WISIX vs. VFSAX

Last updated Jun 25, 2026

WISIX (William Blair International Small Cap Growth Fund) and VFSAX (Vanguard FTSE All-World ex-US Small-Cap Index Fund Admiral Shares) are both Foreign Small & Mid Cap Equities funds. Over the past 5 years, WISIX returned -0.09%/yr vs 5.44%/yr for VFSAX. Their correlation of 0.84 suggests significant overlap in exposure. WISIX charges 1.23%/yr vs 0.16%/yr for VFSAX.

Performance

WISIX vs. VFSAX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in William Blair International Small Cap Growth Fund (WISIX) and Vanguard FTSE All-World ex-US Small-Cap Index Fund Admiral Shares (VFSAX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, WISIX achieves a 10.38% return, which is significantly higher than VFSAX's 7.48% return.

WISIX

• 1D: -2.33%
• 1M: -2.02%
• YTD: 10.38%
• 6M: 10.38%
• 1Y: 10.37%
• 3Y*: 11.13%
• 5Y*: -0.09%
• 10Y*: 6.54%

VFSAX

• 1D: -2.67%
• 1M: -3.16%
• YTD: 7.48%
• 6M: 7.36%
• 1Y: 20.67%
• 3Y*: 15.91%
• 5Y*: 5.44%
• 10Y*: —

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

WISIX vs. VFSAX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019
WISIX William Blair International Small Cap Growth Fund	10.38%	15.31%	0.80%	14.72%	-34.99%	11.01%	29.09%	22.49%
VFSAX Vanguard FTSE All-World ex-US Small-Cap Index Fund Admiral Shares	7.48%	29.89%	2.58%	15.13%	-21.30%	12.68%	11.90%	13.47%

Correlation

The correlation between WISIX and VFSAX is 0.82, 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	0.82
Correlation (3Y) Calculated over the trailing 3-year period	0.82
Correlation (5Y) Calculated over the trailing 5-year period	0.85
Correlation (All Time) Calculated using the full available price history since Feb 7, 2019	0.84

The correlation between WISIX and VFSAX has been stable across timeframes, ranging from 0.82 to 0.85 - a consistent structural relationship.

Return for Risk

WISIX vs. VFSAX — Risk / Return Rank

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

WISIX

WISIX Risk / Return Rank: 13
WISIX Sharpe Ratio Rank: 12
WISIX Sortino Ratio Rank: 12
WISIX Omega Ratio Rank: 13
WISIX Calmar Ratio Rank: 15
WISIX Martin Ratio Rank: 13

VFSAX

VFSAX Risk / Return Rank: 34
VFSAX Sharpe Ratio Rank: 35
VFSAX Sortino Ratio Rank: 32
VFSAX Omega Ratio Rank: 36
VFSAX Calmar Ratio Rank: 31
VFSAX Martin Ratio Rank: 35

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.

WISIX vs. VFSAX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for William Blair International Small Cap Growth Fund (WISIX) and Vanguard FTSE All-World ex-US Small-Cap Index Fund Admiral Shares (VFSAX). 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.

	WISIX	VFSAX	Difference
Sharpe ratio: Return per unit of total volatility	0.81	1.57	-0.75
Sortino ratio: Return per unit of downside risk	1.22	2.16	-0.95
Omega ratio: Gain probability vs. loss probability	1.16	1.29	-0.13
Calmar ratio: Return relative to maximum drawdown	1.19	1.95	-0.75
Martin ratio: Return relative to average drawdown	3.23	7.23	-4.00

WISIX vs. VFSAX - Sharpe Ratio Comparison

The current WISIX Sharpe Ratio is 0.81, which is lower than the VFSAX Sharpe Ratio of 1.57. The chart below compares the historical Sharpe Ratios of WISIX and VFSAX, 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

WISIX vs. VFSAX - Drawdown Comparison

The maximum WISIX drawdown since its inception was -64.84%, which is greater than VFSAX's maximum drawdown of -39.86%. Use the drawdown chart below to compare losses from any high point for WISIX and VFSAX.

Drawdown Indicators

	WISIX	VFSAX	Difference
Max Drawdown Largest peak-to-trough decline	-64.84%	-39.86%	-24.98%
Max Drawdown (1Y) Largest decline over 1 year	-10.09%	-11.48%	+1.39%
Max Drawdown (3Y) Largest decline over 3 years	-17.90%	-14.73%	-3.17%
Max Drawdown (5Y) Largest decline over 5 years	-47.76%	-33.81%	-13.95%
Max Drawdown (10Y) Largest decline over 10 years	-47.76%	—	—
Current Drawdown Current decline from peak	-11.52%	-4.83%	-6.69%
Average Drawdown Average peak-to-trough decline	-16.55%	-9.21%	-7.34%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.71%	3.09%	+0.62%

Volatility

WISIX vs. VFSAX - Volatility Comparison

William Blair International Small Cap Growth Fund (WISIX) has a higher volatility of 6.75% compared to Vanguard FTSE All-World ex-US Small-Cap Index Fund Admiral Shares (VFSAX) at 6.00%. This indicates that WISIX's price experiences larger fluctuations and is considered to be riskier than VFSAX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	WISIX	VFSAX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.75%	6.00%	+0.75%
Volatility (6M) Calculated over the trailing 6-month period	12.80%	12.39%	+0.41%
Volatility (1Y) Calculated over the trailing 1-year period	14.83%	14.27%	+0.56%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	17.48%	15.20%	+2.28%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	17.25%	17.08%	+0.17%

WISIX vs. VFSAX - Expense Ratio Comparison

WISIX has a 1.23% expense ratio, which is higher than VFSAX's 0.16% expense ratio.

Dividends

WISIX vs. VFSAX - Dividend Comparison

WISIX's dividend yield for the trailing twelve months is around 0.55%, less than VFSAX's 3.18% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
VFSAX Vanguard FTSE All-World ex-US Small-Cap Index Fund Admiral Shares	3.18%	3.31%	3.36%	3.06%	2.22%	2.67%	1.85%	3.19%	0.00%	0.00%	0.00%	0.00%
WISIX William Blair International Small Cap Growth Fund	0.55%	0.61%	1.78%	0.88%	0.21%	16.20%	2.09%	0.31%	13.84%	9.94%	0.36%	2.31%

Frequently Asked Questions

Can I hold both WISIX and VFSAX in my portfolio?

WISIX and VFSAX have a correlation of 0.82, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, WISIX or VFSAX?

WISIX has higher volatility (6.75%) compared to VFSAX (6.00%). In terms of maximum drawdown, WISIX dropped -64.84% vs VFSAX's -39.86%.

Which has better risk-adjusted returns?

VFSAX currently has the higher Sharpe Ratio (1.57 vs 0.81), 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.