Columbia Funds Series Trust I

Investment Objective

Columbia Adaptive Retirement 2055 Fund (the 2055 Fund or the Fund) seeks capital appreciation and current income.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. An investor transacting in a class of Fund shares without any front-end sales charge, contingent deferred sales charge, or other asset-based fee for sales or distribution may be required to pay a commission to the financial intermediary for effecting such transactions. Such commission rates are set by the financial intermediary and are not reflected in the tables or the example below.

Shareholder Fees (fees paid directly from your investment)
	Class Adv	Class Inst3
Maximum sales charge (load) imposed on purchases	None	None
Maximum deferred sales charge (load) imposed on redemptions	None	None

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
	Class Adv	Class Inst3
Management fees	0.45%	0.45%
Distribution and/or service (12b-1) fees	0.00%	0.00%
Other expenses^(a)	8.28%	8.07%
Acquired fund fees and expenses^(b)	0.06%	0.06%
Total annual Fund operating expenses	8.79%	8.58%
Less: Fee waivers and/or expense reimbursements^(c)	(8.11%)	(8.08%)
Total annual Fund operating expenses after fee waivers and/or expense reimbursements	0.68%	0.50%

(a)	Other expenses are based on estimated amounts for the Fund's current fiscal year.
(b)	Acquired fund fees and expenses are based on estimated amounts for the Fund's current fiscal year.
(c)	Columbia Management Investment Advisers, LLC and certain of its affiliates have contractually agreed to waive fees and/or to reimburse expenses (excluding transaction costs and certain other investment related expenses, interest, taxes, and infrequent and/or unusual expenses) through July 31, 2021, unless sooner terminated at the sole discretion of the Fund’s Board of Trustees. Under this agreement, the Fund’s net operating expenses, subject to applicable exclusions, will not exceed the annual rates of 0.68% for Class Adv and 0.50% for Class Inst3.

Example

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

■	you invest $10,000 in the applicable class of Fund shares for the periods indicated,
■	your investment has a 5% return each year, and
■	the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above.

Since the waivers and/or reimbursements shown in the Annual Fund Operating Expenses table above expire as indicated in the preceding table, they are reflected in the 1 year example and the 3 year example. Although your actual costs may be higher or lower, based on the assumptions listed above, your costs (based on estimated Fund expenses) would be:

	1 year	3 years
Class Adv (whether or not shares are redeemed)	$69	$218
Class Inst3 (whether or not shares are redeemed)	$51	$160

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Portfolio Turnover

The Fund, underlying funds and exchange-traded funds (ETFs) pay transaction costs, such as commissions, when they buy and sell securities (or “turn over” their portfolios). The Fund will indirectly bear the expenses associated with portfolio turnover of the underlying funds and ETFs. A high portfolio turnover rate may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. Because the Fund is newly organized, portfolio turnover information is not available as of the date of this prospectus.

Principal Investment Strategies

Columbia Management Investment Advisers, LLC (the Investment Manager) manages the Fund using an adaptive risk allocation methodology. The Investment Manager employs quantitative and fundamental methods to identify distinct market states (capital preservation, neutral, bullish and highly bullish) and creates a strategic risk allocation to four broad asset categories (equity securities, fixed income securities issued by governments (rate assets), other fixed income securities (spread assets) and inflation-hedging assets) for each market state that is intended to generate attractive risk-adjusted returns in that market state. Allocations of risk to asset classes may differ significantly across market states. In addition to strategic risk allocations based on the market state, the Investment Manager may make tactical adjustments within and among asset classes and pursue opportunistic strategies in response to changing market, economic or other conditions. For these purposes, risk is the expected volatility (i.e., dispersion of returns) of a security, market, index or asset class, as determined by the Investment Manager.

The Investment Manager allocates the Fund’s risk across global asset classes by reference to a specified “Target Date” (the year referenced in the name of the Fund), and periodically (generally monthly) reallocates risk across these asset classes as market or other conditions change, in an effort to provide capital appreciation and current income consistent with retirement as of the Target Date. As a general matter, the Fund’s overall risk allocation is determined by the Fund’s proximity to its Target Date, with an expectation that the further away the Target Date, the greater the Fund’s exposure to assets with greater expected risk, such as equities, that historically have tended to provide higher return potential relative to asset classes with historically less risk, such as fixed income securities. As time passes, and the Target Date nears, the expectation is that the Fund’s overall risk allocation will become more conservative. Fund risk allocations are managed up to and 25 years beyond the Target Date, and this gradual transition toward historically lower-risk assets over time is known as the “glide path.” Approximately 25 years past the Target Date (the Landing Point), the asset allocation for each market state will become static although the Investment Manager will continue to assess market states and adjust the Fund’s asset allocation in accordance with the glide path for the applicable market state and may make tactical allocation changes as well.

The charts below show the Fund’s expected economic exposure (including leverage) to each of four broad asset categories. As the charts illustrate, the Fund’s economic exposure to the asset categories varies based on the current market state and proximity to the applicable Target Date. The Fund may utilize leverage within certain asset classes and during certain market states in order to maintain attractive expected risk-adjusted returns while adhering to the risk allocation framework. The charts also show that, for each market state, the Fund’s total economic exposure is expected to decline over time, although changes in the Investment Manager’s assessment of the market state may cause the Fund’s actual economic exposure to increase relative to its historical exposure at a time when the Investment Manager’s assessment of the market state was more conservative. The Investment Manager anticipates that the Fund’s net notional investment exposure will be approximately 175% of the net assets of the Fund in the neutral market state, although leverage may be higher or lower in other market states or when the Investment Manager otherwise believes conditions so warrant. A Fund’s actual allocations may differ from the glide path when the Investment Manager makes tactical asset allocation changes. The Investment Manager intends to review the glide paths at least annually and may adjust the glide paths or change its asset categories or classes at any time.

Columbia Adaptive Retirement 2055 Fund

Neutral Glide Path		Bullish Glide Path

Capital Preservation Glide Path		Highly Bullish Glide Path

Although the Target Date is not intended to represent the retirement or other investment goal year of any specific investor, it is a factor in the construction of the glide path. The Investment Manager expects that most investors in the Fund plan to retire on or about the Target Date and that many investors will cease making new investments in the Fund and begin withdrawing from their accounts on or about the Target Date. The Board of Trustees of the Fund has the authority to combine the Fund with another Columbia Adaptive Retirement Fund once a Fund has reached its Landing Point, without obtaining shareholder approval.

The Fund is non-diversified, which means that it can invest a greater percentage of its assets in the securities of fewer issuers than can a diversified fund.

Investment in Underlying Funds

Under normal circumstances, the Fund will gain exposure to equity securities, rate assets, spread assets and inflation-hedging assets by investing in affiliated and unaffiliated funds (Underlying Funds). The glide paths shown above reflect the indirect exposure to the four asset categories gained through investment in the Underlying Funds.

Under normal circumstances, the Investment Manager expects that approximately 80% of each Fund’s net assets will be invested in Columbia Solutions Aggressive Portfolio and Columbia Solutions Conservative Portfolio (the Solutions Series Funds), two mutual funds managed by the Investment Manager through which the Fund expects to gain the desired amount of leverage regarding each of the asset categories. As illustrated in the glide path below, each Fund’s investment in the Solution Series Funds will transition over time, with investments in Columbia Solutions Aggressive Portfolio continuing to decrease until approximately 25 years after the Target Date, the entire 80% of the Fund invested in the Solution Series Funds will be allocated to Columbia Solutions Conservative Portfolio. Under normal

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circumstances, Columbia Solutions Aggressive Portfolio will have more leverage and exposure to equity securities than Columbia Solutions Conservative Portfolio; in certain market states, these differences between these two Funds may be substantial.

Under normal circumstances, the Investment Manager expects that approximately 20% of each Fund’s net assets will be invested in other mutual funds and ETFs. Currently, the Investment Manager intends to invest this portion of the Fund in Columbia Commodity Strategy Fund, a mutual fund managed by the Investment Manager, and third party ETFs. The Investment Manager can modify the list of Underlying Funds and types of instruments in which the Fund invests, or the asset categories, at any time, without the approval of or notice to Fund shareholders, including by adding Underlying Funds introduced after the date of this prospectus.

Summary of the Principal Investment Strategies of the Solution Series Funds

The Solutions Series Funds (referred to together as the Fund) are non-diversified funds that pursue consistent total returns by seeking to allocate risks across multiple asset classes.

Under normal circumstances, the Fund pursues its investment objective by allocating portfolio risk across multiple asset classes in U.S. and non-U.S. markets with the goal of generating consistent risk-adjusted returns. The Investment Manager employs the same methods described above for the Columbia Adaptive Retirement Funds to identify market states and create a strategic risk allocation for each state and to make tactical allocations.

The Investment Manager may use a variety of security and instrument types to gain exposure to equity securities, inflation-hedging assets and fixed income securities. The equity securities in which the Fund may invest include direct or indirect investments in common stocks, preferred stocks and convertible securities. The inflation-hedging assets in which the Fund may invest include direct or indirect investments in inflation-linked bonds and real estate investment trusts. The fixed-income assets in which the Fund may invest include direct and indirect investments in corporate bonds, securities in the to-be-announced market, dollar rolls, exchange-traded notes (including both leveraged and inverse notes), sovereign debt obligations (including emerging market sovereign debt obligations), U.S. Government securities, repurchase agreements and reverse repurchase agreements. These securities or instruments may be issued by U.S. or non-U.S. entities (including issuers in emerging market countries) and they may have any maturity or credit rating. The Fund may also invest in currencies. Although the Fund may invest directly in these securities and instruments, it is expected that the Fund will primarily gain exposure to such securities and instruments through derivatives. The Investment Manager will determine, in its discretion, the categorization of any investment (or portion thereof) within one or more of the general asset class categories.

The Fund may invest in derivatives, such as forward contracts, futures and swaps for both hedging and non-hedging purposes, including, for example, seeking to enhance returns or as a substitute for a position in an underlying asset. The Fund may invest in derivatives to manage the Fund's overall risk exposure. The Fund also expects to use derivatives to obtain leverage (market exposure in excess of the Fund’s assets). The Fund may utilize leverage within certain asset classes and during certain market states in order to maintain attractive expected risk-adjusted returns while adhering to the Fund's risk allocation framework. The Investment Manager anticipates that Columbia Solutions Aggressive Portfolio’s net notional investment exposure will be approximately 199% of the net assets of the Fund and approximately 80% of the portfolio invested in equities in the market state that the Investment Manager expects to be the most frequent, although leverage and the level of equity investment will vary in other market states or when the Investment Manager otherwise believes conditions warrant. The Investment Manager does not currently anticipate that Columbia Solutions Conservative Portfolio will be significantly leveraged and expects the portfolio to be invested approximately 20% in equities in the market state that the Investment Manager expects to be the most frequent.

The Fund may also take short positions, for hedging or investment purposes.

Columbia Adaptive Retirement 2055 Fund

The Fund may invest in privately placed and other securities or instruments that are purchased and sold pursuant to Rule 144A or other exemptions under the Securities Act of 1933, as amended, subject to liquidity determinations and certain regulatory restrictions.

The Fund may hold a significant amount of cash, money market instruments (which may include investments in one or more affiliated or unaffiliated money market funds or similar vehicles), other high-quality, short-term investments, or other liquid assets for investment purposes or to meet its segregation obligations as a result of its investments in derivatives. In certain market conditions, the Fund may have no market positions (i.e., the Fund may hold only cash and cash equivalents) when the Investment Manager believes it is in the best interests of the Fund.

The Fund’s investment strategy may involve the frequent trading of portfolio securities.

Principal Risks

An investment in the Fund involves risks, including specific risks relating to the investment in the Fund based on its investment process and its "fund-of-funds" structure, as well as specific risks related to the underlying funds in which it invests that in the aggregate are principal risks to the Fund, including among others, those described below. More information about underlying funds, including their principal risks, is available in their prospectuses, which are incorporated by reference into this prospectus. This prospectus is not an offer for any of the underlying funds. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Active Management Risk. While security selection is driven by fundamental concepts, a quantitative process is used to construct the portfolio. Additionally, a qualitative review of the quantitative output is conducted by the portfolio managers. Therefore, the Fund’s performance will reflect, in part, the ability of the portfolio managers to make active, qualitative decisions, including allocation decisions that seek to achieve the Fund’s investment objective. The Fund could underperform its benchmark index and/or other funds with similar investment objectives and/or strategies.

Allocation Risk. The Fund uses asset and risk allocation strategies in pursuit of its investment objective. There is a risk that the Fund’s allocation among asset classes or investments will cause the Fund’s shares to lose value or cause the Fund to underperform other funds with similar investment objectives and/or strategies, or that the investments themselves will not produce the returns expected. Although the Fund will pursue its objective by allocating investment risks (measured by volatility expectations) across asset classes that may react differently to various environments, there is no guarantee that it will be successful. The portfolio managers may not correctly estimate expected returns, volatility and correlations of various asset classes, causing the Fund’s risk allocation methodology to fail to meet the Fund’s investment objective.

Commodity Futures Trading Commission (CFTC) Regulatory Risk. Columbia Solutions Aggressive Portfolio does not qualify for an exemption from registration as a “commodity pool” under rules of the Commodity Exchange Act (the CEA). Accordingly, the Fund is a commodity pool under the CEA and the Investment Manager is registered as a “commodity pool operator” under the CEA. The Fund is subject to dual regulation by the SEC and the CFTC. Compliance with the CFTC’s regulatory requirements could increase Fund expenses, adversely affecting the Fund's total return.

Commodity-related Investment Risk. The value of commodities investments will generally be affected by overall market movements and factors specific to a particular industry or commodity, which may include demand for the commodity, weather, embargoes, tariffs, and economic health, political, international, regulatory and other developments. Exposure to commodities and commodities markets may subject the value of the Fund’s investments to greater volatility than other types of investments. Commodities investments may also subject the Fund to counterparty risk and liquidity risk. The Fund may invest in one or more underlying funds that make commodity-related investments through one or more wholly-owned subsidiaries organized outside the U.S. that are generally not subject to U.S. laws (including securities laws) and their protections.

Counterparty Risk. Counterparty risk is the risk that a counterparty to a transaction in a financial instrument held by the Fund or by a special purpose or structured vehicle invested in by the Fund may become insolvent or otherwise fail to perform its obligations. As a result, the Fund may obtain no or limited recovery of its investment, and any recovery may be significantly delayed.

Credit Risk. Credit risk is the risk that the value of debt instruments may decline if the issuer thereof defaults or otherwise becomes unable or unwilling, or is perceived to be unable or unwilling, to honor its financial obligations, such as making payments to the Fund when due. Rating agencies assign credit ratings to certain debt instruments to indicate their credit risk. Unless otherwise provided in the Fund’s Principal Investment Strategies, investment grade

5	Columbia Adaptive Retirement 2055 Fund

debt instruments are those rated at or above BBB- by S&P Global Ratings, or equivalently rated by Moody’s Investors Service, Inc. or Fitch, Inc., or, if unrated, determined by the management team to be of comparable quality. Conversely, below investment grade (commonly called “high-yield” or “junk”) debt instruments are those rated below BBB- by S&P Global Ratings, or equivalently rated by Moody’s Investors Service, Inc. or Fitch, Inc., or, if unrated, determined by the management team to be of comparable quality. A rating downgrade by such agencies can negatively impact the value of such instruments. Lower quality or unrated instruments held by the Fund may present increased credit risk as compared to higher-rated instruments. Non-investment grade debt instruments may be subject to greater price fluctuations and are more likely to experience a default than investment grade debt instruments and therefore may expose the Fund to increased credit risk. If the Fund purchases unrated instruments, or if the ratings of instruments held by the Fund are lowered after purchase, the Fund will depend on analysis of credit risk more heavily than usual.

Derivatives Risk. Derivatives may involve significant risks. Derivatives are financial instruments with a value in relation to, or derived from, the value of an underlying asset(s) or other reference, such as an index, rate or other economic indicator (each an underlying reference). Derivatives may include those that are privately placed or otherwise exempt from SEC registration, including certain Rule 144A eligible securities. Derivatives could result in Fund losses if the underlying reference does not perform as anticipated. Use of derivatives is a highly specialized activity that can involve investment techniques, risks, and tax planning different from those associated with more traditional investment instruments. The Fund’s derivatives strategy may not be successful and use of certain derivatives could result in substantial, potentially unlimited, losses to the Fund regardless of the Fund’s actual investment. A relatively small movement in the price, rate or other economic indicator associated with the underlying reference may result in substantial loss for the Fund. Derivatives may be more volatile than other types of investments. The value of derivatives may be influenced by a variety of factors, including national and international political and economic developments. Potential changes to the regulation of the derivatives markets may make derivatives more costly, may limit the market for derivatives, or may otherwise adversely affect the value or performance of derivatives. Derivatives can increase the Fund’s risk exposure to underlying references and their attendant risks, such as credit risk, market risk, foreign currency risk and interest rate risk, while exposing the Fund to correlation risk, counterparty risk, hedging risk, leverage risk, liquidity risk, pricing risk and volatility risk.

Derivatives Risk – Forward Contracts Risk. A forward contract is an over-the-counter derivative transaction between two parties to buy or sell a specified amount of an underlying reference at a specified price (or rate) on a specified date in the future. Forward contracts are negotiated on an individual basis and are not standardized or traded on exchanges. The market for forward contracts is substantially unregulated and can experience lengthy periods of illiquidity, unusually high trading volume and other negative impacts, such as political intervention, which may result in volatility or disruptions in such markets. A relatively small price movement in a forward contract may result in substantial losses to the Fund, exceeding the amount of the margin paid. Forward contracts can increase the Fund’s risk exposure to underlying references and their attendant risks, such as credit risk, market risk, foreign currency risk and interest rate risk, while also exposing the Fund to correlation risk, counterparty risk, hedging risk, leverage risk, liquidity risk, pricing risk and volatility risk.

Derivatives Risk – Futures Contracts Risk. A futures contract is an exchange-traded derivative transaction between two parties in which a buyer (holding the “long” position) agrees to pay a fixed price (or rate) at a specified future date for delivery of an underlying reference from a seller (holding the “short” position). The seller hopes that the market price on the delivery date is less than the agreed upon price, while the buyer hopes for the contrary. Certain futures contract markets are highly volatile, and futures contracts may be illiquid. Futures exchanges may limit fluctuations in futures contract prices by imposing a maximum permissible daily price movement. The Fund may be disadvantaged if it is prohibited from executing a trade outside the daily permissible price movement. At or prior to maturity of a futures contract, the Fund may enter into an offsetting contract and may incur a loss to the extent there has been adverse movement in futures contract prices. The liquidity of the futures markets depends on participants entering into offsetting transactions rather than making or taking delivery. To the extent participants make or take delivery, liquidity in the futures market could be reduced. Because of the low margin deposits normally required in futures trading, it is possible that the Fund may employ a high degree of leverage in the portfolio. As a result, a relatively small price movement in a futures contract may result in substantial losses to the Fund, exceeding the amount of the margin paid. For certain types of futures contracts, losses are potentially unlimited. Futures markets are highly volatile and the use of futures may increase the volatility of the Fund’s NAV. Futures contracts executed (if any) on foreign exchanges may not provide the same protection as U.S. exchanges. Futures contracts can increase the Fund’s risk exposure to underlying references and their attendant risks, such as credit risk, market risk, foreign currency risk and interest rate risk, while also exposing the Fund to correlation risk, counterparty risk, hedging risk, leverage risk, liquidity risk, pricing risk and volatility risk.

Columbia Adaptive Retirement 2055 Fund

Derivatives Risk – Swaps Risk. In a typical swap transaction, two parties agree to exchange the return earned on a specified underlying reference for a fixed return or the return from another underlying reference during a specified period of time. Swaps may be difficult to value and may be illiquid. Swaps could result in Fund losses if the underlying asset or reference does not perform as anticipated. Swaps create significant investment leverage such that a relatively small price movement in a swap may result in immediate and substantial losses to the Fund. The Fund may only close out a swap with its particular counterparty, and may only transfer a position with the consent of that counterparty. Certain swaps, such as short swap transactions and total return swaps, have the potential for unlimited losses, regardless of the size of the initial investment. Swaps can increase the Fund’s risk exposure to underlying references and their attendant risks, such as credit risk, market risk, foreign currency risk and interest rate risk, while also exposing the Fund to correlation risk, counterparty risk, hedging risk, inflation risk, leverage risk, liquidity risk, pricing risk and volatility risk.

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 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, and some have a higher risk of currency devaluations.

Exchange-Traded Fund (ETF) Risk. Investments in ETFs have unique characteristics, including, but not limited to, the expense structure and additional expenses associated with investing in ETFs. ETFs are subject to, among other risks, tracking risk and passive and, in some cases, active investment risk. In addition, shareholders bear both their proportionate share of the Fund’s expenses, and indirectly the ETF’s expenses, incurred through the Fund’s ownership of the ETF. Because the expenses and costs of an underlying ETF are shared by its investors, redemptions by other investors in the ETF could result in decreased economies of scale and increased operating expenses for such ETF. The ETFs may not achieve their investment objective. The Fund, through its investment in ETFs, may not achieve its investment objective.

Foreign Currency-Related Tax Risk. The Internal Revenue Service might issue regulations treating gains from some of the Fund’s foreign currency-denominated positions as not “qualifying income” and there is a possibility that such regulations might be applied retroactively, in which case, the Fund might not qualify as a regulated investment company for one or more years. In the event the Internal Revenue Service issues such regulations, the Fund’s Board may authorize a significant change in investment strategy or the Fund’s liquidation.

Foreign Securities Risk. Investments in or exposure to foreign securities involve certain risks not associated with investments in or exposure to securities of U.S. companies. Foreign securities subject the Fund to the risks associated with investing in the particular country of an issuer, including political, regulatory, economic, social, diplomatic and other conditions or events (including, for example, military confrontations, war and terrorism), occurring in the country or region, as well as risks associated with less developed custody and settlement practices. Foreign securities may be more volatile and less liquid than securities of U.S. companies, and are subject to the risks associated with potential imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country. 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.

Forward Commitments on Mortgage-Backed Securities (including Dollar Rolls) Risk. When purchasing mortgage-backed securities in the “to be announced” (TBA) market (MBS TBAs), the seller agrees to deliver mortgage-backed securities for an agreed upon price on an agreed upon date, but may make no guarantee as to the specific securities to be delivered. In lieu of taking delivery of mortgage-backed securities, the Fund could enter into dollar rolls, which are transactions in which the Fund sells securities to a counterparty and simultaneously agrees to purchase those or similar securities in the future at a predetermined price. Dollar rolls involve the risk that the market value of the securities the Fund is obligated to repurchase may decline below the repurchase price, or that the counterparty may default on its obligations. These transactions may also increase the Fund’s portfolio turnover rate. If the Fund reinvests the proceeds of the security sold, the Fund will also be subject to the risk that the investments purchased with such proceeds will decline in value (a form of leverage risk). MBS TBAs and dollar rolls are subject to the risk that the counterparty to the transaction may not perform or be unable to perform in accordance with the terms of the instrument.

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Frequent Trading Risk. The portfolio managers may actively and frequently trade investments in the Fund's portfolio to carry out its investment strategies. Frequent trading of investments increases the possibility that the Fund, as relevant, will realize taxable capital gains (including short-term capital gains, which are generally taxable to shareholders at higher rates than long-term capital gains for U.S. federal income tax purposes), which could reduce the Fund's after-tax return. Frequent trading can also mean higher brokerage and other transaction costs, which could reduce the Fund's return. The trading costs and tax effects associated with portfolio turnover may adversely affect the Fund’s performance.

Fund-of-Funds Risk. Determinations regarding asset classes or underlying funds and the Fund’s allocations thereto may not successfully achieve the Fund’s investment objective, in whole or in part. The ability of the Fund to realize its investment objective will depend, in large part, on the extent to which the underlying funds realize their investment objective. There is no guarantee that the underlying funds will achieve their respective investment objectives. The Fund is exposed to the same risks as the underlying funds in direct proportion to the allocation of its assets among the underlying funds. Therefore, to the extent that the Fund invests significantly in a particular underlying fund, the Fund’s performance would be significantly impacted by the performance of such underlying fund. Generally, by investing in a combination of underlying funds, the Fund has exposure to the risks of many areas of the market. By concentrating its investments in relatively few underlying funds, the Fund may have more concentrated market exposures, subjecting the Fund to greater risk of loss should those markets decline or fail to rise. The performance of underlying funds could be adversely affected if other entities that invest in the same underlying funds make relatively large investments or redemptions in such underlying funds. The Fund, and its shareholders, indirectly bear a portion of the expenses of any funds in which the Fund invests. Because the expenses and costs of each underlying fund are shared by its investors, redemptions by other investors in an underlying fund could result in decreased economies of scale and increased operating expenses for such fund. The Investment Manager typically selects underlying funds from among the funds it advises (affiliated funds) and will select an unaffiliated underlying fund only if the desired investment exposure is not available through an affiliated fund. The Investment Manager has a conflict of interest in selecting affiliated underlying funds over unaffiliated underlying funds because it receives management fees from affiliated funds, and in selecting affiliated underlying funds, because the fees paid to it by certain affiliated underlying funds are higher than the fees paid by other affiliated underlying funds. Also, to the extent that the Fund is constrained/restricted from investing (or investing further) in a particular underlying fund for one or more reasons (e.g., underlying fund capacity constraints or regulatory restrictions) or if the Fund chooses to sell its investment in an underlying fund because of poor investment performance or for other reasons, the Fund may have to invest in another underlying fund(s), including less desirable funds – from a strategy or investment performance standpoint – which could have a negative impact on Fund performance. In addition, Fund performance could be negatively impacted if the Investment Manager is unable to identify an appropriate alternate underlying fund(s) in a timely manner or at all.

High-Yield Investments Risk. Securities and other debt instruments held by the Fund that are rated below investment grade (commonly called “high-yield” or “junk” bonds) and unrated debt instruments of comparable quality expose the Fund to a greater risk of loss of principal and income than a fund that invests solely or primarily in investment grade debt instruments. In addition, these investments have greater price fluctuations, are less liquid and are more likely to experience a default than higher-rated debt instruments. High-yield debt instruments are considered to be predominantly speculative with respect to the issuer’s capacity to pay interest and repay principal.

Inflation Risk. Inflation risk is the uncertainty over the future real value (after inflation) of an investment. Inflation rates may change frequently and drastically as a result of various factors, including unexpected shifts in the domestic or global economy, and the Fund’s investments may not keep pace with inflation, which may result in losses to Fund investors.

Inflation-Protected Securities Risk. Inflation-protected debt securities tend to react to changes in real interest rates (i.e., nominal interest rates minus the expected impact of inflation). In general, the price of such securities falls when real interest rates rise, and rises when real interest rates fall. Interest payments on these securities will vary and may be more volatile than interest paid on ordinary bonds. In periods of deflation, the Fund may have no income at all from such investments.

Interest Rate Risk. Interest rate risk is the risk of losses attributable to changes in interest rates. In general, if prevailing interest rates rise, the values of debt instruments tend to fall, and if interest rates fall, the values of debt instruments tend to rise. Changes in the value of a debt instrument usually will not affect the amount of income the Fund receives from it but will generally affect the value of your investment in the Fund. Changes in interest rates may also affect the liquidity of the Fund’s investments in debt instruments. In general, the longer the maturity or duration of a debt instrument, the greater its sensitivity to changes in interest rates. Interest rate declines also may increase prepayments of debt obligations, which, in turn, would increase prepayment risk. Similarly, a period of rising interest rates may negatively impact the Fund’s performance. Actions by governments and central banking authorities can

Columbia Adaptive Retirement 2055 Fund

result in increases in interest rates. Such actions may negatively affect the value of debt instruments held by the Fund, resulting in a negative impact on the Fund's performance and NAV. Any interest rate increases could cause the value of the Fund’s investments in debt instruments to decrease. Rising interest rates may prompt redemptions from the Fund, which may force the Fund to sell investments at a time when it is not advantageous to do so, which could result in losses.

Issuer Risk. An issuer in which the Fund invests or to which it has exposure may perform poorly, and the value of its securities may therefore decline, which would negatively affect the Fund’s performance. Poor performance 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 or other events, conditions or factors. The market capitalization of an issuer may also impact its risk profile. Investments in larger, more established companies may involve certain risks associated with their larger size. For instance, larger, more established companies may be less able to respond quickly to new competitive challenges, such as changes in consumer tastes or innovation from smaller competitors. Also, larger companies are sometimes less able to attain the high growth rates of successful smaller companies, especially during extended periods of economic expansion.

Leverage Risk. Leverage occurs when the Fund increases its assets available for investment using borrowings, short sales, derivatives, or similar instruments or techniques. Use of leverage can produce volatility and may exaggerate changes in the NAV of Fund shares and in the return on the Fund’s portfolio, which may increase the risk that the Fund will lose more than it has invested. If the Fund uses leverage, through the purchase of particular instruments such as derivatives, the Fund may experience capital losses that exceed the net assets of the Fund. Because short sales involve borrowing securities and then selling them, the Fund’s short sales effectively leverage the Fund’s assets. The Fund's assets that are used as collateral to secure the Fund's obligations to return the securities sold short may decrease in value while the short positions are outstanding, which may force the Fund to use its other assets to increase the collateral. Leverage can create an interest expense that may lower the Fund's overall returns. Leverage presents the opportunity for increased net income and capital gains, but may also exaggerate the Fund’s volatility and risk of loss. There can be no guarantee that a leveraging strategy will be successful.

Liquidity Risk. Liquidity risk is the risk associated with any event, circumstance, or characteristic of an investment or market that negatively impacts the Fund’s ability to sell, or realize the proceeds from the sale of, an investment at a desirable time or price. Liquidity risk may arise because of, for example, a lack of marketability of the investment, which means that when seeking to sell its portfolio investments, the Fund could find that selling is more difficult than anticipated, especially during times of high market volatility. Decreases in the number of financial institutions, including banks and broker-dealers, willing to make markets (match up sellers and buyers) in the Fund’s investments or decreases in their capacity or willingness to trade such investments may increase the Fund’s exposure to this risk. The debt market has experienced considerable growth, and financial institutions making markets in instruments purchased and sold by the Fund (e.g., bond dealers) have been subject to increased regulation. The impact of that growth and regulation on the ability and willingness of financial institutions to engage in trading or “making a market” in such instruments remains unsettled. Certain types of investments, such as lower-rated securities or those that are purchased and sold in over-the-counter markets, may be especially subject to liquidity risk. Securities or other assets in which the Fund invests may be traded in the over-the-counter market rather than on an exchange and therefore may be more difficult to purchase or sell at a fair price, which may have a negative impact on the Fund’s performance. Market participants attempting to sell the same or a similar instrument at the same time as the Fund could exacerbate the Fund’s exposure to liquidity risk. The Fund may have to accept a lower selling price for the holding, sell other liquid or more liquid investments that it might otherwise prefer to hold (thereby increasing the proportion of the Fund’s investments in less liquid or illiquid securities), or forego another more appealing investment opportunity. Certain investments that were liquid when purchased by the Fund may later become illiquid, particularly in times of overall economic distress. Changing regulatory, market or other conditions or environments (for example, the interest rate or credit environments) may also adversely affect the liquidity and the price of the Fund's investments. Judgment plays a larger role in valuing illiquid or less liquid investments as compared to valuing liquid or more liquid investments. Price volatility may be higher for illiquid or less liquid investments as a result of, for example, the relatively less frequent pricing of such securities (as compared to liquid or more liquid investments). Generally, the less liquid the market at the time the Fund sells a portfolio investment, the greater the risk of loss or decline of value to the Fund. Overall market liquidity and other factors can lead to an increase in redemptions, which may negatively impact Fund performance and NAV, including, for example, if the Fund is forced to sell investments in a down market. Foreign securities can present enhanced liquidity risks, including as a result of less developed custody, settlement or other practices of foreign markets. Floating rate loans generally are subject to legal or contractual restrictions on resale, may trade infrequently, their value may be impaired when the Fund needs to liquidate such loans, and are typically subject to extended settlement periods, each of which gives rise to liquidity risk.

9	Columbia Adaptive Retirement 2055 Fund

Market Risk. Market risk refers to the possibility that the market values of securities or other investments that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. An investment in the Fund could lose money over short or long periods.

Money Market Fund Investment Risk. An investment in a money market fund is not a bank deposit and is not insured or guaranteed by any bank, the FDIC or any other government agency. Certain money market funds float their NAV while others seek to preserve the value of investments at a stable NAV (typically, $1.00 per share). An investment in a money market fund, even an investment in a fund seeking to maintain a stable NAV per share, is not guaranteed and it is possible for the Fund to lose money by investing in these and other types of money market funds. If the liquidity of a money market fund’s portfolio deteriorates below certain levels, the money market fund may suspend redemptions (i.e., impose a redemption gate) and thereby prevent the Fund from selling its investment in the money market fund or impose a fee of up to 2% on amounts the Fund redeems from the money market fund (i.e., impose a liquidity fee). These measures may result in an investment loss or prohibit the Fund from redeeming shares when the Investment Manager would otherwise redeem shares. In addition to the fees and expenses that the Fund directly bears, the Fund indirectly bears the fees and expenses of any money market funds in which it invests, including affiliated money market funds. By investing in a money market fund, the Fund will be exposed to the investment risks of the money market fund in direct proportion to such investment. To the extent the Fund invests in instruments such as derivatives, the Fund may hold investments, which may be significant, in money market fund shares to cover its obligations resulting from the Fund’s investments in derivatives. Money market funds and the securities they invest in are subject to comprehensive regulations. The enactment of new legislation or regulations, as well as changes in interpretation and enforcement of current laws, may affect the manner of operation, performance and/or yield of money market funds.

Mortgage- and Other Asset-Backed Securities Risk. The value of any mortgage-backed and other asset-backed securities held by the Fund may be affected by, among other things, changes or perceived changes in: interest rates; factors concerning the interests in and structure of the issuer or the originator of the mortgages or other assets; the creditworthiness of the entities that provide any supporting letters of credit, surety bonds or other credit enhancements; or the market's assessment of the quality of underlying assets. Payment of principal and interest on some mortgage-backed securities (but not the market value of the securities themselves) may be guaranteed by the full faith and credit of a particular U.S. Government agency, authority, enterprise or instrumentality, and some, but not all, are also insured or guaranteed by the U.S. Government. Mortgage-backed securities issued by non-governmental issuers (such as commercial banks, savings and loan institutions, private mortgage insurance companies, mortgage bankers and other secondary market issuers) may entail greater risk than obligations guaranteed by the U.S. Government. Mortgage- and other asset-backed securities are subject to prepayment risk, which is the possibility that the underlying mortgage or other asset may be refinanced or prepaid prior to maturity during periods of declining or low interest rates, causing the Fund to have to reinvest the money received in securities that have lower yields. Rising or high interest rates tend to extend the duration of mortgage- and other asset-backed securities, making their prices more volatile and more sensitive to changes in interest rates.

New Fund Risk. Investors in newly formed funds bear the risk that the fund may not be successful in implementing its investment strategy, and may not employ a successful investment strategy, either of which could result in the fund being liquidated at any time without shareholder approval and/or at a time that may not be favorable for certain shareholders. Such a liquidation could have negative tax consequences for shareholders.

Non-Diversified Fund Risk. The Fund is non-diversified, which generally means that it will invest a greater percentage of its total assets in the securities of fewer issuers than a “diversified” fund. This increases the risk that a change in the value of any one investment held by the Fund could affect the overall value of the Fund more than it would affect that of a diversified fund holding a greater number of investments. Accordingly, the Fund's value will likely be more volatile than the value of a more diversified fund.

Prepayment and Extension Risk. Prepayment and extension risk is the risk that a bond or other security or investment might, in the case of prepayment risk, be called or otherwise converted, prepaid or redeemed before maturity and, in the case of extension risk, that the investment might not be called as expected. In the case of prepayment risk, if the investment is converted, prepaid or redeemed before maturity, the portfolio managers may not be able to invest the proceeds in other investments providing as high a level of income, resulting in a reduced yield to the Fund. In the case of mortgage- or other asset-backed securities, as interest rates decrease or spreads narrow, the likelihood of prepayment increases. Conversely, extension risk is the risk that an unexpected rise in interest rates will extend the life of a mortgage- or asset-backed security beyond the prepayment time. If the Fund’s investments are locked in at a lower interest rate for a longer period of time, the portfolio managers may be unable to capitalize on securities with higher interest rates or wider spreads.

Columbia Adaptive Retirement 2055 Fund

Quantitative Model Risk. Investments selected using quantitative methods may perform differently from the market as a whole. There can be no assurance that these methodologies will enable the Fund to achieve its objective or that the models will perform as expected.

Real Estate-Related Investment Risk. Investments in real estate investment trusts (REITs) and in securities of other companies (wherever organized) principally engaged in the real estate industry subject the Fund to, among other things, risks similar to those of direct investments in real estate and the real estate industry in general. These include risks related to general and local economic conditions, possible lack of availability of financing and changes in interest rates or property values. REITs are entities that either own properties or make construction or mortgage loans, and also may include operating or finance companies. The value of interests in a REIT may be affected by, among other factors, changes in the value of the underlying properties owned by the REIT, changes in the prospect for earnings and/or cash flow growth of the REIT itself, defaults by borrowers or tenants, market saturation, decreases in market rates for rents, and other economic, political, or regulatory matters affecting the real estate industry, including REITs. REITs and similar non-U.S. entities depend upon specialized management skills, may have limited financial resources, may have less trading volume in their securities, and may be subject to more abrupt or erratic price movements than the overall securities markets. REITs are also subject to the risk of failing to qualify for favorable tax treatment under the Internal Revenue Code of 1986, as amended. The failure of a REIT to continue to qualify as a REIT for tax purposes can materially and adversely affect its value. In addition, due to recent changes in tax laws, certain tax benefits of REITs may not be passed through to mutual fund shareholders. Some REITs (especially mortgage REITs) are affected by risks similar to those associated with investments in debt securities including changes in interest rates and the quality of credit extended.

Reinvestment Risk. Reinvestment risk is the risk that the Fund will not be able to reinvest income or principal at the same return it is currently earning.

Repurchase Agreements Risk. Repurchase agreements are agreements in which the seller of a security to the Fund agrees to repurchase that security from the Fund at a mutually agreed upon price and time. Repurchase agreements carry the risk that the counterparty may not fulfill its obligations under the agreement. This could cause the Fund's income and the value of your investment in the Fund to decline.

Reverse Repurchase Agreements Risk. Reverse repurchase agreements are agreements in which a Fund sells a security to a counterparty, such as a bank or broker-dealer, in return for cash and agrees to repurchase that security at a mutually agreed upon price and time. Reverse repurchase agreements carry the risk that the market value of the security sold by the Fund may decline below the price at which the Fund must repurchase the security. Reverse repurchase agreements also may be viewed as a form of borrowing, and borrowed assets used for investment creates leverage risk. Leverage can create an interest expense that may lower the Fund's overall returns. Leverage presents the opportunity for increased net income and capital gains, but may also exaggerate the Fund’s volatility and risk of loss. There can be no guarantee that this strategy will be successful.

Rule 144A and Other Exempted Securities Risk. The Fund may invest in privately placed and other securities or instruments exempt from SEC registration (collectively “private placements”), subject to liquidity and other regulatory restrictions. In the U.S. market, private placements are typically sold only to qualified institutional buyers, or qualified purchasers, as applicable. An insufficient number of buyers interested in purchasing private placements at a particular time could adversely affect the marketability of such investments and the Fund might be unable to dispose of them promptly or at reasonable prices, subjecting the Fund to liquidity risk. The Fund may invest in private placements determined to be liquid as well as those determined to be illiquid. Even if determined to be liquid, the Fund’s holdings of private placements may increase the level of Fund illiquidity if eligible buyers are unable or unwilling to purchase them at a particular time. Issuers of Rule 144A eligible securities are required to furnish information to potential investors upon request. However, the required disclosure is much less extensive than that required of public companies and is not publicly available since the offering is not filed with the SEC. Further, issuers of Rule 144A eligible securities can require recipients of the offering information (such as the Fund) to agree contractually to keep the information confidential, which could also adversely affect the Fund’s ability to dispose of the security.

Short Positions Risk. The Fund may establish short positions which introduce more risk to the Fund than long positions (where the Fund owns the instrument or other asset) because the maximum sustainable loss on an instrument or other asset purchased (held long) is limited to the amount paid for the instrument or other asset plus the transaction costs, whereas there is no maximum price of the shorted instrument or other asset when purchased in the open market. Therefore, in theory, short positions have unlimited risk. The Fund’s use of short positions in effect “leverages” the Fund. Leverage potentially exposes the Fund to greater risks of loss due to unanticipated market movements, which may magnify losses and increase the volatility of returns. To the extent the Fund takes a short position in a derivative instrument or other asset, this involves the risk of a potentially unlimited increase in the value of the underlying instrument or other asset.

11	Columbia Adaptive Retirement 2055 Fund

Small- and Mid-Cap Company Securities Risk. Investments in small- and mid-capitalization companies (small- and mid-cap companies) often involve greater risks than investments in larger, more established companies (larger companies) because small- and mid-cap companies tend to have less predictable earnings and may lack the management experience, financial resources, product diversification and competitive strengths of larger companies. Securities of small- and mid-cap companies may be less liquid and more volatile than the securities of larger companies.

Sovereign Debt Risk. A sovereign debtor’s willingness or ability to repay principal and pay interest in a timely manner may be affected by a variety of factors, including its cash flow situation, the extent of its reserves, the availability of sufficient foreign exchange on the date a payment is due, the relative size of the debt service burden to the economy as a whole, the sovereign debtor’s policy toward international lenders, and the political constraints to which a sovereign debtor may be subject.

Target Date Funds Risk. The Fund is a target date fund, and the risks associated with a target date fund include the risk of loss, including losses near, at or after the target date, and there is no guarantee that the Fund will provide adequate income at and through the investor’s retirement or other investment goal.

U.S. Government Obligations Risk. While U.S. Treasury obligations are backed by the “full faith and credit” of the U.S. Government, such securities are nonetheless subject to credit risk (i.e., the risk that the U.S. Government may be, or be perceived to be, unable or unwilling to honor its financial obligations, such as making payments). Securities issued or guaranteed by federal agencies or authorities and U.S. Government-sponsored instrumentalities or enterprises may or may not be backed by the full faith and credit of the U.S. Government.

Volatility Risk. The Fund may have investments that appreciate or decrease significantly in value over short periods of time. This may cause the Fund’s NAV per share to experience significant increases or declines in value over short periods of time, however, all investments long- or short-term are subject to risk of loss.

Performance Information

The Fund is new as of the date of this prospectus and therefore performance information is not available.

When available, the Fund intends to compare its performance to the performance of Dow Jones Target 2055 Index.

When available, updated performance information can be obtained by calling toll-free 800.345.6611 or visiting columbiathreadneedleus.com.

Fund Management

Investment Manager: Columbia Management Investment Advisers, LLC

Portfolio Manager	Title	Role with Fund	Managed Fund Since
Joshua Kutin, CFA	Senior Portfolio Manager and Head of North America Asset Allocation	Lead Portfolio Manager	April 2018
Alexander Wilkinson, CFA, CAIA	Portfolio Manager	Portfolio Manager	April 2018

Purchase and Sale of Fund Shares

You may purchase or redeem shares of the Fund on any business day by contacting the Fund in the ways described below:

NOTE: The Fund’s mailing addresses are changing as follows*:

Online	Regular Mail	Express Mail	By Telephone
	Through October 31, 2018	Through October 31, 2018
columbiathreadneedleus.com/investor/	Columbia Management Investment Services Corp. P.O. Box 8081 Boston, MA 02266-8081	Columbia Management Investment Services Corp. c/o DST Asset Manager Solutions, Inc. 30 Dan Road, Suite 8081 Canton, MA 02021-2809	800.422.3737
	Regular Mail	Express Mail
	Effective November 1, 2018	Effective November 1, 2018
	Columbia Management Investment Services Corp. P.O. Box 219104 Kansas City, MO 64121-9104	Columbia Management Investment Services Corp. c/o DST Asset Manager Solutions, Inc. 430 W 7^th Street, Suite 219104 Kansas City, MO 64105-1407

Columbia Adaptive Retirement 2055 Fund

Based on the dates noted above, mail received at an incorrect address will be forwarded to the correct address, and will not be processed until received, in “good form,” at the correct address. This may affect the trade date you receive for transaction requests, which may negatively impact the value of your purchase or sale.

You may purchase shares and receive redemption proceeds by electronic funds transfer, by check or by wire. If you maintain your account with a broker-dealer or other financial intermediary, you must contact that financial intermediary to buy, sell or exchange shares of the Fund through your account with the intermediary.

The minimum initial investment amounts for the share class offered by the Fund are shown below:

Minimum Initial Investment

Class	Category of eligible account	For accounts other than systematic investment plan accounts	For systematic investment plan accounts
Class Adv	All eligible accounts	$0, $1,000 or $2,000 depending upon the category of eligible investor	$100
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)

More information about these minimums can be found in the Buying, Selling and Exchanging Shares - Buying Shares section of the prospectus. There is no minimum additional investment for any share class.

Tax Information

The Fund normally distributes net investment income and net realized capital gains, if any, to shareholders. These distributions are generally taxable to you as ordinary income or capital gains, unless you are investing through a tax-advantaged account, such as a 401(k) plan or an IRA. The use of a fund-of-funds structure could affect the timing, amount and character of distributions to you and therefore may increase the amount of taxes payable by you. If you are investing through a tax-advantaged account, you may be taxed upon withdrawals from that account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase the Fund through a broker-dealer or other financial intermediary (such as a bank), the Fund and its related companies — including Columbia Management Investment Advisers, LLC (the Investment Manager), Columbia Management Investment Distributors, Inc. (the Distributor) and Columbia Management Investment Services Corp. (the Transfer Agent) — may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your financial advisor to recommend the Fund over another investment. Ask your financial advisor or visit your financial intermediary’s website for more information.

13	Columbia Adaptive Retirement 2055 Fund

Class		Ticker Symbol
Advisor (Class Adv)		CARFX
Institutional 3 (Class Inst3)		CAIJX