WSMDX vs. VIEIX

Last updated Jun 23, 2026

WSMDX (William Blair Small-Mid Cap Growth Fund) and VIEIX (Vanguard Extended Market Index Fund Institutional Shares) are both mutual funds - WSMDX is a Mid Cap Growth Equities fund managed by William Blair, while VIEIX is a Mid Cap Blend Equities fund managed by Vanguard. Over the past 10 years, WSMDX returned 12.73%/yr vs 12.34%/yr for VIEIX. Their correlation of 0.95 suggests significant overlap in exposure. WSMDX charges 1.10%/yr vs 0.05%/yr for VIEIX.

Performance

WSMDX vs. VIEIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in William Blair Small-Mid Cap Growth Fund (WSMDX) and Vanguard Extended Market Index Fund Institutional Shares (VIEIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, WSMDX achieves a 13.60% return, which is significantly lower than VIEIX's 15.70% return. Both investments have delivered pretty close results over the past 10 years, with WSMDX having a 12.73% annualized return and VIEIX not far behind at 12.34%.

WSMDX

• 1D: 1.83%
• 1M: 3.49%
• YTD: 13.60%
• 6M: 10.93%
• 1Y: 26.39%
• 3Y*: 16.26%
• 5Y*: 6.42%
• 10Y*: 12.73%

VIEIX

• 1D: 1.66%
• 1M: 4.42%
• YTD: 15.70%
• 6M: 12.70%
• 1Y: 30.64%
• 3Y*: 19.14%
• 5Y*: 6.96%
• 10Y*: 12.34%

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

WSMDX vs. VIEIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
WSMDX William Blair Small-Mid Cap Growth Fund	13.60%	0.63%	27.55%	18.14%	-22.98%	8.28%	32.38%	30.81%	-2.18%	28.85%
VIEIX Vanguard Extended Market Index Fund Institutional Shares	15.70%	11.42%	15.49%	26.97%	-26.46%	12.46%	32.24%	28.05%	-9.36%	18.12%

Correlation

The correlation between WSMDX and VIEIX is 0.94, 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	0.94
Correlation (3Y) Calculated over the trailing 3-year period	0.94
Correlation (5Y) Calculated over the trailing 5-year period	0.96
Correlation (10Y) Calculated over the trailing 10-year period	0.94
Correlation (All Time) Calculated using the full available price history since Dec 30, 2003	0.95

The correlation between WSMDX and VIEIX has been stable across timeframes, ranging from 0.94 to 0.96 - a consistent structural relationship.

Return for Risk

WSMDX vs. VIEIX — Risk / Return Rank

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

WSMDX

WSMDX Risk / Return Rank: 32
WSMDX Sharpe Ratio Rank: 27
WSMDX Sortino Ratio Rank: 26
WSMDX Omega Ratio Rank: 24
WSMDX Calmar Ratio Rank: 40
WSMDX Martin Ratio Rank: 41

VIEIX

VIEIX Risk / Return Rank: 47
VIEIX Sharpe Ratio Rank: 40
VIEIX Sortino Ratio Rank: 38
VIEIX Omega Ratio Rank: 35
VIEIX Calmar Ratio Rank: 66
VIEIX 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.

WSMDX vs. VIEIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for William Blair Small-Mid Cap Growth Fund (WSMDX) and Vanguard Extended Market Index Fund Institutional Shares (VIEIX). 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.

	WSMDX	VIEIX	Difference
Sharpe ratio: Return per unit of total volatility	1.38	1.71	-0.33
Sortino ratio: Return per unit of downside risk	1.99	2.39	-0.40
Omega ratio: Gain probability vs. loss probability	1.24	1.29	-0.05
Calmar ratio: Return relative to maximum drawdown	2.29	2.98	-0.69
Martin ratio: Return relative to average drawdown	8.34	10.46	-2.12

WSMDX vs. VIEIX - Sharpe Ratio Comparison

The current WSMDX Sharpe Ratio is 1.38, which is comparable to the VIEIX Sharpe Ratio of 1.71. The chart below compares the historical Sharpe Ratios of WSMDX and VIEIX, 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

WSMDX vs. VIEIX - Drawdown Comparison

The maximum WSMDX drawdown since its inception was -50.33%, smaller than the maximum VIEIX drawdown of -58.03%. Use the drawdown chart below to compare losses from any high point for WSMDX and VIEIX.

Drawdown Indicators

	WSMDX	VIEIX	Difference
Max Drawdown Largest peak-to-trough decline	-50.33%	-58.03%	+7.70%
Max Drawdown (1Y) Largest decline over 1 year	-11.50%	-10.25%	-1.25%
Max Drawdown (3Y) Largest decline over 3 years	-25.63%	-26.84%	+1.21%
Max Drawdown (5Y) Largest decline over 5 years	-36.89%	-36.32%	-0.57%
Max Drawdown (10Y) Largest decline over 10 years	-36.89%	-41.62%	+4.73%
Current Drawdown Current decline from peak	0.00%	-0.12%	+0.12%
Average Drawdown Average peak-to-trough decline	-8.45%	-13.81%	+5.36%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.15%	2.91%	+0.24%

Volatility

WSMDX vs. VIEIX - Volatility Comparison

William Blair Small-Mid Cap Growth Fund (WSMDX) has a higher volatility of 6.85% compared to Vanguard Extended Market Index Fund Institutional Shares (VIEIX) at 6.38%. This indicates that WSMDX's price experiences larger fluctuations and is considered to be riskier than VIEIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	WSMDX	VIEIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.85%	6.38%	+0.47%
Volatility (6M) Calculated over the trailing 6-month period	15.04%	13.33%	+1.71%
Volatility (1Y) Calculated over the trailing 1-year period	19.01%	17.81%	+1.20%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	23.17%	22.45%	+0.72%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	22.00%	22.41%	-0.41%

WSMDX vs. VIEIX - Expense Ratio Comparison

WSMDX has a 1.10% expense ratio, which is higher than VIEIX's 0.05% expense ratio.

Dividends

WSMDX vs. VIEIX - Dividend Comparison

WSMDX's dividend yield for the trailing twelve months is around 2.47%, more than VIEIX's 1.00% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
VIEIX Vanguard Extended Market Index Fund Institutional Shares	1.00%	1.14%	1.10%	1.26%	1.16%	1.14%	1.08%	1.31%	1.67%	1.27%	1.45%	1.37%
WSMDX William Blair Small-Mid Cap Growth Fund	2.47%	2.81%	24.90%	7.89%	3.34%	9.30%	1.66%	7.13%	8.88%	5.33%	2.64%	5.31%

Frequently Asked Questions

Can I hold both WSMDX and VIEIX in my portfolio?

With a correlation of 0.94, WSMDX and VIEIX 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, WSMDX or VIEIX?

WSMDX has higher volatility (6.85%) compared to VIEIX (6.38%). In terms of maximum drawdown, WSMDX dropped -50.33% vs VIEIX's -58.03%.

Which has better risk-adjusted returns?

VIEIX currently has the higher Sharpe Ratio (1.71 vs 1.38), 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.