Firm Description William Blair is a global investment firm that offers investment advisory services to clients. William Blair was established in 2014 and is registered as an investment adviser with the U.S. Securities and Exchange Commission (“SEC”). William Blair is affiliated with William Blair & Company, L.L.C. (“William Blair & Company”), a firm that was founded in 1935 and is registered with the SEC as both an investment adviser and a securities broker-dealer. William Blair and William Blair & Company (each of which is a privately held company) are wholly owned subsidiaries of WBC Holdings, L.P., which is wholly owned by current William Blair and William Blair & Company employees (we sometimes refer to such employee owners as ‘partners’ in this Brochure). William Blair was formed as part of an organizational restructuring whereby some investment advisory services previously performed by William Blair & Company are performed by William Blair. William Blair & Company continues to operate as a dually registered investment adviser and securities broker-dealer. Investment Advisory Services William Blair provides investment advisory services to clients and is compensated based on fee schedules as described in Item 5 in this Brochure. William Blair manages accounts for institutional clients and pooled funds such as registered investment companies (including the William Blair Funds), UCITS, private funds (including private funds where an affiliate of William Blair serves as general partner or manager (“Private Funds”)), and collective investment funds, among others. In addition, William Blair manages accounts for wrap fee programs (“Wrap Programs”) and high net worth clients. As further described in Item 10, William Blair also provides model portfolios to certain unified managed account program sponsors. In so doing, William Blair has no investment discretion, no knowledge of the program sponsor’s underlying clients, and no authority to effect trades on behalf of the sponsor’s clients. Availability of Tailored Services for Clients As a discretionary investment manager, we manage portfolios using an array of equity and fixed income strategies and manage accounts in accordance with clients’ investment guidelines. We will accept investment restrictions from clients if the restrictions do not hinder our ability to execute our investment strategies. When managing portfolios for pooled funds, we manage the portfolios in accordance with each fund’s stated investment guidelines and restrictions. We do not tailor investments to the individualized needs of any particular shareholder or fund investor. In addition to portfolio managers and analysts directly employed by William Blair, we utilize resources and personnel of our affiliate, William Blair & Company and our participating affiliates, William Blair International, Ltd (“William Blair International”), William Blair B.V. and William Blair International (Singapore) Pte. Ltd. (“William Blair Singapore”). William Blair International is an asset manager located in London and is registered with the UK Financial Conduct Authority. William Blair Singapore is an investment firm located in Singapore and is registered with the Monetary Authority of Singapore. William Blair B.V. is a licensed investment firm located in the Netherlands, authorized and supervised by the Dutch Authority for the Financial Markets and also supervised by the Dutch Central Bank. William Blair & Company and certain affiliates also maintain sales and client service

offices in Sydney, Australia, Zurich, Switzerland and Stockholm, Sweden. No investment advisory activities are conducted from these locations. William Blair is also an affiliate of SYSTM Wealth Solutions LLC (“SYSTM”), an investment adviser registered with the SEC. SYSTM operates a fee-based platform which affiliated investment advisers (such as William Blair & Company) and unaffiliated investment advisers can utilize to recommend, select, retain, terminate, and monitor sub- managers and model providers (including William Blair). Any arrangements with William Blair International, William Blair Singapore, and William Blair B.V. are subject to various conditions designed to ensure compliance with U.S. laws and regulations and adequate SEC oversight when investment advisory services are provided to U.S. persons. These conditions require, among other things, that certain employees of William Blair International and William Blair Singapore be subject to a Code of Ethics and comply with certain U.S. rules when providing services to William Blair. Please see Item 11 in this Brochure for a more detailed discussion of the Code of Ethics. Wrap Program Services William Blair provides investment advisory services to clients of Wrap Programs sponsored by third-party Wrap Program sponsors (e.g., broker-dealers). Sponsors pay us an investment advisory fee from a portion of the total wrap fee based upon the total assets we manage for Wrap Program sponsors’ clients. A wrap fee program is a program where a client is charged a specified “bundled” fee (generally, a percentage of assets under management) for William Blair Investment Management, LLC – Form ADV Part 2A Page 5 discretionary investment advisory services and trade execution costs and sometimes other services such as custody, recordkeeping and reporting. We manage these accounts using strategy model portfolios (similar to how we manage other separate accounts), but we generally accept fewer client-imposed investment restrictions for these accounts. Because we typically execute Wrap Program account trades through each respective Wrap Program sponsor, these accounts usually are included in the second tier of our trade rotation process, as described more fully in Item 12. In some cases, our compensation under a Wrap Program is lower than our standard fee schedule; however, a client who participates in the wrap fee arrangement should consider that, depending on the level of the wrap fee charged by the Wrap Program sponsor, the overall cost of a Wrap Program fee arrangement can be higher than a client otherwise would pay if the client paid our standard fee schedule and negotiated transaction costs and any other services (e.g., custody, recordkeeping and reporting) through a broker-dealer. William Blair has outsourced several operational functions relating to its Wrap Program services to a third-party service provider (the “Wrap Service Provider”). The Wrap Service Provider utilizes its own internal systems to maintain Wrap Program accounts that William Blair manages for third-party Wrap Program sponsors. Wrap Service Provider is responsible for performing the following functions: new client account initialization and maintenance; trade order generation and routing; confirmation and settlements; client account asset and cash reconciliation; client-imposed guideline monitoring and recordkeeping. Assets under Management As of December 31, 2023, William Blair managed approximately $67 billion in assets on a discretionary basis.