Columbia
  Acorn International®

As with all mutual funds, the Securities and Exchange Commission (SEC) has not approved or disapproved these securities or passed upon the adequacy of this prospectus. Any representation to the contrary is a criminal offense.

Shareholder Fees (fees paid directly from your investment)
	Class A	Class C	Classes Adv, Inst, Inst2, Inst3 and R
Maximum sales charge (load) imposed on purchases (as a % of offering price)	5.75%	None	None
Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)	1.00%(a)	1.00%(b)	None

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
	Class A	Class Adv	Class C	Class Inst	Class Inst2	Class Inst3	Class R
Management fees	0.79%	0.79%	0.79%	0.79%	0.79%	0.79%	0.79%
Distribution and/or service (12b-1) fees	0.25%	0.00%	1.00%	0.00%	0.00%	0.00%	0.50%
Other expenses	0.20%	0.20%	0.20%	0.20%	0.16%	0.10%	0.20%
Total annual Fund operating expenses(c)	1.24%	0.99%	1.99%	0.99%	0.95%	0.89%	1.49%
Less: Fee waivers and/or expense reimbursements(d)	(0.01%)	(0.01%)	(0.01%)	(0.01%)	(0.03%)	(0.01%)	(0.01%)
Total annual Fund operating expenses after fee waivers and/or expense reimbursements	1.23%	0.98%	1.98%	0.98%	0.92%	0.88%	1.48%

(c)

“Total annual Fund operating expenses” include acquired fund fees and expenses (expenses the Fund incurs indirectly through its investments in other investment companies) and may be higher than the ratio of expenses to average net assets shown in the Financial Highlights section of this prospectus because the ratio of expenses to average net assets does not include acquired fund fees and expenses.

(d)

Columbia Wanger Asset Management, LLC (the Investment Manager) has contractually agreed to waive fees and reimburse certain expenses of the Fund, through April 30, 2023, so that ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund's investment in other investment companies, if any) do not exceed the annual rates of 1.23% for Class A shares, 0.98% for Class Adv shares, 1.98% for Class C shares, 0.98% for Class Inst shares, 0.92% for Class Inst2 shares, 0.88% for Class Inst3 shares and 1.48% for Class R shares. This arrangement may only be amended or terminated with approval from the Fund's Board of Trustees and the Investment Manager. The fee waivers and/or expense reimbursements shown in the table also reflect the contractual agreement of the Fund's transfer agent, Columbia Management Investment Services Corp. (the Transfer Agent), to waive a portion of its fees through April 30, 2023, such that the Fund's transfer agency fees do not exceed the annual rates of 0.04% of the average daily net assets of Class Inst2 shares and 0.00% of the average daily net assets of Class Inst3 shares. This arrangement may be terminated at the sole discretion of the Fund's Board of Trustees.

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	1 year	3 years	5 years	10 years
Class A (whether or not shares are redeemed)	$693	$945	$1,216	$1,988
Class Adv (whether or not shares are redeemed)	$100	$314	$546	$1,212
Class C (assuming redemption of all shares at the end of the period)	$301	$623	$1,072	$2,122
Class C (assuming no redemption of shares)	$201	$623	$1,072	$2,122
Class Inst (whether or not shares are redeemed)	$100	$314	$546	$1,212
Class Inst2 (whether or not shares are redeemed)	$94	$300	$523	$1,164
Class Inst3 (whether or not shares are redeemed)	$90	$283	$492	$1,095
Class R (whether or not shares are redeemed)	$151	$470	$812	$1,779

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Year by Year Total Return (%) as of December 31 Each Year*	Best and Worst Quarterly Returns During the Period Shown in the Bar Chart
	Best	2nd Quarter 2020	27.28%
	Worst	1st Quarter 2020	-28.50%

*	Year to Date return as of March 31, 2022: -18.81%

	Share Class Inception Date	1 Year	5 Years	10 Years
Class Inst	09/23/1992
returns before taxes		12.89%	13.39%	9.91%
returns after taxes on distributions		8.95%	9.65%	7.59%
returns after taxes on distributions and sale of Fund shares		10.26%	10.03%	7.69%
Class A returns before taxes	10/16/2000	6.17%	11.78%	8.98%
Class Adv returns before taxes	11/08/2012	12.88%	13.39%	9.88%
Class C returns before taxes	10/16/2000	10.81%	12.26%	8.80%
Class Inst2 returns before taxes	08/02/2011	12.97%	13.46%	9.97%
Class Inst3 returns before taxes	11/08/2012	13.00%	13.51%	10.01%
Class R returns before taxes	08/02/2011	12.34%	12.83%	9.29%
MSCI ACWI ex USA SMID Cap Growth Index (Net) (reflects reinvested dividends net of withholding taxes but reflects no deductions for fees, expenses or other taxes)		8.51%	12.25%	9.34%
MSCI ACWI ex USA SMID Cap Index (Net) (reflects reinvested dividends net of withholding taxes but reflects no deductions for fees, expenses or other taxes)		10.16%	10.30%	8.63%

Portfolio Management		Title		Role with Fund		Service with the Fund Since
Tae Han (Simon) Kim, CFA		Director of International Research, Portfolio Manager and Analyst		Co-Portfolio Manager since 2017		2011
Hans F. Stege		Portfolio Manager and Analyst		Co-Portfolio Manager since 2020		2017

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Class	Category of eligible account	For accounts other than Systematic Investment Plan accounts (as described in the Fund’s Prospectus)	For Systematic Investment Plan accounts
Classes A & C	All accounts other than IRAs	$2,000	$100
	IRAs	$1,000	$100
Classes Adv & Inst	All eligible accounts	$0, $1,000 or $2,000 depending upon the category of eligible investor	$100
Classes Inst2 & R	All eligible accounts	None	N/A
Class Inst3	All eligible accounts	$0, $1,000, $2,000 or $1 million depending upon the category of eligible investor	$100 (for certain eligible investors)

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Investment Objective

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations generally in the range of market capitalizations in the MSCI ACWI ex USA SMID Cap Growth Index (Net), the Fund's primary benchmark, (the Index) at the time of purchase (between $55.8 million and $29.7 billion as of March 31, 2022). 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. 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 and information technology sectors.

Market Risk. The Fund may incur losses due to declines in the value of one or more securities in which it invests. These declines may be due to factors affecting a particular issuer, or the result of, among other things, political, regulatory, market, economic or social developments affecting the relevant market(s) more generally. In addition, turbulence in financial markets and reduced liquidity in equity, credit and/or fixed income markets may negatively

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affect many issuers, which could adversely affect the Fund’s ability to price or value hard-to-value assets in thinly traded and closed markets and could cause significant redemptions and operational challenges. Global economies and financial markets are increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market. These risks may be magnified if certain events or developments adversely interrupt the global supply chain; in these and other circumstances, such risks might affect companies worldwide. As a result, local, regional or global events such as terrorism, war, other conflicts, natural disasters, disease/virus outbreaks and epidemics or other public health issues, recessions, depressions or other events – or the potential for such events – could have a significant negative impact on global economic and market conditions.

The large-scale invasion of Ukraine by Russia in February 2022 has resulted in sanctions and market disruptions including declines in regional and global stock and commodity markets and significant devaluations of Russian currency. The extent and duration of the military action are impossible to predict but could be significant. Market disruption caused by the Russian military action, and any counter measures or responses thereto (including international sanctions, a downgrade in the country’s credit rating, purchasing and financing restrictions, boycotts, tariffs, changes in consumer or purchaser preferences, cyberattacks and espionage) could have severe adverse impacts on regional and/or global securities and commodities markets, including markets for oil and natural gas. These impacts may include reduced market liquidity, distress in credit markets, further disruption of global supply chains, increased risk of inflation, and limited access to investments in certain international markets and/or issuers. These developments and other related events could negatively impact Fund performance.

The pandemic caused by coronavirus disease 2019 and its variants (COVID-19) has resulted in, and may continue to result in, significant global economic and societal disruption and market volatility due to disruptions in market access, resource availability, facilities operations, imposition of tariffs, export controls and supply chain disruption, among others. Such disruptions may be caused, or exacerbated by, quarantines and travel restrictions, workforce displacement and loss in human and other resources. The uncertainty surrounding the magnitude, duration, reach, costs and effects of the global pandemic, as well as actions that have been or could be taken by governmental authorities or other third parties, present unknowns that are yet to unfold. The impacts, as well as the uncertainty over impacts to come, of COVID-19 – and any other infectious illness outbreaks, epidemics and pandemics that may arise in the future – could negatively affect global economies and markets in ways that cannot necessarily be foreseen. In addition, the impact of infectious illness outbreaks and epidemics in less developed countries may be greater due to generally less established healthcare systems, governments and financial markets. Public health crises caused by the COVID-19 outbreak may exacerbate other pre-existing political, social and economic risks in certain countries or globally. The disruptions caused by COVID-19 could prevent the Fund from executing advantageous investment decisions in a timely manner and negatively impact the Fund’s ability to achieve its investment objective. Any such events could have a significant adverse impact on the value and risk profile of the Fund.

Foreign Securities Risk. Investments in or exposure to securities of foreign companies may involve heightened risks relative to investments in or exposure to securities of U.S. companies. For example, foreign markets can be extremely volatile. Foreign securities may also be less liquid, making them more difficult to trade, than securities of

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U.S. companies so that the Fund may, at times, be unable to sell foreign securities at desirable times or prices. Brokerage commissions, custodial costs and other fees are also generally higher for foreign securities. The Fund may have limited or no legal recourse in the event of default with respect to certain foreign securities, including those issued by foreign governments. In addition, foreign governments may impose withholding or other taxes on the Fund’s income, capital gains or proceeds from the disposition of foreign securities, which could reduce the Fund’s return on such securities. In some cases, such withholding or other taxes could potentially be confiscatory. Other risks include: possible delays in the settlement of transactions or in the payment of income; generally less publicly available information about foreign companies; the impact of economic, political, social, diplomatic or other conditions or events (including, for example, military confrontations and actions, war, other conflicts, terrorism and disease/virus outbreaks and epidemics), possible seizure, expropriation or nationalization of a company or its assets or the assets of a particular investor or category of investors; accounting, auditing and financial reporting standards that may be less comprehensive and stringent than those applicable to domestic companies; the imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country; and the generally less stringent standard of care to which local agents may be held in the local markets. In addition, it may be difficult to obtain reliable information about the securities and business operations of certain foreign issuers. Governments or trade groups may compel local agents to hold securities in designated depositories that are not subject to independent evaluation. The less developed a country’s securities market is, the greater the level of risks. Economic sanctions may be, and have been, imposed against certain countries, organizations, companies, entities and/or individuals. Economic sanctions and other similar governmental actions could, among other things, effectively restrict or eliminate the Fund’s ability to purchase or sell securities, and thus may make the Fund’s investments in such securities less liquid or more difficult to value. In addition, as a result of economic sanctions, the Fund may be forced to sell or otherwise dispose of investments at inopportune times or prices, which could result in losses to the Fund and increased transaction costs. These conditions may be in place for a substantial period of time and enacted with limited advance notice to the Fund. The risks posed by sanctions against a particular foreign country, its nationals or industries or businesses within the country may be heightened to the extent the Fund invests significantly in the affected country or region or in issuers from the affected country that depend on global markets. Additionally, investments in certain countries may subject the Fund to a number of tax rules, the application of which may be uncertain. Countries may amend or revise their existing tax laws, regulations and/or procedures in the future, possibly with retroactive effect. Changes in or uncertainties regarding the laws, regulations or procedures of a country could reduce the after-tax profits of the Fund, directly or indirectly, including by reducing the after-tax profits of companies located in such countries in which the Fund invests, or result in unexpected tax liabilities for the Fund.

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Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries, such as China, Russia and certain countries in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile, and may be more susceptible to market manipulation, than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience periods of high inflation or rapid changes in inflation rates and may have hostile relations with other countries. Due to the differences in the nature and quality of financial information of issuers of emerging market securities, including auditing and financial reporting standards, financial information and disclosures about such issuers may be unavailable or, if made available, may be considerably less reliable than publicly available information about other foreign securities.

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Geographic Focus Risk. The Fund may be particularly susceptible to risks related to economic, political, regulatory or other events or conditions affecting issuers and countries within the specific geographic regions in which the Fund invests. Currency devaluations could occur in countries that have not yet experienced currency devaluation to date, or could continue to occur in countries that have already experienced such devaluations. As a result, the Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund.

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Asia Pacific Region. A number of countries in the Asia Pacific region are considered underdeveloped or developing, including from a political, economic and/or social perspective, and may have relatively unstable governments and economies based on limited business, industries and/or natural resources or commodities. Events in any one country within the region may impact that country, other countries in the region or the region as a whole. As a result, events in the region will generally have a greater effect on the Fund than if the Fund were more geographically diversified in a region with more developed countries and economies. This could result in increased volatility in the value of the Fund’s investments and losses for the Fund. Continued growth of economies and securities markets in the region will require sustained economic and fiscal discipline, as well as continued commitment to governmental and regulatory reforms. Development also may be influenced by international economic conditions, including those in the United States and Japan, and by world demand for goods or natural resources produced in countries in the Asia Pacific region. Securities markets in the region are generally smaller and have a lower trading volume than those in the United States, which may result in the securities of some companies in the region being less liquid than U.S. or other foreign securities. Some currencies, inflation rates or interest rates in the Asia Pacific region are or can be volatile, and some countries in the region may restrict the flow of money in and out of the country. The risks described under “Emerging Market Securities Risk” and  “Foreign Securities Risk” may be more pronounced due to the Fund’s focus on investments in the region.

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Europe. The Fund is particularly susceptible to risks related to economic, political, regulatory or other events or conditions, including acts of war or other conflicts in the region, affecting issuers and countries in Europe. Countries in Europe are often closely connected and interdependent, and events in one European country can have an adverse impact on, and potentially spread to, other European countries. Most developed countries in Western Europe are members of the EU, and many are also members of the European Economic and Monetary Union (EMU). European countries can be significantly affected by the tight fiscal and monetary controls that the EMU imposes on its members and with which candidates for EMU membership are required to comply. In addition, significant private and public sectors’ debt problems of a single EU country can pose economic risks to the EU as a whole. Unemployment in Europe has historically been higher than in the United States and public deficits are an ongoing concern in many European countries. As a result, the Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. If securities of issuers in Europe fall out of favor, it may cause the Fund to underperform other funds that do not focus their investments in this region of the world. The UK’s departure from the EU single market became effective January 1, 2021 with the end of the Brexit transition period and the post‐Brexit trade deal between the UK and EU taking effect on December 31, 2020. The impact of any partial or complete dissolution of the EU on the UK and European economies and the broader global economy could be significant, resulting in negative impacts on currency and financial markets generally, such as increased volatility

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and illiquidity, and potentially lower economic growth in markets in the UK, Europe and globally, which may adversely affect the value of your investment in the Fund. The impact of Brexit in the near‐ and long‐term is still unknown and could have additional adverse effects on economies, financial markets, currencies and asset valuations around the world. Any attempt by the Fund to hedge against or otherwise protect its portfolio or to profit from such circumstances may fail and, accordingly, an investment in the Fund could lose money over short or long periods. For more information on the risks associated with Brexit, see the Statement of Additional Information.

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business within one or more economic sectors, including the industrials and information technology sectors. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly. Generally, the more broadly the Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility.

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Industrials Sector. The Fund is more susceptible to the particular risks that may affect companies in the industrials sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the industrials sector are subject to certain risks, including changes in supply and demand for their specific product or service and for industrial sector products in general, including decline in demand for such products due to rapid technological developments and frequent new product introduction. Performance of such companies may be affected by factors including government regulation, world events, economic conditions and risks for environmental damage and product liability claims.

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Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which may negatively affect the Fund’s performance. Underperformance of an issuer may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters, military confrontations and actions, war, terrorism, disease/virus outbreaks and epidemics or other events, conditions and factors.

The Fund’s investment objective and non-fundamental investment policies (including its principal and additional investment strategies) can be changed by the Board without shareholder approval, but may require notice to shareholders in certain instances. The Fund’s fundamental investment policies, as identified in the Fund’s Statement of Additional Information (SAI), may be changed only with Board and shareholder approval in accordance with the voting requirements of the 1940 Act. For additional information about changing the Fund’s fundamental and non-fundamental investment policies, see the SAI.

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The Fund may enter into derivative transactions or otherwise have exposure to derivative transactions through underlying investments. The Fund expects to enter into such transactions primarily in the form of stock index futures in order to obtain exposure to the overall sector of the market represented by a particular stock index or to invest the Fund’s uninvested cash balances in a manner that the Investment Manager believes aligns more closely with the Fund’s investment strategy than simply holding short-term fixed income investments or cash equivalents (known as cash equitization). Derivatives are financial contracts whose values are, for example, based on (or “derived” from) traditional securities (such as a stock or bond), assets (such as a commodity like gold or a foreign currency), reference rates (such as the Secured Overnight Financing Rate (commonly known as SOFR) or the London Interbank Offered Rate (commonly known as LIBOR)) or market indices (such as the Standard & Poor's (S&P) 500^® Index). The use of derivatives is a highly specialized activity which involves investment techniques and risks different from those associated with ordinary portfolio securities transactions. Derivatives involve special risks and may result in losses or may limit the Fund's potential gain from favorable market movements. Derivative strategies typically expose the Fund to gains and losses in excess of the amount actually invested in the derivative. This characteristic of a derivative (known as "leverage") may exaggerate a loss, potentially causing the Fund to lose more money than it would have lost had it invested in the underlying security or other asset directly. The values of derivatives may move in unexpected ways, especially in unusual (including distressed) market conditions, and may result in increased volatility in the value of the derivative and/or the Fund’s shares, among other consequences. The use of derivatives may also increase the amount of taxes payable by shareholders holding shares in a taxable account. Other risks arise from the Fund's potential inability to terminate or to sell derivative positions. A liquid secondary market may not always exist for the Fund's derivative positions at times when the Fund might wish to terminate or to sell such positions. Over-the-counter instruments (investments not traded on an exchange) may be illiquid, and transactions in derivatives traded in the over-the-counter market are subject to the risk that the other party will not meet its obligations. The use of derivatives also involves the risks of mispricing or improper valuation and that changes in the value of the derivative may not correlate perfectly with the underlying security, asset, reference rate or index. The Fund also may not be able to find a suitable derivative transaction counterparty, and thus may be unable to engage in derivative transactions when it is deemed favorable to do so, or at all. U.S. federal legislation has been enacted that provides for new clearing, margin, reporting and registration requirements for participants in the derivatives market. These changes could restrict and/or impose significant costs or other burdens upon the Fund’s participation in derivatives transactions. The U.S. government and the European Union (and some other jurisdictions) have enacted regulations and similar requirements that prescribe clearing, margin, reporting and registration requirements for participants in the derivatives market. These requirements are evolving and their ultimate impact on the Fund remains unclear but such impact could include restricting and/or imposing significant costs or other burdens upon the Fund’s participation in derivatives transactions. Additionally, in October 2020, the SEC adopted new regulations governing the use of derivatives by registered investment companies. Once effective, Rule 18f-4 will, among other things, require funds that invest in derivative instruments beyond a specified limited amount to apply a value-at-risk based limit to their use of certain derivative instruments and establish a comprehensive derivatives risk management program. A fund that uses derivative instruments in a limited amount will not be subject to the full requirements of Rule 18f-4. Compliance with Rule 18f-4 will not be required until August 2022. Rule 18f-4 could have an adverse impact on the Fund’s performance and ability to implement its investment strategies as it has historically. For more information on the risks of derivative investments and strategies, see the SAI.

LIBOR Phase-Out Risk. Many derivatives and other financial instruments utilize or are permitted to utilize a floating interest rate based on LIBOR. On July 27, 2017, the United Kingdom's Financial Conduct Authority (FCA) announced its intention to phase out the use of LIBOR by the end of 2021. The FCA and the ICE Benchmark Administration have since announced that a majority of U.S. dollar LIBOR settings will cease publication after June 30, 2023. A subset of

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non-U.S. dollar LIBOR settings are continuing to be published on a “synthetic” basis and it is possible that a subset of U.S. dollar LIBOR settings will also be published after June 30, 2023 on a “synthetic” basis. Any such publications are, or would be considered, non-representative of the underlying market. Uncertainty related to the liquidity impact of changes in reference rates, and how to appropriately adjust these rates at the time of transition, poses risks for the Fund. It is difficult to predict the full impact of the transition away from LIBOR on the Fund until new reference rates and fallbacks for both legacy and new products, instruments and contracts are commercially accepted and market practices become more settled. The Investment Manager monitors the Fund's LIBOR exposure risks, including the extent to which any derivative and/or debt investments allow for the utilization of alternative rate(s), such as the Secured Overnight Financing Rate (SOFR), which the U.S. Federal Reserve is promoting as the alternative reference rate to LIBOR.

The Investment Manager and its affiliate, Columbia Management Investment Advisers, LLC (Columbia Management), each serves as investment adviser to mutual funds and ETFs using the Columbia brand (Columbia Funds), including mutual funds that are structured as “fund-of-funds”, and provides asset-allocation services to (i) shareholders by investing in shares of other Columbia Funds, which may include the Fund (collectively referred to in this section as Underlying Funds), and (ii) discretionary managed accounts (collectively referred to as affiliated products) that invest exclusively in Underlying Funds. These affiliated products, individually or collectively, may own a significant percentage of the outstanding shares of one or more Underlying Funds, and the Investment Manager and Columbia Management seek to balance potential conflicts of interest between the affiliated products and the Underlying Funds in which they invest. The affiliated products’ investment in the Underlying Funds may have the effect of creating economies of scale, possibly resulting in lower expense ratios for the Underlying Funds, because the affiliated products may own substantial portions of the shares of Underlying Funds. However, redemption of Underlying Fund shares by one or more affiliated products could cause the expense ratio of the Underlying Fund to increase, as its fixed costs would be spread over a smaller asset base. Because of large positions of certain affiliated products, the Underlying Funds may experience relatively large inflows and outflows of cash due to affiliated products’ purchases and sales of Underlying Fund shares. Although the Investment Manager or Columbia Management may seek to minimize the impact of these transactions where possible, for example, by structuring them over a reasonable period of time or through other measures, Underlying Funds may experience increased expenses as they buy and sell portfolio securities to manage the cash flow effect related to these transactions. Further, when the Investment Manager or Columbia Management structures transactions over a reasonable period of time in order to manage the potential impact of the buy and sell decisions for the affiliated products, those affiliated products, including funds-of-funds, may pay more or less (for purchase activity), or receive more or less (for redemption activity), for shares of the Underlying Funds than if the transactions were executed in one transaction. In addition, substantial redemptions by affiliated products within a short period of time could require the Underlying Fund to liquidate positions more rapidly than would otherwise be desirable, which may have the effect of reducing or eliminating potential gain or causing it to realize a loss. In order to meet such redemptions, the Underlying Fund may be forced to sell its liquid (or more liquid) positions, leaving the Underlying Fund holding, post-redemption, a relatively larger position in illiquid investments (i.e., any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment) or less liquid securities. Substantial redemptions may also adversely affect the ability of the Underlying Fund to implement its investment strategy. The Investment Manager or Columbia Management also has a conflict of interest in determining the allocation of affiliated products’ assets among the Underlying Funds, as it earns different fees from the various Underlying Funds.

The Fund may invest cash, including cash collateral received in connection with its securities lending program, in shares of money market funds, including funds advised by affiliates of the Investment Manager. These funds are not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. The Fund and its shareholders indirectly bear a portion of the expenses of any money market fund or other fund in which the Fund may invest.

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Portfolio Holdings Versus the Benchmarks

The Fund does not limit its investments to the securities within its benchmarks, and accordingly the Fund's holdings may diverge significantly from those of the benchmarks selected by the Investment Manager. In addition, the Fund may invest in securities outside the industry and geographic sectors represented in its benchmarks. The Fund's weightings in individual securities, and in industry and geographic sectors, may also vary considerably from those of its benchmarks.

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Other Expenses

“Other expenses” consist of the fees the Fund pays to its administrator, custodian, transfer agent, auditors, lawyers and trustees, costs relating to compliance and miscellaneous expenses. Generally, these expenses are allocated on a pro rata basis across all share classes. These expenses include certain sub-transfer agency and shareholder servicing fees. Transfer agency fees and certain shareholder servicing fees, however, are class specific. They differ by share class because the shareholder services provided to each share class may be different. Accordingly, the differences in “other expenses” among share classes are primarily the result of the different transfer agency and shareholder servicing fees applicable to each share class. For more information on these fees, see Choosing a Share Class — Financial Intermediary Compensation.

The Investment Manager has contractually agreed to waive fees and reimburse certain expenses of the Fund through April 30, 2023, so that ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings, and expenses associated with the Fund’s investment in other investment companies, if any) do not exceed the annual rates of:

Columbia Acorn International
Class A	1.23%
Class Adv	0.98%
Class C	1.98%
Class Inst	0.98%
Class Inst2	0.92%
Class Inst3	0.88%
Class R	1.48%

The Transfer Agent has contractually agreed to waive a portion of the fees payable by the Fund such that through April 30, 2023, fees paid by the Fund to the Transfer Agent do not exceed the annual rates of (i) 0.04% of the average daily net assets of Class Inst2 shares of the Fund and (ii) 0.00% of the average daily net assets of Class Inst3 shares of the Fund unless sooner terminated at the sole discretion of the Fund's Board of Trustees.

Effect of Fee Waivers and/or Expense Reimbursements on Past Performance. The Fund’s returns shown in the Performance Information section of this prospectus reflect the effect of fee waivers and/or reimbursements of Fund expenses by the Investment Manager and/or its affiliates that were in place during the performance period shown in the Performance Information section of this prospectus. Without such fee waivers/expense reimbursements, the Fund’s returns might have been lower.

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Primary Service Provider Contracts

Columbia Wanger Asset Management, LLC is located at 71 S. Wacker Drive, Suite 2500, Chicago, Illinois 60606. As of March 31, 2022, the Investment Manager had assets under management of approximately $9.2 billion. The Investment Manager is a registered investment adviser and wholly-owned subsidiary of Columbia Management, which is a wholly-owned subsidiary of Ameriprise Financial. In addition to serving as an investment adviser to mutual funds, the Investment Manager acts as an investment manager for other private funds and institutional accounts.

A discussion regarding the basis for the Board’s approval of the renewal of the Fund’s investment management services agreement with the Investment Manager is available in the Fund’s annual report to shareholders for the fiscal year ended December 31, 2021.

The Investment Manager and its investment advisory affiliates, including Columbia Management (Affiliates), around the world may coordinate in providing services to their clients. From time to time, the Investment Manager may engage its Affiliates to provide a variety of services such as investment research, investment monitoring, trading, and discretionary investment management (including portfolio management and proxy voting) to certain accounts

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managed by the Investment Manager, including the Fund. These Affiliates will provide services to the Fund and other accounts of the Investment Manager either pursuant to delegation agreements, personnel-sharing agreements or similar inter-company or other arrangements or relationships and the Fund will pay no additional fees and expenses as a result of any such arrangements or relationships. These Affiliates, like the Investment Manager, are direct or indirect subsidiaries of Ameriprise Financial and are registered with the appropriate respective regulators and, where required, the SEC and the Commodity Futures Trading Commission in the United States.

Pursuant to some of these arrangements or relationships, certain personnel of Columbia Management and other Affiliates may serve as “associated persons” or officers of the Investment Manager and, in this capacity, subject to the oversight and supervision of the Investment Manager and consistent with the investment objectives, policies and limitations set forth in this prospectus and the Fund's SAI, and with the Investment Manager’s and the Funds’ compliance policies and procedures, may provide such services to the Fund.

Portfolio Management		Title		Role with Fund		Service with the Fund Since
Tae Han (Simon) Kim, CFA		Director of International Research, Portfolio Manager and Analyst		Co-Portfolio Manager since 2017		2011
Hans F. Stege		Portfolio Manager and Analyst		Co-Portfolio Manager since 2020		2017

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Shares of the Fund are distributed by Columbia Management Investment Distributors, Inc., which is located at 290 Congress Street, Boston, MA 02210. The Distributor is a registered broker-dealer and an indirect, wholly-owned subsidiary of Ameriprise Financial. The Distributor and its affiliates may pay commissions, distribution and service fees and/or other compensation to entities, including Ameriprise Financial affiliates, for selling shares and providing services to investors.

Columbia Management Investment Services Corp. is a registered transfer agent and wholly-owned subsidiary of Ameriprise Financial. The Transfer Agent is located at 290 Congress Street, Boston, MA 02210, and its responsibilities include processing purchases, redemptions and exchanges of Fund shares, calculating and paying distributions, maintaining shareholder records, preparing account statements and providing customer service. The Transfer Agent has engaged DST Asset Manager Solutions, Inc. to provide various shareholder or “sub-transfer agency” services. In addition, the Transfer Agent enters into agreements with various financial intermediaries through which you may hold Fund shares, pursuant to which the Transfer Agent pays these financial intermediaries for providing certain shareholder services. Depending on the type of account, the Fund pays the Transfer Agent a per account fee for each open account and compensates the Transfer Agent for certain out-of-pocket expenses, including certain payments to financial intermediaries through which shares are held. In addition, subject to certain limitations, the Fund compensates the Transfer Agent for payments made to financial intermediaries for the shareholder services that the intermediaries provide, in amounts that vary by share class and with the type of intermediary and the type of shareholder services provided. The Transfer Agent is contractually obligated to oversee such intermediaries for the purpose of reasonably assuring their compliance with applicable law and the terms of their agreements to provide the shareholder services. For more information about Shareholder Services fees, see Choosing a Share Class — Financial Intermediary Compensation.

As described in More Information About the Fund - Primary Service Provider Contracts, the Investment Manager, Administrator, Sub-Administrator, Distributor and Transfer Agent are all affiliates of Ameriprise Financial. In addition to the services that they provide to the Fund, they also provide substantially similar services (for which they are compensated) to other clients and customers, including the Columbia Funds. Ameriprise Financial and its other affiliates may also provide services (for which they are compensated) to the Fund, other Columbia Funds or other clients and customers.

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Ameriprise Financial and certain of its affiliates are involved in the normal course of business in legal proceedings which include regulatory inquiries, arbitration and litigation, including class actions concerning matters arising in connection with the conduct of its activities as a diversified financial services firm. Ameriprise Financial believes that the Fund is not currently the subject of, and that neither Ameriprise Financial nor any of its affiliates are the subject of, any pending legal, arbitration or regulatory proceedings that are likely to have a material adverse effect on the Fund or the ability of Ameriprise Financial or its affiliates to perform under their contracts with the Fund. Information regarding certain pending and settled legal proceedings may be found in the Fund’s shareholder reports and in the SAI. Additionally, Ameriprise Financial is required to make quarterly (10-Q), annual (10-K) and, as necessary, 8-K filings with the SEC on legal and regulatory matters that relate to Ameriprise Financial and its affiliates. Copies of these filings may be obtained by accessing the SEC website at sec.gov.

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The Funds

Financial Intermediaries

The term “financial intermediary” refers to the selling and servicing agents that are authorized to sell and/or service shares of the Funds. Financial intermediaries include broker-dealers and financial advisors as well as firms that employ broker-dealers and financial advisors, including, for example, brokerage firms, banks, investment advisers, third party administrators and other firms in the financial services industry.

Omnibus Accounts

The term “omnibus account” refers to a financial intermediary’s account with the Fund (held directly through the Transfer Agent) that represents the combined holdings of, and transactions in, Fund shares of one or more clients of the financial intermediary (beneficial Fund shareholders). Omnibus accounts are held in the name of the financial intermediaries and not in the name of the beneficial Fund shareholders invested in the Fund through omnibus accounts.

Retirement Plans and Omnibus Retirement Plans

The term “retirement plan” refers to retirement plans created under Sections 401(a), 401(k), 457 and 403(b) of the Internal Revenue Code of 1986, as amended (the Code), and non-qualified deferred compensation plans governed by Section 409A of the Code and similar plans, but does not refer to individual retirement plans, such as traditional IRAs and Roth IRAs. The term “omnibus retirement plan” refers to a retirement plan that has a plan-level or omnibus account with the Transfer Agent.

Networked Accounts

Networking, offered by the Depository Trust & Clearing Corporation’s Wealth Management Services (WMS), is the industry standard IT system for mutual fund account reconciliation and dividend processing.

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Front-End Sales Charge Calculation

The front-end sales charge is calculated as a percentage of the offering price.

The dollar amount of any applicable front-end sales charge is the difference between the offering price of the shares you buy and the NAV of those shares. To determine the front-end sales charge you will pay when you buy Class A shares, the Fund will add the amount of your investment to the value of your account (and any other accounts eligible for aggregation of which you or your financial intermediary notifies the Fund) and base the sales charge on the aggregate amount. For information on account value aggregation, sales charge waivers and other important information, see Choosing a Share Class — Reductions/Waivers of Sales Charges.

Contingent Deferred Sales Charge

A contingent deferred sales charge (CDSC) is a sales charge applied at the time you sell your shares, unlike a front-end sales charge that is applied at the time of purchase. A CDSC can vary based on the length of time that you have held your shares. A CDSC is applied to the NAV at the time of your purchase or sale, whichever is lower, and will not be applied to any shares you receive through Fund distribution reinvestments or any amount that represents appreciation in the value of your shares. For purposes of calculating a CDSC, the start of the holding period is generally the first day of the month in which your purchase was made.

When you place an order to sell shares of a class that has a CDSC, the Fund will first redeem any shares that are not subject to a CDSC, followed by those you have held the longest. This means that if a CDSC is imposed, you cannot designate the individual shares being redeemed for U.S. federal income tax purposes. You should consult your tax advisor about the tax consequences of investing in the Fund. In certain circumstances, the CDSC may not apply. See Choosing a Share Class — Reductions/Waivers of Sales Charges for details.

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Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
Class A	Eligibility: Available to the general public for investment Minimum Initial Investment: $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts (as described below))	5.75% maximum, declining to 0.00% on investments of $1 million or more	CDSC on certain investments of between $1 million and $50 million redeemed within 18 months after purchase charged as follows: • 1.00% CDSC if redeemed within 12 months after purchase and • 0.50% CDSC if redeemed more than 12, but less than 18, months after purchase	Reductions: yes, see Choosing a Share Class — Reductions/Waivers of Sales Charges – Class A Shares Front-End Sales Charge Reductions Waivers: yes, on Fund distribution reinvestments. For additional waivers, see Choosing a Share Class — Reductions/Waivers of Sales Charges – Class A Shares Front-End Sales Charge Waivers, as well as Choosing a Share Class — CDSC Waivers – Class A and Class C Financial intermediary-specific waivers are also available, see Appendix A	Service Fee: 0.25%
Class Adv	Eligibility: Available only to (i) omnibus retirement plans, including self-directed brokerage accounts within omnibus retirement plans that clear through institutional no transaction fee (NTF) platforms; retirement plans; (ii) trust companies or similar institutions; (iii) broker-dealers, banks, trust companies and similar institutions that clear Fund share transactions for their client or customer investment advisory or similar accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Adv eligibility apart from selling, servicing or similar agreements; (iv) 501(c)(3) charitable organizations; (v) 529 plans; (vi) health savings accounts; (vii) investors participating in a fee-based advisory program sponsored by a financial intermediary or other entity that is not compensated by the Fund for those services, other than payments for shareholder servicing or sub-accounting performed in place	None	None	N/A	None

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Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
	of the Transfer Agent; and (viii) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Adv shares within such platform. Minimum Initial Investment: None, except in the case of (viii) above, which is $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts)
Class C	Eligibility: Available to the general public for investment Minimum Initial Investment: $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) Conversion Feature: Yes. Effective April 1, 2021, Class C shares generally automatically convert to Class A shares of the same Fund in the month of or the month following the 8-year anniversary of the Class C shares purchase date. Prior to April 1, 2021, Class C shares generally automatically converted to Class A shares of the same Fund in the month of or the month following the 10-year anniversary of the Class C shares purchase date.(a)	None	1.00% on certain investments redeemed within one year of purchase	Waivers: yes, on Fund distribution reinvestments. For additional waivers, see Choosing a Share Class — CDSC Waivers – Class A and Class C Financial intermediary-specific CDSC waivers are also available, see Appendix A	Distribution Fee: 0.75% Service Fee: 0.25%
Class Inst	Eligibility: Available only to certain eligible investors, which are subject to different minimum investment requirements, ranging from $0 to $2,000, including investors who purchase Fund shares through commissionable brokerage platforms where the financial intermediary holds the shares in an omnibus account and, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst shares within such platform; closed to (i) accounts of financial intermediaries that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund	None	None	N/A	None

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Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
	trading platforms that have been given specific written notice from the Transfer Agent of the termination of their eligibility for new purchases of Class Inst shares and (ii) omnibus group retirement plans, subject to certain exceptions(d) Minimum Initial Investment: See Eligibility above
Class Inst2	Eligibility: Available only to (i) certain registered investment advisers and family offices that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Inst2 eligibility apart from selling, servicing or similar agreements; (ii) omnibus retirement plans(d); (iii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst2 shares within such platform and that Fund shares are held in an omnibus account; and (iv) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst2 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst2 shares within such platform. Minimum Initial Investment: None	None	None	N/A	None
Class Inst3	Eligibility: Available to: (i) group retirement plans that maintain plan-level or omnibus accounts with the Fund(d); (ii) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst3 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst3 shares within such platform; (iii) collective trust funds; (iv) affiliated or unaffiliated mutual funds (e.g., funds operating as funds-of-funds); (v) fee-based platforms of financial intermediaries (or the clearing intermediary they trade through) that have an agreement with the	None	None	N/A	None

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Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
	Distributor or an affiliate thereof that specifically authorizes the financial intermediary to offer and/or service Class Inst3 shares within such platform, provided also that Fund shares are held in an omnibus account; (vi) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; (vii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; and (viii) bank trust departments, subject to an agreement with the Distributor that specifically authorizes offering Class Inst3 shares and provided that Fund shares are held in an omnibus account. In each case above where noted that Fund shares are required to be held in an omnibus account, the Distributor, may, in its discretion, determine to waive this requirement. Minimum Initial Investment: No minimum for the eligible investors described in (i), (iii), (iv) and (v) above; $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) for the eligible investors described in (vi) above; and $1 million for all other eligible investors, unless waived in the discretion of the Distributor
Class R	Eligibility: Available only to eligible retirement plans, health savings accounts and, in the sole discretion of the Distributor, other types of retirement accounts held through platforms maintained by financial intermediaries approved by the Distributor Minimum Initial Investment: None	None	None	N/A	Distribution Fee: 0.50%

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Sales charges, commissions, and distribution fees compensate financial intermediaries (typically your financial advisor) for selling shares to you, and service fees compensate financial intermediaries for maintaining and servicing the shares held in your account with them. Distribution and service fees are discussed in a separate sub-section below. Depending on which share class you choose and the financial intermediary through which you purchase your shares, you may pay these charges at potentially different levels at the outset as a front-end sales charge, at the time you sell your shares as a CDSC and/or over time in the form of distribution and/or service fees. You may be required to pay brokerage commissions and other fees to financial intermediaries when transacting in any class of Fund shares, including those that do not assess any front-end sales charge, contingent deferred sales charge, or other asset-based fee for sales or distribution. Such brokerage commissions and other fees are set by the financial intermediary.

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The Distributor may also pay your financial intermediary a cumulative commission when you buy Class A shares in amounts not subject to a front-end sales charge, according to the following schedules (assets initially purchased into Class A shares of Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund that were purchased without the application of a front-end sales charge are excluded for purposes of calculating a financial intermediary’s commission under these schedules):

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■

In addition to the above automatic conversion of Class C to Class A shares policy, the Transfer Agent seeks to convert Class C shares as soon as administratively feasible, regardless of how long such shares have been owned, to Class A shares of the same Fund for Direct-at-Fund Accounts (as defined below) that do not or no longer have a financial intermediary assigned to them. Direct-at-Fund Accounts that do not have a financial intermediary assigned to them are not permitted to purchase Class C shares; Class C share purchase orders received by Direct-at-Fund Accounts that do not have a financial intermediary assigned to the account will automatically be invested in Class A shares of the same Fund.

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Your “Immediate Family” and Account Value Aggregation

For purposes of obtaining a breakpoint discount for Class A shares, the value of your account will be deemed to include the value of all applicable shares in eligible Fund accounts that are held by you and your “immediate family,” which includes your spouse, domestic partner, parent, step-parent, legal guardian, child under 21, step-child under 21, father-in-law and mother-in-law, provided that you and your immediate family members share the same mailing address. Any Fund accounts linked together for account value aggregation purposes as of the close of business on September 3, 2010 will be permitted to remain linked together. Group retirement plan accounts are valued at the retirement plan level.

The following accounts are eligible for account value aggregation as described above, provided that they are invested in Class A (excluding, in the case of Direct-at-Fund Accounts, Funds that do not assess a front-end sales charge, including Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund, unless such shares were purchased via an exchange from Class A shares of a Fund on which you paid the Class A share applicable front-end sales charge), Class C, Class E, Class Inst or Class V shares of a Fund, or non-retirement plan accounts invested in Class Adv, Class Inst2 or Class Inst3 shares of a Fund: individual or joint accounts; Roth and traditional Individual Retirement Accounts (IRAs); Simplified Employee Pension accounts (SEPs), Savings Investment Match Plans for Employees of Small Employers accounts (SIMPLEs) and Tax Sheltered Custodial Accounts (TSCAs); Uniform Gifts to Minors Act (UGMA)/Uniform Transfers to Minors Act (UTMA) accounts for which you, your spouse, or your domestic partner is parent or guardian of the minor child; revocable trust accounts for which you or an immediate family member, individually, is the beneficial owner/grantor; accounts held in the name of your, your spouse’s, or your domestic partner’s sole proprietorship or single owner limited liability company or S corporation; qualified retirement plan assets, provided that you are the sole owner of the business sponsoring the plan, are the sole participant (other than a spouse) in the plan, and have no intention of adding participants to the plan; and investments in wrap accounts.

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In addition, certain types of purchases of Class A shares may be made at NAV. The Distributor may waive front-end sales charges on (i) purchases (including exchanges) of Class A shares in accounts of financial intermediaries that have entered into agreements with the Distributor to offer Fund shares to self-directed investment brokerage accounts that may or may not charge a transaction fee to customers; (ii) exchanges of Class Inst shares of a Fund for Class A shares of the Fund; (iii) purchases of Class A shares on brokerage mutual fund-only platforms of financial intermediaries that have an agreement with the Distributor that specifically authorizes the offering of Class A shares within such platform; (iv) purchases through certain wrap fee or other products or programs that involve fee-based compensation arrangements that have, or clear trades through a financial intermediary that has, a selling agreement with the Distributor; (v) purchases through state sponsored 529 Plans; (vi) purchases through banks, trust companies, and thrift institutions acting as fiduciaries; (vii) purchases through certain employee benefit plans and certain qualified deferred compensation plans; and (viii) purchases of Class A shares in Direct-at-Fund Accounts (as defined below) that do not have a financial intermediary assigned to them. For a more complete description of these eligible transactions, see Appendix S to the SAI.

As noted in the table below, you can redeem shares of certain classes (see Redeemed Share Class below) and use such redemption proceeds to buy shares of the Corresponding Repurchase Class without paying an otherwise applicable sales charge and/or CDSC (other than, in the case of Direct-at-Fund Accounts, redemptions from Funds that do not assess a front-end sales charge, including Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund, unless such shares were purchased via an exchange from Class A shares of a Fund on which you paid the Class A share applicable front-end sales charge) within 90 days, up to the amount of the redemption proceeds.

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Class A shares also applies to purchases of funds that do not pay an up-front sales commission on Class A shares, which includes Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund. For Class C shares, the Distributor begins to pay these fees 12 months after purchase. However, for Class C shares, financial intermediaries may opt to decline the up-front payment described in Choosing a Share Class – Sales Charges and Commissions – Class C Shares – Commissions and instead may receive these fees immediately after purchase. If the intermediary opts to receive the up-front payment, the Distributor retains the distribution and service fee for the first 12 months following the sale of Class C shares in order to recover the up-front payment made to financial intermediaries and to pay for other related expenses. For Class R shares, the Distributor begins to pay these fees immediately after purchase.

The Distributor, the Investment Manager and their affiliates make payments, from their own resources, to financial intermediaries, including other Ameriprise Financial affiliates, for marketing/sales support services relating to the Funds (Marketing Support Payments). Such payments are generally based upon one or more of the following factors: average net assets of the Funds attributable to that financial intermediary; gross sales of the Funds attributable to that financial intermediary; reimbursement of ticket charges (fees that a financial intermediary charges its representatives for effecting transactions in Fund shares); or a negotiated lump sum payment. While the financial arrangements may vary for each financial intermediary, Marketing Support Payments to any one financial intermediary are generally between 0.01% and 0.40% on an annual basis for payments based on average net assets of the Fund attributable to the financial intermediary, and between 0.05% and 0.25% on an annual basis for firms receiving a payment based on gross sales of the Funds attributable to the financial intermediary. The Distributor, the Investment Manager and their affiliates make payments with respect to a Fund or the Columbia Funds generally on a basis other than those described above or in larger amounts when dealing with certain financial intermediaries. Not all financial intermediaries receive Marketing Support Payments. The Distributor, the Investment Manager and their affiliates do not make Marketing Support Payments with respect to Class Inst3 shares of the Columbia Acorn Funds.

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Share Price Determination

The price you pay or receive when you buy, sell or exchange shares is the Fund's next determined net asset value (or NAV) per share for a given share class. The Fund calculates the NAV per share for each class of shares of the Fund at the end of each business day, with the value of the Fund's shares based on the total value of all of the securities and other assets that it holds as of such specified time.

NAV Calculation

Each of the Fund's share classes calculates its NAV per share as follows:

NAV per share =  (Value of assets of the share class) – (Liabilities of the share class)
Number of outstanding shares of the class

Business Days

A business day is any day that the New York Stock Exchange (NYSE) is open. A business day ends at (i) the scheduled close of the NYSE for such day (usually 4:00 p.m. Eastern Time or such other time as the NYSE may schedule), (ii) the scheduled close of the NYSE (usually 4:00 p.m. Eastern Time) on any business day on which the NYSE has an unscheduled close or intraday trading halt or other disruption, regardless of the time of such unscheduled close, halt or disruption or whether trading resumes, or (iii) such other time as the Board may from time to time determine. On holidays and other days when the NYSE is closed, the Fund’s NAV is not calculated and the Fund does not accept buy or sell orders. However, the value of the Fund’s assets may still be affected on such days to the extent that the Fund holds foreign securities that trade on days that foreign securities markets are open.

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For shares held directly with the Funds’ Transfer Agent, if your shares are sold, the Transfer Agent will remit the sale proceeds to you. The Transfer Agent will send you written notification in advance of any automatic sale, which will provide details on how you may avoid such an automatic sale. Generally, you may avoid such an automatic sale by raising your account balance to at least $250, consolidating your multiple accounts you may have with the Funds through an exchange (so as to maintain at least $250 in each of your accounts), or setting up a Systematic Investment Plan. For more information, contact the Transfer Agent or your financial intermediary. The Transfer Agent's contact information (toll-free number and mailing addresses) as well as the Funds’ website address can be found at the beginning of the section Choosing a Share Class.

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The automatic sale of Fund shares in accounts under $250 and the annual minimum balance fee described above do not apply to shareholders of Class Adv, Class Inst2, Class Inst3 and Class R shares; shareholders holding their shares through financial intermediary networked accounts; wrap fee and omnibus accounts; accounts with active monthly Systematic Investment Plans; certain qualified retirement plans; and health savings accounts. The automatic sale of Fund shares of accounts under the applicable minimum account balance does not apply to individual retirement plans.

Specific Buying and Exchanging Limitations — If the Fund detects that an investor has made two “material round trips” in any 28-day period, it will generally reject the investor's future purchase orders, including exchange purchase orders, involving any Fund.

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These limits generally do not apply to automated transactions or transactions by registered investment companies in a “fund-of-funds” structure. These limits do not apply to payroll deduction contributions by retirement plan participants, transactions initiated by a retirement plan sponsor or certain other retirement plan transactions consisting of rollover transactions, loan repayments and disbursements, and required minimum distribution redemptions. They may be modified or rescinded for accounts held by certain retirement plans to conform to plan limits, for considerations relating to the Employee Retirement Income Security Act of 1974 or regulations of the Department of Labor, and for certain asset allocation or wrap programs. Accounts known to be under common ownership or control generally will be counted together, but accounts maintained or managed by a common intermediary generally will not be considered to be under common ownership or control. The Fund reserves the right to modify these restrictions at any time without prior notice to shareholders. In addition, the Fund may, in its sole discretion, reinstate trading privileges that have been revoked under the Fund's Excessive Trading Policies and Procedures.

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Fund shares can be held in a variety of ways. You can hold Fund shares through an account established and held through the financial intermediary through which you purchased Fund shares, or you or your financial intermediary can establish an account directly with the Fund, in which case you will receive Fund account transaction confirmations and statements from the Transfer Agent, and not your financial intermediary (Direct-at-Fund Accounts). Direct-at-Fund Accounts include accounts held at the Transfer Agent that do not or no longer have a financial intermediary assigned to them.

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Class C shares are available to the general public for investment, except that Direct-at-Fund Accounts that do not have a financial intermediary assigned to them are not permitted to purchase Class C shares; Class C share purchase orders received on or after such date from Direct-at-Fund Accounts that do not have a financial intermediary assigned to the account will automatically be invested in Class A shares of the same Fund.

Class Inst2 shares are available only to (i) certain registered investment advisers and family offices that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Inst2 eligibility apart from selling, servicing or similar agreements; (ii) omnibus retirement plans; (iii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst2 shares within such platform and that Fund shares are held in an omnibus account; and (iv) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst2 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst2 shares within such platform. Prior to November 8, 2012, Class Inst2

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Class Inst3 shares are available to: (i) group retirement plans that maintain plan-level or omnibus accounts with the Fund (through the Transfer Agent); (ii) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst3 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst3 shares within such platform; (iii) collective trust funds; (iv) affiliated or unaffiliated mutual funds (e.g., funds operating as funds-of-funds); (v) fee-based platforms of financial intermediaries (or the clearing intermediary that they trade through) that have an agreement with the Distributor or an affiliate thereof that specifically authorizes the financial intermediary to offer and/or service Class Inst3 shares within such platform, provided also that Fund shares are held in an omnibus account; (vi) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; (vii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; and (viii) bank trust departments, subject to an agreement with the Distributor that specifically authorizes offering Class Inst3 shares and provided that Fund shares are held in an omnibus account. In each case above where noted that Fund shares are required to be held in an omnibus account, the Distributor may, in its discretion, determine to waive this requirement.

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(b)

The minimum initial investment in Class Adv shares is $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) for commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customers, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Adv shares within such platform; for all other eligible Class Adv share investors (see Buying Shares – Eligible Investors – Class Adv Shares above), there is no minimum initial investment. The minimum initial investment amount for Class Inst shares is $0, $1,000 or $2,000 depending upon the category of eligible investor. See — Class Inst Shares Minimum Initial Investments below. The minimum initial investment amount for Systematic Investment Plan accounts is the same as the amount set forth in the first two rows of the table, as applicable.

(c)

There is no minimum initial investment in Class Inst3 shares for: group retirement plans that maintain plan-level or omnibus accounts with the Fund; collective trust funds; affiliated or unaffiliated mutual funds (e.g., funds operating as funds-of-funds); and fee -based platforms of financial intermediaries (or the clearing intermediary that they trade through) that have an agreement with the Distributor or an affiliate thereof that specifically authorizes the financial intermediary to offer and/or service Class Inst3 shares within such platform and Fund shares are held in an omnibus account. The minimum initial investment in Class Inst3 shares is $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) for commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and Fund shares are held in an omnibus account. The minimum initial investment in Class Inst3 shares is $1 million, unless waived in the discretion of the Distributor, for the following investors: institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst3 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst3 shares within such platform; and bank trust departments, subject to an agreement with the Distributor that specifically authorizes offering Class Inst3 shares and provided that Fund shares are held in an omnibus account. The Distributor may, in its discretion, waive the $1 million minimum initial investment required for these Class Inst3 investors. In each case above where noted that Fund shares are required to be held in an omnibus account, the Distributor, may, in its discretion, determine to waive this requirement.

Minimum investment and related requirements may be modified at any time, with or without prior notice. If your account is closed and then re-opened with a Systematic Investment Plan, your account must meet the then-current applicable minimum initial investment.

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55

The Systematic Investment Plan allows you to schedule regular purchases via automatic transfers from your bank account to the Fund on a monthly, quarterly or semiannual basis. Contact the Transfer Agent or your financial intermediary to set up the plan. Systematic Investment Plans may not be available for all share classes. With the exception of Columbia Government Money Market Fund, Systematic Investment Plan purchases will be confirmed on your quarterly account statement. Columbia Government Money Market Fund Systematic Investment Plan purchases will be confirmed at the time of the purchase. If establishing a Systematic Investment Plan to reduce the initial fund minimum, the plan needs to be established monthly to avoid the small account fee.

■	You generally may make a purchase only into a Fund that is accepting investments.

56	Prospectus 2022

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57

■

The Distributor, in its sole discretion, reserves the right to liquidate Fund shares (of any class of the Fund) held in an omnibus account of a financial intermediary that clears Fund share transactions through a clearing intermediary or platform that charges certain maintenance fees to the Fund if the value of the omnibus account, at the Fund share class (i.e., CUSIP) level, falls below $100,000 (a CUSIP Liquidation Event). The Distributor will provide at least 90 days’ notice of a CUSIP Liquidation Event to financial intermediaries with impacted omnibus accounts. Shareholders invested in the Fund through such omnibus accounts can request through their financial intermediary a tax-free exchange to Class A shares or shareholders can consider holding their Fund shares in a Direct-at-Fund Account, provided requirements to transfer the account are fulfilled. You should discuss your options with your financial intermediary.

58	Prospectus 2022

■

A sales charge may apply when you exchange shares of a Fund that were not assessed a sales charge at the time you purchased such shares. If you invest through a Direct-at-Fund Account in Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund, Columbia U.S. Treasury Index Fund or any other Columbia Fund that does not impose a front-end sales charge and then you exchange into a Fund that does assess a sales charge, your transaction is subject to a front-end sales charge if you exchange into Class A shares and to a CDSC if you exchange into Class C shares of the Columbia Funds.

■

If you purchased Class A shares of a Columbia Fund that imposes a front-end sales charge (and you paid any applicable sales charge) and you then exchange those shares into Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund, Columbia U.S. Treasury Index Fund or any other Columbia Fund that does not impose a front-end sales charge, you may exchange that amount to Class A of another Fund in the future, including dividends earned on that amount, without paying a sales charge.

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Exchanges out of Class C shares to another share class of the same Fund are not permissible on Direct-at-Fund Accounts, except that the Transfer Agent seeks to convert Class C shares as soon as administratively feasible to Class A shares of the same Fund for Direct-at-Fund Accounts that do not or no longer have a financial intermediary assigned to them. Direct-at-Fund Accounts that do not have a financial intermediary assigned to them are not permitted to purchase Class C shares. Class C share purchase orders received by Direct-at-Fund Accounts that do not have a financial intermediary assigned to the account will automatically be invested in Class A shares of the same Fund. Exchanges out of Class C shares to another share class of the same Fund within commissionable brokerage accounts are permitted only (1) when the shareholder moves from a commissionable brokerage account to a fee-based advisory program or (2) when the exchange is part of a share class conversion (or a similar multiple shareholder transaction event) instituted by a financial intermediary and such conversion or similar type event is preapproved by the Distributor.

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Distributions to Shareholders

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61

■

Distributions of the Fund's ordinary income and net short-term capital gain, if any, generally are taxable to you as ordinary income. Distributions of the Fund's net long-term capital gain, if any, generally are taxable to you as long-term capital gain. Whether capital gains are long-term or short-term is determined by how long the Fund has owned the investments that generated them, rather than how long you have owned your shares. Certain events may require the Fund to sell significant amounts of appreciated securities, and make large capital gain dividends relative to the Fund’s NAV. Such events may include large net shareholder redemptions, portfolio re-balancing or fund mergers. The Fund generally provides estimates of expected capital gain dividends (if any) prior to the distribution on columbiathreadneedleus.com.

62	Prospectus 2022

Taxes

The information provided above is only a summary of how U.S. federal income taxes may affect your investment in the Fund. It is not intended as a substitute for careful tax planning. Your investment in the Fund may have other tax implications. It does not apply to certain types of investors who may be subject to special rules, including foreign or tax-exempt investors or those holding Fund shares through a tax-advantaged account, such as a 401(k) plan or IRA. Please see the SAI for more detailed tax information. You should consult with your own tax advisor about the particular tax consequences to you of an investment in the Fund, including the effect of any foreign, state and local taxes, and the effect of possible changes in applicable tax laws.

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The financial highlights table is intended to help you understand the Fund’s financial performance for the past five fiscal years. Certain information reflects financial results for a single Fund share. Per share net investment income (loss) amounts are calculated based on average shares outstanding during the period. The total return in the table represents the rate that an investor would have earned (or lost) on an investment in the Fund assuming all dividends and distributions had been reinvested. Total return does not reflect payment of sales charges, if any. Total return and portfolio turnover are not annualized for periods of less than one year. The portfolio turnover rate is calculated without regard to purchase and sales transactions of short-term instruments and certain derivatives, if any. If such transactions were included, the Fund’s portfolio turnover rate might be higher. The names of certain share classes may have changed during the periods shown below (see Appendix S to the SAI for details). This information has been audited by PricewaterhouseCoopers LLP, an independent registered public accounting firm, whose report, along with the Fund’s financial statements, is included in the Fund’s annual report, which is available upon request. The independent registered public accounting firm’s report and the Fund’s financial statements are also incorporated by reference into the SAI.

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65

	Net asset value, beginning of period	Net investment income (loss)	Net realized and unrealized gain (loss)	Total from investment operations	Distributions from net investment income	Distributions from net realized gains	Total distributions to shareholders
Class A
Year Ended 12/31/2021	$34.31	0.01	4.08	4.09	(0.38)	(4.83)	(5.21)
Year Ended 12/31/2020	$34.20	0.06	4.51	4.57	(0.20)	(4.26)	(4.46)
Year Ended 12/31/2019	$29.48	0.25	8.19	8.44	(0.65)	(3.07)	(3.72)
Year Ended 12/31/2018	$46.51	0.23	(7.41)	(7.18)	(0.29)	(9.56)	(9.85)
Year Ended 12/31/2017	$37.71	0.25	11.71	11.96	(0.67)	(2.49)	(3.16)
Advisor Class
Year Ended 12/31/2021	$34.95	0.05	4.20	4.25	(0.55)	(4.83)	(5.38)
Year Ended 12/31/2020	$34.67	0.16	4.58	4.74	(0.20)	(4.26)	(4.46)
Year Ended 12/31/2019	$29.84	0.33	8.30	8.63	(0.73)	(3.07)	(3.80)
Year Ended 12/31/2018	$46.95	0.46	(7.61)	(7.15)	(0.40)	(9.56)	(9.96)
Year Ended 12/31/2017	$38.03	0.36	11.82	12.18	(0.77)	(2.49)	(3.26)
Class C
Year Ended 12/31/2021	$31.43	(0.24)	3.72	3.48	(0.01)	(4.83)	(4.84)
Year Ended 12/31/2020	$31.92	(0.17)	4.14	3.97	(0.20)	(4.26)	(4.46)
Year Ended 12/31/2019	$27.63	0.00(e)	7.65	7.65	(0.29)	(3.07)	(3.36)
Year Ended 12/31/2018	$44.57	(0.05)	(7.09)	(7.14)	(0.24)	(9.56)	(9.80)
Year Ended 12/31/2017	$36.18	(0.06)	11.20	11.14	(0.26)	(2.49)	(2.75)
Institutional Class
Year Ended 12/31/2021	$34.47	0.10	4.09	4.19	(0.55)	(4.83)	(5.38)
Year Ended 12/31/2020	$34.25	0.14	4.54	4.68	(0.20)	(4.26)	(4.46)
Year Ended 12/31/2019	$29.51	0.33	8.21	8.54	(0.73)	(3.07)	(3.80)
Year Ended 12/31/2018	$46.57	0.34	(7.44)	(7.10)	(0.40)	(9.56)	(9.96)
Year Ended 12/31/2017	$37.74	0.37	11.73	12.10	(0.78)	(2.49)	(3.27)
Institutional 2 Class
Year Ended 12/31/2021	$34.46	0.12	4.09	4.21	(0.59)	(4.83)	(5.42)
Year Ended 12/31/2020	$34.22	0.16	4.54	4.70	(0.20)	(4.26)	(4.46)
Year Ended 12/31/2019	$29.49	0.35	8.20	8.55	(0.75)	(3.07)	(3.82)
Year Ended 12/31/2018	$46.54	0.37	(7.43)	(7.06)	(0.43)	(9.56)	(9.99)
Year Ended 12/31/2017	$37.72	0.38	11.72	12.10	(0.79)	(2.49)	(3.28)
Institutional 3 Class
Year Ended 12/31/2021	$34.99	0.15	4.14	4.29	(0.62)	(4.83)	(5.45)
Year Ended 12/31/2020	$34.67	0.19	4.59	4.78	(0.20)	(4.26)	(4.46)
Year Ended 12/31/2019	$29.83	0.37	8.30	8.67	(0.76)	(3.07)	(3.83)
Year Ended 12/31/2018	$46.95	0.51	(7.62)	(7.11)	(0.45)	(9.56)	(10.01)
Year Ended 12/31/2017	$38.02	0.40	11.83	12.23	(0.81)	(2.49)	(3.30)
Class R
Year Ended 12/31/2021	$34.24	(0.08)	4.07	3.99	(0.21)	(4.83)	(5.04)
Year Ended 12/31/2020	$34.22	(0.01)	4.49	4.48	(0.20)	(4.26)	(4.46)
Year Ended 12/31/2019	$29.44	0.06	8.27	8.33	(0.48)	(3.07)	(3.55)
Year Ended 12/31/2018	$46.51	0.12	(7.39)	(7.27)	(0.24)	(9.56)	(9.80)
Year Ended 12/31/2017	$37.71	0.21	11.63	11.84	(0.55)	(2.49)	(3.04)

Notes to Financial Highlights
(a)	In addition to the fees and expenses that the Fund bears directly, the Fund indirectly bears a pro rata share of the fees and expenses of any other funds in which it invests, if any. Such indirect expenses are not included in the Fund's reported expense ratios.
(b)	Had the Investment Manager and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.
(c)	The benefits derived from expense reductions had an impact of less than 0.01%.
(d)	Ratios include line of credit interest expense which is less than 0.01%.
(e)	Rounds to zero.

66	Prospectus 2022

	Net asset value, end of period	Total return	Total gross expense ratio to average net assets(a)	Total net expense ratio to average net assets(a)	Net investment income (loss) ratio to average net assets	Portfolio turnover	Net assets, end of period (000's)
Class A
Year Ended 12/31/2021	$33.19	12.63% (b)	1.24%	1.23% (c)	0.03%	27%	$282,125
Year Ended 12/31/2020	$34.31	14.68% (b)	1.28% (d)	1.24% (c), (d)	0.21%	55%	$283,478
Year Ended 12/31/2019	$34.20	29.56% (b)	1.27% (d)	1.24% (c), (d)	0.76%	32%	$307,872
Year Ended 12/31/2018	$29.48	(16.13%) (b)	1.25% (d)	1.24% (c), (d)	0.51%	32%	$296,349
Year Ended 12/31/2017	$46.51	31.91%	1.23%	1.20% (c)	0.56%	37%	$465,830
Advisor Class
Year Ended 12/31/2021	$33.82	12.88% (b)	0.99%	0.98% (c)	0.14%	27%	$9,279
Year Ended 12/31/2020	$34.95	14.98% (b)	1.03% (d)	0.99% (c), (d)	0.52%	55%	$22,549
Year Ended 12/31/2019	$34.67	29.86% (b)	1.02% (d)	0.99% (c), (d)	1.00%	32%	$12,733
Year Ended 12/31/2018	$29.84	(15.90%) (b)	1.00% (d)	0.99% (c), (d)	0.97%	32%	$12,740
Year Ended 12/31/2017	$46.95	32.21%	0.98%	0.98% (c)	0.81%	37%	$99,578
Class C
Year Ended 12/31/2021	$30.07	11.76% (b)	1.99%	1.98% (c)	(0.74%)	27%	$10,687
Year Ended 12/31/2020	$31.43	13.82% (b)	2.02% (d)	1.99% (c), (d)	(0.57%)	55%	$19,998
Year Ended 12/31/2019	$31.92	28.61% (b)	2.02% (d)	2.00% (c), (d)	0.01%	32%	$18,749
Year Ended 12/31/2018	$27.63	(16.76%) (b)	2.00% (d)	1.99% (c), (d)	(0.11%)	32%	$22,817
Year Ended 12/31/2017	$44.57	30.93%	1.98%	1.97% (c)	(0.15%)	37%	$63,787
Institutional Class
Year Ended 12/31/2021	$33.28	12.89% (b)	0.99%	0.98% (c)	0.28%	27%	$1,727,042
Year Ended 12/31/2020	$34.47	14.99% (b)	1.03% (d)	0.99% (c), (d)	0.46%	55%	$1,760,927
Year Ended 12/31/2019	$34.25	29.89% (b)	1.02% (d)	0.99% (c), (d)	1.01%	32%	$1,947,995
Year Ended 12/31/2018	$29.51	(15.93%) (b)	1.00% (d)	0.99% (c), (d)	0.76%	32%	$1,824,055
Year Ended 12/31/2017	$46.57	32.24%	0.98%	0.98% (c)	0.85%	37%	$3,116,383
Institutional 2 Class
Year Ended 12/31/2021	$33.25	12.97% (b)	0.95%	0.92%	0.34%	27%	$126,973
Year Ended 12/31/2020	$34.46	15.06% (b)	0.97% (d)	0.92% (d)	0.53%	55%	$129,576
Year Ended 12/31/2019	$34.22	29.95% (b)	0.97% (d)	0.93% (d)	1.06%	32%	$183,763
Year Ended 12/31/2018	$29.49	(15.85%) (b)	0.93% (d)	0.93% (d)	0.81%	32%	$160,488
Year Ended 12/31/2017	$46.54	32.27%	0.93%	0.93%	0.87%	37%	$422,916
Institutional 3 Class
Year Ended 12/31/2021	$33.83	13.00% (b)	0.90%	0.88%	0.40%	27%	$179,991
Year Ended 12/31/2020	$34.99	15.10% (b)	0.93% (d)	0.88% (d)	0.60%	55%	$277,614
Year Ended 12/31/2019	$34.67	30.04% (b)	0.92% (d)	0.89% (d)	1.12%	32%	$239,441
Year Ended 12/31/2018	$29.83	(15.82%) (b)	0.88% (d)	0.88% (d)	1.10%	32%	$198,933
Year Ended 12/31/2017	$46.95	32.36%	0.88%	0.88%	0.89%	37%	$725,247
Class R
Year Ended 12/31/2021	$33.19	12.34% (b)	1.49%	1.48% (c)	(0.22%)	27%	$3,691
Year Ended 12/31/2020	$34.24	14.40% (b)	1.53% (d)	1.49% (c), (d)	(0.04%)	55%	$3,398
Year Ended 12/31/2019	$34.22	29.21% (b)	1.52% (d)	1.50% (c), (d)	0.19%	32%	$3,696
Year Ended 12/31/2018	$29.44	(16.32%) (b)	1.50% (d)	1.49% (c), (d)	0.26%	32%	$10,049
Year Ended 12/31/2017	$46.51	31.58%	1.49%	1.48% (c)	0.46%	37%	$13,218

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As noted in the Choosing a Share Class section of the prospectus, the sales charge reductions and waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. This Appendix A describes financial intermediary-specific reductions and/or waiver policies applicable to Fund shares purchased and held through the particular financial intermediary. A reduction and/or waiver that is specific to a particular financial intermediary is not available to Direct-at-Fund Accounts and does not apply in any case to non-omnibus positions wherever held. These reductions and/or waivers may apply to purchases, sales, and exchanges of Fund shares. A shareholder transacting in Fund shares through a financial intermediary identified below should carefully read the terms and conditions of the reductions and/or waivers. Please consult your financial intermediary with respect to any sales charge reduction/waiver described below.

■

Shares exchanged from Class C shares of the same fund in the month of or following the 7-year anniversary of the purchase date. To the extent that the Fund’s Class C Shares – Conversion to Class A Shares policy (stated outside this Appendix A) provides for a waiver with respect to exchanges of Class C shares or the conversion of Class C shares following a shorter holding period, that waiver will apply.

A-1	Prospectus 2022

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A-2

A-3	Prospectus 2022

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A-4

A-5	Prospectus 2022

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A-6

Effective July 1, 2018, shareholders purchasing Columbia Fund shares through a Morgan Stanley Wealth Management transactional brokerage account will be eligible only for the following front-end sales charge waivers with respect to Class A shares, which may differ from and may be more limited than those disclosed elsewhere in this prospectus or the Fund’s SAI.

Front-End Sales Charge Waivers on Class A Shares Available at Morgan Stanley Wealth Management Effective July 1, 2018:

■	Employer-sponsored retirement plans (e.g., 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans).  For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs, SAR-SEPs or Keogh plans.
■	Morgan Stanley employee and employee-related accounts according to Morgan Stanley’s account linking rules.
■	Shares purchased through reinvestment of dividends and capital gains distributions when purchasing shares of the same fund.
■	Shares purchased through a Morgan Stanley self-directed brokerage account.
■	Class C (i.e., level-load) shares that are no longer subject to a CDSC and are exchanged for Class A shares of the same fund pursuant to Morgan Stanley Wealth Management’s share class exchange program.
■	Shares purchased from the proceeds of redemptions from another Columbia Fund, provided (i) the repurchase occurs within 90 days following the redemption, (ii) the redemption and purchase occur in the same account, and (iii) redeemed shares were subject to a front-end or deferred sales charge.

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A-8

 U.S. Bancorp Investments, Inc. (USBI)

The following information has been provided by USBI:

Effective September of 2021, shareholders purchasing Columbia Fund shares through a USBI platform or who own shares for which USBI is the broker-dealer, where the shares are held in an omnibus account, will only be eligible for the following front-end sales charge waivers and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI.

All other sales charge waivers and reduction described elsewhere in this prospectus or the Fund’s SAI still apply.

USBI Conversion of Class C shares

Class C (i.e., level-load) shares that are no longer subject to a contingent deferred sales charge are systematically converted to the Class A shares of the same fund pursuant to USBI’s share class exchange policy.

A-9	Prospectus 2022

Columbia Threadneedle Investments is the global brand name of the Columbia and Threadneedle group of companies.
The Fund is distributed by Columbia Management Investment Distributors, Inc., 290 Congress Street, Boston, MA 02210.

© 2022 Columbia Management Investment Advisers, LLC. All rights reserved.

PRO111_12_M01_(05/22)