Columbia Funds Series Trust

Summary Prospectus

June 25, 2014

Columbia Mid Cap Index Fund

Class		Ticker Symbol
Class A Shares		NTIAX
Class I Shares		CIDIX
Class R5 Shares		CPXRX
Class Z Shares		NMPAX

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.columbiamanagement.com/web/columbia/forms-literature/fund-literature. You can also get this information at no cost by calling 800.345.6611 or by sending an email to serviceinquiries@columbiamanagement.com. This Summary Prospectus incorporates by reference the Fund’s prospectus, dated June 25, 2014, 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 Mid Cap Index Fund (the Fund) seeks total return before fees and expenses that corresponds to the total return of the Standard & Poor’s (S&P) MidCap 400^® Index.

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.

Shareholder Fees (fees paid directly from your investment)
	Class A	Classes I, R5 and Z
Maximum sales charge (load) imposed on purchases (as a % of offering price)	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)	None	None

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
	Class A	Class I	Class R5	Class Z
Management fees	0.10%	0.10%	0.10%	0.10%
Distribution and/or service (12b-1) fees	0.25%	0.00%	0.00%	0.00%
Other expenses^(a)	0.31%	0.12%	0.17%	0.31%
Acquired fund fees and expenses	0.01%	0.01%	0.01%	0.01%
Total annual Fund operating expenses^(b)	0.67%	0.23%	0.28%	0.42%
Less: Fee waivers and/or expense reimbursements^(c)	(0.21%)	(0.02%)	(0.07%)	(0.21%)
Total annual Fund operating expenses after fee waivers and/or expense reimbursements	0.46%	0.21%	0.21%	0.21%

(a)	Other expenses for Class A, Class R5, and Class Z shares have been restated to reflect contractual changes to certain fees paid by the Fund.
(b)	“Total annual Fund operating expenses” include acquired fund fees and expenses (expenses the Fund incurs indirectly through its investments in other investment companies) and may be higher than “Net Expenses” shown in the Financial Highlights section of this prospectus because “Net Expenses” do not include acquired fund fees and expenses.
(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, acquired fund fees and expenses, and extraordinary expenses) until June 30, 2015, 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 0.45% for Class A, 0.20% for Class I, 0.20% for Class R5 and 0.20% 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 Mid Cap Index 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)	$47	$193	$352	$815
Class I (whether or not shares are redeemed)	$22	$ 72	$128	$291
Class R5 (whether or not shares are redeemed)	$22	$ 83	$150	$349
Class Z (whether or not shares are redeemed)	$22	$114	$214	$509

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 14% of the average value of its portfolio.

Principal Investment Strategies

Under normal circumstances, the Fund invests at least 80% of its net assets (including the amount of any borrowings for investment purposes) in common stocks that comprise the S&P MidCap 400 Index (the Index). The Fund may invest in derivatives, consisting of stock index futures, as substitutes for the underlying securities in the Index.

Different common stocks have different weightings in the Index, depending on the amount of stock outstanding and the stock’s current price. In seeking to match the performance of the Index, Columbia Management Investment Advisers, LLC (the Investment Manager) attempts to allocate the Fund’s assets among common stocks in approximately the same weightings as the Index. This is referred to as a passive or indexing approach to investing. As a result of the Fund’s indexing approach to investing, the Fund will typically emphasize within the portfolio those economic sectors emphasized by the Index, such as the financial services sector.

The Fund attempts to achieve at least a 95% correlation between the performance of the Index and the Fund’s investment results, before fees and expenses.

Principal Risks

An investment in the Fund involves risk, 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.

Derivatives Risk. Losses involving derivative instruments may be substantial, because a relatively small movement in the price of an underlying security, instrument, commodity, currency or index may result in a substantial loss for the Fund. In addition to the potential for increased losses, the use of derivative instruments may lead to increased volatility within the Fund. Derivative investments will typically increase the Fund’s exposure to principal risks to which it is otherwise exposed, and may expose the Fund to additional risks, including correlation risk, counterparty risk, hedging risk, leverage risk and/or liquidity risk.

Columbia Mid Cap Index Fund

Derivatives Risk/Futures Contracts Risk. The loss that may be incurred in entering into futures contracts may exceed the amount of the premium paid and may be potentially unlimited. Futures markets are highly volatile and the use of futures may increase the volatility of the Fund’s NAV. Additionally, as a result of the low collateral deposits normally involved in futures trading, a relatively small price movement in a futures contract may result in substantial losses to the Fund. Futures contracts may be illiquid. Furthermore, exchanges may limit fluctuations in futures contract prices during a trading session by imposing a maximum permissible price movement on each futures contract. The Fund may be disadvantaged if it is prohibited from executing a trade outside the daily permissible price movement. Futures contracts executed on foreign exchanges may not provide the same protection as U.S. exchanges. These transactions involve additional risks, including counterparty risk, hedging risk and pricing risk.

Index Risk. The Fund's value will generally decline when the performance of its targeted index declines. In addition, because the Fund may not hold all issues included in its index, it may not always be fully invested. The Fund also bears advisory, administrative and other expenses and transaction costs in trading securities, which the index does not bear. Accordingly, the Fund's performance will likely fail to match the performance of its targeted index, after taking expenses into account. It is not possible to invest directly in an index.

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.

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. Although equity securities generally tend to have greater price volatility than debt securities, under certain market conditions debt securities may have comparable or greater price volatility.

Mid-Cap Company Securities Risk. Investments in mid-capitalization companies (mid-cap companies) often involve greater risks than investments in larger, more established companies (larger companies) because 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, and may be less liquid than the securities of larger companies.

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business in a related group of industries within an economic sector, including the financial services sector. Companies in the same economic sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. The more a fund diversifies its investments, the more it spreads risk and potentially reduces the risks of loss and volatility.

The Fund may be more susceptible to the particular risks that may affect companies in the financial services sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the financial services sector are subject to certain risks, including the risk of regulatory change, decreased liquidity in credit markets and unstable interest rates. Such companies may have concentrated portfolios, such as a high level of loans to real estate developers, which makes them vulnerable to economic conditions that affect that industry. Performance of such companies may be affected by competitive pressures and exposure to investments or agreements that, under certain circumstances, may lead to losses (e.g., subprime loans). Companies in the financial services sector are subject to extensive governmental regulation that may limit the amount and types of loans and other financial commitments they can make, and interest rates and fees that they may charge. In addition, profitability of such companies is largely dependent upon the availability and the cost of capital.

Tracking Error Risk. The Fund will not track its benchmark index perfectly and the Fund may not outperform the index. The tools that the Investment Manager uses to replicate the index are not perfect and the Fund’s performance may be impacted by the size of the Fund’s portfolio, the effectiveness of sampling techniques, transaction costs, management fees and expenses, brokerage commissions and fees, the extent and timing of cash flows in and out of the Fund and changes in the index.

3	Columbia Mid Cap Index Fund

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. The bar chart shows how the Fund’s Class A share performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with benchmark performance.

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. 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-deferred 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.

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 columbiamanagement.com.

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}	_19.84%
	_Worst	_{4th Quarter 2008}	_-25.53%

*	Year to Date return as of March 31, 2014: 2.91%

Average Annual Total Returns After Applicable Sales Charges (for periods ended December 31, 2013)

	Share Class Inception Date	1 Year	5 Years	10 Years
Class A	05/31/2000
returns before taxes		32.92%	21.35%	9.96%
returns after taxes on distributions		31.53%	20.59%	8.97%
returns after taxes on distributions and sale of Fund shares		19.54%	17.56%	8.09%
Class I returns before taxes	09/27/2010	33.20%	21.65%	10.24%
Class R5 returns before taxes	11/08/2012	33.35%	21.67%	10.25%
Class Z returns before taxes	03/31/2000	33.28%	21.65%	10.24%
S&P MidCap 400 Index (reflects no deductions for fees, expenses or taxes)		33.50%	21.89%	10.36%

Columbia Mid Cap Index Fund

Fund Management

Investment Manager: Columbia Management Investment Advisers, LLC

Portfolio Manager	Title	Role with Fund	Managed Fund Since
Alfred Alley III, CFA	Portfolio Manager	Co-manager	2009
Vadim Shteyn	Associate Portfolio Manager	Co-manager	2011

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
columbiamanagement.com		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
Class A	All accounts other than IRAs	$2,000	$100
Class A	IRAs	$1,000	$100
Class I	All eligible accounts	None	N/A
Class R5	Combined underlying accounts of eligible registered investment advisers	$100,000	N/A
Class R5	Omnibus retirement plans	None	N/A
Class Z	All eligible accounts	$0, $1,000 or $2,000 depending upon the category of eligible investor	$100

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. 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.

5	Columbia Mid Cap Index Fund

225 Franklin Street, Boston, MA 02110

800.345.6611 columbiamanagement.com

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