank: 26
STMGX Martin Ratio Rank: 29

TRSSX

TRSSX Risk / Return Rank: 43
TRSSX Sharpe Ratio Rank: 35
TRSSX Sortino Ratio Rank: 37
TRSSX Omega Ratio Rank: 33
TRSSX Calmar Ratio Rank: 55
TRSSX Martin Ratio Rank: 54

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.

STMGX vs. TRSSX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Beacon Stephens Mid-Cap Growth Fund (STMGX) and T. Rowe Price Institutional Small Cap Stock Fund (TRSSX). 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.

	STMGX	TRSSX	Difference
Sharpe ratio: Return per unit of total volatility	1.14	1.58	-0.45
Sortino ratio: Return per unit of downside risk	1.66	2.36	-0.70
Omega ratio: Gain probability vs. loss probability	1.20	1.28	-0.08
Calmar ratio: Return relative to maximum drawdown	1.78	2.73	-0.95
Martin ratio: Return relative to average drawdown	6.21	10.29	-4.08

STMGX vs. TRSSX - Sharpe Ratio Comparison

The current STMGX Sharpe Ratio is 1.14, which is comparable to the TRSSX Sharpe Ratio of 1.58. The chart below compares the historical Sharpe Ratios of STMGX and TRSSX, 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

STMGX vs. TRSSX - Drawdown Comparison

The maximum STMGX drawdown since its inception was -57.58%, roughly equal to the maximum TRSSX drawdown of -56.38%. Use the drawdown chart below to compare losses from any high point for STMGX and TRSSX.

Drawdown Indicators

	STMGX	TRSSX	Difference
Max Drawdown Largest peak-to-trough decline	-57.58%	-56.38%	-1.20%
Max Drawdown (1Y) Largest decline over 1 year	-10.84%	-10.73%	-0.11%
Max Drawdown (3Y) Largest decline over 3 years	-22.50%	-30.88%	+8.38%
Max Drawdown (5Y) Largest decline over 5 years	-36.59%	-32.12%	-4.47%
Max Drawdown (10Y) Largest decline over 10 years	-36.59%	-37.85%	+1.26%
Current Drawdown Current decline from peak	-0.74%	0.00%	-0.74%
Average Drawdown Average peak-to-trough decline	-10.13%	-8.99%	-1.14%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.11%	2.82%	+0.29%

Volatility

STMGX vs. TRSSX - Volatility Comparison

American Beacon Stephens Mid-Cap Growth Fund (STMGX) has a higher volatility of 6.38% compared to T. Rowe Price Institutional Small Cap Stock Fund (TRSSX) at 6.00%. This indicates that STMGX's price experiences larger fluctuations and is considered to be riskier than TRSSX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	STMGX	TRSSX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.38%	6.00%	+0.38%
Volatility (6M) Calculated over the trailing 6-month period	13.49%	14.65%	-1.16%
Volatility (1Y) Calculated over the trailing 1-year period	17.05%	18.55%	-1.50%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	20.94%	22.32%	-1.38%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	20.94%	21.61%	-0.67%

STMGX vs. TRSSX - Expense Ratio Comparison

STMGX has a 1.14% expense ratio, which is higher than TRSSX's 0.66% expense ratio.

Dividends

STMGX vs. TRSSX - Dividend Comparison

STMGX's dividend yield for the trailing twelve months is around 31.02%, more than TRSSX's 9.11% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
STMGX American Beacon Stephens Mid-Cap Growth Fund	31.02%	34.38%	4.86%	0.00%	3.42%	7.49%	1.45%	3.60%	9.39%	5.40%	6.65%	5.62%
TRSSX T. Rowe Price Institutional Small Cap Stock Fund	9.11%	10.57%	19.63%	5.45%	5.37%	8.52%	4.54%	6.13%	13.45%	6.53%	0.80%	7.07%

Frequently Asked Questions

Can I hold both STMGX and TRSSX in my portfolio?

STMGX and TRSSX have a correlation of 0.80, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, STMGX or TRSSX?

STMGX has higher volatility (6.38%) compared to TRSSX (6.00%). In terms of maximum drawdown, STMGX dropped -57.58% vs TRSSX's -56.38%.

Which has better risk-adjusted returns?

TRSSX currently has the higher Sharpe Ratio (1.58 vs 1.14), 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.