WBGSX Performance — William Blair Growth Fund, Class N
Data updated: 2026-08-14
WBGSX returned +7.32% year to date and +14.23% over one year to Jun 2026. Annualised returns are +16.41% over 3 years and +8.55% over 5 years. The fund trailed its US Large Growth category average: $100 invested three years ago grew to $158, against $175 for the category, and to $114 over one year, against $117. Volatility over the past three years was 17.65% a year. In the 12 months to Jun 2026 the fund took in a net $11.8M, and assets reached $226.76M.
WBGSX Growth of $100
What $100 invested in William Blair Growth Fund grew to, compounded from monthly returns reported on SEC Form N-PORT, against the US Large Growth category average over the same months.
| Period | WBGSX | Category average |
|---|---|---|
| 1 year (Jul 2025 – Jun 2026) | $114 | $117 |
| 3 years (Jul 2023 – Jun 2026) | $158 | $175 |
| 5 years (Jul 2021 – Jun 2026) | $151 | $166 |
| Since data start (Jul 2019 – Jun 2026) | $250 | $271 |
WBGSX Trailing Returns
Total returns to Jun 2026, from SEC N-PORT.
| Period | Total return |
|---|---|
| YTD | +7.32% |
| 1 year | +14.23% |
| 3 years (annualised) | +16.41% |
| 5 years (annualised) | +8.55% |
WBGSX Annual Returns
Calendar-year total returns of William Blair Growth Fund, compounded from monthly SEC N-PORT returns. Partial years show the months covered.
| Year | Total return |
|---|---|
| 2026 (Jan–Jun) | +7.32% |
| 2025 | +10.19% |
| 2024 | +21.81% |
| 2023 | +37.77% |
| 2022 | −29.64% |
| 2021 | +22.07% |
| 2020 | +35.94% |
| 2019 (Jul–Dec) | +7.83% |
WBGSX 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 | −1.5% | −4.9% | −5.6% | +13.7% | +8.6% | −1.8% | — | — | — | — | — | — |
| 2025 | +2.8% | −6.4% | −9.1% | +0.4% | +9.3% | +7.8% | +2.8% | +1.4% | +2.9% | +4.0% | −2.7% | −1.9% |
| 2024 | +2.8% | +6.1% | +1.7% | −4.4% | +3.7% | +3.3% | −0.3% | +1.7% | +2.4% | −1.3% | +7.1% | −2.4% |
| 2023 | +9.6% | −2.5% | +5.4% | +1.7% | +3.2% | +6.5% | +3.3% | −1.3% | −4.6% | −2.6% | +10.9% | +4.2% |
| 2022 | −8.6% | −2.7% | +2.3% | −11.9% | −2.8% | −8.3% | +12.1% | −5.4% | −11.1% | +5.1% | +5.7% | −6.1% |
| 2021 | −1.3% | +4.5% | +1.1% | +5.7% | −1.7% | +4.3% | +2.9% | +3.5% | −4.2% | +7.4% | −2.5% | +1.0% |
| 2020 | +1.9% | −6.1% | −10.4% | +13.3% | +8.1% | +2.6% | +6.7% | +6.8% | −3.7% | −2.1% | +11.1% | +5.8% |
| 2019 | — | — | — | — | — | — | +2.5% | −0.7% | −1.0% | +1.2% | +3.1% | +2.5% |
WBGSX Risk
Risk measures from monthly returns over Jul 2023 – Jun 2026.
- 3-year volatility (annualised): 17.65%
- 3-year Sharpe ratio: 0.67 (vs 4.5% risk-free rate)
- Best month: +13.66% (Apr 2026)
- Worst month: −9.10% (Mar 2025)
WBGSX Fund Flows
Monthly money in and out of William Blair Growth Fund, from SEC Form N-PORT.
- 12-month net flow: $11.8M
- 12-month gross sales (incl. reinvestments): $60.5M
- Sales ÷ redemptions: 1.24×
| Month | Sales | Redemptions | Net flow |
|---|---|---|---|
| Jun 2026 | $628K | $1.9M | −$1.3M |
| May 2026 | $1.2M | $4.6M | −$3.4M |
| Apr 2026 | $669K | $3.5M | −$2.8M |
| Mar 2026 | $478K | $4.1M | −$3.6M |
| Feb 2026 | $763K | $4.1M | −$3.3M |
| Jan 2026 | $1.2M | $3.6M | −$2.4M |
| Dec 2025 | $52.6M | $10.7M | $41.9M |
| Nov 2025 | $492K | $4.5M | −$4.0M |
| Oct 2025 | $483K | $3.3M | −$2.8M |
| Sep 2025 | $878K | $1.9M | −$1.0M |
| Aug 2025 | $491K | $4.3M | −$3.8M |
| Jul 2025 | $616K | $2.1M | −$1.5M |
WBGSX Assets Under Management
Net assets of William Blair Growth Fund by report date, from SEC N-PORT filings.
| Report date | Net assets |
|---|---|
| 2026-06-30 | $226.76M |
| 2026-03-31 | $193.52M |
| 2025-12-31 | $228.41M |
| 2025-09-30 | $247.36M |
| 2025-06-30 | $236.96M |
| 2025-03-31 | $207.84M |
| 2024-12-31 | $249.99M |
| 2024-09-30 | $254.05M |
| 2024-06-30 | $261.38M |
| 2024-03-31 | $260.13M |
| 2023-12-31 | $239.26M |
| 2023-09-30 | $221.59M |
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.