MFEIX vs. VIIIX

Last updated Jun 3, 2026

MFEIX (MFS Growth I) and VIIIX (Vanguard Institutional Index Fund Institutional Plus Shares) are both mutual funds - MFEIX is a Large Cap Growth Equities fund managed by MFS, while VIIIX is a Large Cap Blend Equities fund managed by Vanguard. Over the past 10 years, MFEIX returned 17.71%/yr vs 15.72%/yr for VIIIX. Their correlation of 0.90 suggests significant overlap in exposure. MFEIX charges 0.60%/yr vs 0.02%/yr for VIIIX.

Performance

MFEIX vs. VIIIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in MFS Growth I (MFEIX) and Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, MFEIX achieves a 6.65% return, which is significantly lower than VIIIX's 11.55% return. Over the past 10 years, MFEIX has outperformed VIIIX with an annualized return of 17.71%, while VIIIX has yielded a comparatively lower 15.72% annualized return.

MFEIX

• 1D: 1.14%
• 1M: 4.91%
• YTD: 6.65%
• 6M: 5.81%
• 1Y: 18.57%
• 3Y*: 26.76%
• 5Y*: 14.29%
• 10Y*: 17.71%

VIIIX

• 1D: 0.27%
• 1M: 5.24%
• YTD: 11.55%
• 6M: 11.93%
• 1Y: 29.56%
• 3Y*: 23.12%
• 5Y*: 14.31%
• 10Y*: 15.72%

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

MFEIX vs. VIIIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
MFEIX MFS Growth I	6.65%	12.34%	49.67%	36.15%	-31.14%	23.59%	31.65%	37.69%	2.30%	30.86%
VIIIX Vanguard Institutional Index Fund Institutional Plus Shares	11.55%	17.87%	26.29%	25.79%	-18.14%	28.69%	18.41%	31.48%	-4.41%	21.82%

Correlation

The correlation between MFEIX and VIIIX is 0.90, 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	0.90
Correlation (3Y) Calculated over the trailing 3-year period	0.91
Correlation (5Y) Calculated over the trailing 5-year period	0.93
Correlation (10Y) Calculated over the trailing 10-year period	0.91
Correlation (All Time) Calculated using the full available price history since Jul 8, 1997	0.90

The correlation between MFEIX and VIIIX has been stable across timeframes, ranging from 0.90 to 0.93 - a consistent structural relationship.

Return for Risk

MFEIX vs. VIIIX — Risk / Return Rank

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

MFEIX

MFEIX Risk / Return Rank: 14
MFEIX Sharpe Ratio Rank: 17
MFEIX Sortino Ratio Rank: 16
MFEIX Omega Ratio Rank: 16
MFEIX Calmar Ratio Rank: 11
MFEIX Martin Ratio Rank: 12

VIIIX

VIIIX Risk / Return Rank: 75
VIIIX Sharpe Ratio Rank: 77
VIIIX Sortino Ratio Rank: 69
VIIIX Omega Ratio Rank: 69
VIIIX Calmar Ratio Rank: 74
VIIIX Martin Ratio Rank: 84

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.

MFEIX vs. VIIIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for MFS Growth I (MFEIX) and Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX). 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.

	MFEIX	VIIIX	Difference
Sharpe ratio Return per unit of total volatility	1.23	2.55	-1.32
Sortino ratio Return per unit of downside risk	1.72	3.46	-1.74
Omega ratio Gain probability vs. loss probability	1.22	1.46	-0.25
Calmar ratio Return relative to maximum drawdown	1.13	3.38	-2.26
Martin ratio Return relative to average drawdown	3.67	15.85	-12.18
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

MFEIX vs. VIIIX - Sharpe Ratio Comparison

The current MFEIX Sharpe Ratio is 1.23, which is lower than the VIIIX Sharpe Ratio of 2.55. The chart below compares the historical Sharpe Ratios of MFEIX and VIIIX, 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

	MFEIX	VIIIX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.23	2.55	-1.32
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.66	0.85	-0.20
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.84	0.87	-0.04
Sharpe Ratio (All Time) Calculated using the full available price history	0.44	0.50	-0.05

Drawdowns

MFEIX vs. VIIIX - Drawdown Comparison

The maximum MFEIX drawdown since its inception was -72.24%, which is greater than VIIIX's maximum drawdown of -55.18%. Use the drawdown chart below to compare losses from any high point for MFEIX and VIIIX.

Drawdown Indicators

	MFEIX	VIIIX	Difference
Max Drawdown Largest peak-to-trough decline	-72.24%	-55.18%	-17.06%
Max Drawdown (1Y) Largest decline over 1 year	-17.30%	-8.90%	-8.40%
Max Drawdown (3Y) Largest decline over 3 years	-23.24%	-18.75%	-4.49%
Max Drawdown (5Y) Largest decline over 5 years	-36.11%	-24.50%	-11.61%
Max Drawdown (10Y) Largest decline over 10 years	-36.11%	-33.79%	-2.32%
Current Drawdown Current decline from peak	0.00%	0.00%	0.00%
Average Drawdown Average peak-to-trough decline	-23.73%	-10.02%	-13.71%
Ulcer Index Depth and duration of drawdowns from previous peaks	5.31%	1.90%	+3.41%

Volatility

MFEIX vs. VIIIX - Volatility Comparison

MFS Growth I (MFEIX) has a higher volatility of 3.55% compared to Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX) at 2.82%. This indicates that MFEIX's price experiences larger fluctuations and is considered to be riskier than VIIIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	MFEIX	VIIIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	3.55%	2.82%	+0.73%
Volatility (6M) Calculated over the trailing 6-month period	12.25%	8.99%	+3.26%
Volatility (1Y) Calculated over the trailing 1-year period	15.86%	11.88%	+3.98%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	21.90%	16.89%	+5.01%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	21.24%	18.06%	+3.18%

MFEIX vs. VIIIX - Expense Ratio Comparison

MFEIX has a 0.60% expense ratio, which is higher than VIIIX's 0.02% expense ratio.

Dividends

MFEIX vs. VIIIX - Dividend Comparison

MFEIX's dividend yield for the trailing twelve months is around 14.06%, more than VIIIX's 2.41% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
MFEIX MFS Growth I	14.06%	14.99%	25.47%	4.86%	1.05%	2.76%	3.57%	1.57%	3.78%	2.50%	1.61%	3.65%
VIIIX Vanguard Institutional Index Fund Institutional Plus Shares	2.41%	2.11%	3.66%	2.66%	3.39%	4.79%	3.07%	2.86%	2.45%	1.84%	2.38%	2.47%

Frequently Asked Questions

Can I hold both MFEIX and VIIIX in my portfolio?

With a correlation of 0.90, MFEIX and VIIIX 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, MFEIX or VIIIX?

MFEIX has higher volatility (3.55%) compared to VIIIX (2.82%). In terms of maximum drawdown, MFEIX dropped -72.24% vs VIIIX's -55.18%.

Which has better risk-adjusted returns?

VIIIX currently has the higher Sharpe Ratio (2.55 vs 1.23), 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.