VIMSX vs. VEMPX

Last updated Jun 4, 2026

VIMSX (Vanguard Mid Cap Index Fund) and VEMPX (Vanguard Extended Market Index Fund Institutional Plus Shares) are both Mid Cap Blend Equities funds from Vanguard. Over the past 10 years, VIMSX returned 11.40%/yr vs 12.21%/yr for VEMPX. With a 0.95 correlation, they move nearly in lockstep. VIMSX charges 0.17%/yr vs 0.04%/yr for VEMPX.

Performance

VIMSX vs. VEMPX - Performance Comparison

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

Returns By Period

In the year-to-date period, VIMSX achieves a 10.48% return, which is significantly lower than VEMPX's 14.93% return. Over the past 10 years, VIMSX has underperformed VEMPX with an annualized return of 11.40%, while VEMPX has yielded a comparatively higher 12.21% annualized return.

VIMSX

• 1D: 0.90%
• 1M: 3.66%
• YTD: 10.48%
• 6M: 10.13%
• 1Y: 18.59%
• 3Y*: 16.52%
• 5Y*: 7.88%
• 10Y*: 11.40%

VEMPX

• 1D: 1.07%
• 1M: 5.80%
• YTD: 14.93%
• 6M: 13.66%
• 1Y: 30.15%
• 3Y*: 20.16%
• 5Y*: 6.93%
• 10Y*: 12.21%

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

VIMSX vs. VEMPX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
VIMSX Vanguard Mid Cap Index Fund	10.48%	11.08%	14.52%	16.40%	-18.80%	24.36%	18.04%	30.85%	-9.35%	19.12%
VEMPX Vanguard Extended Market Index Fund Institutional Plus Shares	14.93%	11.43%	15.50%	26.98%	-26.45%	12.48%	32.24%	28.06%	-9.35%	18.13%

Correlation

The correlation between VIMSX and VEMPX 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 (10Y) Calculated over the trailing 10-year period	0.95
Correlation (All Time) Calculated using the full available price history since Dec 14, 2010	0.95

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

Return for Risk

VIMSX vs. VEMPX — Risk / Return Rank

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

VIMSX

VIMSX Risk / Return Rank: 35
VIMSX Sharpe Ratio Rank: 31
VIMSX Sortino Ratio Rank: 30
VIMSX Omega Ratio Rank: 29
VIMSX Calmar Ratio Rank: 41
VIMSX Martin Ratio Rank: 44

VEMPX

VEMPX Risk / Return Rank: 48
VEMPX Sharpe Ratio Rank: 41
VEMPX Sortino Ratio Rank: 39
VEMPX Omega Ratio Rank: 37
VEMPX Calmar Ratio Rank: 66
VEMPX Martin Ratio Rank: 55

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.

VIMSX vs. VEMPX - Risk-Adjusted Trends Comparison

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

	VIMSX	VEMPX	Difference
Sharpe ratio: Return per unit of total volatility	1.60	1.87	-0.27
Sortino ratio: Return per unit of downside risk	2.29	2.61	-0.32
Omega ratio: Gain probability vs. loss probability	1.28	1.32	-0.04
Calmar ratio: Return relative to maximum drawdown	2.42	3.13	-0.71
Martin ratio: Return relative to average drawdown	9.19	11.09	-1.89
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

VIMSX vs. VEMPX - Sharpe Ratio Comparison

The current VIMSX Sharpe Ratio is 1.60, which is comparable to the VEMPX Sharpe Ratio of 1.87. The chart below compares the historical Sharpe Ratios of VIMSX and VEMPX, 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

	VIMSX	VEMPX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.60	1.87	-0.27
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.45	0.31	+0.14
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.60	0.55	+0.06
Sharpe Ratio (All Time) Calculated using the full available price history	0.48	0.55	-0.07

Drawdowns

VIMSX vs. VEMPX - Drawdown Comparison

The maximum VIMSX drawdown since its inception was -58.96%, which is greater than VEMPX's maximum drawdown of -41.62%. Use the drawdown chart below to compare losses from any high point for VIMSX and VEMPX.

Drawdown Indicators

	VIMSX	VEMPX	Difference
Max Drawdown Largest peak-to-trough decline	-58.96%	-41.62%	-17.34%
Max Drawdown (1Y) Largest decline over 1 year	-8.14%	-10.25%	+2.11%
Max Drawdown (3Y) Largest decline over 3 years	-19.31%	-26.83%	+7.52%
Max Drawdown (5Y) Largest decline over 5 years	-27.63%	-36.32%	+8.69%
Max Drawdown (10Y) Largest decline over 10 years	-39.29%	-41.62%	+2.33%
Current Drawdown Current decline from peak	0.00%	0.00%	0.00%
Average Drawdown Average peak-to-trough decline	-8.07%	-7.97%	-0.10%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.14%	2.89%	-0.75%

Volatility

VIMSX vs. VEMPX - Volatility Comparison

The current volatility for Vanguard Mid Cap Index Fund (VIMSX) is 2.97%, while Vanguard Extended Market Index Fund Institutional Plus Shares (VEMPX) has a volatility of 4.69%. This indicates that VIMSX experiences smaller price fluctuations and is considered to be less risky than VEMPX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	VIMSX	VEMPX	Difference
Volatility (1M) Calculated over the trailing 1-month period	2.97%	4.69%	-1.72%
Volatility (6M) Calculated over the trailing 6-month period	9.28%	12.46%	-3.18%
Volatility (1Y) Calculated over the trailing 1-year period	12.30%	17.17%	-4.87%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	17.64%	22.34%	-4.70%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	18.93%	22.36%	-3.43%

VIMSX vs. VEMPX - Expense Ratio Comparison

VIMSX has a 0.17% expense ratio, which is higher than VEMPX's 0.04% 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

VIMSX vs. VEMPX - Dividend Comparison

VIMSX's dividend yield for the trailing twelve months is around 1.23%, more than VEMPX's 1.02% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
VEMPX Vanguard Extended Market Index Fund Institutional Plus Shares	1.02%	1.15%	1.11%	1.27%	1.17%	1.15%	1.09%	1.32%	1.68%	1.27%	1.46%	1.39%
VIMSX Vanguard Mid Cap Index Fund	1.23%	1.03%	1.37%	1.39%	1.46%	1.00%	1.34%	1.37%	1.68%	1.24%	1.34%	1.33%

Frequently Asked Questions

Can I hold both VIMSX and VEMPX in my portfolio?

With a correlation of 0.92, VIMSX and VEMPX 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, VIMSX or VEMPX?

VEMPX has higher volatility (4.69%) compared to VIMSX (2.97%). In terms of maximum drawdown, VIMSX dropped -58.96% vs VEMPX's -41.62%.

Which has better risk-adjusted returns?

VEMPX currently has the higher Sharpe Ratio (1.87 vs 1.60), 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.