BIGIX vs. WILIX

Last updated Jun 24, 2026

BIGIX (William Blair International Growth Fund Class I) and WILIX (William Blair International Leaders Fund) are both Foreign Large Cap Equities funds from William Blair. Over the past 10 years, BIGIX returned 9.53%/yr vs 9.99%/yr for WILIX. With a 0.97 correlation, they move nearly in lockstep. Both charge a 0.90% expense ratio.

Performance

BIGIX vs. WILIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in William Blair International Growth Fund Class I (BIGIX) and William Blair International Leaders Fund (WILIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

The year-to-date returns for both investments are quite close, with BIGIX having a 18.66% return and WILIX slightly higher at 18.80%. Both investments have delivered pretty close results over the past 10 years, with BIGIX having a 9.53% annualized return and WILIX not far ahead at 9.99%.

BIGIX

• 1D: 0.75%
• 1M: 5.34%
• YTD: 18.66%
• 6M: 18.96%
• 1Y: 28.55%
• 3Y*: 14.86%
• 5Y*: 3.64%
• 10Y*: 9.53%

WILIX

• 1D: 1.63%
• 1M: 4.92%
• YTD: 18.80%
• 6M: 19.51%
• 1Y: 30.86%
• 3Y*: 14.51%
• 5Y*: 4.02%
• 10Y*: 9.99%

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

BIGIX vs. WILIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
BIGIX William Blair International Growth Fund Class I	18.66%	18.17%	2.38%	15.43%	-28.46%	8.95%	32.01%	30.66%	-17.71%	29.48%
WILIX William Blair International Leaders Fund	18.80%	23.21%	-0.50%	13.10%	-28.55%	10.16%	26.79%	31.76%	-12.43%	30.03%

Correlation

The correlation between BIGIX and WILIX 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	0.96
Correlation (5Y) Calculated over the trailing 5-year period	0.97
Correlation (10Y) Calculated over the trailing 10-year period	0.97
Correlation (All Time) Calculated using the full available price history since Jan 2, 2013	0.97

The correlation between BIGIX and WILIX has been stable across timeframes, ranging from 0.92 to 0.97 - a consistent structural relationship.

Return for Risk

BIGIX vs. WILIX — Risk / Return Rank

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

BIGIX

BIGIX Risk / Return Rank: 42
BIGIX Sharpe Ratio Rank: 43
BIGIX Sortino Ratio Rank: 39
BIGIX Omega Ratio Rank: 49
BIGIX Calmar Ratio Rank: 38
BIGIX Martin Ratio Rank: 41

WILIX

WILIX Risk / Return Rank: 43
WILIX Sharpe Ratio Rank: 44
WILIX Sortino Ratio Rank: 39
WILIX Omega Ratio Rank: 48
WILIX Calmar Ratio Rank: 41
WILIX Martin Ratio Rank: 42

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.

BIGIX vs. WILIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for William Blair International Growth Fund Class I (BIGIX) and William Blair International Leaders Fund (WILIX). 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.

	BIGIX	WILIX	Difference
Sharpe ratio: Return per unit of total volatility	1.77	1.80	-0.03
Sortino ratio: Return per unit of downside risk	2.42	2.43	-0.01
Omega ratio: Gain probability vs. loss probability	1.35	1.35	0.00
Calmar ratio: Return relative to maximum drawdown	2.21	2.31	-0.10
Martin ratio: Return relative to average drawdown	8.23	8.45	-0.22

BIGIX vs. WILIX - Sharpe Ratio Comparison

The current BIGIX Sharpe Ratio is 1.77, which is comparable to the WILIX Sharpe Ratio of 1.80. The chart below compares the historical Sharpe Ratios of BIGIX and WILIX, 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

BIGIX vs. WILIX - Drawdown Comparison

The maximum BIGIX drawdown since its inception was -65.22%, which is greater than WILIX's maximum drawdown of -41.01%. Use the drawdown chart below to compare losses from any high point for BIGIX and WILIX.

Drawdown Indicators

	BIGIX	WILIX	Difference
Max Drawdown Largest peak-to-trough decline	-65.22%	-41.01%	-24.21%
Max Drawdown (1Y) Largest decline over 1 year	-13.21%	-13.67%	+0.46%
Max Drawdown (3Y) Largest decline over 3 years	-17.09%	-18.21%	+1.12%
Max Drawdown (5Y) Largest decline over 5 years	-41.03%	-41.01%	-0.02%
Max Drawdown (10Y) Largest decline over 10 years	-41.03%	-41.01%	-0.02%
Current Drawdown Current decline from peak	0.00%	0.00%	0.00%
Average Drawdown Average peak-to-trough decline	-17.13%	-9.75%	-7.38%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.53%	3.72%	-0.19%

Volatility

BIGIX vs. WILIX - Volatility Comparison

William Blair International Growth Fund Class I (BIGIX) and William Blair International Leaders Fund (WILIX) have volatilities of 7.59% and 7.60%, respectively, indicating that both stocks experience similar levels of price fluctuations. This suggests that the risk associated with both stocks, as measured by volatility, is nearly the same. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	BIGIX	WILIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	7.59%	7.60%	-0.01%
Volatility (6M) Calculated over the trailing 6-month period	14.54%	15.27%	-0.73%
Volatility (1Y) Calculated over the trailing 1-year period	16.55%	17.56%	-1.01%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	16.98%	18.08%	-1.10%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	17.31%	17.81%	-0.50%

BIGIX vs. WILIX - Expense Ratio Comparison

Both BIGIX and WILIX have an expense ratio of 0.90%.

Dividends

BIGIX vs. WILIX - Dividend Comparison

BIGIX's dividend yield for the trailing twelve months is around 15.55%, more than WILIX's 6.72% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
BIGIX William Blair International Growth Fund Class I	15.55%	18.45%	7.49%	3.52%	7.84%	11.41%	1.11%	1.29%	9.05%	1.54%	1.80%	1.18%
WILIX William Blair International Leaders Fund	6.72%	7.98%	0.58%	0.45%	0.19%	2.82%	0.80%	0.56%	4.14%	2.17%	1.01%	0.74%

Frequently Asked Questions

Can I hold both BIGIX and WILIX in my portfolio?

With a correlation of 0.92, BIGIX and WILIX 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, BIGIX or WILIX?

WILIX has higher volatility (7.60%) compared to BIGIX (7.59%). In terms of maximum drawdown, BIGIX dropped -65.22% vs WILIX's -41.01%.

Which has better risk-adjusted returns?

WILIX currently has the higher Sharpe Ratio (1.80 vs 1.77), 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.