VMGIX vs. VIIIX

Last updated Jun 23, 2026

VMGIX (Vanguard Mid-Cap Growth Index Fund) and VIIIX (Vanguard Institutional Index Fund Institutional Plus Shares) are both mutual funds - VMGIX is a Mid Cap Growth Equities fund managed by Vanguard, while VIIIX is a S&P 500 fund tracking the S&P 500 Index. Over the past 10 years, VMGIX returned 12.28%/yr vs 15.65%/yr for VIIIX. Their correlation of 0.91 suggests significant overlap in exposure. VMGIX charges 0.19%/yr vs 0.02%/yr for VIIIX.

Performance

VMGIX vs. VIIIX - Performance Comparison

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

Returns By Period

The year-to-date returns for both investments are quite close, with VMGIX having a 9.81% return and VIIIX slightly higher at 10.19%. Over the past 10 years, VMGIX has underperformed VIIIX with an annualized return of 12.28%, while VIIIX has yielded a comparatively higher 15.65% annualized return.

VMGIX

• 1D: 1.61%
• 1M: 5.06%
• YTD: 9.81%
• 6M: 7.50%
• 1Y: 12.91%
• 3Y*: 15.44%
• 5Y*: 6.64%
• 10Y*: 12.28%

VIIIX

• 1D: 1.09%
• 1M: 0.47%
• YTD: 10.19%
• 6M: 9.68%
• 1Y: 27.18%
• 3Y*: 21.39%
• 5Y*: 14.24%
• 10Y*: 15.65%

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

VMGIX vs. VIIIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
VMGIX Vanguard Mid-Cap Growth Index Fund	9.81%	10.56%	15.51%	23.79%	-28.93%	20.32%	34.30%	33.69%	-5.73%	21.72%
VIIIX Vanguard Institutional Index Fund Institutional Plus Shares	10.19%	17.87%	26.29%	25.79%	-18.14%	28.69%	18.41%	31.48%	-4.41%	21.82%

Correlation

The correlation between VMGIX and VIIIX is 0.84, 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	0.84
Correlation (3Y) Calculated over the trailing 3-year period	0.87
Correlation (5Y) Calculated over the trailing 5-year period	0.90
Correlation (10Y) Calculated over the trailing 10-year period	0.89
Correlation (All Time) Calculated using the full available price history since Aug 24, 2006	0.91

The correlation between VMGIX and VIIIX has been stable across timeframes, ranging from 0.84 to 0.91 - a consistent structural relationship.

VMGIX vs. VIIIX - Sectors Allocation Comparison

Sectors	VMGIX	VIIIX
Technology	32.5%	39.1%
Industrials	23.2%	7.8%
Consumer Cyclical	12.8%	9.9%
Healthcare	8.9%	8.3%
Financial Services	6.9%	10.9%
Real Estate	4.5%	1.8%
Communication Services	3.6%	10.7%
Utilities	3.2%	2.1%
Energy	1.9%	3.1%
Basic Materials	1.6%	1.7%
Consumer Defensive	0.8%	4.5%

Return for Risk

VMGIX vs. VIIIX — Risk / Return Rank

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

VMGIX

VMGIX Risk / Return Rank: 10
VMGIX Sharpe Ratio Rank: 10
VMGIX Sortino Ratio Rank: 10
VMGIX Omega Ratio Rank: 10
VMGIX Calmar Ratio Rank: 9
VMGIX Martin Ratio Rank: 9

VIIIX

VIIIX Risk / Return Rank: 66
VIIIX Sharpe Ratio Rank: 64
VIIIX Sortino Ratio Rank: 59
VIIIX Omega Ratio Rank: 61
VIIIX Calmar Ratio Rank: 68
VIIIX Martin Ratio Rank: 79

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.

VMGIX vs. VIIIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Vanguard Mid-Cap Growth Index Fund (VMGIX) 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.

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.

	VMGIX	VIIIX	Difference
Sharpe ratio: Return per unit of total volatility	0.78	2.17	-1.39
Sortino ratio: Return per unit of downside risk	1.18	2.93	-1.75
Omega ratio: Gain probability vs. loss probability	1.14	1.39	-0.25
Calmar ratio: Return relative to maximum drawdown	0.82	3.04	-2.22
Martin ratio: Return relative to average drawdown	2.45	13.74	-11.29

VMGIX vs. VIIIX - Sharpe Ratio Comparison

The current VMGIX Sharpe Ratio is 0.78, which is lower than the VIIIX Sharpe Ratio of 2.17. The chart below compares the historical Sharpe Ratios of VMGIX 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.

Drawdowns

VMGIX vs. VIIIX - Drawdown Comparison

The maximum VMGIX drawdown since its inception was -60.20%, which is greater than VIIIX's maximum drawdown of -55.18%. Use the drawdown chart below to compare losses from any high point for VMGIX and VIIIX.

Drawdown Indicators

	VMGIX	VIIIX	Difference
Max Drawdown Largest peak-to-trough decline	-60.20%	-55.18%	-5.02%
Max Drawdown (1Y) Largest decline over 1 year	-15.99%	-8.90%	-7.09%
Max Drawdown (3Y) Largest decline over 3 years	-21.67%	-18.75%	-2.92%
Max Drawdown (5Y) Largest decline over 5 years	-37.25%	-24.50%	-12.75%
Max Drawdown (10Y) Largest decline over 10 years	-37.25%	-33.79%	-3.46%
Current Drawdown Current decline from peak	0.00%	-1.36%	+1.36%
Average Drawdown Average peak-to-trough decline	-9.99%	-10.00%	+0.01%
Ulcer Index Depth and duration of drawdowns from previous peaks	5.36%	1.96%	+3.40%

Volatility

VMGIX vs. VIIIX - Volatility Comparison

Vanguard Mid-Cap Growth Index Fund (VMGIX) has a higher volatility of 6.83% compared to Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX) at 4.77%. This indicates that VMGIX'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

	VMGIX	VIIIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.83%	4.77%	+2.06%
Volatility (6M) Calculated over the trailing 6-month period	13.70%	9.91%	+3.79%
Volatility (1Y) Calculated over the trailing 1-year period	16.91%	12.47%	+4.44%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	21.57%	16.99%	+4.58%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	21.07%	18.10%	+2.97%

VMGIX vs. VIIIX - Expense Ratio Comparison

VMGIX has a 0.19% expense ratio, which is higher than VIIIX's 0.02% expense ratio. However, both funds are considered low-cost compared to the broader market, where average expense ratios usually range from 0.3% to 0.9%.

Dividends

VMGIX vs. VIIIX - Dividend Comparison

VMGIX's dividend yield for the trailing twelve months is around 0.49%, less than VIIIX's 2.44% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
VIIIX Vanguard Institutional Index Fund Institutional Plus Shares	2.44%	2.11%	3.66%	2.66%	3.39%	4.79%	3.07%	2.86%	2.45%	1.84%	2.38%	2.47%
VMGIX Vanguard Mid-Cap Growth Index Fund	0.49%	0.52%	0.56%	0.60%	0.64%	0.23%	0.46%	0.67%	0.70%	0.61%	0.70%	0.69%

Frequently Asked Questions

Can I hold both VMGIX and VIIIX in my portfolio?

VMGIX and VIIIX have a correlation of 0.84, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, VMGIX or VIIIX?

VMGIX has higher volatility (6.83%) compared to VIIIX (4.77%). In terms of maximum drawdown, VMGIX dropped -60.20% vs VIIIX's -55.18%.

Which has better risk-adjusted returns?

VIIIX currently has the higher Sharpe Ratio (2.17 vs 0.78), 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.