MEFAX vs. MIEYX

Last updated Jun 4, 2026

MEFAX (MassMutual Mid Cap Growth Fund) and MIEYX (MM S&P 500 Index Fund) are both mutual funds - MEFAX is a Mid Cap Growth Equities fund managed by MassMutual, while MIEYX is a S&P 500 fund tracking the S&P 500 Index. Over the past 10 years, MEFAX returned 10.34%/yr vs 14.60%/yr for MIEYX. Their correlation of 0.91 suggests significant overlap in exposure. MEFAX charges 1.20%/yr vs 0.46%/yr for MIEYX.

Performance

MEFAX vs. MIEYX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in MassMutual Mid Cap Growth Fund (MEFAX) and MM S&P 500 Index Fund (MIEYX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, MEFAX achieves a 5.52% return, which is significantly lower than MIEYX's 11.45% return. Over the past 10 years, MEFAX has underperformed MIEYX with an annualized return of 10.34%, while MIEYX has yielded a comparatively higher 14.60% annualized return.

MEFAX

• 1D: 0.19%
• 1M: 3.55%
• YTD: 5.52%
• 6M: 4.60%
• 1Y: 11.13%
• 3Y*: 10.06%
• 5Y*: 3.32%
• 10Y*: 10.34%

MIEYX

• 1D: 0.13%
• 1M: 5.77%
• YTD: 11.45%
• 6M: 11.46%
• 1Y: 28.32%
• 3Y*: 22.16%
• 5Y*: 13.68%
• 10Y*: 14.60%

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

MEFAX vs. MIEYX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
MEFAX MassMutual Mid Cap Growth Fund	5.52%	3.19%	10.80%	19.11%	-24.58%	13.75%	25.52%	40.75%	-3.88%	24.12%
MIEYX MM S&P 500 Index Fund	11.45%	17.27%	24.36%	25.76%	-18.63%	28.02%	17.87%	30.98%	-5.26%	18.90%

Correlation

The correlation between MEFAX and MIEYX is 0.77, which is moderate. They share some common price drivers but move independently often enough to provide real diversification benefit when combined.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.77
Correlation (3Y) Calculated over the trailing 3-year period	0.85
Correlation (5Y) Calculated over the trailing 5-year period	0.89
Correlation (10Y) Calculated over the trailing 10-year period	0.89
Correlation (All Time) Calculated using the full available price history since Jun 1, 2000	0.91

The correlation between MEFAX and MIEYX shifts across timeframes, from 0.77 (1 year) to 0.91 (all time), reflecting how their relationship changes across market environments.

Return for Risk

MEFAX vs. MIEYX — Risk / Return Rank

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

MEFAX

MEFAX Risk / Return Rank: 12
MEFAX Sharpe Ratio Rank: 11
MEFAX Sortino Ratio Rank: 11
MEFAX Omega Ratio Rank: 10
MEFAX Calmar Ratio Rank: 13
MEFAX Martin Ratio Rank: 15

MIEYX

MIEYX Risk / Return Rank: 70
MIEYX Sharpe Ratio Rank: 72
MIEYX Sortino Ratio Rank: 64
MIEYX Omega Ratio Rank: 64
MIEYX Calmar Ratio Rank: 71
MIEYX Martin Ratio Rank: 81

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.

MEFAX vs. MIEYX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for MassMutual Mid Cap Growth Fund (MEFAX) and MM S&P 500 Index Fund (MIEYX). 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.

	MEFAX	MIEYX	Difference
Sharpe ratio Return per unit of total volatility	0.85	2.46	-1.61
Sortino ratio Return per unit of downside risk	1.31	3.34	-2.03
Omega ratio Gain probability vs. loss probability	1.15	1.45	-0.30
Calmar ratio Return relative to maximum drawdown	1.19	3.28	-2.09
Martin ratio Return relative to average drawdown	4.35	15.26	-10.91
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

MEFAX vs. MIEYX - Sharpe Ratio Comparison

The current MEFAX Sharpe Ratio is 0.85, which is lower than the MIEYX Sharpe Ratio of 2.46. The chart below compares the historical Sharpe Ratios of MEFAX and MIEYX, 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

	MEFAX	MIEYX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	0.85	2.46	-1.61
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.12	0.54	-0.42
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.43	0.65	-0.22
Sharpe Ratio (All Time) Calculated using the full available price history	0.39	0.40	-0.01

Drawdowns

MEFAX vs. MIEYX - Drawdown Comparison

The maximum MEFAX drawdown since its inception was -56.04%, roughly equal to the maximum MIEYX drawdown of -55.63%. Use the drawdown chart below to compare losses from any high point for MEFAX and MIEYX.

Drawdown Indicators

	MEFAX	MIEYX	Difference
Max Drawdown Largest peak-to-trough decline	-56.04%	-55.63%	-0.41%
Max Drawdown (1Y) Largest decline over 1 year	-10.45%	-8.92%	-1.53%
Max Drawdown (3Y) Largest decline over 3 years	-34.46%	-36.63%	+2.17%
Max Drawdown (5Y) Largest decline over 5 years	-45.14%	-36.63%	-8.51%
Max Drawdown (10Y) Largest decline over 10 years	-45.14%	-36.63%	-8.51%
Current Drawdown Current decline from peak	-14.03%	-2.43%	-11.60%
Average Drawdown Average peak-to-trough decline	-11.43%	-12.57%	+1.14%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.85%	1.91%	+0.94%

Volatility

MEFAX vs. MIEYX - Volatility Comparison

MassMutual Mid Cap Growth Fund (MEFAX) has a higher volatility of 3.87% compared to MM S&P 500 Index Fund (MIEYX) at 2.84%. This indicates that MEFAX's price experiences larger fluctuations and is considered to be riskier than MIEYX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	MEFAX	MIEYX	Difference
Volatility (1M) Calculated over the trailing 1-month period	3.87%	2.84%	+1.03%
Volatility (6M) Calculated over the trailing 6-month period	11.26%	8.99%	+2.27%
Volatility (1Y) Calculated over the trailing 1-year period	14.63%	11.89%	+2.74%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	27.46%	25.50%	+1.96%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	23.93%	22.57%	+1.36%

MEFAX vs. MIEYX - Expense Ratio Comparison

MEFAX has a 1.20% expense ratio, which is higher than MIEYX's 0.46% expense ratio.

Dividends

MEFAX vs. MIEYX - Dividend Comparison

MEFAX's dividend yield for the trailing twelve months is around 32.37%, more than MIEYX's 15.82% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
MEFAX MassMutual Mid Cap Growth Fund	32.37%	34.16%	21.40%	7.62%	20.71%	29.49%	6.92%	12.81%	12.06%	7.66%	5.32%	10.27%
MIEYX MM S&P 500 Index Fund	15.82%	17.63%	32.89%	7.13%	33.24%	13.29%	16.29%	6.38%	19.14%	21.81%	4.19%	2.29%

Frequently Asked Questions

Can I hold both MEFAX and MIEYX in my portfolio?

MEFAX and MIEYX have a correlation of 0.77, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, MEFAX or MIEYX?

MEFAX has higher volatility (3.87%) compared to MIEYX (2.84%). In terms of maximum drawdown, MEFAX dropped -56.04% vs MIEYX's -55.63%.

Which has better risk-adjusted returns?

MIEYX currently has the higher Sharpe Ratio (2.46 vs 0.85), 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.