Columbia Wanger Asset Management, LLC (“Columbia Wanger”), an investment adviser registered with the U.S. Securities and Exchange Commission, serves as the investment adviser for the Columbia Acorn Funds, the Wanger Advisors Trust and other institutional accounts. Columbia Wanger and its predecessors have managed mutual funds, since 1992. Columbia Wanger, a Delaware limited liability company based in Chicago, Illinois, is wholly owned by Columbia Management Investment Advisers, LLC (“CMIA” or “Columbia Management Investment Advisers”), a Minnesota limited liability company. CMIA is a wholly owned subsidiary of Ameriprise Financial, Inc. (“Ameriprise Financial”). This disclosure document describes the investment advisory services offered by Columbia Wanger and in this disclosure document, “we,” “our,” “us,” “the firm,” or “our firm” and similar words mean Columbia Wanger. We are providing this disclosure document to persons who receive or who may receive investment advisory services in order to ensure compliance with the Investment Advisers Act of 1940, as amended (the “Advisers Act”). Our General Services Columbia Wanger provides professional management of global equity assets using in-house resources to seek superior long-term results. We follow a fundamental, research-intensive investment style characterized by unconventional stock picking and multiyear time horizon. We seek to build wealth for our clients and communicate clearly, honestly and creatively with them. We attract and retain the best talent by creating a stimulating and financially rewarding environment. We develop the skills of our people to serve the needs of our clients, in the belief that the firm’s growth and profitability rest on our clients’ satisfaction. Columbia Wanger Funds Columbia Wanger is the investment adviser to the following open-end mutual funds (the “Funds”), that are series or portfolios of Columbia Acorn Trust and Wanger Advisors Trust, two registered investment companies sponsored by Columbia Wanger: Columbia Acorn Trust Columbia Acorn European Fund Columbia Acorn Fund Columbia Acorn International Columbia Acorn International Select Columbia Thermostat Fund Wanger Advisors Trust Wanger Acorn Wanger International Investment Policies and Objectives We currently manage $6.4 billion (as of December 31, 2023) in discretionary assets (reported as Regulatory Assets Under Management). Columbia Acorn Fund, and Wanger Acorn (a variable annuity fund) are our domestic small- cap funds, which invest a majority of their net assets in the common stock of small- and mid-sized companies with market capitalizations generally in the range of market capitalizations in the Russell 2500 Growth Index, the Funds’ benchmark, (the Index) at the time of purchase (between $5.5 million and $24 billion as of March 31, 2023). The market capitalization range and composition of companies in the Index are subject to change. As such, the size of the companies in which the Funds invest may change. Columbia Acorn International Fund is our international small- cap fund, which invest a majority of its net assets in the common stock of small- and midsized companies with market capitalizations generally in the range of market capitalizations in the MSCI ACWI ex USA SMID Cap Growth Index (Net), the Funds’ primary benchmark, (the Index) at the time of purchase (between $92 million and $9.9 billion as of March 31, 2023). The market capitalization range and composition of companies in the Index are subject to change. As such, the size of the companies in which the Fund invests may change. We do not sell successful stocks solely because they have appreciated beyond an arbitrary capitalization limit. Our domestic mid-cap fund, Wanger Acorn invests a majority of its net assets in the common stock of small- and midsized companies with market capitalizations generally in the range of market capitalizations in the Russell 2500 Growth Index, the Fund’s benchmark, (the Index) at the time of purchase (between $5.5 million and $24 billion as of March 31, 2023). The market capitalization range and composition of companies in the Index are subject to change. As such, the size of the companies in which the Fund invests may change. Our international mid-cap fund, Columbia Acorn International Select (a variable annuity fund), invest a majority of their net assets in the common stock of small- and midsized companies with market capitalizations generally in the range of market capitalizations in the MSCI ACWI ex USA Growth Index (Net), the Fund’s primary benchmark, (the Index) at the time of purchase (between $635 million and $1.9 trillion as of March 31, 2023). The market capitalization range and composition of companies in the Index are subject to change. As such, the size of the companies in which the Funds invest may change. Columbia Acorn European Fund is our European small-cap fund, which invests primarily in common stock of small- and mid- sized companies with market capitalizations generally in the range of market capitalizations in the MSCI AC Europe Small Cap Index (Net), the Fund’s benchmark, (the Index) at the time of purchase (between $128.6 million and $8.4 billion as of March 31, 2023). The market capitalization range and composition of companies in the Index are subject to change. As such, the size of the companies in which the Fund invests may change. As such, the size of the companies in which the Fund invests may change. The Fund determines a company’s market capitalization at the time of investment. As long as a majority of its net assets are invested in companies within the Index, the Fund may continue to hold and make new investments in a security even if the company’s market capitalization grows beyond the market capitalization of the largest company within the Index or falls below the market capitalization of the smallest company within the Index. The Investment Manager from time to time emphasizes one or more sectors in selecting the Fund’s investments, including the industrials, information technology, and health care sectors. The investment objectives, strategies and risks of the particular funds are set forth in each Fund’s prospectus. Our style is not easily defined, but most closely resembles GARP -- growth at a reasonable price. Our mission is to buy growing, undervalued companies, grow with them, and sell them when their growth slows or we believe they are fully valued. We are particularly interested in underfollowed stocks and niche companies. We like companies that benefit from long-term trends that we identify. We use dividend discount, private market value, and cash flow models to value stocks. We especially like companies with hidden values beyond reported EPS, such as unusually high free cash flow (due to goodwill, tax loss carryforwards, or other factors), masked earnings power (often caused by a startup or underperforming division offsetting a great core business), or hidden assets. We usually avoid companies in highly competitive or unpredictable industries, such as airlines, commodity semiconductors, and many natural resource areas. Our best brokers filter their analysts’ work and target us with only ideas that fit our style. They recognize that we are not interested in all of their firm’s ideas, but that we will take major positions in stocks that fit. Columbia Wanger invests client assets in certain small to medium capitalization companies, both U.S. and foreign, that it believes have growth potential, financial strength and fundamental

value. Although Columbia Wanger invests its managed assets primarily in equity securities, it may also invest in other types of securities. At a client’s request, substantially all of the client’s portfolio may be invested in:
• U.S. securities (a “domestic portfolio”),
• non-U.S. securities (an “international portfolio”), or a portfolio including both U.S. and non-U.S. securities (a “global portfolio”). Investments are generally long-term (at least three to five years); although an investment may be liquidated within a shorter period if Columbia Wanger deems it advisable. Columbia Wanger also considers any investment policies and restrictions to which a client is subject or which the client has established for Columbia Wanger. Columbia Wanger may invest certain discretionary client accounts in shares of one or more mutual funds advised by Columbia Wanger or its affiliates. Columbia Wanger generally will make such investments only to the extent specifically authorized by each client in its investment management agreement. Offering Brands In marketing our services to prospective clients, we use Columbia Threadneedle Investments, the global brand of the Columbia and Threadneedle group of companies. We may also use various other offering brands. Columbia Threadneedle Investments North America is the operating division within Columbia Management Investment Advisers that we market to institutional clients. Columbia Threadneedle Investments North America and Columbia Management Capital Advisers claim compliance with the Global Investment Performance Standards (GIPS®). In accordance with GIPS®, all fee-paying discretionary (as defined by GIPS®) accounts within Columbia Threadneedle Investments North America and Columbia Management Capital Advisers are included in one or more composites that consist of accounts with similar objectives, strategies and risk tolerances. GIPS® also sets forth requirements for calculating and presenting investment manager performance in a fair and consistent manner. We also market certain strategies and products under the Seligman brand, and from time to time we may market Seligman Investments as an offering brand within Columbia Threadneedle Investments North America. Global Asset Management As we seek to enhance our investment capabilities and the support services provided to our clients, we may utilize services from, and provide services to, some of our U.S. affiliates (“U.S. Advisory Affiliates”) and non-U.S. affiliates (“Non-U.S. Advisory Affiliates”). For example, we engage certain of our U.S. Advisory Affiliates and Non-U.S. Advisory Affiliates that engage in investment advisory services (collectively, “Advisory Affiliates”) to provide (jointly or in coordination with us) services relating to client relations, investment monitoring, account administration, investment research, trading and discretionary investment management (including portfolio management and risk management) to certain of our clients and accounts we manage, including certain Funds and separately managed accounts. In some circumstances, an Advisory Affiliate may delegate responsibility for providing those services to another Advisory Affiliate. In addition, we provide certain similar services to our Advisory Affiliates for accounts they manage. Under personnel-sharing and other arrangements, our personnel may act on behalf of one of our U.S. Advisory Affiliates for purposes of providing some of those services for that U.S. Advisory Affiliate to its clients, such as funds and/or separately managed accounts, and some of our U.S. Advisory Affiliates’ personnel may act on behalf of our clients, including Funds and separately managed accounts. Certain of our employees and officers are also officers of certain U.S. Advisory Affiliates, and employees and officers of our U.S. Advisory Affiliates are also officers of ours. We believe that harnessing the collective expertise of our firm and our Advisory Affiliates benefits our clients. In this regard, we have certain portfolio management, trading, research, distribution and client servicing teams at both our firm and certain of our Advisory Affiliates (through subadvisory, delegation or other intercompany arrangements) operating jointly to provide a better client experience. These joint teams use expanded and shared capabilities, including the sharing of research and other information by investment personnel (e.g., portfolio managers, analysts and traders) relating to economic perspectives, market analysis and equity and fixed income securities analysis. The joint teams also have expanded capabilities to provide services in various local or regional markets. To facilitate the collaborative approach noted above, we may enter into subadvisory agreements, delegation agreements, intercompany agreements and “participating affiliate” arrangements with certain of our Non-U.S. Advisory Affiliates, including Threadneedle International Ltd. (“TINTL”), Threadneedle Asset Management Ltd. (“TAML”), Threadneedle Management Luxembourg S.A. (“TMLSA”) and Threadneedle Investments Singapore (Pte.) Limited (“TIS”), Threadneedle Investments Services Limited (“TISL”), Columbia Threadneedle Asset Management Limited (“CTML”), Columbia Threadneedle Fund Management Limited (“CTFML”), Columbia Threadneedle Investment Business Limited (“CTIBL”), Columbia Threadneedle Netherlands B.V. (“CTNL”), Pyrford International (“Pyrford”), Thames River Capital LLP (“Thames”) and Ameriprise India, LLP (“Ameriprise India”) each of which, like us, is a direct or indirect wholly-owned investment advisory subsidiary of Ameriprise Financial. Each of TINTL, TAML, TMLSA, TIS, CTML, CTIBL, CTNL, Thames and Pyrford is registered with the appropriate respective regulators in their home jurisdictions and Ameriprise India is exempt from such registration. In addition, each of TINTL, CTML, and Pyrford is also registered with the SEC as an investment adviser and TINTL is also registered with the United States Commodity Futures Trading Commission (“CFTC”) as a commodity trading advisor. As part of any “participating affiliate” arrangements, certain employees of our Non-U.S. Advisory Affiliates serve as “associated persons” of ours when providing certain of these services to our clients, including acting as portfolio managers and placing orders for trade execution, and in this capacity are subject to our oversight and supervision. To the extent that we so engage one or more of our Non-U.S. Advisory Affiliates in this manner, we remain responsible for and oversee the services provided by employees of such Non-U.S. Advisory Affiliates(s) to our clients. In addition to relationships with our Non-U.S. Advisory Affiliates, we have entered into subadvisory agreements, personnel-sharing agreements, delegation agreements and/or other intercompany arrangements for portfolio management and certain investment-related services, which may include managing portfolios, placing orders for trade execution and/or research sharing with our U.S. Advisory Affiliates, including Columbia Management Investment Advisers, LLC (“CMIA”) which is an SEC-registered investment adviser. In addition, we may provide certain investment-related support services to Advisory Affiliates and their clients. These Advisory Affiliates may also provide certain similar services to us and our clients. Such support services include, but are not limited to, traditional “middle office” and utility functions, such as trade processing, valuation, proxy voting administration and client and regulatory reporting.