STMGX vs. SSMHX

Last updated Jun 24, 2026

STMGX (American Beacon Stephens Mid-Cap Growth Fund) and SSMHX (State Street Small/Mid Cap Equity Index Portfolio) are both Mid Cap Growth Equities funds. Over the past 10 years, STMGX returned 14.17%/yr vs 12.38%/yr for SSMHX. Their correlation of 0.91 suggests significant overlap in exposure. STMGX charges 1.14%/yr vs 0.02%/yr for SSMHX.

Performance

STMGX vs. SSMHX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Beacon Stephens Mid-Cap Growth Fund (STMGX) and State Street Small/Mid Cap Equity Index Portfolio (SSMHX). 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 SSMHX's 15.05% return. Over the past 10 years, STMGX has outperformed SSMHX with an annualized return of 14.17%, while SSMHX has yielded a comparatively lower 12.38% 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%

SSMHX

• 1D: 0.09%
• 1M: 4.28%
• YTD: 15.05%
• 6M: 12.78%
• 1Y: 29.58%
• 3Y*: 18.38%
• 5Y*: 5.97%
• 10Y*: 12.38%

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

STMGX vs. SSMHX - 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%
SSMHX State Street Small/Mid Cap Equity Index Portfolio	15.05%	12.90%	10.73%	25.21%	-25.43%	13.08%	32.46%	28.00%	-9.21%	18.26%

Correlation

The correlation between STMGX and SSMHX is 0.92, indicating a strong positive relationship between their price movements. Combining them offers limited diversification - they tend to fall together during downturns.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.92
Correlation (3Y) Calculated over the trailing 3-year period	0.91
Correlation (5Y) Calculated over the trailing 5-year period	0.93
Correlation (10Y) Calculated over the trailing 10-year period	0.91
Correlation (All Time) Calculated using the full available price history since Aug 17, 2015	0.91

The correlation between STMGX and SSMHX has been stable across timeframes, ranging from 0.91 to 0.93 - a consistent structural relationship.

Return for Risk

STMGX vs. SSMHX — 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

SSMHX

SSMHX Risk / Return Rank: 50
SSMHX Sharpe Ratio Rank: 42
SSMHX Sortino Ratio Rank: 41
SSMHX Omega Ratio Rank: 37
SSMHX Calmar Ratio Rank: 70
SSMHX Martin Ratio Rank: 60

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. SSMHX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Beacon Stephens Mid-Cap Growth Fund (STMGX) and State Street Small/Mid Cap Equity Index Portfolio (SSMHX). 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	SSMHX	Difference
Sharpe ratio: Return per unit of total volatility	1.14	1.76	-0.63
Sortino ratio: Return per unit of downside risk	1.66	2.47	-0.81
Omega ratio: Gain probability vs. loss probability	1.20	1.30	-0.11
Calmar ratio: Return relative to maximum drawdown	1.78	3.08	-1.29
Martin ratio: Return relative to average drawdown	6.21	11.10	-4.89

STMGX vs. SSMHX - Sharpe Ratio Comparison

The current STMGX Sharpe Ratio is 1.14, which is lower than the SSMHX Sharpe Ratio of 1.76. The chart below compares the historical Sharpe Ratios of STMGX and SSMHX, 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. SSMHX - Drawdown Comparison

The maximum STMGX drawdown since its inception was -57.58%, which is greater than SSMHX's maximum drawdown of -41.61%. Use the drawdown chart below to compare losses from any high point for STMGX and SSMHX.

Drawdown Indicators

	STMGX	SSMHX	Difference
Max Drawdown Largest peak-to-trough decline	-57.58%	-41.61%	-15.97%
Max Drawdown (1Y) Largest decline over 1 year	-10.84%	-10.03%	-0.81%
Max Drawdown (3Y) Largest decline over 3 years	-22.50%	-30.38%	+7.88%
Max Drawdown (5Y) Largest decline over 5 years	-36.59%	-34.84%	-1.75%
Max Drawdown (10Y) Largest decline over 10 years	-36.59%	-41.61%	+5.02%
Current Drawdown Current decline from peak	-0.74%	-0.11%	-0.63%
Average Drawdown Average peak-to-trough decline	-10.13%	-9.10%	-1.03%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.11%	2.78%	+0.33%

Volatility

STMGX vs. SSMHX - Volatility Comparison

American Beacon Stephens Mid-Cap Growth Fund (STMGX) has a higher volatility of 6.38% compared to State Street Small/Mid Cap Equity Index Portfolio (SSMHX) at 5.97%. This indicates that STMGX's price experiences larger fluctuations and is considered to be riskier than SSMHX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	STMGX	SSMHX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.38%	5.97%	+0.41%
Volatility (6M) Calculated over the trailing 6-month period	13.49%	13.16%	+0.33%
Volatility (1Y) Calculated over the trailing 1-year period	17.05%	17.56%	-0.51%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	20.94%	22.52%	-1.58%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	20.94%	22.44%	-1.50%

STMGX vs. SSMHX - Expense Ratio Comparison

STMGX has a 1.14% expense ratio, which is higher than SSMHX's 0.02% expense ratio.

Dividends

STMGX vs. SSMHX - Dividend Comparison

STMGX's dividend yield for the trailing twelve months is around 31.02%, more than SSMHX's 6.19% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
SSMHX State Street Small/Mid Cap Equity Index Portfolio	6.19%	7.12%	0.00%	1.56%	2.31%	16.30%	2.91%	3.65%	6.43%	4.01%	1.71%	0.73%
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%

Frequently Asked Questions

Can I hold both STMGX and SSMHX in my portfolio?

With a correlation of 0.92, STMGX and SSMHX move almost identically. Holding both adds very little diversification - you're essentially doubling your position in the same market segment. Choosing one is usually more capital-efficient.

Which is riskier, STMGX or SSMHX?

STMGX has higher volatility (6.38%) compared to SSMHX (5.97%). In terms of maximum drawdown, STMGX dropped -57.58% vs SSMHX's -41.61%.

Which has better risk-adjusted returns?

SSMHX currently has the higher Sharpe Ratio (1.76 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.