WISIX vs. OAKEX

Last updated Jul 14, 2026

WISIX (William Blair International Small Cap Growth Fund) and OAKEX (Oakmark International Small Cap Fund) are both Foreign Small & Mid Cap Equities funds. Over the past 10 years, WISIX returned 6.01%/yr vs 7.95%/yr for OAKEX. Their correlation of 0.81 suggests significant overlap in exposure. WISIX charges 1.23%/yr vs 1.34%/yr for OAKEX.

Performance

WISIX vs. OAKEX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in William Blair International Small Cap Growth Fund (WISIX) and Oakmark International Small Cap Fund (OAKEX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, WISIX achieves a 8.96% return, which is significantly higher than OAKEX's -1.73% return. Over the past 10 years, WISIX has underperformed OAKEX with an annualized return of 6.01%, while OAKEX has yielded a comparatively higher 7.95% annualized return.

WISIX

• 1D: 0.72%
• 1M: -1.98%
• 6M: 6.98%
• YTD: 8.96%
• 1Y: 6.61%
• 3Y*: 10.15%
• 5Y*: -0.64%
• 10Y*: 6.01%

OAKEX

• 1D: 0.94%
• 1M: -0.32%
• 6M: -2.71%
• YTD: -1.73%
• 1Y: -2.01%
• 3Y*: 9.77%
• 5Y*: 4.16%
• 10Y*: 7.95%

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

WISIX vs. OAKEX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
WISIX William Blair International Small Cap Growth Fund	8.96%	15.31%	0.80%	14.72%	-34.99%	11.01%	29.09%	34.22%	-24.27%	32.71%
OAKEX Oakmark International Small Cap Fund	-1.73%	29.51%	-3.00%	19.59%	-14.50%	17.90%	5.00%	31.91%	-23.71%	26.03%

Correlation

The correlation between WISIX and OAKEX is 0.75, 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	0.75
Correlation (3Y) Calculated over the trailing 3-year period	0.78
Correlation (5Y) Calculated over the trailing 5-year period	0.81
Correlation (10Y) Calculated over the trailing 10-year period	0.78
Correlation (All Time) Calculated using the full available price history since Nov 2, 2005	0.81

The correlation between WISIX and OAKEX has been stable across timeframes, ranging from 0.75 to 0.81 - a consistent structural relationship.

Return for Risk

WISIX vs. OAKEX — Risk / Return Rank

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

WISIX

WISIX Risk / Return Rank: 8
WISIX Sharpe Ratio Rank: 7
WISIX Sortino Ratio Rank: 7
WISIX Omega Ratio Rank: 8
WISIX Calmar Ratio Rank: 9
WISIX Martin Ratio Rank: 8

OAKEX

OAKEX Risk / Return Rank: 2
OAKEX Sharpe Ratio Rank: 2
OAKEX Sortino Ratio Rank: 2
OAKEX Omega Ratio Rank: 2
OAKEX Calmar Ratio Rank: 2
OAKEX Martin Ratio Rank: 2

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. OAKEX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for William Blair International Small Cap Growth Fund (WISIX) and Oakmark International Small Cap Fund (OAKEX). 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	OAKEX	Difference
Sharpe ratio: Return per unit of total volatility	0.37	-0.19	+0.56
Sortino ratio: Return per unit of downside risk	0.62	-0.16	+0.78
Omega ratio: Gain probability vs. loss probability	1.08	0.98	+0.10
Calmar ratio: Return relative to maximum drawdown	0.56	-0.16	+0.72
Martin ratio: Return relative to average drawdown	1.47	-0.45	+1.92

WISIX vs. OAKEX - Sharpe Ratio Comparison

The current WISIX Sharpe Ratio is 0.37, which is higher than the OAKEX Sharpe Ratio of -0.19. The chart below compares the historical Sharpe Ratios of WISIX and OAKEX, 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. OAKEX - Drawdown Comparison

The maximum WISIX drawdown since its inception was -64.84%, smaller than the maximum OAKEX drawdown of -70.12%. Use the drawdown chart below to compare losses from any high point for WISIX and OAKEX.

Drawdown Indicators

	WISIX	OAKEX	Difference
Max Drawdown Largest peak-to-trough decline	-64.84%	-70.12%	+5.28%
Max Drawdown (1Y) Largest decline over 1 year	-10.09%	-17.18%	+7.09%
Max Drawdown (3Y) Largest decline over 3 years	-17.70%	-17.18%	-0.52%
Max Drawdown (5Y) Largest decline over 5 years	-47.76%	-38.40%	-9.36%
Max Drawdown (10Y) Largest decline over 10 years	-47.76%	-49.61%	+1.85%
Current Drawdown Current decline from peak	-12.66%	-6.79%	-5.87%
Average Drawdown Average peak-to-trough decline	-16.54%	-13.47%	-3.07%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.84%	6.22%	-2.38%

Volatility

WISIX vs. OAKEX - Volatility Comparison

William Blair International Small Cap Growth Fund (WISIX) has a higher volatility of 6.30% compared to Oakmark International Small Cap Fund (OAKEX) at 4.83%. This indicates that WISIX's price experiences larger fluctuations and is considered to be riskier than OAKEX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	WISIX	OAKEX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.30%	4.83%	+1.47%
Volatility (6M) Calculated over the trailing 6-month period	13.24%	12.22%	+1.02%
Volatility (1Y) Calculated over the trailing 1-year period	15.15%	15.10%	+0.05%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	17.52%	17.77%	-0.25%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	17.19%	18.29%	-1.10%

WISIX vs. OAKEX - Expense Ratio Comparison

WISIX has a 1.23% expense ratio, which is lower than OAKEX's 1.34% expense ratio.

Dividends

WISIX vs. OAKEX - Dividend Comparison

WISIX's dividend yield for the trailing twelve months is around 0.56%, less than OAKEX's 5.34% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
OAKEX Oakmark International Small Cap Fund	5.34%	5.24%	6.38%	1.83%	1.89%	0.61%	1.87%	0.21%	8.93%	3.64%	3.09%	5.06%
WISIX William Blair International Small Cap Growth Fund	0.56%	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 OAKEX in my portfolio?

WISIX and OAKEX have a correlation of 0.75, 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 OAKEX?

WISIX has higher volatility (6.30%) compared to OAKEX (4.83%). In terms of maximum drawdown, WISIX dropped -64.84% vs OAKEX's -70.12%.

Which has better risk-adjusted returns?

WISIX currently has the higher Sharpe Ratio (0.37 vs -0.19), 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.