WILIX Performance — William Blair International Leaders Fund, Class I
Data updated: 2026-08-14
WILIX returned +16.59% year to date and +23.85% over one year to Jun 2026. Annualised returns are +13.12% over 3 years and +3.65% over 5 years. Against its International Mid-Cap Growth category average the fund came out behind over three years but ahead over one: $100 invested three years ago grew to $145, against $147 for the category, and to $124 over one year, against $115. Volatility over the past three years was 16.14% a year. In the 12 months to Jun 2026 the fund lost a net $90.5M, and assets reached $1.19B.
WILIX Growth of $100
What $100 invested in William Blair International Leaders Fund grew to, compounded from monthly returns reported on SEC Form N-PORT, against the International Mid-Cap Growth category average over the same months.
| Period | WILIX | Category average |
|---|---|---|
| 1 year (Jul 2025 – Jun 2026) | $124 | $115 |
| 3 years (Jul 2023 – Jun 2026) | $145 | $147 |
| 5 years (Jul 2021 – Jun 2026) | $120 | $129 |
| Since data start (Jul 2019 – Jun 2026) | $176 | $183 |
WILIX Trailing Returns
Total returns to Jun 2026, from SEC N-PORT.
| Period | Total return |
|---|---|
| YTD | +16.59% |
| 1 year | +23.85% |
| 3 years (annualised) | +13.12% |
| 5 years (annualised) | +3.65% |
WILIX Annual Returns
Calendar-year total returns of William Blair International Leaders Fund, compounded from monthly SEC N-PORT returns. Partial years show the months covered.
| Year | Total return |
|---|---|
| 2026 (Jan–Jun) | +16.59% |
| 2025 | +23.16% |
| 2024 | −0.50% |
| 2023 | +13.09% |
| 2022 | −28.55% |
| 2021 | +10.19% |
| 2020 | +26.79% |
| 2019 (Jul–Dec) | +9.20% |
WILIX Monthly Returns
Monthly total returns as reported on SEC Form N-PORT.
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2026 | +6.8% | +5.2% | −11.1% | +8.8% | +7.0% | +0.3% | — | — | — | — | — | — |
| 2025 | +4.0% | +0.5% | −3.2% | +4.8% | +5.5% | +3.6% | −2.1% | +2.5% | +1.9% | +3.7% | −2.9% | +3.0% |
| 2024 | −0.2% | +5.1% | +1.8% | −5.3% | +4.6% | +0.2% | +0.6% | +2.8% | −1.0% | −4.2% | −0.7% | −3.5% |
| 2023 | +8.0% | −3.1% | +3.7% | +0.6% | −1.2% | +3.5% | +0.7% | −5.3% | −5.7% | −4.0% | +10.5% | +6.2% |
| 2022 | −10.9% | −4.4% | +0.1% | −9.4% | −1.7% | −9.2% | +10.1% | −7.0% | −10.8% | +7.8% | +10.8% | −4.8% |
| 2021 | −0.7% | +0.8% | −1.4% | +5.4% | +2.8% | −0.5% | +2.9% | +4.1% | −6.1% | +5.1% | −4.2% | +2.3% |
| 2020 | −0.7% | −5.4% | −13.4% | +8.1% | +6.7% | +5.3% | +7.2% | +6.1% | −1.0% | −2.1% | +10.7% | +5.1% |
| 2019 | — | — | — | — | — | — | −0.9% | −1.3% | +0.9% | +3.6% | +3.0% | +3.7% |
WILIX Risk
Risk measures from monthly returns over Jul 2023 – Jun 2026.
- 3-year volatility (annualised): 16.14%
- 3-year Sharpe ratio: 0.53 (vs 4.5% risk-free rate)
- Best month: +10.49% (Nov 2023)
- Worst month: −11.13% (Mar 2026)
WILIX Fund Flows
Monthly money in and out of William Blair International Leaders Fund, from SEC Form N-PORT.
- 12-month net flow: −$90.5M
- 12-month gross sales (incl. reinvestments): $257.3M
- Sales ÷ redemptions: 0.74×
| Month | Sales | Redemptions | Net flow |
|---|---|---|---|
| Jun 2026 | $12.2M | $35.4M | −$23.2M |
| May 2026 | $10.9M | $31.8M | −$20.9M |
| Apr 2026 | $10.1M | $17.0M | −$6.9M |
| Mar 2026 | $15.2M | $14.2M | $1.0M |
| Feb 2026 | $14.2M | $54.1M | −$39.9M |
| Jan 2026 | $20.6M | $29.6M | −$9.0M |
| Dec 2025 | $98.9M | $64.4M | $34.4M |
| Nov 2025 | $6.6M | $14.2M | −$7.6M |
| Oct 2025 | $9.1M | $41.5M | −$32.4M |
| Sep 2025 | $8.5M | $15.5M | −$6.9M |
| Aug 2025 | $9.4M | $18.9M | −$9.6M |
| Jul 2025 | $41.7M | $11.2M | $30.5M |
WILIX Assets Under Management
Net assets of William Blair International Leaders Fund by report date, from SEC N-PORT filings.
| Report date | Net assets |
|---|---|
| 2026-06-30 | $1.19B |
| 2026-03-31 | $1.06B |
| 2025-12-31 | $1.11B |
| 2025-09-30 | $1.16B |
| 2025-06-30 | $1.12B |
| 2025-03-31 | $1.11B |
| 2024-12-31 | $1.16B |
| 2024-09-30 | $1.19B |
| 2024-06-30 | $1.17B |
| 2024-03-31 | $1.15B |
| 2023-12-31 | $1.09B |
| 2023-09-30 | $995.46M |
For information only. Not investment advice: figures are as reported in SEC filings and may contain errors or be out of date. Past performance does not guarantee future results.