WBSIX
Small Cap Growth Fund
Share Class
Daily NAV (USD)
$34.36
As of 11/13/2025
Morningstar rating: overall
As of 09/30/2025
Out of 512 Funds
Read Morningstar CriteriaMORNINGSTAR CRITERIA
Overall Morningstar Rating for Small Cap Growth Fund, as of Sep 30, 2025 rated against 512 Funds in Small Growth category based on risk adjusted total return.
Documents
Why Consider This Fund?
Approach
- Invests in high quality, small cap growth companies that we believe can sustain more durable growth than the market expects
- Employs a differentiated approach highlighted by the strategy's distinguishing characteristics of valuation sensitivity, contrarian bias and smaller-cap exposure
- Seeks to exploit market inefficiencies derived from the short-term focus of other investors
Fund Facts
OTHER VEHICLES:
| Fund Facts | As of 10/31/2025 |
|---|---|
| Total Net Assets ($Million) | $1,006 |
| Number of Holdings | 92 |
| Inception Date | 12/27/1999 |
| Expense Ratio (Gross) | 1.12% |
| Expense Ratio (Net) | 0.99% |
| Ticker Symbol | WBSIX |
| CUSIP | 093001485 |
| Benchmark | Russell 2000® Growth Index |
| Morningstar Category | Small Growth |
The Fund's Adviser has contractually agreed to waive fees and/or reimburse expenses to limit fund operating expenses until 4/30/26.
Performance
RETURN:As of 10/31/2025 | AVERAGE ANNUAL RETURNS: As of 10/31/2025 | |||||||
| Fund | Inception | Month | YTD | 1-YR | 3-YR | 5-YR | 10-YR | Since Inception |
|---|---|---|---|---|---|---|---|---|
| Small Cap Growth Fund Class I | 12/27/1999 | -0.76% | -0.76% | 6.50% | 11.16% | 9.40% | 12.06% | 11.61% |
| Russell 2000® Growth Index | - | 3.24% | 15.27% | 18.81% | 14.42% | 8.94% | 9.65% | 6.42% |
Performance cited represents past performance. Past performance does not guarantee future results and current performance may be lower or higher than the data quoted. Returns shown assume reinvestment of dividends and capital gains. Investment returns and principal will fluctuate with market and economic conditions and you may have a gain or loss when you sell shares. Class N shares are available to the general public without a sales load. Class I and Class R6 shares are available only to investors who meet certain eligibility requirements.
The benchmark shown represents the Fund’s performance benchmark, which is different from the Fund’s regulatory benchmark. The Fund’s regulatory benchmark is the Russell 3000 Index and is included in the Fund’s prospectus.
Ratings and Rankings
Morningstar Category: Small Growth
Overall
512 Funds in Category
3-YR
512 Funds in Category
5-YR
496 Funds in Category
10-YR
390 Funds in Category
Lipper Category: Small-Cap Growth Funds
1-YR
Rank: 367
540 Funds in Category
3-YR
Rank: 204
517 Funds in Category
5-YR
Rank: 103
503 Funds in Category
10-YR
Rank: 44
388 Funds in Category
Portfolio Characteristics
As of 10/31/2025
| Portfolio Composition | |
|---|---|
| Wgtd Avg Market Cap ($Billion) | $5.07 |
| Median Market Cap ($Billion) | $3.66 |
| P/E Ratio (Next 12 Months) | 24.6 |
| EPS Growth (Long-Term) | 16.4% |
| Trailing 1-Year Turnover | 87.0% |
| Cash | 3.6% |
| Standard Deviation (10 Year) | |
| 19.90% |
| 21.12% |
| Top 10 Holdings | % of Fund |
|---|---|
| The Brink's Company | 2.1% |
| Diebold Nixdorf, Incorporated | 1.8% |
| Twist Bioscience Corporation | 1.8% |
| Amicus Therapeutics, Inc. | 1.8% |
| Globus Medical, Inc. | 1.8% |
| Primo Brands Corporation | 1.7% |
| Doximity, Inc. | 1.7% |
| Mercury Systems, Inc. | 1.7% |
| Establishment Labs Holdings Inc. | 1.6% |
| Balchem Corporation | 1.6% |
| Total | 17.6% |
Portfolio Allocations
| Range | % of Fund |
|---|---|
| > $5.0B | 40.7% |
| $3.0B - $5.0B | 23.9% |
| $1.0B - $3.0B | 32.0% |
| < $1.0B | 3.4% |
| Total | 100.0% |
| Sector | % of Fund | % Benchmark |
|---|---|---|
| Health Care | 24.7% | 23.1% |
| Industrials | 21.4% | 22.7% |
| Information Technology | 19.5% | 23.1% |
| Consumer Discretionary | 10.1% | 8.3% |
| Financials | 10.1% | 9.5% |
| Materials | 4.5% | 3.2% |
| Consumer Staples | 2.9% | 2.0% |
| Energy | 2.5% | 3.0% |
| Real Estate | 2.2% | 1.9% |
| Exchange-Traded Funds | 1.1% | 0.0% |
| Communication Services | 1.0% | 2.6% |
| Utilities | 0.0% | 0.6% |
| Total | 100.0% |
Management
Please carefully consider the William Blair Funds’ investment objectives, risks, charges, and expenses before investing. This and other information is contained in the Funds’ prospectus and summary prospectus, which you may obtain by calling 1-800-742-7272. Read the prospectus and summary prospectus carefully before investing. Investing includes the risk of loss.
The William Blair Funds are distributed by William Blair & Company, L.L.C., member FINRA/SIPC.
Risks: The Fund’s returns will vary, and you could lose money by investing in the Fund. The Fund invests most of its assets in equity securities of small cap domestic growth companies where the primary risk is that the value of the equity securities it holds might decrease in response to the activities of those companies or market and economic conditions. Individual securities may not perform as expected or a strategy used by the Adviser may fail to produce its intended result. Investing in smaller companies involves special risks, including higher volatility and lower liquidity. Small cap stocks are also more sensitive to purchase/sale transactions and changes in the issuer’s financial condition. These risks are intensified for investments in micro-cap companies. Individual securities may not perform as expected or a strategy used by the Adviser may fail to produce its intended result. Convertible securities may be called before intended, which may have an adverse effect on investment objectives. The Fund is not intended to be a complete investment program. The Fund is designed for long-term investors.
For most recent net asset values and year-to-date total return information, please click here.
Top ten holdings are shown as % of total net assets. Sector and market-cap diversification exclude cash equivalents. Information about the Fund’s holdings should not be considered investment advice. There is no guarantee that the Fund will continue to hold any one particular security or stay invested in any one particular sector. Holdings are subject to change at any time.
The Russell 2000® Growth Index consists of small-capitalization companies with above average price-to-book ratios and forecasted growth rates. The Index is unmanaged, does not incur fees or expenses, and cannot be invested in directly.
The Morningstar Small Growth Category represents the average annual composite performance of all mutual funds listed in the Small Growth Category by Morningstar.
The Morningstar Rating for funds, or "star rating", is calculated for managed products (including mutual funds, variable annuity and variable life subaccounts, exchange-traded funds, closed-end funds, and separate accounts) with at least a three-year history. Exchange- traded funds and open-ended mutual funds are considered a single population for comparative purposes. It is calculated based on a Morningstar Risk-Adjusted Return measure that accounts for variation in a managed product’s monthly excess performance, placing more emphasis on downward variations and rewarding consistent performance. The top 10% of products in each product category receive 5 stars, the next 22.5% receive 4 stars, the next 35% receive 3 stars, the next 22.5% receive 2 stars, and the bottom 10% receive 1 star. The Overall Morningstar Rating for a managed product is derived from a weighted average of the performance figures associated with its three-, five-, and 10-year (if applicable) Morningstar Rating metrics. The weights are: 100% three-year rating for 36-59 months of total returns, 60% five-year rating/40% three-year rating for 60-119 months of total returns, and 50% 10-year rating/30% five-year rating/20% three-year rating for 120 or more months of total returns. While the 10 year overall star rating formula seems to give the most weight to the 10-year period, the most recent three-year period actually has the greatest impact because it is included in all three rating periods.
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Lipper Ratings are based on a Fund’s average annual total return.
Ratings and rankings are one measure of performance. Ratings may vary among share classes. Ratings reflect expense limitations in effect during the period, without such limitations returns would be lower. Past performance does not guarantee future results.
For your reference, this link contains additional notices and disclaimers required by our data suppliers.
Weighted Average Market Capitalization: Market capitalization refers to the total market value of each company’s outstanding shares. The Weighted Average Market Capitalization for a portfolio is calculated as the average market capitalization of the stocks within the portfolio, weighted by the amount of each stock owned. Unweighted Median Market Capitalization: This calculation represents the median market capitalization of the stocks in the portfolio, regardless of the amount of each stock owned. P/E (Price/Earnings) Ratio: This ratio is a measure of valuation. It relates the price of the stock to the earnings per share (EPS) of the company. A stock with a higher P/E ratio would be considered more expensive relative to another stock with a lower P/E. An investor may pay a higher P/E for a stock for several reasons including, but not limited to, an expectation that the company possesses higher returns on invested capital, less economic sensitivity, higher consistency of earnings and/or higher earnings growth potential. EPS (Earnings Per Share) Growth Rate (Projected): This measure represents the weighted average of forecasted growth in earnings expected to be experienced by the stocks within the portfolio over the next 3-5 years. From a portfolio perspective, the portfolio P/E ratio and EPS Growth Rate are weighted averages of the individual holdings’ P/E ratios and EPS Growth Rates. Trailing 1-Year Turnover: This figure reflects the portfolio’s trading activity by calculating the amount of the portfolio’s holdings bought or sold over the prior year, expressed as a percentage of the portfolio’s average market value. Turnover figures may be related to the amount of trading costs experienced by the portfolio. Standard Deviation: A measure of the portfolio’s risk. A higher standard deviation represents a greater dispersion of returns, and thus, a greater amount of risk. Standard deviation returns shown are annualized and calculated using monthly returns. Funds without a 10-year history are reported against the Fund’s inception date. If the Fund’s inception date does not fall on the first day of a given month, the annualized standard deviation is calculated based on the first day of the month following the Fund’s inception date.
Any investment or strategy mentioned herein may not be appropriate for every investor. There can be no assurance that investment objectives will be met. Products and services listed are available only to residents of this jurisdiction and may only be available to certain categories of investors. The information on this website does not constitute an offer for products or services, or a solicitation of an offer to any persons outside of this jurisdiction who are prohibited from receiving such information under applicable laws and regulations. Nothing on this webpage should be construed as advice and is therefore not a recommendation to buy or sell shares.
William Blair Investment Management, LLC is an investment adviser registered with the U.S. Securities and Exchange Commission.

