STMGX vs. AGEYX

Last updated Jul 17, 2026

STMGX (American Beacon Stephens Mid-Cap Growth Fund) and AGEYX (American Beacon Developing World Income Fund Class Y) are both mutual funds - STMGX is a Mid Cap Growth Equities fund managed by American Beacon, while AGEYX is a Emerging Markets Bonds fund tracking the JPMorgan® EMBI Global Diversified Index. Over the past 10 years, STMGX returned 13.47%/yr vs 7.76%/yr for AGEYX. At a 0.24 correlation, their price movements are largely independent. Both charge a 1.14% expense ratio.

Performance

STMGX vs. AGEYX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Beacon Stephens Mid-Cap Growth Fund (STMGX) and American Beacon Developing World Income Fund Class Y (AGEYX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, STMGX achieves a 10.63% return, which is significantly higher than AGEYX's 8.07% return. Over the past 10 years, STMGX has outperformed AGEYX with an annualized return of 13.47%, while AGEYX has yielded a comparatively lower 7.76% annualized return.

STMGX

• 1D: -0.53%
• 1M: 0.86%
• 6M: 5.44%
• YTD: 10.63%
• 1Y: 15.46%
• 3Y*: 14.41%
• 5Y*: 6.19%
• 10Y*: 13.47%

AGEYX

• 1D: 0.00%
• 1M: 0.49%
• 6M: 6.52%
• YTD: 8.07%
• 1Y: 19.24%
• 3Y*: 16.09%
• 5Y*: 8.46%
• 10Y*: 7.76%

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

STMGX vs. AGEYX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
STMGX American Beacon Stephens Mid-Cap Growth Fund	10.63%	12.98%	13.16%	25.22%	-28.31%	12.29%	39.82%	31.31%	1.71%	27.97%
AGEYX American Beacon Developing World Income Fund Class Y	8.07%	19.15%	15.85%	13.10%	-12.62%	6.91%	2.54%	13.49%	-3.42%	15.26%

Correlation

The correlation between STMGX and AGEYX is 0.30, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.30
Correlation (3Y) Calculated over the trailing 3-year period	0.27
Correlation (5Y) Calculated over the trailing 5-year period	0.28
Correlation (10Y) Calculated over the trailing 10-year period	0.24
Correlation (All Time) Calculated using the full available price history since Jan 2, 2015	0.24

Return for Risk

STMGX vs. AGEYX — Risk / Return Rank

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

STMGX

STMGX Risk / Return Rank: 20
STMGX Sharpe Ratio Rank: 17
STMGX Sortino Ratio Rank: 17
STMGX Omega Ratio Rank: 15
STMGX Calmar Ratio Rank: 24
STMGX Martin Ratio Rank: 27

AGEYX

AGEYX Risk / Return Rank: 99
AGEYX Sharpe Ratio Rank: 100
AGEYX Sortino Ratio Rank: 99
AGEYX Omega Ratio Rank: 99
AGEYX Calmar Ratio Rank: 98
AGEYX Martin Ratio Rank: 98

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. AGEYX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Beacon Stephens Mid-Cap Growth Fund (STMGX) and American Beacon Developing World Income Fund Class Y (AGEYX). 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	AGEYX	Difference
Sharpe ratio: Return per unit of total volatility	0.94	5.18	-4.24
Sortino ratio: Return per unit of downside risk	1.41	8.65	-7.24
Omega ratio: Gain probability vs. loss probability	1.16	2.42	-1.26
Calmar ratio: Return relative to maximum drawdown	1.50	6.14	-4.64
Martin ratio: Return relative to average drawdown	5.18	27.47	-22.30

STMGX vs. AGEYX - Sharpe Ratio Comparison

The current STMGX Sharpe Ratio is 0.94, which is lower than the AGEYX Sharpe Ratio of 5.18. The chart below compares the historical Sharpe Ratios of STMGX and AGEYX, 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. AGEYX - Drawdown Comparison

The maximum STMGX drawdown since its inception was -57.58%, which is greater than AGEYX's maximum drawdown of -22.24%. Use the drawdown chart below to compare losses from any high point for STMGX and AGEYX.

Drawdown Indicators

	STMGX	AGEYX	Difference
Max Drawdown Largest peak-to-trough decline	-57.58%	-22.24%	-35.34%
Max Drawdown (1Y) Largest decline over 1 year	-10.84%	-3.15%	-7.69%
Max Drawdown (3Y) Largest decline over 3 years	-22.50%	-4.77%	-17.73%
Max Drawdown (5Y) Largest decline over 5 years	-36.59%	-22.24%	-14.35%
Max Drawdown (10Y) Largest decline over 10 years	-36.59%	-22.24%	-14.35%
Current Drawdown Current decline from peak	-2.72%	0.00%	-2.72%
Average Drawdown Average peak-to-trough decline	-10.11%	-3.51%	-6.60%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.13%	0.70%	+2.43%

Volatility

STMGX vs. AGEYX - Volatility Comparison

American Beacon Stephens Mid-Cap Growth Fund (STMGX) has a higher volatility of 4.92% compared to American Beacon Developing World Income Fund Class Y (AGEYX) at 0.84%. This indicates that STMGX's price experiences larger fluctuations and is considered to be riskier than AGEYX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	STMGX	AGEYX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.92%	0.84%	+4.08%
Volatility (6M) Calculated over the trailing 6-month period	13.58%	2.96%	+10.62%
Volatility (1Y) Calculated over the trailing 1-year period	17.24%	3.73%	+13.51%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	21.00%	5.17%	+15.83%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	20.87%	4.97%	+15.90%

STMGX vs. AGEYX - Expense Ratio Comparison

Both STMGX and AGEYX have an expense ratio of 1.14%.

Dividends

STMGX vs. AGEYX - Dividend Comparison

STMGX's dividend yield for the trailing twelve months is around 31.07%, more than AGEYX's 9.86% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
AGEYX American Beacon Developing World Income Fund Class Y	9.86%	9.99%	12.16%	9.64%	7.50%	7.90%	7.34%	8.61%	9.88%	7.30%	8.43%	7.03%
STMGX American Beacon Stephens Mid-Cap Growth Fund	31.07%	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 AGEYX in my portfolio?

STMGX and AGEYX have a correlation of 0.30, 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 AGEYX?

STMGX has higher volatility (4.92%) compared to AGEYX (0.84%). In terms of maximum drawdown, STMGX dropped -57.58% vs AGEYX's -22.24%.

Which has better risk-adjusted returns?

AGEYX currently has the higher Sharpe Ratio (5.18 vs 0.94), 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.