AMCPX vs. MIGFX

Last updated Jun 4, 2026

AMCPX (American Funds AMCAP Fund Class A) and MIGFX (MFS Massachusetts Investors Growth Stock Fund) are both Large Cap Growth Equities funds. Over the past 10 years, AMCPX returned 12.36%/yr vs 14.65%/yr for MIGFX. Their correlation of 0.89 suggests significant overlap in exposure. AMCPX charges 0.65%/yr vs 0.70%/yr for MIGFX.

Performance

AMCPX vs. MIGFX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Funds AMCAP Fund Class A (AMCPX) and MFS Massachusetts Investors Growth Stock Fund (MIGFX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, AMCPX achieves a 6.34% return, which is significantly higher than MIGFX's -0.34% return. Over the past 10 years, AMCPX has underperformed MIGFX with an annualized return of 12.36%, while MIGFX has yielded a comparatively higher 14.65% annualized return.

AMCPX

• 1D: -0.77%
• 1M: 3.82%
• YTD: 6.34%
• 6M: 6.01%
• 1Y: 21.86%
• 3Y*: 19.82%
• 5Y*: 9.39%
• 10Y*: 12.36%

MIGFX

• 1D: -0.62%
• 1M: 3.14%
• YTD: -0.34%
• 6M: 0.15%
• 1Y: 9.70%
• 3Y*: 15.64%
• 5Y*: 10.07%
• 10Y*: 14.65%

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

AMCPX vs. MIGFX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
AMCPX American Funds AMCAP Fund Class A	6.34%	17.68%	21.11%	31.04%	-28.67%	20.57%	21.42%	26.35%	-4.42%	22.08%
MIGFX MFS Massachusetts Investors Growth Stock Fund	-0.34%	9.97%	27.25%	24.13%	-19.20%	26.06%	22.55%	39.89%	0.81%	28.68%

Correlation

The correlation between AMCPX and MIGFX is 0.89, 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	0.89
Correlation (3Y) Calculated over the trailing 3-year period	0.91
Correlation (5Y) Calculated over the trailing 5-year period	0.92
Correlation (10Y) Calculated over the trailing 10-year period	0.92
Correlation (All Time) Calculated using the full available price history since May 4, 1973	0.89

The correlation between AMCPX and MIGFX has been stable across timeframes, ranging from 0.89 to 0.92 - a consistent structural relationship.

Return for Risk

AMCPX vs. MIGFX — Risk / Return Rank

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

AMCPX

AMCPX Risk / Return Rank: 27
AMCPX Sharpe Ratio Rank: 30
AMCPX Sortino Ratio Rank: 28
AMCPX Omega Ratio Rank: 30
AMCPX Calmar Ratio Rank: 19
AMCPX Martin Ratio Rank: 27

MIGFX

MIGFX Risk / Return Rank: 9
MIGFX Sharpe Ratio Rank: 11
MIGFX Sortino Ratio Rank: 10
MIGFX Omega Ratio Rank: 10
MIGFX Calmar Ratio Rank: 8
MIGFX Martin Ratio Rank: 8

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.

AMCPX vs. MIGFX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Funds AMCAP Fund Class A (AMCPX) and MFS Massachusetts Investors Growth Stock Fund (MIGFX). 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.

	AMCPX	MIGFX	Difference
Sharpe ratio: Return per unit of total volatility	1.56	0.83	+0.73
Sortino ratio: Return per unit of downside risk	2.19	1.22	+0.96
Omega ratio: Gain probability vs. loss probability	1.28	1.15	+0.14
Calmar ratio: Return relative to maximum drawdown	1.60	0.76	+0.84
Martin ratio: Return relative to average drawdown	6.51	2.55	+3.96
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

AMCPX vs. MIGFX - Sharpe Ratio Comparison

The current AMCPX Sharpe Ratio is 1.56, which is higher than the MIGFX Sharpe Ratio of 0.83. The chart below compares the historical Sharpe Ratios of AMCPX and MIGFX, 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

	AMCPX	MIGFX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.56	0.83	+0.73
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.49	0.58	-0.09
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.66	0.81	-0.14
Sharpe Ratio (All Time) Calculated using the full available price history	0.59	0.39	+0.20

Drawdowns

AMCPX vs. MIGFX - Drawdown Comparison

The maximum AMCPX drawdown since its inception was -62.37%, roughly equal to the maximum MIGFX drawdown of -61.83%. Use the drawdown chart below to compare losses from any high point for AMCPX and MIGFX.

Drawdown Indicators

	AMCPX	MIGFX	Difference
Max Drawdown Largest peak-to-trough decline	-62.37%	-61.83%	-0.54%
Max Drawdown (1Y) Largest decline over 1 year	-14.18%	-13.77%	-0.41%
Max Drawdown (3Y) Largest decline over 3 years	-19.71%	-18.68%	-1.03%
Max Drawdown (5Y) Largest decline over 5 years	-36.90%	-26.67%	-10.23%
Max Drawdown (10Y) Largest decline over 10 years	-36.90%	-32.42%	-4.48%
Current Drawdown Current decline from peak	-0.77%	-2.40%	+1.63%
Average Drawdown Average peak-to-trough decline	-9.58%	-18.96%	+9.38%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.49%	4.11%	-0.62%

Volatility

AMCPX vs. MIGFX - Volatility Comparison

American Funds AMCAP Fund Class A (AMCPX) and MFS Massachusetts Investors Growth Stock Fund (MIGFX) have volatilities of 3.57% and 3.42%, respectively, indicating that both stocks experience similar levels of price fluctuations. This suggests that the risk associated with both stocks, as measured by volatility, is nearly the same. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	AMCPX	MIGFX	Difference
Volatility (1M) Calculated over the trailing 1-month period	3.57%	3.42%	+0.15%
Volatility (6M) Calculated over the trailing 6-month period	11.42%	9.84%	+1.58%
Volatility (1Y) Calculated over the trailing 1-year period	14.56%	12.68%	+1.88%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	19.24%	17.52%	+1.72%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	18.72%	18.21%	+0.51%

AMCPX vs. MIGFX - Expense Ratio Comparison

AMCPX has a 0.65% expense ratio, which is lower than MIGFX's 0.70% expense ratio.

Dividends

AMCPX vs. MIGFX - Dividend Comparison

AMCPX's dividend yield for the trailing twelve months is around 8.21%, less than MIGFX's 11.43% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
AMCPX American Funds AMCAP Fund Class A	8.21%	8.73%	8.19%	3.26%	7.54%	3.43%	3.88%	4.90%	7.84%	5.37%	3.81%	8.86%
MIGFX MFS Massachusetts Investors Growth Stock Fund	11.43%	11.39%	17.15%	4.11%	4.49%	10.47%	7.43%	7.39%	10.76%	6.87%	5.12%	6.51%

Frequently Asked Questions

Can I hold both AMCPX and MIGFX in my portfolio?

AMCPX and MIGFX have a correlation of 0.89, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, AMCPX or MIGFX?

AMCPX has higher volatility (3.57%) compared to MIGFX (3.42%). In terms of maximum drawdown, AMCPX dropped -62.37% vs MIGFX's -61.83%.

Which has better risk-adjusted returns?

AMCPX currently has the higher Sharpe Ratio (1.56 vs 0.83), 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.