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As of 3/31/2014

Standardized Returns

  Month YTD 1 Yr. 3 Yrs. 5 Yrs. 10 Yrs. Life of Fund
2/1/2006
Mid Cap Growth Fund -1.68% 0.07% 16.10% 9.87% 20.63% -- 8.31%
Russell Midcap® Growth Index -1.85% 2.04% 24.22% 13.52% 24.73% -- 8.09%
Morningstar Mid-Cap Growth Category -1.95% 1.19% 23.40% 11.74% 22.17% -- --
Morningstar Quartile Ranking in Category----444----
Fund's Ranking / # of Funds in Peer Group----688 / 707507 / 641445 / 556----
Morningstar Rating----------
Expense Ratio (Gross): 1.42%
Expense Ratio (Capped): 1.35%

Calendar Year Total Returns

  2013 2012 2011 2010 2009 2008 2007 2006†
Mid Cap Growth Fund 28.77% 10.90% 1.65% 24.01% 36.03% -34.71% 14.62% 4.60%
Russell Midcap® Growth Index 35.74% 15.81% -1.65% 26.38% 46.29% -44.32% 11.43% 4.28%
† Since Fund’s inception on 2/1/06 through 12/31/06.


The Fund’s Adviser has contractually agreed to waive fees and/or reimburse expenses to limit fund operating expenses until 4/30/14.

For most recent net asset values and year-to-date total return information, please click here.

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. For the most current month-end performance information, please call +1 800 742 7272, or visit our Web site at www.williamblairfunds.com. Class N shares are available to the general public without a sales load. Class I shares are available only to investors who meet certain eligibility requirements.

The Russell Midcap® Growth Index is an index that is constructed to provide a comprehensive and unbiased barometer of the
mid-cap growth market. The Index is unmanaged, does not incur fees or expenses, and cannot be invested in directly.


The Morningstar Mid-Cap Growth Category represents the average annual composite performance of all mutual funds listed in the Mid-Cap Growth Category by Morningstar.

Morningstar Ratings™ are as of 3/31/2014 and are subject to change every month. The ratings are based on a risk-adjusted return measure that accounts for variation in a fund's monthly performance, placing more emphasis on downward variations and rewarding consistent performance. The top 10% of funds in each Category receive 5 stars, the next 22.5% receive 4 stars, the middle 35% receive 3 stars, the next 22.5% receive 2 stars, and the bottom 10% receive 1 star. The Overall Morningstar Rating for a fund is derived from a weighted average of the performance figures associated with its three-, five-, and ten-year (if applicable) Morningstar Rating metrics.

Morningstar Quartile Rankings are based on Morningstar Percentile Ranking in Morningstar Category, where 1% - 25% = first quartile(1); 26% - 50% = second quartile(2); 51% - 75% = third quartile(3); and 76% - 100% = fourth quartile(4). The Morningstar Percentile Ranking compares a Fund's Morningstar risk and return scores with all the Funds in the same Category, where 1% = Best and 100% = Worst.

Morningstar Ranking / # of Funds in Category displays the fund's actual rank within its Morningstar Category based on average annual total return and number of Funds in that Category.

©2014 Morningstar, Inc. All rights reserved. The information contained herein: (1) is proprietary to Morningstar and/or its content providers; (2) may not be copied or distributed; and (3) is not warranted to be accurate, complete or timely. Neither Morningstar nor its content providers are responsible for any damages or losses arising from any use of this information.