MIGFX vs. AMCPX

Last updated Jun 4, 2026

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

Performance

MIGFX vs. AMCPX - Performance Comparison

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

Returns By Period

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

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%

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%

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

MIGFX vs. AMCPX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
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%
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%

Correlation

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

Return for Risk

MIGFX vs. AMCPX — Risk / Return Rank

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

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

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

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.

MIGFX vs. AMCPX - Risk-Adjusted Trends Comparison

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

	MIGFX	AMCPX	Difference
Sharpe ratio: Return per unit of total volatility	0.83	1.56	-0.73
Sortino ratio: Return per unit of downside risk	1.22	2.19	-0.96
Omega ratio: Gain probability vs. loss probability	1.15	1.28	-0.14
Calmar ratio: Return relative to maximum drawdown	0.76	1.60	-0.84
Martin ratio: Return relative to average drawdown	2.55	6.51	-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.

MIGFX vs. AMCPX - Sharpe Ratio Comparison

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

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

Drawdowns

MIGFX vs. AMCPX - Drawdown Comparison

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

Drawdown Indicators

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

Volatility

MIGFX vs. AMCPX - Volatility Comparison

MFS Massachusetts Investors Growth Stock Fund (MIGFX) and American Funds AMCAP Fund Class A (AMCPX) have volatilities of 3.42% and 3.57%, 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

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

MIGFX vs. AMCPX - Expense Ratio Comparison

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

Dividends

MIGFX vs. AMCPX - Dividend Comparison

MIGFX's dividend yield for the trailing twelve months is around 11.43%, more than AMCPX's 8.21% 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 MIGFX and AMCPX in my portfolio?

MIGFX and AMCPX 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, MIGFX or AMCPX?

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

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.