VMIAX vs. VIIIX

Last updated Jun 24, 2026

VMIAX (Vanguard Materials Index Fund Admiral Shares) and VIIIX (Vanguard Institutional Index Fund Institutional Plus Shares) are both mutual funds - VMIAX is a Materials fund managed by Vanguard, while VIIIX is a S&P 500 fund tracking the S&P 500 Index. Over the past 10 years, VMIAX returned 10.65%/yr vs 15.87%/yr for VIIIX. Their correlation of 0.81 suggests significant overlap in exposure. VMIAX charges 0.10%/yr vs 0.02%/yr for VIIIX.

Performance

VMIAX vs. VIIIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Vanguard Materials Index Fund Admiral Shares (VMIAX) 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, VMIAX achieves a 13.21% return, which is significantly higher than VIIIX's 9.78% return. Over the past 10 years, VMIAX has underperformed VIIIX with an annualized return of 10.65%, while VIIIX has yielded a comparatively higher 15.87% annualized return.

VMIAX

• 1D: -0.08%
• 1M: 2.70%
• YTD: 13.21%
• 6M: 11.71%
• 1Y: 22.94%
• 3Y*: 11.94%
• 5Y*: 7.17%
• 10Y*: 10.65%

VIIIX

• 1D: -0.37%
• 1M: 0.10%
• YTD: 9.78%
• 6M: 8.78%
• 1Y: 25.51%
• 3Y*: 21.80%
• 5Y*: 13.75%
• 10Y*: 15.87%

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

VMIAX vs. VIIIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
VMIAX Vanguard Materials Index Fund Admiral Shares	13.21%	12.26%	0.45%	13.69%	-11.77%	27.15%	19.37%	23.59%	-17.38%	23.68%
VIIIX Vanguard Institutional Index Fund Institutional Plus Shares	9.78%	17.87%	26.29%	25.79%	-18.14%	28.69%	18.41%	31.48%	-4.41%	21.82%

Correlation

The correlation between VMIAX and VIIIX is 0.59, 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	0.59
Correlation (3Y) Calculated over the trailing 3-year period	0.66
Correlation (5Y) Calculated over the trailing 5-year period	0.73
Correlation (10Y) Calculated over the trailing 10-year period	0.76
Correlation (All Time) Calculated using the full available price history since Feb 2, 2004	0.81

Over the past year, the correlation between VMIAX and VIIIX has dropped to 0.59 - well below their long-term average of 0.81, suggesting their price drivers have been diverging.

VMIAX vs. VIIIX - Sectors Allocation Comparison

Sectors	VMIAX	VIIIX
Basic Materials	90.2%	1.7%
Consumer Cyclical	8.3%	9.9%
Industrials	1.0%	7.8%
Energy	0.5%	3.1%
Healthcare	0.5%	8.3%
Technology	0.1%	39.1%
Consumer Defensive	0.0%	4.5%
Communication Services	-	10.7%
Financial Services	-	10.9%
Real Estate	-	1.8%
Utilities	-	2.1%

Return for Risk

VMIAX vs. VIIIX — Risk / Return Rank

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

VMIAX

VMIAX Risk / Return Rank: 26
VMIAX Sharpe Ratio Rank: 26
VMIAX Sortino Ratio Rank: 25
VMIAX Omega Ratio Rank: 23
VMIAX Calmar Ratio Rank: 28
VMIAX Martin Ratio Rank: 27

VIIIX

VIIIX Risk / Return Rank: 65
VIIIX Sharpe Ratio Rank: 64
VIIIX Sortino Ratio Rank: 57
VIIIX Omega Ratio Rank: 59
VIIIX Calmar Ratio Rank: 68
VIIIX Martin Ratio Rank: 78

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.

VMIAX vs. VIIIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Vanguard Materials Index Fund Admiral Shares (VMIAX) 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.

	VMIAX	VIIIX	Difference
Sharpe ratio: Return per unit of total volatility	1.34	2.15	-0.81
Sortino ratio: Return per unit of downside risk	1.94	2.91	-0.97
Omega ratio: Gain probability vs. loss probability	1.23	1.39	-0.16
Calmar ratio: Return relative to maximum drawdown	1.84	3.02	-1.17
Martin ratio: Return relative to average drawdown	5.85	13.62	-7.77

VMIAX vs. VIIIX - Sharpe Ratio Comparison

The current VMIAX Sharpe Ratio is 1.34, which is lower than the VIIIX Sharpe Ratio of 2.15. The chart below compares the historical Sharpe Ratios of VMIAX 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

VMIAX vs. VIIIX - Drawdown Comparison

The maximum VMIAX drawdown since its inception was -62.17%, which is greater than VIIIX's maximum drawdown of -55.18%. Use the drawdown chart below to compare losses from any high point for VMIAX and VIIIX.

Drawdown Indicators

	VMIAX	VIIIX	Difference
Max Drawdown Largest peak-to-trough decline	-62.17%	-55.18%	-6.99%
Max Drawdown (1Y) Largest decline over 1 year	-13.41%	-8.90%	-4.51%
Max Drawdown (3Y) Largest decline over 3 years	-23.21%	-18.75%	-4.46%
Max Drawdown (5Y) Largest decline over 5 years	-25.45%	-24.50%	-0.95%
Max Drawdown (10Y) Largest decline over 10 years	-41.02%	-33.79%	-7.23%
Current Drawdown Current decline from peak	-3.76%	-1.72%	-2.04%
Average Drawdown Average peak-to-trough decline	-9.62%	-10.00%	+0.38%
Ulcer Index Depth and duration of drawdowns from previous peaks	4.22%	1.97%	+2.25%

Volatility

VMIAX vs. VIIIX - Volatility Comparison

Vanguard Materials Index Fund Admiral Shares (VMIAX) has a higher volatility of 6.41% compared to Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX) at 4.68%. This indicates that VMIAX'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

	VMIAX	VIIIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.41%	4.68%	+1.73%
Volatility (6M) Calculated over the trailing 6-month period	14.67%	9.84%	+4.83%
Volatility (1Y) Calculated over the trailing 1-year period	18.43%	12.50%	+5.93%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	19.75%	16.98%	+2.77%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	21.29%	18.11%	+3.18%

VMIAX vs. VIIIX - Expense Ratio Comparison

VMIAX has a 0.10% 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

VMIAX vs. VIIIX - Dividend Comparison

VMIAX's dividend yield for the trailing twelve months is around 1.36%, less than VIIIX's 2.45% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
VIIIX Vanguard Institutional Index Fund Institutional Plus Shares	2.45%	2.11%	3.66%	2.66%	3.39%	4.79%	3.07%	2.86%	2.45%	1.84%	2.38%	2.47%
VMIAX Vanguard Materials Index Fund Admiral Shares	1.36%	1.55%	1.70%	1.72%	1.98%	1.33%	1.67%	1.94%	2.02%	1.63%	1.73%	2.31%

Frequently Asked Questions

Can I hold both VMIAX and VIIIX in my portfolio?

VMIAX and VIIIX have a correlation of 0.59, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, VMIAX or VIIIX?

VMIAX has higher volatility (6.41%) compared to VIIIX (4.68%). In terms of maximum drawdown, VMIAX dropped -62.17% vs VIIIX's -55.18%.

Which has better risk-adjusted returns?

VIIIX currently has the higher Sharpe Ratio (2.15 vs 1.34), 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.