VEMPX vs. VIIIX

Last updated Jun 9, 2026

VEMPX (Vanguard Extended Market Index Fund Institutional Plus Shares) and VIIIX (Vanguard Institutional Index Fund Institutional Plus Shares) are both mutual funds - VEMPX is a Mid Cap Blend Equities fund managed by Vanguard, while VIIIX is a S&P 500 fund tracking the S&P 500 Index. Over the past 10 years, VEMPX returned 11.71%/yr vs 15.32%/yr for VIIIX. Their correlation of 0.88 suggests significant overlap in exposure. VEMPX charges 0.04%/yr vs 0.02%/yr for VIIIX.

Performance

VEMPX vs. VIIIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Vanguard Extended Market Index Fund Institutional Plus Shares (VEMPX) 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, VEMPX achieves a 11.27% return, which is significantly higher than VIIIX's 8.42% return. Over the past 10 years, VEMPX has underperformed VIIIX with an annualized return of 11.71%, while VIIIX has yielded a comparatively higher 15.32% annualized return.

VEMPX

• 1D: -3.30%
• 1M: 1.03%
• YTD: 11.27%
• 6M: 9.73%
• 1Y: 24.36%
• 3Y*: 18.45%
• 5Y*: 6.09%
• 10Y*: 11.71%

VIIIX

• 1D: -2.63%
• 1M: -0.08%
• YTD: 8.42%
• 6M: 8.48%
• 1Y: 24.54%
• 3Y*: 21.94%
• 5Y*: 13.54%
• 10Y*: 15.32%

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

VEMPX vs. VIIIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
VEMPX Vanguard Extended Market Index Fund Institutional Plus Shares	11.27%	11.43%	15.50%	26.98%	-26.45%	12.48%	32.24%	28.06%	-9.35%	18.13%
VIIIX Vanguard Institutional Index Fund Institutional Plus Shares	8.42%	17.87%	26.29%	25.79%	-18.14%	28.69%	18.41%	31.48%	-4.41%	21.82%

Correlation

The correlation between VEMPX and VIIIX is 0.83, 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	0.83
Correlation (3Y) Calculated over the trailing 3-year period	0.83
Correlation (5Y) Calculated over the trailing 5-year period	0.86
Correlation (10Y) Calculated over the trailing 10-year period	0.86
Correlation (All Time) Calculated using the full available price history since Dec 14, 2010	0.88

The correlation between VEMPX and VIIIX has been stable across timeframes, ranging from 0.83 to 0.88 - a consistent structural relationship.

VEMPX vs. VIIIX - Sectors Allocation Comparison

Sectors	VEMPX	VIIIX
Technology	19.8%	35.7%
Industrials	19.3%	8.3%
Financial Services	14.6%	11.6%
Healthcare	13.3%	8.5%
Consumer Cyclical	9.7%	10.2%
Real Estate	6.0%	1.9%
Energy	5.1%	3.5%
Basic Materials	4.2%	1.8%
Communication Services	3.3%	11.3%
Consumer Defensive	2.7%	4.9%
Utilities	2.0%	2.4%

Return for Risk

VEMPX vs. VIIIX — Risk / Return Rank

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

VEMPX

VEMPX Risk / Return Rank: 35
VEMPX Sharpe Ratio Rank: 30
VEMPX Sortino Ratio Rank: 28
VEMPX Omega Ratio Rank: 27
VEMPX Calmar Ratio Rank: 48
VEMPX Martin Ratio Rank: 44

VIIIX

VIIIX Risk / Return Rank: 59
VIIIX Sharpe Ratio Rank: 56
VIIIX Sortino Ratio Rank: 49
VIIIX Omega Ratio Rank: 53
VIIIX Calmar Ratio Rank: 62
VIIIX Martin Ratio Rank: 75

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.

VEMPX vs. VIIIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Vanguard Extended Market Index Fund Institutional Plus Shares (VEMPX) 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.

	VEMPX	VIIIX	Difference
Sharpe ratio: Return per unit of total volatility	1.49	2.13	-0.65
Sortino ratio: Return per unit of downside risk	2.10	2.87	-0.78
Omega ratio: Gain probability vs. loss probability	1.26	1.39	-0.13
Calmar ratio: Return relative to maximum drawdown	2.54	2.92	-0.38
Martin ratio: Return relative to average drawdown	8.96	13.57	-4.61
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

VEMPX vs. VIIIX - Sharpe Ratio Comparison

The current VEMPX Sharpe Ratio is 1.49, which is lower than the VIIIX Sharpe Ratio of 2.13. The chart below compares the historical Sharpe Ratios of VEMPX 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

	VEMPX	VIIIX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.49	2.13	-0.65
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.27	0.80	-0.53
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.52	0.85	-0.33
Sharpe Ratio (All Time) Calculated using the full available price history	0.54	0.49	+0.05

Drawdowns

VEMPX vs. VIIIX - Drawdown Comparison

The maximum VEMPX drawdown since its inception was -41.62%, smaller than the maximum VIIIX drawdown of -55.18%. Use the drawdown chart below to compare losses from any high point for VEMPX and VIIIX.

Drawdown Indicators

	VEMPX	VIIIX	Difference
Max Drawdown Largest peak-to-trough decline	-41.62%	-55.18%	+13.56%
Max Drawdown (1Y) Largest decline over 1 year	-10.25%	-8.90%	-1.35%
Max Drawdown (3Y) Largest decline over 3 years	-26.83%	-18.75%	-8.08%
Max Drawdown (5Y) Largest decline over 5 years	-36.32%	-24.50%	-11.82%
Max Drawdown (10Y) Largest decline over 10 years	-41.62%	-33.79%	-7.83%
Current Drawdown Current decline from peak	-3.30%	-2.94%	-0.36%
Average Drawdown Average peak-to-trough decline	-7.96%	-10.01%	+2.05%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.90%	1.91%	+0.99%

Volatility

VEMPX vs. VIIIX - Volatility Comparison

Vanguard Extended Market Index Fund Institutional Plus Shares (VEMPX) has a higher volatility of 5.84% compared to Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX) at 3.81%. This indicates that VEMPX'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

	VEMPX	VIIIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	5.84%	3.81%	+2.03%
Volatility (6M) Calculated over the trailing 6-month period	12.93%	9.41%	+3.52%
Volatility (1Y) Calculated over the trailing 1-year period	17.53%	12.19%	+5.34%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	22.39%	16.93%	+5.46%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	22.38%	18.08%	+4.30%

VEMPX vs. VIIIX - Expense Ratio Comparison

VEMPX has a 0.04% 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

VEMPX vs. VIIIX - Dividend Comparison

VEMPX's dividend yield for the trailing twelve months is around 1.05%, less than VIIIX's 2.48% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
VEMPX Vanguard Extended Market Index Fund Institutional Plus Shares	1.05%	1.15%	1.11%	1.27%	1.17%	1.15%	1.09%	1.32%	1.68%	1.27%	1.46%	1.39%
VIIIX Vanguard Institutional Index Fund Institutional Plus Shares	2.48%	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 VEMPX and VIIIX in my portfolio?

VEMPX and VIIIX have a correlation of 0.83, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, VEMPX or VIIIX?

VEMPX has higher volatility (5.84%) compared to VIIIX (3.81%). In terms of maximum drawdown, VEMPX dropped -41.62% vs VIIIX's -55.18%.

Which has better risk-adjusted returns?

VIIIX currently has the higher Sharpe Ratio (2.13 vs 1.49), 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.