Columbia Funds Series Trust

Summary Prospectus

September 1, 2017

Columbia AMT-Free California Intermediate Muni Bond Fund

Class		Ticker Symbol
Class A Shares		NACMX
Class C Shares		CCICX
Class R4 Shares		CCMRX
Class R5 Shares		CNBRX
Class Y Shares		CCBYX
Class Z Shares		NCMAX

Before you invest, you may want to review the Fund’s prospectus, which contains more information about the Fund and its risks. You can find the Fund’s prospectus, statement of additional information and other information about the Fund online at https://www.columbiathreadneedleus.com/resources/literature. You can also get this information at no cost by calling 800.345.6611 or by sending an email to serviceinquiries@columbiathreadneedle.com. This Summary Prospectus incorporates by reference the Fund’s prospectus, dated September 1, 2017, and current Statement of Additional Information.

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

Investment Objective

Columbia AMT-Free California Intermediate Muni Bond Fund (the Fund) seeks current income exempt from U.S. federal income tax and California individual income tax, consistent with moderate fluctuation of principal.

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. You may qualify for sales charge discounts if you and members of your immediate family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible funds distributed by Columbia Management Investment Distributors, Inc. (the Distributor). More information about these and other sales charge discounts and waivers is available from your financial intermediary, and can be found in the Choosing a Share Class section beginning on page 21 of the Fund’s prospectus, in Appendix A to the prospectus beginning on page A-1 and in Appendix S to the Statement of Additional Information (SAI) under Sales Charge Waivers beginning on page S-1.

Shareholder Fees (fees paid directly from your investment)
	Class A	Class C	Classes R4, R5, Y and Z
Maximum sales charge (load) imposed on purchases (as a % of offering price)	3.00%	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)	0.75% ^(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 C	Class R4	Class R5	Class Y	Class Z
Management fees	0.47%	0.47%	0.47%	0.47%	0.47%	0.47%
Distribution and/or service (12b-1) fees	0.25%	1.00%	0.00%	0.00%	0.00%	0.00%
Other expenses^(c)	0.15%	0.15%	0.15%	0.09%	0.05%	0.15%
Total annual Fund operating expenses	0.87%	1.62%	0.62%	0.56%	0.52%	0.62%
Less: Fee waivers and/or expense reimbursements^(d)	(0.13%)	(0.13%)	(0.13%)	(0.13%)	(0.14%)	(0.13%)
Total annual Fund operating expenses after fee waivers and/or expense reimbursements	0.74%	1.49%	0.49%	0.43%	0.38%	0.49%

(a)	This charge is imposed on certain investments of $500,000 or more redeemed within 12 months after purchase, with certain limited exceptions.
(b)	This charge applies to redemptions within 12 months after purchase, with certain limited exceptions.
(c)	Other expenses have been restated to reflect current transfer agency fees paid by the Fund and other expenses for Class Y shares are based on estimated amounts for the Fund’s current fiscal year.
(d)	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, acquired fund fees and expenses, and infrequent and/or unusual expenses) through August 31, 2018, 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 0.74% for Class A, 1.49% for Class C, 0.49% for Class R4, 0.43% for Class R5, 0.38% for Class Y and 0.49% for Class Z.

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.

1	Columbia AMT-Free California Intermediate Muni Bond Fund

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

	1 year	3 years	5 years	10 years
Class A (whether or not shares are redeemed)	$373	$557	$755	$1,329
Class C (assuming redemption of all shares at the end of the period)	$252	$498	$869	$1,911
Class C (assuming no redemption of shares)	$152	$498	$869	$1,911
Class R4 (whether or not shares are redeemed)	$ 50	$185	$333	$ 762
Class R5 (whether or not shares are redeemed)	$ 44	$166	$300	$ 689
Class Y (whether or not shares are redeemed)	$ 39	$153	$277	$ 639
Class Z (whether or not shares are redeemed)	$ 50	$185	$333	$ 762

Portfolio Turnover

The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 17% of the average value of its portfolio.

Principal Investment Strategies

As a matter of non-fundamental policy (which may be changed without shareholder approval), under normal circumstances, the Fund invests at least 80% of its net assets (including the amount of any borrowings for investment purposes) in securities that pay interest exempt from U.S. federal income tax (including the federal alternative minimum tax (AMT)) and California individual income tax. These securities are issued by or on behalf of the State of California and its political subdivisions, agencies, authorities and instrumentalities, by other qualified issuers and by funds that invest in such securities. Qualified issuers include issuers located in U.S. territories, commonwealths and possessions, such as Guam, Puerto Rico and the U.S. Virgin Islands. The Fund may invest up to 20% of its net assets in securities that pay interest subject to taxation. In addition, as a matter of non-fundamental policy, the Fund will not invest in securities that pay interest subject to the federal AMT. The non-fundamental policies discussed above may be changed by the Fund’s Board of Trustees without shareholder approval as long as shareholders are given at least 60 days’ advance written notice of such change.

The Fund normally invests at least 80% of its total assets in municipal securities that, at the time of purchase, are rated investment grade or are unrated but determined to be of comparable quality. The Fund may invest up to 10% of its total assets in debt instruments that, at the time of purchase, are rated below investment grade or are unrated but determined to be of comparable quality (commonly referred to as “high-yield” investments or “junk” bonds).

While the Fund may invest in securities of any maturity, under normal circumstances, the Fund’s dollar-weighted average maturity will be between three and ten years.

Principal Risks

An investment in the Fund involves risks, including those described below. 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. Due to its active management, the Fund could underperform its benchmark index and/or other funds with similar investment objectives and/or strategies.

Changing Distribution Level Risk. The Fund will normally receive income which may include interest, dividends and/or capital gains, depending upon its investments. The amount of the distributions the Fund pays will vary and generally depends on the amount of income the Fund earns (less expenses) on its portfolio holdings, and capital gains or losses it recognizes. A decline in the Fund’s income or net capital gains from its investments may reduce its distribution level.

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. Debt instruments backed by an issuer's taxing authority may be subject to legal limits on the issuer's power to increase taxes or otherwise to raise revenue, or may be dependent on

Columbia AMT-Free California Intermediate Muni Bond Fund

legislative appropriation or government aid. Certain debt instruments are backed only by revenues derived from a particular project or source, rather than by an issuer's taxing authority, and thus may have a greater risk of default. Rating agencies assign credit ratings to certain debt instruments to indicate their credit risk. 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 (commonly called “high-yield” or “junk”) 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.

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.

Interest Rate Risk. Interest rate risk is the risk of losses attributable to changes in interest rates. In general, if prevailing interest rates (which are currently near historic lows) 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 the Fund's shares. 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 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.

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. The municipal securities market is an over-the-counter market, which means that the Fund purchases and sells investments through municipal bond dealers. The Fund’s ability to sell investments held in its portfolio is dependent on the willingness and ability of market participants to provide bids that, in the view of portfolio management, reflect current market prices. Adverse market conditions could result in a lack of liquidity by reducing the number of ready buyers.

3	Columbia AMT-Free California Intermediate Muni Bond 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.

Municipal Securities Risk. Municipal securities are debt obligations generally issued to obtain funds for various public purposes, including general financing for state and local governments, or financing for a specific project or public facility, and include obligations of the governments of the U.S. territories, commonwealths and possessions such as Guam, Puerto Rico and the U.S. Virgin Islands to the extent such obligations are exempt from state and U.S. federal income taxes. Municipal securities may be fully or partially backed by the taxing authority of the local government, by the credit of a private issuer, by the current or anticipated revenues from a specific project or specific assets or by domestic or foreign entities providing credit support, such as letters of credit, guarantees or insurance, and are generally classified into general obligation bonds and special revenue obligations. General obligation bonds are backed by an issuer's taxing authority and may be vulnerable to limits on a government's power or ability to raise revenue or increase taxes. They may also depend for payment on legislative appropriation and/or funding or other support from other governmental bodies. Revenue obligations are payable from revenues generated by a particular project or other revenue source, and are typically subject to greater risk of default than general obligation bonds because investors can look only to the revenue generated by the project or other revenue source backing the project, rather than to the general taxing authority of the state or local government issuer of the obligations. Because many municipal securities are issued to finance projects in sectors such as education, health care, transportation and utilities, conditions in those sectors can affect the overall municipal market.

Issuers in a state, territory, commonwealth or possession in which the Fund invests may experience significant financial difficulties. Such financial difficulties may lead to credit rating downgrade(s) of such issuers which, in turn, could affect the market values and marketability of many or all municipal obligations of issuers in such state, territory, commonwealth or possession. The value of the Fund’s shares will be negatively impacted to the extent it invests in such securities. The Fund’s annual and semiannual reports show the Fund’s investment exposures at a point in time. The risk of investing in the Fund is directly correlated to the Fund’s investment exposures.

Because the Fund invests substantially in municipal securities issued by the state identified in the Fund’s name and political sub-divisions of that state, the Fund will be particularly affected by adverse tax, legislative, regulatory, demographic or political changes as well as changes impacting the state's financial, economic or other condition and prospects. In addition, because of the relatively small number of issuers of tax-exempt securities in the state, the Fund may invest a higher percentage of assets in a single issuer and, therefore, be more exposed to the risk of loss than a fund that invests more broadly. The value of municipal and other securities owned by the Fund also may be adversely affected by future changes in federal or state income tax laws.

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 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.

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.

Tax Risk. Municipal securities generally pay interest that, in the opinion of bond counsel, is free from U.S. federal income tax (and in some cases, the U.S. federal alternative minimum tax). Income from tax-exempt municipal obligations could be declared taxable, possibly retroactively, because of unfavorable changes in tax laws, adverse interpretations by the Internal Revenue Service, the non-compliant conduct of a bond issuer or under other circumstances. In such event, then the value of the security would likely fall and, as a shareholder of the Fund, you may be required to file an amended tax return and pay additional taxes.

Performance Information

The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. Class Y shares of the Fund commenced operations after the periods shown in the table below and, therefore, performance information is not yet available. The bar chart shows how the Fund’s Class A share performance (without sales charges) has varied for each full calendar year shown. If the sales charges were

Columbia AMT-Free California Intermediate Muni Bond Fund

reflected, returns shown would be lower. The table below the bar chart compares the Fund’s returns (after applicable sales charges shown in the Shareholder Fees table in this prospectus) for the periods shown with a broad measure of market performance, as well as another measure of performance for markets in which the Fund may invest.

The performance of one or more share classes shown in the table below begins before the indicated inception date for such share class. The returns shown for each such share class include the returns of the Fund’s Class Z shares (adjusted to reflect the higher class-related operating expenses of such classes, where applicable) for periods prior to its inception date. Any share class, such as Class Y shares, that does not have available performance would have annual returns substantially similar to those of Class A shares. Except for differences in annual returns resulting from differences in expenses and sales charges (where applicable), the share classes of the Fund would have substantially similar annual returns because all share classes of the Fund invest in the same portfolio of securities.

The after-tax returns shown in the Average Annual Total Returns table below are calculated using the highest historical individual U.S. federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-advantaged accounts such as 401(k) plans or Individual Retirement Accounts (IRAs). The after-tax returns are shown only for Class A shares and will vary for other share classes. Returns after taxes on distributions and sale of Fund shares are higher than before-tax returns for certain periods shown because they reflect the tax benefit of capital losses realized on the redemption of Fund shares.

The Fund’s past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting columbiathreadneedle.com/us.

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	_{3rd Quarter 2009}	_7.20%
	_Worst	_{4th Quarter 2010}	_-3.81%

*	Year to Date return as of June 30, 2017: 3.05%

Average Annual Total Returns After Applicable Sales Charges (for periods ended December 31, 2016)

	Share Class Inception Date	1 Year	5 Years	10 Years
Class A	09/09/2002
returns before taxes		-3.35%	2.13%	3.44%
returns after taxes on distributions		-3.35%	2.13%	3.44%
returns after taxes on distributions and sale of Fund shares		-0.84%	2.30%	3.37%
Class C returns before taxes	09/11/2002	-2.14%	1.97%	2.97%
Class R4 returns before taxes	03/19/2013	-0.09%	3.02%	4.02%
Class R5 returns before taxes	11/08/2012	0.00%	3.09%	4.05%
Class Z returns before taxes	08/19/2002	-0.08%	3.02%	4.02%
Bloomberg Barclays California 3-15 Year Blend Municipal Bond Index (reflects no deductions for fees, expenses or taxes)		-0.34%	3.10%	4.42%
Bloomberg Barclays 3-15 Year Blend Municipal Bond Index (reflects no deductions for fees, expenses or taxes)		-0.05%	2.73%	4.23%

5	Columbia AMT-Free California Intermediate Muni Bond Fund

Fund Management

Investment Manager: Columbia Management Investment Advisers, LLC

Portfolio Manager	Title	Role with Fund	Managed Fund Since
Brian McGreevy	Senior Portfolio Manager	Co-Portfolio Manager	2011
Paul Fuchs, CFA	Senior Portfolio Manager	Co-Portfolio Manager	2012

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:

Online		Regular Mail		Express Mail		By Telephone
investor.columbiathreadneedle.com/us		Columbia Funds, c/o Columbia Management Investment Services Corp. P.O. Box 8081 Boston, MA 02266-8081		Columbia Funds, c/o Columbia Management Investment Services Corp. 30 Dan Road, Suite 8081 Canton, MA 02021-2809		800.422.3737

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 classes 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
Classes A & C	All accounts other than IRAs	$2,000	$100
Classes A & C	IRAs	$1,000	$100
Classes R4 & Z	All eligible accounts	$0, $1,000 or $2,000 depending upon the category of eligible investor	$100
Class R5	All eligible accounts	None	N/A
Class Y	All eligible accounts	$0, $1,000, $2,000 or $1 million depending upon the category of eligible investor	$100 (for certain eligible investors)

There is no minimum additional investment for any share class.

Tax Information

Generally, a substantial portion of the Fund’s distributions consists of exempt-interest dividends, which are generally not taxable to you for U.S. federal income tax purposes or for purposes of the U.S. federal alternative minimum tax. A portion of the Fund’s distributions may not qualify as exempt-interest dividends; such distributions will generally be 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. 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.

Columbia AMT-Free California Intermediate Muni Bond Fund

Columbia Threadneedle Investments is the global brand name of the Columbia and Threadneedle group of companies.

columbiathreadneedle.com/us

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