STMGX vs. VCPIX

Last updated Jun 4, 2026

STMGX (American Beacon Stephens Mid-Cap Growth Fund) and VCPIX (Vanguard Core-Plus Bond Fund Investor Shares) are both mutual funds - STMGX is a Mid Cap Growth Equities fund managed by American Beacon, while VCPIX is a Total Bond Market fund managed by Vanguard. Over the past 3 years, STMGX returned 17.25%/yr vs 5.30%/yr for VCPIX. At a 0.23 correlation, their price movements are largely independent. STMGX charges 1.14%/yr vs 0.30%/yr for VCPIX.

Performance

STMGX vs. VCPIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Beacon Stephens Mid-Cap Growth Fund (STMGX) and Vanguard Core-Plus Bond Fund Investor Shares (VCPIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, STMGX achieves a 11.65% return, which is significantly higher than VCPIX's 0.62% return.

STMGX

• 1D: 0.71%
• 1M: 8.63%
• YTD: 11.65%
• 6M: 10.19%
• 1Y: 21.54%
• 3Y*: 17.25%
• 5Y*: 7.34%
• 10Y*: 13.85%

VCPIX

• 1D: 0.00%
• 1M: 0.51%
• YTD: 0.62%
• 6M: 0.67%
• 1Y: 6.04%
• 3Y*: 5.30%
• 5Y*: —
• 10Y*: —

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

STMGX vs. VCPIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021
STMGX American Beacon Stephens Mid-Cap Growth Fund	11.65%	12.98%	13.16%	25.22%	-28.31%	1.63%
VCPIX Vanguard Core-Plus Bond Fund Investor Shares	0.62%	8.01%	2.83%	6.64%	-12.68%	0.35%

Correlation

The correlation between STMGX and VCPIX 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	0.25
Correlation (All Time) Calculated using the full available price history since Oct 15, 2021	0.23

Return for Risk

STMGX vs. VCPIX — Risk / Return Rank

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

STMGX

STMGX Risk / Return Rank: 26
STMGX Sharpe Ratio Rank: 24
STMGX Sortino Ratio Rank: 23
STMGX Omega Ratio Rank: 21
STMGX Calmar Ratio Rank: 32
STMGX Martin Ratio Rank: 33

VCPIX

VCPIX Risk / Return Rank: 35
VCPIX Sharpe Ratio Rank: 35
VCPIX Sortino Ratio Rank: 37
VCPIX Omega Ratio Rank: 36
VCPIX Calmar Ratio Rank: 35
VCPIX Martin Ratio Rank: 31

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. VCPIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Beacon Stephens Mid-Cap Growth Fund (STMGX) and Vanguard Core-Plus Bond Fund Investor Shares (VCPIX). 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.

	STMGX	VCPIX	Difference
Sharpe ratio: Return per unit of total volatility	1.41	1.70	-0.30
Sortino ratio: Return per unit of downside risk	2.02	2.53	-0.52
Omega ratio: Gain probability vs. loss probability	1.24	1.31	-0.08
Calmar ratio: Return relative to maximum drawdown	2.11	2.23	-0.12
Martin ratio: Return relative to average drawdown	7.45	7.25	+0.19
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

STMGX vs. VCPIX - Sharpe Ratio Comparison

The current STMGX Sharpe Ratio is 1.41, which is comparable to the VCPIX Sharpe Ratio of 1.70. The chart below compares the historical Sharpe Ratios of STMGX and VCPIX, 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

	STMGX	VCPIX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.41	1.70	-0.30
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.35	—	—
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.67	—	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.46	0.17	+0.29

Drawdowns

STMGX vs. VCPIX - Drawdown Comparison

The maximum STMGX drawdown since its inception was -57.58%, which is greater than VCPIX's maximum drawdown of -17.33%. Use the drawdown chart below to compare losses from any high point for STMGX and VCPIX.

Drawdown Indicators

	STMGX	VCPIX	Difference
Max Drawdown Largest peak-to-trough decline	-57.58%	-17.33%	-40.25%
Max Drawdown (1Y) Largest decline over 1 year	-10.84%	-2.72%	-8.12%
Max Drawdown (3Y) Largest decline over 3 years	-22.50%	-5.68%	-16.82%
Max Drawdown (5Y) Largest decline over 5 years	-36.59%	—	—
Max Drawdown (10Y) Largest decline over 10 years	-36.59%	—	—
Current Drawdown Current decline from peak	0.00%	-1.12%	+1.12%
Average Drawdown Average peak-to-trough decline	-10.16%	-6.60%	-3.56%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.07%	0.83%	+2.24%

Volatility

STMGX vs. VCPIX - Volatility Comparison

American Beacon Stephens Mid-Cap Growth Fund (STMGX) has a higher volatility of 4.24% compared to Vanguard Core-Plus Bond Fund Investor Shares (VCPIX) at 1.23%. This indicates that STMGX's price experiences larger fluctuations and is considered to be riskier than VCPIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	STMGX	VCPIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.24%	1.23%	+3.01%
Volatility (6M) Calculated over the trailing 6-month period	12.70%	2.60%	+10.10%
Volatility (1Y) Calculated over the trailing 1-year period	16.27%	3.57%	+12.70%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	20.83%	5.69%	+15.14%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	20.89%	5.69%	+15.20%

STMGX vs. VCPIX - Expense Ratio Comparison

STMGX has a 1.14% expense ratio, which is higher than VCPIX's 0.30% expense ratio.

Dividends

STMGX vs. VCPIX - Dividend Comparison

STMGX's dividend yield for the trailing twelve months is around 30.79%, more than VCPIX's 4.74% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
STMGX American Beacon Stephens Mid-Cap Growth Fund	30.79%	34.38%	4.86%	0.00%	3.42%	7.49%	1.45%	3.60%	9.39%	5.40%	6.65%	5.62%
VCPIX Vanguard Core-Plus Bond Fund Investor Shares	4.74%	4.76%	5.08%	4.46%	3.15%	0.25%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%

Frequently Asked Questions

Can I hold both STMGX and VCPIX in my portfolio?

STMGX and VCPIX 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 VCPIX?

STMGX has higher volatility (4.24%) compared to VCPIX (1.23%). In terms of maximum drawdown, STMGX dropped -57.58% vs VCPIX's -17.33%.

Which has better risk-adjusted returns?

VCPIX currently has the higher Sharpe Ratio (1.70 vs 1.41), 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.