WBCIX Performance — William Blair Small-Mid Cap Core Fund, Class I
Data updated: 2026-08-14
WBCIX returned +15.59% year to date and +20.78% over one year to Jun 2026. Annualised returns are +11.18% over 3 years and +5.67% over 5 years. Against its US Mid-Cap Value category average the fund came out behind over three years but ahead over one: $100 invested three years ago grew to $137, against $148 for the category, and to $121 over one year, against $120. Volatility over the past three years was 16.59% a year. In the 12 months to Jun 2026 the fund took in a net $96.8M, and assets reached $268.90M.
WBCIX Growth of $100
What $100 invested in William Blair Small-Mid Cap Core Fund grew to, compounded from monthly returns reported on SEC Form N-PORT, against the US Mid-Cap Value category average over the same months.
| Period | WBCIX | Category average |
|---|---|---|
| 1 year (Jul 2025 – Jun 2026) | $121 | $120 |
| 3 years (Jul 2023 – Jun 2026) | $137 | $148 |
| 5 years (Jul 2021 – Jun 2026) | $132 | $154 |
| Since data start (Oct 2019 – Jun 2026) | $201 | $209 |
WBCIX Trailing Returns
Total returns to Jun 2026, from SEC N-PORT.
| Period | Total return |
|---|---|
| YTD | +15.59% |
| 1 year | +20.78% |
| 3 years (annualised) | +11.18% |
| 5 years (annualised) | +5.67% |
WBCIX Annual Returns
Calendar-year total returns of William Blair Small-Mid Cap Core Fund, compounded from monthly SEC N-PORT returns. Partial years show the months covered.
| Year | Total return |
|---|---|
| 2026 (Jan–Jun) | +15.59% |
| 2025 | +1.27% |
| 2024 | +12.02% |
| 2023 | +13.24% |
| 2022 | −17.11% |
| 2021 | +26.65% |
| 2020 | +20.61% |
| 2019 (Oct–Dec) | +6.87% |
WBCIX 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 | +3.1% | +1.2% | −5.7% | +8.7% | +3.6% | +4.3% | — | — | — | — | — | — |
| 2025 | +3.8% | −4.4% | −7.1% | −2.7% | +3.7% | +4.2% | +1.0% | +2.5% | +0.5% | −0.9% | +1.8% | −0.5% |
| 2024 | −3.7% | +6.5% | +2.7% | −6.1% | +3.6% | −2.3% | +7.8% | +1.5% | +1.8% | −1.7% | +8.8% | −6.1% |
| 2023 | +10.1% | −2.4% | −4.0% | +0.1% | −3.0% | +7.8% | +4.2% | −3.5% | −5.3% | −6.6% | +9.2% | +8.0% |
| 2022 | −8.2% | +3.3% | +1.2% | −9.7% | −0.3% | −9.4% | +10.2% | −3.1% | −9.1% | +8.4% | +6.8% | −5.7% |
| 2021 | +0.3% | +9.4% | +2.8% | +4.2% | +0.1% | +0.7% | +0.1% | +1.1% | −2.3% | +7.0% | −2.2% | +3.5% |
| 2020 | −1.4% | −7.6% | −19.8% | +11.5% | +9.7% | +0.2% | +4.1% | +5.1% | −4.3% | +2.6% | +15.5% | +8.6% |
| 2019 | — | — | — | — | — | — | — | — | — | +0.7% | +4.0% | +2.1% |
WBCIX Risk
Risk measures from monthly returns over Jul 2023 – Jun 2026.
- 3-year volatility (annualised): 16.59%
- 3-year Sharpe ratio: 0.40 (vs 4.5% risk-free rate)
- Best month: +9.16% (Nov 2023)
- Worst month: −7.10% (Mar 2025)
WBCIX Fund Flows
Monthly money in and out of William Blair Small-Mid Cap Core Fund, from SEC Form N-PORT.
- 12-month net flow: $96.8M
- 12-month gross sales (incl. reinvestments): $190.0M
- Sales ÷ redemptions: 2.04×
| Month | Sales | Redemptions | Net flow |
|---|---|---|---|
| Jun 2026 | $1.3M | $4.3M | −$3.0M |
| May 2026 | $715K | $5.2M | −$4.4M |
| Apr 2026 | $24.1M | $13.8M | $10.2M |
| Mar 2026 | $108.4M | $1.4M | $107.1M |
| Feb 2026 | $1.5M | $6.0M | −$4.5M |
| Jan 2026 | $31.1M | $31.4M | −$356K |
| Dec 2025 | $4.4M | $4.1M | $297K |
| Nov 2025 | $882K | $7.5M | −$6.6M |
| Oct 2025 | $1.1M | $12.7M | −$11.6M |
| Sep 2025 | $2.7M | $2.7M | $9K |
| Aug 2025 | $2.1M | $2.1M | −$5K |
| Jul 2025 | $11.7M | $2.0M | $9.7M |
WBCIX Assets Under Management
Net assets of William Blair Small-Mid Cap Core Fund by report date, from SEC N-PORT filings.
| Report date | Net assets |
|---|---|
| 2026-06-30 | $268.90M |
| 2026-03-31 | $226.16M |
| 2025-12-31 | $122.95M |
| 2025-09-30 | $144.03M |
| 2025-06-30 | $128.90M |
| 2025-03-31 | $114.78M |
| 2024-12-31 | $176.85M |
| 2024-09-30 | $186.53M |
| 2024-06-30 | $197.16M |
| 2024-03-31 | $206.84M |
| 2023-12-31 | $196.29M |
| 2023-09-30 | $159.30M |
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.