UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

INFORMATION REQUIRED IN PROXY STATEMENT

SCHEDULE 14A INFORMATION

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

Filed by the Registrant x☒

Filed by a Party other than the Registrant ¨☐

Check the appropriate box:

William Blair Funds

(Name of Registrant as Specified in Its Charter)

Payment of Filing Fee (Check the appropriate box):

WILLIAM BLAIR FUNDS

WILLIAM BLAIR SHORT-TERM BOND FUND

222 WEST ADAMS STREET(FORMERLY, THE WILLIAM BLAIR INCOME FUND)

150 NORTH RIVERSIDE PLAZA

CHICAGO, ILLINOIS 60606

November     , 2021

Dear Shareholder,

You are cordially invited to attend a special meeting of the shareholders of William Blair Short-Term Bond Fund (formerly known as William Blair Income Fund) (the “Fund”), a series of William Blair Funds (the “Trust”), to be held virtually on January 13, 2022 at 12:00 p.m. Central time (the “Meeting”). The Meeting will be conducted as a virtual meeting hosted by means of a live webcast. The Board of Trustees of the Trust has implemented a virtual meeting format primarily to reflect our and global concerns regarding the spread of COVID-19. Shareholders will be able to listen, vote, and submit questions from their home or any location with Internet connectivity.

At the Meeting, you will be asked to consider and act upon the following proposals (the “Proposals”):

The following Q&A is provided to assist you in understanding the Proposals. The Proposals are described in greater detail in the enclosed proxy statement.

Your vote is important. Whether or not you expect to attend the Meeting, it is important that your shares be represented. Your immediate response will help reduce the need for the Fund to conduct additional proxy solicitations. Please review the proxy statement and then vote by Internet, telephone or mail as soon as possible. If you vote by mail, please sign and return all of the proxy cards included in this package.

IMPORTANT INFORMATION TO HELP YOU UNDERSTAND

AND VOTE ON THE PROPOSALS

While we strongly encourage you to read the full text of the enclosed Proxy Statement, we are also providing you with a brief overview of the subject of the shareholder vote. Your vote is important.

QUESTIONS AND ANSWERS

Q. What am I being asked to vote on?

A. At a special meeting of shareholders (the “Meeting”) of William Blair Short-Term Bond Fund (formerly known as William Blair Income Fund) (the “Fund”), you will be asked to vote on the following proposals with respect to the Fund, and to transact any other business as may properly come before the Meeting or any adjournment or postponement thereof: to approve a change in the Fund’s fundamental investment objective and to approve a change in fundamental investment policy for the Fund as described in the proxy statement (the “Proposals”).

Q. Why are the Proposals being recommended?

A. The marketplace for short-term, investment grade, fixed income funds has evolved since the inception of the Fund. William Blair Investment Management, LLC (the “Adviser” or “WBIM”), the Fund’s investment adviser, believes that certain changes to the Fund’s investment objective and fundamental investment policies could enable the Adviser to manage the Fund more effectively and in a manner more consistent with investor needs and reflective of the growth and structure of the bond market. Therefore, shareholders are being asked to approve these changes in the Fund’s investment objective and fundamental investment policy. Under the Investment Company Act of 1940 (the “1940 Act”), changes to a fund’s fundamental investment policy or to a fund’s fundamental investment objective require shareholder approval.

Q. What revisions are being made to the fundamental investment objective of the Fund?

A.Currently the objective of the Fund is:

The William Blair Short-Term Bond Fund seeks a high level of current income with relative stability of principal.

The Adviser recommends changing the objective to read as follows:

The William Blair Short-Term Bond Fund seeks to generate current income, consistent with relative stability of capital.

The Adviser believes this change would align the Fund’s investment objective with the expected future management of the Fund and management’s understanding of shareholder investment expectations for short-term bond funds. If Proposal 1 is approved by shareholders, the Fund’s investment objective would continue to be fundamental, meaning it could not be changed further in the future without shareholder approval.

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Q. What revisions are being made to the fundamental investment policy of the Fund?

A.The Fund may currently invest up to 10% of its total assets in below A- rated debt. To more closely align with the portfolio management team’s expectations for managing the Fund and in light of growth in the percentage of investment grade debt represented by BBB- rated debt, the investment team believes it is appropriate to have additional flexibility to be able to invest a larger portion of the Fund’s total assets in BBB rated debt. The Adviser expects that any increase in BBB- rated debt will not materially diverge from the Fund’s current risk/return profile.

The Fund currently has the following fundamental investment policy:

“As a matter of fundamental policy, under normal market conditions, the Fund invests at least 90% of its total assets in the following: (a) U.S. dollar-denominated corporate debt securities (domestic or foreign) with long-term ratings of “A-” or better, or an equivalent rating, by at least one of the following three nationally recognized statistical rating organizations: Fitch Ratings, Moody’s Investors Service, Inc. and Standard & Poor’s, a division of The McGraw-Hill Companies, Inc. (“Rating Organizations”); (b) obligations of or guaranteed by the U.S. Government, its agencies or instrumentalities; (c) collateralized obligations, which are debt securities issued by a corporation, trust or custodian, or by a U.S. Government agency or instrumentality, that are collateralized (i.e., secured as to payment of interest and/or principal) by a portfolio or pool of assets, such as mortgages, mortgage-backed securities, debit balances on credit card accounts or U.S. Government securities (the Fund may invest in collateralized obligations that are not guaranteed by a U.S. Government agency or instrumentality only if the collateralized obligations are rated “A-” or better, or an equivalent rating, by one of the Rating Organizations); and (d) commercial paper obligations rated within the highest grade by one of the Rating Organizations.”

It is proposed that the fundamental policy by revised to read as follows:

As a matter of fundamental policy, under normal market conditions, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in bonds.

The revised policy will both allow the desired flexibility to invest in BBB-rated securities to a greater degree and satisfy the regulatory requirement that the Fund adopt a policy to invest at least 80% of its net assets in bonds consistent with its new name. For purposes of the policy, “bonds” would include all types of fixed income instruments.

Assuming that the fundamental policy is revised as indicated above, the Adviser would also include the following additional disclosure in the Fund’s principal investment strategies:

“The Fund invests primarily in U.S. dollar denominated, investment grade fixed income securities. A security is considered to be investment grade if it is rated in one of the highest four categories by at least one nationally recognized statistical rating organization (“Rating Organization”) at the time of investment.”

Proposal 2 could incrementally increase the risk profile of the Fund. The lower the rating of a bond, the greater the risk is that the issuer could default on its obligation to make payments under the bond. The Adviser notes however that any security rated BBB- or higher is still considered investment grade.

The Adviser does not intend to purchase securities rated below “BBB-” at the time of purchase. However, securities that are downgraded below BBB- after purchase may continue to be held by the Fund. In addition,

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this policy is not a fundamental policy and may be changed in the future by the Board without shareholder approval.

Increasing the amount the Fund may invest in below A- rated debt allows for greater diversification within the Fund, which the Adviser believes would allow for better risk management. Fixed income investors can earn returns primarily through two methods: credit risk or interest rate (duration) risk. The Adviser intends to manage the average duration of the Fund along with investing in a broader range of bonds having different credit ratings. The Adviser would prefer to earn returns with an appropriate mix of credit and interest rate risk. The Adviser believes this change allows it to better balance those risks in the Fund.

Q. Why are you sending me this information?

A. You are receiving these proxy materials because you own shares of the Fund and have the right to vote on these very important proposals concerning your investment.

Q. Has the Board of Trustees (the “Board”) of William Blair Funds approved the Proposals and how does the Board recommend that I vote?

A. The Board unanimously approved the Proposals at a meeting held on October 26-27, 2021 and recommends that you voteFOR the Proposals.

Q. Who will bear the costs related to this proxy solicitation?

A. The cost of the proxy solicitation will be borne by the Fund; however, by virtue of the operation of the expense limitation arrangements currently in effect with respect to the Fund, these costs will ultimately be borne by WBIM. Broadridge Financial Services, Inc. (“Broadridge”) has been engaged to assist in the solicitation of proxies for the Fund at an estimated cost of $40,000, plus reimbursement for reasonable expenses. However, the exact cost will depend on the amount and types of services rendered.

Q. Who is entitled to vote?

A. If you owned shares of the Fund as of the close of business on November 19, 2021 (the “Record Date”), you are entitled to vote those shares.

Q. When and where will the Meeting be held?

A. After considering the continuing health impacts of COVID-19, related governmental orders and guidance, and the wellbeing of shareholders, employees, and communities, the Board has determined to hold the Meeting only by means of remote communication through a live internet webcast. An in-person meeting at a physical location will not be held.

Q. How do I vote my shares?

A. For your convenience, there are several ways you can vote:

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Q. What vote is required to approve the Proposals?

A. Approval of each Proposal requires the affirmative vote of a “majority of the outstanding voting securities” of the Fund, which under the 1940 Act means an affirmative vote of the lesser of (a) 67% or more of the shares of the Fund present at the Meeting or represented by proxy if the holders of more than 50% of the outstanding shares are present or represented by proxy, or (b) more than 50% of the outstanding shares of the Fund. For purposes of the Proposals, all shareholders vote together, regardless of which class they own.

The Proposals are independent of each other. Therefore, it may be the case that one Proposal may be approved while another is not.

Q. What happens if I sign and return my proxy card but do not mark my vote?

A. Your proxy will be voted in favor of the Proposals.

Q. May I revoke my proxy?

A. You may revoke your proxy at any time before it is exercised at the meeting by giving notice of your revocation to the Fund in writing, or by the execution and delivery of a later-dated proxy. Your notice of revocation must be received by [                ], 2021 no later than [    ] [a.m./p.m.] [ET / CT]. You may also revoke your proxy by attending and voting at the Meeting.

Q. Whom should I call for additional information about this Proxy Statement?

A. If you need any assistance or have any questions regarding the Proposals or how to vote your shares, please call the Fund’s proxy information line at 1-833-934-2740 and follow the recorded instructions.

THE ATTACHED PROXY STATEMENT CONTAINS MORE DETAILED INFORMATION

ABOUT THE PROPOSALS. PLEASE READ IT CAREFULLY. YOUR VOTE IS IMPORTANT.

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WILLIAM BLAIR FUNDS

WILLIAM BLAIR SHORT-TERM BOND FUND

(FORMERLY, WILLIAM BLAIR INCOME FUND)

150 NORTH RIVERSIDE PLAZA

CHICAGO, ILLINOIS 60606

NOTICE OF SPECIAL MEETING OF SHAREHOLDERS

TO BE HELD AUGUST 2, 2012JANUARY 13, 2022

November     , 20122021

To the Shareholders:

You are invited to attend a special meeting of the shareholders of William Blair Short-Term Bond Fund (formerly known as William Blair Income Fund, the “Fund”), a series of William Blair Funds (the “Trust”), to be held in the 2nd Floor Conference Roomvirtually on January 13, 2022 at 222 West Adams Street, Chicago, Illinois, 60606, on Thursday, August 2, 2012 at 2:12:00 p.m. Central time (the “Meeting”) for the following purposespurposes:

The Board of Trustees of the Trust has fixed the close of business on June     , 2012November 19, 2021 as the record date for determining the shareholders of the TrustFund entitled to notice of and to vote at the meetingMeeting or any adjournments or postponements thereof. Shareholders are entitled to one vote for each share held and a proportionate fractional vote for each fractional share held.

You will be able to attend the Meeting online, submit your questions during the Meeting and vote your shares electronically. To participate in the Meeting, shareholders must register in advance by visiting                         .com and submitting the required information to William Blair Investment Management, LLC (the “Adviser” or “WBIM”).

Shareholders whose shares are registered directly with the Fund in the shareholder’s name will be asked to submit their name and control number found on the shareholder’s proxy card in order to register to participate in and vote at the Meeting. Shareholders whose shares are held by a broker, bank or other nominee must first obtain a “legal proxy” from the applicable nominee/record holder, who will then provide the shareholder with a newly-issued control number. We note that obtaining a legal proxy may take several days. Requests for registration should be received no later than 4:00 p.m., Central time, on                 , 2021, but in any event must be received by the scheduled time for commencement of the Meeting. Once shareholders have obtained a new control number, they must visit                         .com and submit their name and newly-issued control number in order to register to participate in and vote at the Meeting.

After shareholders have submitted their registration information, they will receive an email that confirms that their registration request has been received and is under review by the Adviser. Once a shareholder’s registration request has been accepted, the shareholder will receive (i) an email containing an event link and dial-in information to attend the Meeting, and (ii) an email with a password to enter at the

event link in order to access the Meeting. Shareholders may vote before or during the Meeting at                         .com. Only shareholders of the Fund present virtually or by proxy will be able to vote, or otherwise exercise the powers of a shareholder, at the Meeting.

The Meeting webcast will begin promptly at 12:00 p.m. Central time. We encourage you to access the Meeting prior to the start time. For additional information on how you can attend and participate in the virtual Meeting, please see the instructions beginning on the first page of the proxy statement that follows. Because the Meeting will be a completely virtual meeting, there will be no physical location for shareholders to attend.

In order to avoid delay and additional expense and to assure that your shares are represented, please vote as promptly as possible, regardless of whether or not you plan to attend the meeting. You may vote by mail, telephone or over the Internet. To vote by mail, please mark, sign, date and mail the enclosed proxy card. No postage is required if mailed in the United States. To vote by telephone, please call the toll-free number located on your proxy card and follow the recorded instructions, using your proxy card as a guide. To vote over the Internet, go to the Internet address provided on your proxy card and follow the instructions, using your proxy card as a guide.

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PROXY STATEMENT

WILLIAM BLAIR FUNDS

WILLIAM BLAIR SHORT-TERM BOND FUND

222 WEST ADAMS STREET(FORMERLY, WILLIAM BLAIR INCOME FUND)

150 NORTH RIVERSIDE PLAZA

CHICAGO, ILLINOIS 60606

November     , 20122021

Important Notice Regarding the Availability of Proxy Materials for the Shareholder Meeting to be Held on August 2, 2012:January 13, 2022:

The Proxy Materials are available at [insert website]at: [www.ProxyVote.com]

GENERAL

The accompanying proxy is solicited by the Board of Trustees of William Blair Funds (the “Board” and each member thereof a “Trustee”) for voting at the special meeting of shareholders of William Blair Short-Term Bond Fund (formerly known as William Blair Income Fund) (the “Fund”), a series of William Blair Funds (the “Trust”), to be held virtually on August 2, 2012January 13, 2022 at 2:12:00 p.m. Central time in the 2nd Floor Conference Room at 222 West Adams Street, Chicago, Illinois, 60606, and at any and all adjournments or postponements thereof (the “Meeting”). This proxy statement and the enclosed proxy are first being mailed to shareholders on or about , 2012.November __, 2021.

Shareholders are being asked to consider

The Meeting will be a virtual meeting conducted exclusively via live webcast starting at 12:00 p.m. Central time. You will be able to attend the Meeting online, submit your questions during the Meeting and vote your shares. To participate in the Meeting, shareholders must register in advance by visiting                     .com and submitting the required information to William Blair Investment Management, LLC (the “Adviser” or “WBIM”).

Shareholders whose shares are registered directly with the Fund in the shareholder’s name will be asked to submit their name and control number found on the shareholder’s proxy card in order to register to participate in and vote at the Meeting. Shareholders whose shares are held by a broker, bank or other nominee must first obtain a “legal proxy” from the applicable nominee/record holder, who will then provide the shareholder with a newly-issued control number. We note that obtaining a legal proxy may take several days. Requests for registration should be received no later than 4:00 p.m., Central time, on                     , 2021, but in any event must be received by the scheduled time for commencement of the Meeting. Once shareholders have obtained a new control number, they must visit                         .com and submit their name and newly-issued control number in order to register to participate in and vote at the Meeting.

After shareholders have submitted their registration information, they will receive an email that confirms that their registration request has been received and is under review by the Adviser. Once a shareholder’s registration request has been accepted, the shareholder will receive (i) an email containing an event link and dial-in information to attend the Meeting, and (ii) an email with a password to enter at the event link in order to access the Meeting. Shareholders may vote before or during the Meeting at                     .com . Only shareholders of the Fund present virtually or by proxy will be able to vote, or otherwise exercise the powers of a shareholder, at the Meeting.

In light of the rapidly changing developments related to COVID-19, we are pleased to offer our shareholders a completely virtual Meeting, which provides worldwide access and communication, while protecting the health and safety of our shareholders and the Fund’s officers. We are committed to ensuring that shareholders will be afforded the same rights and opportunities to participate as they would at an in-person meeting. We will try to answer as many shareholder-submitted questions as time permits that comply with the Meeting rules of conduct. However, we reserve the right to edit profanity or other inappropriate language, or to exclude questions that are not pertinent to meeting matters or that are otherwise inappropriate. If substantially similar questions are received, we will group such questions together and provide a single response to avoid repetition.

Shareholders Entitled to Vote

The Board has fixed the close of business on November 19, 2021 as the record date (the “Record Date”) for the determination of shareholders entitled to notice of and to vote at the Meeting. As of the Record Date, [            ] shares of the Fund were issued and outstanding in the following classes:

Required Vote

(Growth Fund, Large Cap Growth Fund, Small Cap Growth Fund, Mid Cap Growth Fund, Small-Mid Cap Growth Fund, Global Growth Fund, International Growth Fund, Institutional International Growth Fund, International Equity Fund, Institutional International Equity Fund, International Small Cap Growth Fund, Emerging Markets Growth Fund, Emerging Leaders Growth Fund, Small Cap Value Fund, Mid Cap Value Fund, Bond Fund, Income Fund, Low Duration Fund and Ready Reserves Fund only)

Shareholders of each Fund will vote together as a single class to elect Trustees to the Board and will vote separately by Fund to approve the amendment(s) to each Fund’s fundamental investment restrictions. A quorum of shareholders is required to take action at the Meeting. Holders of one-third of the outstanding shares of the Trust representedFund, present in person or by proxy, will constitute a quorum of shareholders at the Meeting. If a quorum is present at the Meeting: (1) the affirmative vote of more than 50% of the shares of the Trust present at the Meeting, either in person or by proxy, will be required to elect each of the current Trustees to the Board; (2)then the affirmative vote of a plurality“majority of the sharesoutstanding voting securities” of the Trust entitledFund, as defined in the Investment Company Act of 1940 (the “1940 Act”) is required for shareholders to vote atapprove the Meeting will be required to electProposals. A “majority of the Nominee to filloutstanding voting securities” is defined in the current vacancy on the Board of Trustees; and (3) the affirmative vote of1940 Act as the lesser of (i)(a) 67% or more of the shares of a Fund present at the Meeting, if the holders of more than 50% of the outstanding shares of the Fund are present at the Meeting or represented in person or by proxy, or (ii)(b) more than 50% of the outstanding shares of the FundFund.

If a proxy card is properly executed and returned accompanied by instructions to withhold authority (an abstention), the shares represented thereby will be required to approve the amended fundamental investment restrictions for each Fund. Abstentions and “broker non-votes” (i.e., shares held by brokers or nominees as to which (i) instructions have not been received from the beneficial owners or the persons entitled to vote, and (ii) the broker or nominee does not have the discretionary voting power on a particular matter) will be treatedcounted as shares present at the meeting for quorum and voting purposes. Therefore, abstentions and broker non-votes will have the effect of a negativeentitled to vote for purposes of the electiondetermining whether a quorum is present, but will not be counted as a vote in favor of the current TrusteesProposals. Accordingly, abstentions effectively will be a vote against the Proposals. Ordinarily, broker non-votes, if any, would be counted as shares present and the approvalentitled to vote for purposes of determining whether a quorum is present, but would not be counted as a vote in favor of the amended fundamental investment restrictions. AbstentionsProposals. However, because the Proposals are considered non-routine, broker non-votes are inapplicable to this solicitation and broker non-votes will have no effectimpact on establishing quorum or the votes cast for purposes ofor against the election of the Nominee to fill the current Board vacancy.Proposals.

Each valid proxy will be voted in accordance with the instructions provided on the proxy and as the persons named in the proxy determine on such other business as may come before the Meeting. If no instructions are given, the proxy will be votedFOR the election of the Trustees andFOR the approval of the amended fundamental investment restrictions.Proposals. Shareholders are entitled to one vote for each share held and a proportionate fractional vote for each fractional share held. Shareholders may vote

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by filling out and signing the enclosed proxy card and returning it in the postage paid envelope provided. Shareholders may also vote by telephone or over the Internet. Please see the instructions on your proxy card for telephone voting and Internet voting. Shareholders will have an opportunity to review their voting instructions and make any necessary changes before submitting their voting instructions and terminating their telephone call or Internet link. Shareholders who execute proxiesa proxy in any of the above

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manners may revoke the proxiestheir proxy at any time before theytheir shares are voted, either by sending the Trust a written notice of revocation, by delivering a duly executed proxy bearing a later date, or by attending the Meeting and voting in person. For directions on how to attend the Meeting in person, please call                     .

The Board has fixed the close of business on June     , 2012 as the record date (the “Record Date”) for the determination of shareholders entitled to notice of and to vote at the Meeting. As

PROPOSALS

TO APPROVE A CHANGE IN THE FUND’S FUNDAMENTAL INVESTMENT OBJECTIVE AND FUNDAMENTAL INVESTMENT POLICY

Background and Description of the Record Date,                  sharesProposals

The marketplace for short-term, investment grade, fixed income funds has evolved since the inception of the Trust were issuedFund. The Adviser believes that certain changes to the Fund’s investment objective and outstandingfundamental investment policies could enable the Adviser to manage the Fund more effectively and in the following seriesa manner more consistent with investor needs and classes:

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PROPOSAL 1

ELECTION OF TRUSTEES TO THE BOARD

(All Funds)

General

At the Meeting, shareholdersreflective of the Trust will begrowth and structure of the bond market. Therefore, shareholders are being asked to elect eight individuals to constitute the Board of the Trust. The Board has nominated Vann A. Avedisian, Phillip O. Peterson, Lisa A. Pollina, Donald J. Reaves, Donald L. Seeley, Michelle R. Seitz, Thomas J. Skelly, and Richard W. Smirl as the individuals to be elected as Trustees of the Trust. Mr. Peterson, Ms. Pollina, Mr. Reaves, Mr. Seeley, Ms. Seitz, Mr. Skelly and Mr. Smirl are all current Trustees of the Trust. Mr. Peterson, Mr. Reaves, Mr. Seeley, Ms. Seitz, and Mr. Skelly were electedapprove these changes to the Board by shareholders in 2006. Mr. SmirlFund’s fundamental investment objective and Ms. Pollina were appointed to the Board in 2010 and 2011, respectively, by the then sitting Trustees of the Trust in accordance with the provisions of the Trust’s Declaration of Trust and Section 16(a) offundamental investment policy. Under the Investment Company Act of 1940 as amended (the “1940 Act”). Mr. Avedisian is not currently, changes to a Trusteefund’s fundamental investment policy or to a fund’s fundamental investment objective require shareholder approval.

Proposal 1 – To approve a change to the Fund’s Fundamental Investment Objective

Proposal 1 relates to a proposed change to the Fund’s fundamental investment objective.    Currently the objective of the Trust and uponFund is:

The William Blair Short-Term Bond Fund seeks a high level of current income with relative stability of principal.

The Adviser recommends changing the recommendationobjective to read as follows:

The William Blair Short-Term Bond Fund seeks to generate current income, consistent with relative stability of capital.

The Adviser believes this change would align the Fund’s investment objective with the expected future management of the NominatingFund and Governance Committee is being presentedmanagement’s understanding of shareholder investment expectations for electionshort-term bond funds. If shareholders approve Proposal 1, the Adviser will operate the Fund under the revised investment objective. The Fund’s investment objective would continue to fillbe fundamental, meaning it could not be changed further in the vacancy created whenfuture without shareholder approval. If shareholders do not approve Proposal 1, the Fund will continue to be managed with the investment objective of seeking a Trustee retired from the Board on February 22, 2012. Ms. Pollina and Messrs. Peterson, Reaves, Seeley and Skelly (the “Independent Trustees”) and Mr. Avedisian (the “Nominee”) are not interested personshigh level of current income with relative stability of principal.

Proposal 2 – To approve changes to certain of the Trust as defined in the 1940 Act. Ms. Seitz and Mr. Smirl are considered interested persons of the Trust as defined in the 1940 Act (“Interested Trustees”) dueFund’s Fundamental Investment Policy

Proposal 2 relates to their employment with the Trust’s investment advisor and principal underwriter, William Blair & Company, L.L.C. (“William Blair” or the “Advisor”).

Each nominee electeda proposed changed to the Board will serve as a Trustee of the Trust until the election and qualification of a successor or until death, retirement, or resignation or removal as provided forFund’s fundamental investment policy with respect to investment in the Declaration of Trust. It is the Board’s policyBBB rated debt securities. The Adviser believes that retirement for Independent Trustees occurs no later than at the conclusion of the first regularly scheduled Board meeting of the Trust’s fiscal year that occurs after the earlier of (a) the Trustee’s 72nd birthday or (b) the 15th anniversary of the date that the Independent Trustee was first elected or appointed as a member of the Board of Trustees.

All the nominees listed below have consented to serve as Trustees of the Trust, if elected. In case any nominee shall be unable or shall fail to act as a Trustee by virtue of an unexpected occurrence, persons named as proxies will vote in their discretion for such other nominee or nominees as the current Trustees may recommend. The following table presents certain information about the nominees. Each nominee’s year of birth is set forth after his or her name. The mailing address for each nominee is 222 West Adams Street, Chicago, Illinois 60606.approved, Proposal 2 would provide

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Nomineesthe Adviser more flexibility to invest the Fund’s assets in a manner that could result in improved investment performance for Election as Trustees

Independent Trustees/Nominee

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Interested Trustees

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Board of Trusteesthe Fund.

The primary responsibility of the Board of Trustees isFund may currently invest up to represent the interests of the shareholders of the Trust and to provide oversight of the management of the Trust. The slate of nominees proposed for election at the Meeting is comprised of two individuals who would be Interested Trustees and six individuals who would be Independent Trustees. SEC rules currently require a majority of the board members of a fund to be “independent” if the fund takes advantage of certain exemptive rules under the 1940 Act. If the proposed Board is approved by shareholders, 75% will be Independent Trustees.

The Trust’s day to day operations are managed by the Advisor and other service providers who have been approved by the Board. In light of the general characteristics of the Trust, including the number of funds, the nature of the funds’ investments and the historical relationship between the Trust and the Advisor, the Board has developed a leadership structure that encourages all Trustees to participate equally in Trust governance. The Board believes that the leadership structure fosters the type of meaningful dialogue between the Advisor and the Independent Trustees that results in an appropriate balance of cooperation with and oversight of the Advisor. The Board has elected Michelle Seitz, an Interested Trustee, to serve as Chairperson of the Board and because of the Board’s leadership structure, no Independent Trustee has been designated as a lead independent trustee.

Generally, the Board acts by majority vote of all the Trustees, including a majority vote of the Independent Trustees if required by applicable law. The Board has established two standing committees, the Audit Committee and the Nominating and Governance Committee, each comprised entirely of the Independent Trustees, to which it has delegated certain responsibilities as described below. The Board and its committees meet periodically throughout the year to oversee the Trust’s activities, including reviewing at one or more meetings, the Trust’s contractual arrangements with the Advisor and other service providers, the operation of the Trust’s investment policies, compliance and regulatory matters and the Funds’ investment performance. The Independent Trustees are represented by independent legal counsel at Board and committee meetings. As part10% of its general oversight of the Trust, the Board is involvedtotal assets in the risk oversight of the Trust directly and through its committees. The Board reviews the investment performance of the funds with the Advisor, including meeting regularlybelow A-rated debt. To more closely align with the portfolio managers, at each of its regularly scheduled quarterly Board meetings. In addition,management team’s expectations for managing the Board must approve any material changes to a Fund’s investment policies or restrictions. With respect to compliance matters, the Trust’s Chief Compliance Officer provides the annual compliance report required by Rule 38a-1 under the 1940 Act, a quarterly report to the Board regarding the operation of the Trust’s compliance policiesFund and procedures, including any material compliance issues that arose during the quarter, and meets in executive session with the Audit Committee at its quarterly meetings. With respect to valuation, the Board and its Valuation Committee oversee a pricing committee comprised of Trust officers and Advisor personnel and the Board has approved Valuation Procedures, including fair valuation

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procedures, applicable to valuing the Funds’ securities, which the Board reviews at least annually. The Audit Committee is responsible for monitoring the Trust’s accounting policies, financial reporting and internal control systems, as well as the work of the independent registered public accounting firm and the Audit Committee reports its activities to the Board on a regular basis. The Nominating and Governance Committee is primarily responsible for the identification and recommendation of individuals for Board membership and for overseeing the administration of the Trust’s Governance Procedures and Guidelines and the Nominating and Governance Committee reports its activities to the Board on a regular basis.

During 2011, the Board met five times. Each current Trustee attended at least 75% of the respective meetings of the Board and the Committees (if a member thereof) held during 2011.

The members of the Audit Committee, all of whom are Independent Trustees, include Messrs. Peterson (Chairperson), Reaves, Seeley and Skelly and Ms. Pollina. It is expected that, if elected, Mr. Avedisian will be appointed as a member of the Audit Committee. The Audit Committee held four meetings in 2011.

The members of the Nominating and Governance Committee, all of whom are Independent Trustees, include Messrs. Reaves (Chairperson), Peterson, Seeley and Skelly and Ms. Pollina. It is expected that, if elected, Mr. Avedisian will be appointed as a member of the Nominating and Governance Committee. A copy of the Nominating and Governance Committee Charter is attached as Appendix A. The Nominating and Governance Committee held eight meetings in 2011.

Pursuant to the Trust’s Governance Procedures and Guidelines, the Nominating and Governance Committee will independently evaluate candidates for Board membership. In evaluating candidates for Board membership, the Nominating and Governance Committee will take into account such factors as it deems appropriate, including the professional experience, education and skills of the candidate and the overall diversity of the Board’s composition. The Nominating and Governance Committee believes the Board generally benefits from diversity of background, experience and views among its members, and considers this a factor in evaluating the composition of the Board, but has not adopted any specific policy in this regard. Suggestions for candidates may be submitted to the Committee by other Trustees, by shareholders or by the Advisor. Shareholders may submit suggestions for candidates by sending a resume of the candidate to the Secretary of the Trust, 222 West Adams Street, Chicago, Illinois 60606, for the attention of the Chairperson of the Nominating and Governance Committee. There is no difference in the manner in which the Nominating and Governance Committee evaluates candidates recommended by shareholders versus candidates recommended by other parties. Each Trustee/Nominee was recommended to the Board as a candidate for election by the Nominating and Governance Committee. Mr. Avedisian, who is not currently a Trustee of the Trust, was recommended to the Nominating and Governance Committee by the Advisor.

The members of the Valuation Committee include Mr. Smirl and Mr. Skelly. The other Independent Trustees are designated as alternate members in the event that Mr. Skelly is unavailable. The Valuation Committee held no meetings in 2011.

The Board has adopted a policy that absent personal circumstances that do not permit a Trustee to attend, all Trustees are expected to be present at each meeting of shareholders in order to facilitate communications with shareholders. Under circumstances where no Trustee is available to attend a shareholders meeting, the Board may designate a senior officer of the Trust to be present and to report back to the Board.

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Trustee/Nominee Qualifications

The following is a brief discussion of the experiences and qualifications that led to the conclusion that each Trustee/Nominee should serve as a Trustee. Generally, the professional, business and educational experience of each Trustee/Nominee was considered in determining his or her qualifications to serve as a Trustee of the Trust. Each current Trustee’s previous record of service as a Trustee or officer of the Trust was considered and served to demonstrate his or her understanding of and commitment to the Trust. With respect to each Trustee/Nominee, the Board considered, among other factors, the following experiences and qualifications:

The Board considered Vann A. Avedisian’s professional experience serving in various executive positions with companies in the real estate industry, including co-founding and serving as a Managing Director of Oxford Capital Partners, Inc. and, currently, directing the capital market activities of Highgate Holdings, where he is a Principal. The Board considered the executive, financial, operations and risk management experience that Mr. Avedisian gained over the course of his career. The Board also considered Mr. Avedisian’s experience serving as a director of various private organizations, including service as the compensation committee chair of a large privately-owned business.

The Board considered Phillip O. Peterson’s professional training and experience as a certified public accountant and auditor, including his experience as a partner of KPMG overseeing a large group of audit, tax and consulting personnel providing professional services to mutual fund and investment management clients. The Board considered the executive, financial, audit and investment experience that Mr. Peterson gained over the course of his career. The Board also considered Mr. Peterson’s contributions to various published guides addressing generally accepted auditing and accounting standards for mutual fund companies. Further, the Board considered Mr. Peterson’s experience serving on the boards of other mutual fund complexes.

The Board considered Lisa A. Pollina’s professional experience serving in various executive and consulting positions with companies in the global financial services industry, including serving as a Global Financial Institutions Executive with Bank of America and currently, as a senior advisor to the head of RBC Financial Group’s International Banking and Insurance division. The Board considered the executive, financial, operations, investment and risk management experience that Ms. Pollina gained over the course of her career. The Board also considered Ms. Pollina’s experience serving as a director or trustee of various public and private organizations.

The Board considered Donald J. Reaves’s professional experience serving in various executive positions at major U.S. universities, including Chief Financial Officer at the University of Chicago and Brown University, and currently, as Chancellor of Winston-Salem State University. The Board considered the executive, financial, audit, investment and risk management experience that Mr. Reaves gained over the course of his career. The Board also considered Mr. Reaves’ experience serving as a director or trustee of various public and private organizations, including serving in multiple leadership positions on such boards.

The Board considered Donald L. Seeley’s professional experience serving as treasurer or chief financial officer of several public companies, including most recently as Chief Financial Officer of True North Communications, Inc. The Board also considered Mr. Seeley’s experience teaching a graduate portfolio management course at the University of Arizona. The Board considered the executive, financial, audit and investment experience that Mr. Seeley gained over the course of his career. The Board also considered Mr. Seeley’s experience serving as a director or trustee of various public and private organizations, including service as the audit committee chair of four public companies over the past ten years.

The Board considered Thomas J. Skelly’s professional experience serving in various executive positions at Accenture, including his experience as the managing partner of Accenture’s U.S. operations

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and as the chairman of the Accenture Pension Fund. The Board considered the executive, operations, information technology, financial and investment experience that Mr. Skelly gained over the course of his career. The Board also considered Mr. Skelly’s experience serving as a director or trustee of a public company and various private organizations. Further, the Board considered Mr. Skelly’s service on various advisory boards for private and public companies.

The Board considered Michelle R. Seitz’s professional experience in the financial services industry, including as a Principal of William Blair & Company, L.L.C. where she serves as the head of William Blair’s Investment Management division. The Board considered the executive, investment and financial experience that Ms. Seitz gained over the course of her career. The Board also considered that because of Ms. Seitz’s positions with William Blair, she is involved in the day-to-day management of the Advisor and the Trust.

The Board considered Richard W. Smirl’s professional training and experience as an attorney and his executive and operational experience gained as a Principal of William Blair & Company, L.L.C., including serving as Chief Operating Officer for William Blair’s Investment Management division. The Board considered the executive, legal, and operational experience that Mr. Smirl gained over the course of his career. The Board considered that because of Mr. Smirl’s positions with William Blair, he is involved in the day-to-day management of the Advisor and the Trust. The Board also noted that Mr. Smirl served as the Chief Compliance Officer for the Trust from 2004 to 2009.

References to the experience and qualifications of each Trustee/Nominee are pursuant to requirements of the Securities and Exchange Commission, do not constitute holding out of the Board or any Trustee/Nominee as having any special expertise and shall not impose any greater responsibility or liability on any such person or on the Board by reason thereof.

Shareholder Communication with the Trustees

To facilitate shareholder communications with the Board (or with any individual Trustee), shareholders are instructed to forward correspondence (including suggestions for Trustee candidates) by U.S. mail or other courier service to the Secretary of the Trust, 222 West Adams Street, Chicago, Illinois 60606. Correspondence addressed to the Board will be forwarded to the Chairperson of the Nominating and Governance Committee and correspondence addressed to a specific Trustee will be forwarded to that Trustee.

Compensation of Trustees

Independent Trustees receive an annual retainer of $40,000 plus $5,000 for each Board meeting attended in person plus expenses, $2,000 for each Board and/or committee meeting by telephone and $5,000 for committee meetings held on a different day from a Board meeting (except for meetings of the Valuation Committee for which the Trustees receive no additional compensation). Chairpersons of the Audit Committee and Nominating and Governance Committee each receive an additional retainer of $4,000 for serving in such positions. The Independent Trustees receive one-half of the annual retainer in cash and the other half is invested in Fund shares as directed by the Independent Trustees. The Interested Trustees and officers affiliated with the Advisor receive no compensation from the Trust.

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The following table sets forth the compensation earned from the Trust for the year ended December 31, 2011 by the Independent Trustees:

Trustee Fund Ownership

Each of the current Trustees own shares of the Funds. Appendix B hereto lists the dollar range of shares of each Fund beneficially owned by each Independent Trustee/Nominee and Interested Trustee and the amount of shares each Independent Trustee/Nominee and Interested Trustee owns individually and as a group with the officers of Trust. Appendix B also lists all shareholders known to the Trust to beneficially own more than 5% of any class of any Fund as of             , 2012. Finally, Appendix B contains information on certain Independent Trustees’ holdings in certain affiliates of the Advisor.

Fund Officers

The following table presents information about the executive officers of the Trust. Each individual’s year of birth is set forth after his or her name. The Trust’s officers, except the Chief Compliance Officer, are elected annually by the Board. The Trust’s Chief Compliance Officer is designated by the Board and may only be removed by action of the Board, including a majority of the Independent Trustees. The Length of Time Served for all officers indicates the year the individual first became an officer of the Trust. The mailing address for each officer is 222 West Adams Street, Chicago, Illinois 60606.

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Required Vote

Election of the current Trustees requires the affirmative vote of more than 50% of the shares of the Trust present at the Meeting, either in person or by proxy. Election of Mr. Avedisian to fill the current vacancy on the Board requires the affirmative vote of a plurality of the shares of the Trust entitled to vote at the Meeting.

Recommendation of the Board

The Board recommends that shareholders voteFOR the election of the each Trustee/Nominee named above.

INTRODUCTION TO PROPOSALS 2A AND 2B

Pursuant to the requirements of the 1940 Act, the Trust has adopted certain fundamental investment restrictions for each Fund that cannot be changed without shareholder approval. For the most part, identical fundamental investment restrictions have been adopted for each Fund. However, in light of recent guidancegrowth in the percentage of investment grade debt represented by BBB rated debt, the investment team believes it is appropriate to have additional flexibility to be able to invest a larger portion of the Fund’s total assets in BBB rated debt. The Adviser expects that any increase in BBB rated debt will not materially diverge from the staffFund’s current risk/return profile.

The Fund currently has the following principal investment strategies:

“As a matter of fundamental policy, under normal market conditions, the Fund invests at least 90% of its total assets in the following: (a) U.S. dollar-denominated corporate debt securities (domestic or foreign) with long-term ratings of “A-” or better, or an equivalent rating, by at least one of the Securitiesfollowing three nationally recognized statistical rating organizations: Fitch Ratings, Moody’s Investors Service, Inc. and Exchange Commission (the “SEC”), the Trust adopted slightly different fundamental investment restrictions with respect to portfolio concentration (“Concentration Policy”) and investments in commodities (“Commodities Policy”) for new FundsStandard & Poor’s, a division of the Trust that were created in 2011. BecauseThe McGraw-Hill Companies, Inc. (“Rating Organizations”); (b) obligations of the amendments made to the Concentration and Commodities Policies for the new Funds, the Advisor proposed to the Board that the Concentration and Commodities Policies be standardized across the Funds as set forth in Proposals 2(a) and 2(b) below. The Advisor explained to the Board that standardizing the Concentration and Commodities Policies across the Funds would simplify the process of monitoring the Funds’ compliance with their fundamental investment restrictions. The Advisor also informed the Board that the amendments to the Concentration and Commodities Policies were not expected to have any material effect on the portfolio management of the applicable Funds.

The Board has voted to adopt the amended Concentration Policy and Commodities Policy for each Fund listed below and recommends that shareholders of each applicable Fund approve the amended Concentration Policy and Commodities Policy for their Fund.

PROPOSAL 2A

APPROVAL OF AMENDED FUNDAMENTAL INVESTMENT RESTRICTION WITH RESPECT TO PORTFOLIO CONCENTRATION

(Growth Fund, Large Cap Growth Fund, Small Cap Growth Fund, Mid Cap Growth Fund, Small-Mid Cap Growth Fund, Global Growth Fund, International Growth Fund, Institutional International Growth Fund, International Equity Fund, Institutional

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International Equity Fund, International Small Cap Growth Fund, Emerging Markets Growth Fund, Emerging Leaders Growth Fund, Emerging Markets Small Cap Growth Fund, Large Cap Value Fund, Small Cap Value Fund, Mid Cap Value Fund, Bond Fund, Income Fund, Low Duration Fund, Macro Allocation Fund and Commodity Strategy Long/Short Fund only)

The current Concentration Policy for each Fund listed above is:

Concentration.The Fund will not make investments that will result in the concentration (as that term is defined in the 1940 Act, any rule or order thereunder, or SEC staff interpretation thereof) of its investments in the securities of issuers primarily engaged in the same industry, provided that this restriction does not limit the Fund from investing in obligations issued or guaranteed by the U.S. Government, its agencies or instrumentalities,instrumentalities; (c) collateralized obligations, which are debt securities issued by a corporation, trust or custodian, or by a U.S. Government agency or instrumentality, that are collateralized (i.e., secured as to payment of interest and/or principal) by a portfolio or pool of assets, such as mortgages, mortgage-backed securities, debit balances on credit card accounts or U.S. Government securities (the Fund may invest in tax-exempt securities.collateralized obligations that are not guaranteed by a U.S. Government agency or instrumentality only if the collateralized obligations are rated “A-” or better, or an equivalent rating, by one of the Rating Organizations); and (d) commercial paper obligations rated within the highest grade by one of the Rating Organizations.”

This restriction also does not limitIt is proposed that the fundamental policy be revised to read as follows:

As a matter of fundamental policy, under normal market conditions, the Fund from investinginvests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in instruments, such as repurchase agreements, secured by obligations issued or guaranteed by the U.S. Government, its agencies or instrumentalities.bonds.

The proposed amended Concentration Policy (markedrevised policy will both allow the desired flexibility to show changes) for each Fund is:

Concentration.The Fund will not make investments that will resultinvest in BBB-rated securities to a greater degree and satisfy the concentration (as that term is defined in the 1940 Act, any rule or order thereunder, or SEC staff interpretation thereof) of its investments in the securities of issuers primarily engaged in the same industry, provided that this restriction does not limit the Fund from investing in obligations issued or guaranteed by the U.S. Government, its agencies or instrumentalities, or in tax-exempt securitiesissued by governments or political subdivisions of governments.

This restriction also does not limit the Fund from investing in instruments, such as repurchase agreements, secured by obligations issued or guaranteed by the U.S. Government, its agencies or instrumentalities.

The amended Concentration Policy for each applicable Fund would clarifyregulatory requirement that the Fund is not limited byadopt a policy to invest at least 80% of its Concentration Policy from investingnet assets in tax-exempt securities issued by governments or political subdivisions of governments. Nonebonds consistent with its new name. For purposes of the applicable Funds’policy, “bonds” would include all types of fixed income instruments.

Assuming that Proposal 2 is approved by shareholders, the Adviser would also include the following additional disclosure in the Fund’s principal investment strategies currently contemplate investmentsstrategies:

“The Fund invests primarily in tax-exempt securities and, therefore, the amendmentU.S. dollar denominated, investment grade fixed income securities. A security is considered to the Concentration Policybe investment grade if it is not expected to have a material effect on anyrated in one of the Funds, other thanhighest four categories by at least one nationally recognized statistical rating organization (“Rating Organization”) at the time of investment.”

The Fund also currently has a non-fundamental investment policy that up to simplify the compliance oversight function.

Required Vote

Shareholders of each Fund will vote separately on the approval10% of the amended Concentration Policy. ApprovalFund’s total assets may be invested in debt securities that at the time of the amended Concentration Policy requires the affirmative vote of the lesser of (i) 67% of the shares ofpurchase are rated lower than “A-” but at least “BBB-” (or its equivalent) by at least one nationally recognized statistical rating organization, so long as the Fund present at the Meeting ifdoes not invest more than 50%3% of the outstanding sharesits total net assets in securities of the Fundany single issuer whose securities are representedrated “BBB-”. Securities that are downgraded below “BBB-” (or its equivalent) after purchase may continue to be held in person or by proxy, or (ii) more than 50% of the shares of the Fund.

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If Proposal 2 is approved by shareholders, this non-fundamental investment policy would be updated to (i) permit the Fund to invest up to 100% of its total assets in in debt securities that at the time of purchase are rated at least “BBB-” (or its equivalent) by at least one nationally recognized statistical rating organization and (ii) eliminate the restriction on investing more than 3% of the Fund’s total net assets in securities of any single issuer whose securities are rated “BBB-”.

The Adviser does not intend to purchase securities rated below “BBB-”at the time of purchase. However, securities that are downgraded below BBB- after purchase may continue to be held by the Fund. In addition, this policy is not a fundamental policy and may be changed in the future by the Board without shareholder approval.

Proposal 2 could incrementally increase the risk profile of the Fund. The lower the rating of a bond, the greater the risk is that the issuer could default on its obligation to make payments under the bond. The Adviser notes however that any security rated BBB- or higher is still considered investment grade.

Increasing the amount the Fund may invest in below A- rated debt allows for greater diversification within the Fund, which the Adviser believes would allow for better risk management. Fixed income investors can earn returns primarily through two methods: credit risk or interest rate (duration) risk. The Adviser intends to manage the average duration of the Fund along with investing in a broader range of bonds having different credit ratings. In the current market environment, the Adviser intends to lower the average duration of the Fund which should decrease the interest rate risk of the Fund. For example, as active managers in a rising rate environment, the Adviser would prefer to hold a shorter-duration, BBB- rated security, based on fundamentals and relative value. The Adviser would prefer to earn returns with an appropriate mix of credit and interest rate risk. The Adviser believes this change allows it to better balance those risks in the Fund. In this example, the trade-off is credit risk for interest rate risk. This is especially important in a rising interest rate environment, as it would take longer to recoup the loss on a longer-duration instrument that has greater interest rate sensitivity. Higher-quality instruments, given their lower coupons, tend to have higher sensitivity to interest rate movements.

These changes are proposed to allow the Adviser to be better positioned to manage the risk profile of the Fund in a variety of market environments.

If shareholders approve Proposal 2, the Adviser will operate the Fund under the revised fundamental investment policy. If shareholders of the Fund do not approve Proposal 2, the Fund will continue to operate under its existing fundamental investment policy as described in the Fund’s current registration statement and as summarized in this proxy statement.

Review of the Proposals and Recommendation of the Board

At a meeting held on October The26-27, 2021, the Board recommendsconsidered the Proposals and voted unanimously to approve the Proposals. In determining to recommend that shareholders voteFOR to approve the Proposals, the Board considered, among other factors, that the Proposals constitute part of a broader repositioning of the Fund intended to enable the Adviser to manage the Fund more effectively and in a manner more consistent with investor needs and reflective of the growth and structure of the bond market. In particular, the Board considered the Adviser’s statements that the Adviser believes the Fund would benefit from changing its fundamental investment objective and fundamental investment policy because those changes would allow the Fund greater flexibility to pursue a broader universe of investment opportunities, and that the changes to the fundamental investment objective and fundamental investment policies would be beneficial in executing the Adviser’s strategy for the Fund. The Board considered that a fund that invests a larger percentage of its assets in a lower rated securities could be more susceptible to negative events affecting those issuers, and in that regard, considered the Adviser’s belief that the potential benefits of investing more of the Fund’s assets in lower rated securities as part of the Fund’s revised strategy

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justify the related risks, and noted the Adviser’s discussion of portfolio risk management at the October meeting. Additionally, the Board considered that the costs associated with seeking shareholder approval of the amended Concentration Policy.

PROPOSAL 2B

APPROVAL OF AMENDED FUNDAMENTAL INVESTMENT RESTRICTION WITH RESPECT TO INVESTMENTS IN COMMODITIES

(Growth Fund, Large Cap Growth Fund, Small Cap Growth Fund, Mid Cap Growth Fund, Small-Mid Cap Growth Fund, Global Growth Fund, International Growth Fund, Institutional International Growth Fund, International Equity Fund, Institutional International Equity Fund, International Small Cap Growth Fund, Emerging Markets Growth Fund, Emerging Leaders Growth Fund, Small Cap Value Fund, Mid Cap Value Fund, Bond Fund, Income Fund, Low Duration Fund and Ready Reserves Fund only)

The current Commodities Policy for each Fund listed above is:

Commodities.The Fund mayProposals would not purchase or sell physical commodities unless acquired as a result of ownership of securities or other instruments; however, this restriction shall not preventbe borne by the Fund from engagingshareholders given the expense limitation arrangements currently in transactions involving futures contracts, options or other derivative instruments or investing in securities that are secured by physical commodities.

The proposed amended Commodities Policy (marked to show changes) for each Fund is:

Commodities.The Fund may not purchase or sellphysicalcommodities unless acquired as a result of ownership of securities or other instruments; however, this restriction shall not prevent the Fund from engaging in transactions involving futures contracts, options or other derivative instruments or investing in securities that are secured byphysicalcommodities.

Commodities may include both physical commodities (e.g., wheat, corn, cotton and gold) and financial commodities (e.g., currencies, stock indices and interest rates). The staff of the SEC has recently provided guidance that a fund’s investment policyeffect with respect to commodities should apply to all commodities and not just physical commodities. The amended fundamental investment restriction would continue to allow the applicable Funds to engage in derivatives transactions related to commodities, including forward foreign currency transactions. None of the applicable Funds’ investment strategies currently contemplate direct investments in physical or financial commodities, and, therefore, the amendment to the Commodities Policy is not expected to have a material effect on any of the Funds, other than to simplify the compliance oversight function. In addition, the amendment to the Commodities Policy would not affect the Funds’ ability to engage derivative transactions related to commodities, including forward foreign currency transactions.

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Required Vote

Shareholders of each Fund will vote separately on the approval of the amended Commodities Policy. Approval of the amended Commodities Policy requires the affirmative vote of the lesser of (i) 67% of the shares of the Fund present at the Meeting if more than 50% of the outstanding shares of the Fund are represented in person or by proxy, or (ii) more than 50% of the shares of the Fund.

Recommendation ofTHE BOARD OF TRUSTEES UNANIMOUSLY RECOMMEND THAT YOU VOTE IN

FAVOR OF THE PROPOSALS.

MISCELLANEOUS

Investment Adviser, Principal Underwriter and Administrator

WBIM and William Blair & Company, L.L.C. (“WBC”), each located at 150 North Riverside Plaza, Chicago, Illinois 60606, are respectively the Board

The Board recommends that shareholders voteFORTrust’s investment adviser and principal underwriter and distributor. Pursuant to a management agreement, the approval ofAdviser acts as the amended Commodities Policy.

INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

The Board, including the Independent Trustees, has selected Ernst & Young LLP (“E&Y”)investment adviser to act as independent registered public accounting firm to audit the books and recordseach series of the Trust, for the current fiscal year. E&Y has served the Trust in this capacity since the Trust was organized and has no direct or indirect financial interest in the Trust or any Fund except as the independent registered public accounting firm. A representative of E&Y is expected to be present, in person or by telephone, at the Meeting and will be available to respond to any appropriate questions raised at the Meeting and may make a statement.

In connection with the audit of the 2011 financial statements, the Trust entered into an engagement letter with E&Y. The terms of the engagement letter required by E&Y, and agreed to by the Audit Committee, include provisions in which the parties consent to the sole jurisdiction of the courts of the State of Illinois located in Cook County or in the courts of the United States of America located in the Northern District of Illinois, as well as a waiver of right to a trial by jury and an exclusion of punitive damages.

Audit Fees

For the fiscal years ended December 31, 2010 and 2011 E&Y, billed the Trust $501,000 and $559,500, respectively, for professional services rendered for the audit of the Trust’s annual financial statements or services that are normally provided in connection with statutory and regulatory filings.

Audit-Related Fees

For the fiscal years ended December 31, 2010 and 2011, E&Y billed the Trust $8,000 and $3,000, respectively, for assurance and related services that are reasonably related to the performance of the audit of the Trust’s financial statements and that are not reported above, such as reviewing prospectuses and SEC filings. For the fiscal years ended December 31, 2010 and 2011, E&Y provided no audit-related services to William Blair or any ofmanages its control affiliates that were for engagements directly related to the Trust’s operations and financial reporting.

Tax Fees

For the fiscal years ended December 31, 2010 and 2011, E&Y billed the Trust $117,850 and $138,500, respectively, for professional services rendered for tax compliance, tax advice and tax planning. Such services consisted of preparation of tax returns, year-end distribution review, qualifying dividend income analysis and computation of foreign tax credit pass through. For the fiscal years ended December 31, 2011 and 2012, E&Y did not bill William Blair or any of its control affiliates for any tax services that were for engagements directly related to the Trust’s operations and financial reporting.

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All Other Fees

For the fiscal years ended December 31, 2010 and 2011, E&Y did not bill the Trust for products and services other than the services reported above. For the fiscal years ended December 31, 2010 and 2010, E&Y provided no other services to William Blair or any of its control affiliates that were for engagements directly related to the Trust’s operations and financial reporting.

Audit Committee Pre-Approval Policies and Procedures

Pursuant to Trust’s Audit Committee Charter (the “Charter”), the Audit Committee is responsible for pre-approving any engagement of the principal accountant to provide non-prohibited services to the Trust, including the fees and other compensation to be paid to the principal accountant, to the extent required by Rule 2-01(c)(7) of Regulation S-X. Pursuant to the Charter, the Audit Committee is also responsible for pre-approving any engagement of the principal accountant, including the fees and other compensation to be paid to the principal accountant, to provide non-audit services to the Trust’s investment advisor (or any entity controlling, controlled by, or under common control with the adviser that provides ongoing services to the Trust), if the engagement relates directly to the operations and financial reporting of the Trust, to the extent required by Rule 2-01(c)(7) of Regulation S-X. The Chair of the Audit Committee may grant the pre-approval referenced above for non-prohibited and non-audit services. All such delegated pre-approvals will be presented to the Audit Committee no later than the next Audit Committee meeting.

Non-Audit Fees

For the fiscal years ended December 31, 2010 and 2011, E&Y billed the Trust $117,850 and $138,500, respectively, in non-audit fees (tax services). For the same periods, E&Y billed William Blair and its control affiliates $97,000 and $119,000 (Custodian SAS70 Report), respectively, in non-audit fees. The Trust’s Audit Committee has considered whether the provision of non-audit services that were rendered to William Blair or any of its control affiliates that were not pre-approved pursuant to Rule 2-01(c)(7)(ii) of Regulation S-X is compatible with maintaining E&Y’s independence.

MISCELLANEOUS

Investment Manager and Principal Underwriter

William Blair, 222 West Adams Street, Chicago, Illinois 60606, is the Trust’s investment advisor and manager. William Blair is responsible for providing investment advisory and management services to the Funds, including making decisions regarding Fund portfolio transactions, andinvestments, administers its business affairs, furnishes office facilities and equipment, provides clerical, bookkeeping and administrative services, provides shareholder and information services. William Blair is also the principal underwriterservices and distributorpermits any of its partners or employees to serve without compensation as trustees or officers of the Trust andFund if elected to such positions. The Distributor acts as agent of the Trust in the sale of itsFund shares. WBIM and WBC are collectively referred to herein as “William Blair.”

William Blair was founded over 7580 years ago by William McCormick Blair. Today, the firm hasAs of September 30, 2021, William Blair had over 10001,700 employees including 170 principals.

The Investment Management Department204 partners. WBIM oversees the assets of the Trust, along with corporate pension plans, endowments and foundations and individual accounts. The department currently managesfoundations. As of September 30, 2021, WBIM managed over $$77.4 billion in equities, fixed-incomefixed income securities, derivatives and cash equivalents.

The Advisor firmly believes that clients are best served when portfolio managers are encouraged to draw on their experience and develop new ideas. This philosophy has helped build a hard-working, results-oriented team of over             portfolio managers, supported by a team of analysts. The AdvisorAdviser is registered as an investment advisoradviser under the Investment Advisers Act of 1940.

State Street Bank and Trust Company, located at One Lincoln Street, Boston, Massachusetts, 02111, provides custodian, valuation and certain administrative services to the Trust pursuant to various agreements.

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Proxy Solicitation and Expenses

Solicitation of proxiesIn addition to solicitations by personal interview, mail, telephone and electronic mailsolicitations also may be made by telephone, through the Internet or in person by officers of the Trust andor employees of William Blair, none of whomthe Adviser and by certain financial services firms and their representatives, who will receive any additionalno extra compensation for such service, and a third-party solicitation agent. All costs incurred in connection with the Meeting (including the cost of solicitation of proxies) will be paid by the Trust. The Trusttheir services. Broadridge Financial Services, Inc. (“Broadridge”) has been engaged             (“            ”) to assist in the solicitation of proxies. It is anticipated thatproxies for the Trust at an estimated cost of $40,000, plus reimbursement for reasonable expenses. However, the exact cost will depend on the amount and types of services rendered. The cost of proxy solicitation services provided by             will be approximately $        , plus reimbursement of reasonable expenses. As the Meeting date approaches, you may receive a call from a representative of             who may ask you for authority, by telephone, to permit             to sign a proxy on your behalf.             will record all instructions it receives from shareholders by telephone, and the proxies it signs in accordance with those instructions, in accordance with the procedures set forth below.

When receiving your instructions by telephone, the             representative is required to ask you for your full name, address, social security or employer identification number, title (if the person giving the proxy is authorized to act for an entity, such as a corporation), the number of shares of a Fund owned, and to confirm that you have received the proxy statement in the mail. If the information you provide matches the information provided toborne by the Trust, thenFund; however, by virtue of the representative will explainoperation of the process.             is not permitted to recommend to you how to vote, other than to read any recommendation includedexpense limitation arrangements currently in the proxy statement.             will record your instructions and transmit themeffect with respect to the official tabulator, and within 72 hours, send you a letter or mailgram to confirm your vote. That letterFund, these costs will also ask you to call             immediately if the confirmation does not reflect your instructions correctly. Any telephonic voting will follow procedures designed to ensure accuracy and prevent fraud, including requiring identifying shareholder information, recording the shareholder’s instructions, and confirming to the shareholder after the fact.ultimately be borne by WBIM.

Shareholders may also vote by mail, telephone or over the Internet. Please seeShareholders who vote by telephone or over the Internet will have an opportunity to review their voting instructions and make any necessary changes before submitting their voting instructions and terminating their telephone call or Internet link. If a shareholder wishes to participate in the Meeting, but does not wish to give a proxy by telephone or over the Internet, the shareholder may still submit the proxy card for instructions on how to vote overoriginally sent with this proxy statement or attend the Internet.Meeting by means of remote communication. Should shareholders require additional information regarding the proxy or a replacement a proxy card, they may contact Broadridge toll-free at .1-833-934-2740.

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Adjournment

If a quorum is not present, the Meeting may be adjourned to a later date by the affirmative vote of a majority of the shares present, in person or by proxy, at the Meeting.present. In the event that a quorum is present at the Meeting, but sufficient votes to elect the Trustees or approve the amended fundamental investment restrictionsProposals are not received, the persons named as proxies may propose one or more adjournments of the Meeting to permit further solicitation of proxies. Any such adjournment willmust be approved by the affirmative vote of a majority of the shares present, in person or by proxy, at the Meeting. It is anticipated that the persons named as proxies would vote in favor of any adjournment. The Meeting may be adjourned without further notice to shareholders, but the Meeting may not be adjourned for more than six months beyond the originally scheduled meeting date.

Proposals of Shareholders

The Trust does not generally hold annual shareholders’ meetings but will hold special meetings as required or deemed desirable. Because the Trust does not hold regular shareholders’ meetings, the anticipated date of the next shareholders’ meeting (if any) cannot be provided. Shareholders wishing to submit proposals for inclusion in a proxy statement for a subsequent shareholders’ meeting of the Trust, including submitting nominees for election as Trustees, should send their written proposals to the William Blair Funds, Secretary of the Trust at 222 West Adams Street,150 North Riverside Plaza, Chicago, Illinois 60606. Proposals must be received in a reasonable time before the Trust begins to print and mail its proxy materials for the meeting. The timely submission of a proposal does not guarantee its inclusion.

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Other Matters to Come Before the Meeting

The Board is not aware of any matters that will be presented for action at the Meeting other than the ProposalProposals set forth herein. Should any other matters requiring a vote of shareholders arise, the proxy in the accompanying form will confer upon the person or persons entitled to vote the shares represented by such proxy the discretionary authority to vote the shares with respect to any such other matters.

Householding Information

In order to reduce the amount of mail you receive and to help reduce Fund expenses, the Trust generally sends a single copy of any shareholder report and prospectus to each household unless instructed otherwise by a shareholder within the household. If you do not want the mailing of these documents to be combined with those for other members of your household, or if you wish to receive a single copy for your household, please call 1-800-742-7272.1-800-742-7272 or submit your request in writing to the William Blair Funds at 150 North Riverside Plaza, Chicago, Illinois 60606.

A copy of the Trust’s most recent annual and semi-annual report is available without charge upon request by writing to the Trust, 222 West Adams Street,William Blair Funds, 150 North Riverside Plaza, Chicago, Illinois 60606 or by calling 1-800-742-7272. Reports are also available on the William Blair Funds website at ww.williamblairfunds.comwww.williamblairfunds.com or at the website of the Securities and Exchange Commission at www.sec.gov.

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Please complete, sign, date and return the enclosed proxy card(s) (or take advantage of available telephonic or Internet voting procedures; see the proxy card for instructions) promptly. No postage is required if mailed in the United States.

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AppendixEXHIBIT A

WILLIAM BLAIR FUNDS5% or Greater Owners

NOMINATING AND GOVERNANCE COMMITTEE CHARTERAs of September 30, 2021, the persons listed in the table below are known to the Trust to be record and/or beneficial owners of 5% or more of a class of shares of the Fund as indicated below. Shareholders who have the power to vote a large percentage of shares (at least 25%) of a Fund can control a Fund and could determine the outcome of a shareholders’ meeting with respect to that Fund.

ADOPTED OCTOBER 24, 2000,

AMENDED OCTOBER 26, 2004,

* The entities set forth in this column are the shareholders of record and may be deemed to be the beneficial owners of certain of the shares listed for certain purposes under the securities laws. However, these entities generally do not have an economic interest in these shares and would ordinarily disclaim any beneficial ownership therein.

APRIL 19, 2005, OCTOBER 25, 2005

AND OCTOBER 25, 2011As of September 30, 2021, no Trustee owned more than 1% of the shares of any class of the Fund except as set forth in the table below:

The NominatingAs of September 30, 2021, all management personnel (i.e., Trustees and Governance Committee is a committeeOfficers of the BoardTrust) as a group owned beneficially more than 1% of the Trust. Its primary function is to identify and recommend individuals for membership on the Board and oversee the administrationoutstanding shares of Class R6 shares of the Board Governance Procedures and Guidelines.Fund, as disclosed below. As of the same date, all management personnel as a group did not own beneficially more than 1% of the outstanding shares of either Class N or Class I shares of the Fund.

The Nominating and Governance Committee shall be comprised of three or more board members as determined by the Board, each of whom shall be an independent trustee and free from any relationship that, in the opinion of the Board, would interfere with the exercise of his or her independent judgment as a member of the Nominating and Governance Committee. For purposes of the Nominating and Governance Committee, a trustee is independent if he or she is not an “interested person” of the Trust as that term is defined in the Investment Company Act of 1940.

The members of the Nominating and Governance Committee shall be elected by the Board annually and serve until their successors shall be duly elected and qualified. The Chair shall be elected by the members of the Nominating and Governance Committee by majority vote.

Class N										Class I										Class R6
Number of Shares					Percent of Shares					Number of Shares					Percent of Shares					Number of Shares					Percent of Shares
		—					—					—					—					15,927					60.77	%

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The Nominating and Governance Committee shall meet two times annually, or more frequently as circumstances dictate. Special meetings (including telephone meetings) may be called by the Chair or a majority of the members of the Nominating and Governance Committee upon reasonable notice to the other members of the Nominating and Governance Committee.

  WILLIAM BLAIR FUNDS

  150 NORTH RIVERSIDE PLAZA, 48TH FLOOR

  CHICAGO, ILLINOIS 60606

To fulfill its responsibilities and duties the Nominating and Governance Committee shall:

To vote by Internet

1)  Read the Proxy Statement and have the proxy card below at hand.

2)  Go to website www.proxyvote.com or scan the QR Barcode above

3)  Follow the instructions provided on the website.

		A.	Board Nominations	To vote by Telephone 1)  Read the Proxy Statement and Functionshave the proxy card below at hand. 2)  Call 1-800-690-6903 3)  Follow the instructions.
				To vote by Mail 1)  Read the Proxy Statement. 2)  Check the appropriate boxes on the proxy card below. 3)  Sign and date the proxy card. 4)  Return the proxy card in the envelope provided. To attend and vote at the virtual meeting, please register by going to Virtual Shareholder Meeting at https://viewproxy.com/WilliamBlairIncomeFund/ broadridgevsm/