MEFAX vs. FMDGX

Last updated Jun 24, 2026

MEFAX (MassMutual Mid Cap Growth Fund) and FMDGX (Fidelity Mid Cap Growth Index Fund) are both Mid Cap Growth Equities funds. Over the past 5 years, MEFAX returned 2.43%/yr vs 5.63%/yr for FMDGX. With a 0.95 correlation, they move nearly in lockstep. MEFAX charges 1.20%/yr vs 0.05%/yr for FMDGX.

Performance

MEFAX vs. FMDGX - Performance Comparison

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

Returns By Period

In the year-to-date period, MEFAX achieves a 4.72% return, which is significantly higher than FMDGX's 3.82% return.

MEFAX

• 1D: 0.00%
• 1M: 1.46%
• YTD: 4.72%
• 6M: 3.27%
• 1Y: 9.16%
• 3Y*: 9.36%
• 5Y*: 2.43%
• 10Y*: 10.68%

FMDGX

• 1D: -0.11%
• 1M: 1.82%
• YTD: 3.82%
• 6M: 1.82%
• 1Y: 5.26%
• 3Y*: 15.69%
• 5Y*: 5.63%
• 10Y*: —

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

MEFAX vs. FMDGX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019
MEFAX MassMutual Mid Cap Growth Fund	4.72%	3.19%	10.80%	19.11%	-24.58%	13.75%	25.52%	11.93%
FMDGX Fidelity Mid Cap Growth Index Fund	3.82%	8.60%	22.03%	25.79%	-26.67%	12.67%	34.84%	4.63%

Correlation

The correlation between MEFAX and FMDGX is 0.92, 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	0.92
Correlation (3Y) Calculated over the trailing 3-year period	0.93
Correlation (5Y) Calculated over the trailing 5-year period	0.95
Correlation (All Time) Calculated using the full available price history since Jul 17, 2019	0.95

The correlation between MEFAX and FMDGX has been stable across timeframes, ranging from 0.92 to 0.95 - a consistent structural relationship.

Return for Risk

MEFAX vs. FMDGX — Risk / Return Rank

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

MEFAX

MEFAX Risk / Return Rank: 10
MEFAX Sharpe Ratio Rank: 9
MEFAX Sortino Ratio Rank: 9
MEFAX Omega Ratio Rank: 8
MEFAX Calmar Ratio Rank: 11
MEFAX Martin Ratio Rank: 13

FMDGX

FMDGX Risk / Return Rank: 5
FMDGX Sharpe Ratio Rank: 5
FMDGX Sortino Ratio Rank: 5
FMDGX Omega Ratio Rank: 5
FMDGX Calmar Ratio Rank: 5
FMDGX Martin Ratio Rank: 6

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. FMDGX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for MassMutual Mid Cap Growth Fund (MEFAX) and Fidelity Mid Cap Growth Index Fund (FMDGX). 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.

	MEFAX	FMDGX	Difference
Sharpe ratio: Return per unit of total volatility	0.67	0.36	+0.31
Sortino ratio: Return per unit of downside risk	1.05	0.62	+0.43
Omega ratio: Gain probability vs. loss probability	1.12	1.07	+0.05
Calmar ratio: Return relative to maximum drawdown	0.96	0.42	+0.55
Martin ratio: Return relative to average drawdown	3.50	1.20	+2.30

MEFAX vs. FMDGX - Sharpe Ratio Comparison

The current MEFAX Sharpe Ratio is 0.67, which is higher than the FMDGX Sharpe Ratio of 0.36. The chart below compares the historical Sharpe Ratios of MEFAX and FMDGX, 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

MEFAX vs. FMDGX - Drawdown Comparison

The maximum MEFAX drawdown since its inception was -56.04%, which is greater than FMDGX's maximum drawdown of -38.59%. Use the drawdown chart below to compare losses from any high point for MEFAX and FMDGX.

Drawdown Indicators

	MEFAX	FMDGX	Difference
Max Drawdown Largest peak-to-trough decline	-56.04%	-38.59%	-17.45%
Max Drawdown (1Y) Largest decline over 1 year	-10.45%	-14.75%	+4.30%
Max Drawdown (3Y) Largest decline over 3 years	-34.46%	-25.30%	-9.16%
Max Drawdown (5Y) Largest decline over 5 years	-45.14%	-38.59%	-6.55%
Max Drawdown (10Y) Largest decline over 10 years	-45.14%	—	—
Current Drawdown Current decline from peak	-14.69%	-2.08%	-12.61%
Average Drawdown Average peak-to-trough decline	-11.43%	-11.14%	-0.29%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.87%	5.09%	-2.22%

Volatility

MEFAX vs. FMDGX - Volatility Comparison

The current volatility for MassMutual Mid Cap Growth Fund (MEFAX) is 5.22%, while Fidelity Mid Cap Growth Index Fund (FMDGX) has a volatility of 5.70%. This indicates that MEFAX experiences smaller price fluctuations and is considered to be less risky than FMDGX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	MEFAX	FMDGX	Difference
Volatility (1M) Calculated over the trailing 1-month period	5.22%	5.70%	-0.48%
Volatility (6M) Calculated over the trailing 6-month period	11.96%	13.38%	-1.42%
Volatility (1Y) Calculated over the trailing 1-year period	15.15%	17.07%	-1.92%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	27.52%	22.45%	+5.07%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	23.97%	24.30%	-0.33%

MEFAX vs. FMDGX - Expense Ratio Comparison

MEFAX has a 1.20% expense ratio, which is higher than FMDGX's 0.05% expense ratio.

Dividends

MEFAX vs. FMDGX - Dividend Comparison

MEFAX's dividend yield for the trailing twelve months is around 32.62%, more than FMDGX's 1.79% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FMDGX Fidelity Mid Cap Growth Index Fund	1.79%	1.85%	0.47%	0.63%	0.81%	6.43%	0.36%	0.29%	0.00%	0.00%	0.00%	0.00%
MEFAX MassMutual Mid Cap Growth Fund	32.62%	34.16%	21.40%	7.62%	20.71%	29.49%	6.92%	12.81%	12.06%	7.66%	5.32%	10.27%

Frequently Asked Questions

Can I hold both MEFAX and FMDGX in my portfolio?

With a correlation of 0.92, MEFAX and FMDGX move almost identically. Holding both adds very little diversification - you're essentially doubling your position in the same market segment. Choosing one is usually more capital-efficient.

Which is riskier, MEFAX or FMDGX?

FMDGX has higher volatility (5.70%) compared to MEFAX (5.22%). In terms of maximum drawdown, MEFAX dropped -56.04% vs FMDGX's -38.59%.

Which has better risk-adjusted returns?

MEFAX currently has the higher Sharpe Ratio (0.67 vs 0.36), 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.