Summary Prospectus
April 1, 2015

Loomis Sayles Emerging Markets Opportunities Fund

Ticker Symbol: Class A (LEOAX), Class C (LEOCX), Class N (LEONX) and Class Y (LEOYX)

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 and other information about the Fund online at ngam.natixis.com/funddocuments. You can also get this information at no cost by calling 800-225-5478 or by sending an e-mail request to NatixisFunds@ngam.natixis.com. The Fund's Prospectus and Statement of Additional Information, each dated April 1, 2015, are incorporated by reference into this Summary Prospectus.

Fund Summary

Investment Goal

The Fund seeks to provide high total investment return through a combination of high current income and capital appreciation.

Fund Fees & Expenses

The following table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in the Natixis Fund Complex. More information about these and other discounts is available from your financial professional and in the section "How Sales Charges Are Calculated" on page 49 of the Prospectus and on page 104 in the section "Reduced Sales Charges" of the Statement of Additional Information ("SAI").

Shareholder Fees

(fees paid directly from your investment)	Class A		Class C		Class N	Class Y
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	4.50	%	None		None	None
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, as applicable)	None1		1.00	%	None	None
Redemption fees	None		None		None	None

¹ A 1.00% contingent deferred sales charge ("CDSC") may apply to certain purchases of Class A shares of $1,000,000 or more that are redeemed within eighteen months of the date of purchase.

Annual Fund Operating Expenses

(expenses that you pay each year as a percentage of the value of your investment)	Class A		Class C		Class N		Class Y
Management fees	0.75	%	0.75	%	0.75	%	0.75	%
Distribution and/or service (12b-1) fees	0.25	%	1.00	%	0.00	%	0.00	%
Other expenses1	0.69	%	0.68	%	7.51	%	0.69	%
Acquired fund fees and expenses2	0.03	%	0.03	%	0.03	%	0.03	%
Total annual fund operating expenses	1.72	%	2.46	%	8.29	%	1.47	%
Fee waiver and/or expense reimbursement3,4	0.44	%	0.43	%	7.31	%	0.44	%
Total annual fund operating expenses after fee waiver and/or expense reimbursement	1.28	%	2.03	%	0.98	%	1.03	%

¹ Other expenses have been restated to reflect current custodian and transfer agency fees for the Fund effective October 1, 2014.

² The expense information shown in the table differs from the expense information disclosed in the Fund's financial highlights table because the financial highlights table reflects the operating expenses of the Fund and does not include acquired fund fees and expenses.

³ Loomis, Sayles & Company, L.P. ("Loomis Sayles" or the "Adviser") has given a binding contractual undertaking to the Fund to limit the amount of the Fund's total annual fund operating expenses to 1.25%, 2.00%, 0.95% and 1.00% of the Fund's average daily net assets for Class A, C, N and Y shares, respectively, exclusive of brokerage expenses, interest expense, taxes, acquired fund fees and expenses, organizational and extraordinary expenses, such as litigation and indemnification expenses. This undertaking is in effect through March 31, 2016 and may be terminated before then only with the consent of the Fund's Board of Trustees. The Adviser will be permitted to recover, on a class-by-class basis, management fees waived and/or expenses reimbursed to the extent that expenses in later periods fall below 1.25%, 2.00%, 0.95% and 1.00% of the Fund's average daily net assets for Class A, C, N and Y shares, respectively. The Fund will not be obligated to repay any such waived/reimbursed fees and expenses more than one year after the end of the fiscal year in which the fees or expenses were waived/reimbursed.

⁴ NGAM Advisors has given a binding contractual undertaking to the Fund to reimburse any and all transfer agency expenses for Class N shares. This undertaking is in effect through March 31, 2016 and may be terminated before then only with the consent of the Fund's Board of Trustees.

Example

This 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 assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods (except where indicated). The example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same, except that the example is based on the Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement for the first year and on the Total Annual Fund Operating Expenses for the remaining periods. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

If shares are redeemed:	1 year		3 years		5 years		10 years
Class A	$	575	$	927	$	1,302	$	2,354
Class C	$	306	$	726	$	1,272	$	2,764
Class N	$	100	$	1,768	$	3,329	$	6,802
Class Y	$	105	$	422	$	761	$	1,720

If shares are not redeemed:	1 year		3 years		5 years		10 years
Class C	$	206	$	726	$	1,272	$	2,764

Portfolio Turnover

The Fund pays 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 for you if your 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 period February 10, 2014 (the Fund's inception date) through November 30, 2014, the Fund's portfolio turnover rate was 58% of the average value of its portfolio.

Investments, Risks and Performance

Principal Investment Strategies

The Fund will typically invest the majority of its assets in fixed-income securities and derivative instruments based on fixed-income securities. Under normal market conditions, the Fund expects to invest at least 80% of its net assets (plus any borrowings made for investment purposes) in investments that are economically tied to emerging market countries. These investments may include, among other things, securities, currencies and derivative instruments.  The Fund may invest in foreign currencies and may engage in other foreign currency transactions for investment or hedging purposes. The Fund may also invest up to 20% of its assets in equity securities (including common stock, preferred stock and investment companies). Securities purchased by the Fund may be denominated in any currency.

Emerging market countries include any country determined by the Adviser to have an emerging market economy, taking into account a number of factors. These factors may include whether the country has a low- to middle-income economy according to the International Bank for Reconstruction and Development (also known as the World Bank), the country's foreign currency debt rating, its location and neighboring countries, its political and economic stability and the development of its financial and capital markets. These countries may include those located in Latin America and the Caribbean, Asia, Africa, the former Soviet Union, the Middle East and the developing countries of Europe (primarily Central and Eastern Europe).

In deciding which investments to buy and sell, the Adviser combines a bottom-up, fundamental approach with a broad, macroeconomic and country-specific top-down analysis. The Adviser uses proprietary quantitative tools to allocate risks, to understand correlations and interdependencies of portfolio investments and to simulate portfolio outcomes under different market scenarios. All portfolio positions are monitored for risk efficiency, with the goal of limiting specific country, issuer, industry and sector risks.

The fixed-income securities in which the Fund may invest include, but are not limited to, public or private debt obligations of any type issued by corporations, governments (including their agencies, instrumentalities and sponsored entities), supranational entities, partnerships and trusts. The Fund may invest in fixed-income securities of any maturity, duration or credit quality (including below investment grade fixed-income securities (also known as "junk bonds")). There is no minimum credit rating for securities in which the Fund will invest. Below investment grade fixed-income securities are rated below investment grade quality (i.e., none of the three major ratings agencies (Moody's Investor Service, Inc., Fitch Ratings, Inc. or Standard & Poor's Ratings Group, Inc.) have rated the securities in one of its top four ratings categories) or, if unrated, are determined by the Adviser to be of comparable quality. The Fund may also invest in convertible securities, inflation-linked bonds, securities issued pursuant to Rule 144 under the Securities Act of 1933 ("Rule 144A securities"), step coupon securities, zero-coupon securities and variable and floating rate securities issued by any of the above-named entities.

The Fund may invest in derivative instruments including, but not limited to, futures contracts, forward contracts, options and swap transactions (such as interest rate swaps and credit default swaps) for both investment and hedging purposes. The Fund may, at times, invest a substantial portion of its assets in derivatives and securities used to support its obligations under those derivatives. The Fund will pursue its investment goal by generally obtaining its long investment exposures through direct cash investments and derivatives and short investment exposures substantially through derivatives. A "long" investment exposure is an investment that rises in value with a corresponding rise in the value of an asset, asset class or index and declines in value with a corresponding decline in the value of that asset, asset class or index. A "short" investment exposure is an investment that rises in value with a corresponding decline in the value of an asset, asset class or index and declines in value with a corresponding rise in the value of that asset, asset class or index.

Although the Fund typically invests the majority of its assets in fixed-income securities and derivative instruments, the Fund may hold a significant portion of its assets in cash (including non-U.S. currencies) and/or invest in money market instruments or other high quality debt securities if the Adviser believes current market conditions do not provide sufficient investment opportunities. The Fund may miss certain investment opportunities if it uses such a strategy and thus may not achieve its investment objective.

The Fund is non-diversified, which means that it may invest a greater percentage of its assets in a particular issuer and may invest in fewer issuers than a diversified fund. Because the Fund may invest in the securities of a limited number of issuers, an investment in the Fund may involve a higher degree of risk than would be present in a diversified fund.

Principal Risks

The principal risks of investing in the Fund are summarized below. The Fund does not represent a complete investment program. You may lose money by investing in the Fund.

Below Investment Grade Fixed-Income Securities Risk: The Fund's investments in below investment grade fixed-income securities, also known as "junk bonds," may be subject to greater risks than other fixed-income securities, including being subject to greater levels of interest rate risk, credit risk (including a greater risk of default) and liquidity risk. The ability of the issuer to make principal and interest payments is predominantly speculative for below investment grade fixed-income securities.

Changing Distribution Level Risk: The amount of the distributions paid by the Fund will vary and generally depends on the amount of interest income and/or dividends received by the Fund on the securities it holds.  The Fund may not be able to pay distributions or may have to reduce its distribution level if the interest income and/or dividends the Fund receives from its investments decline.

Credit/Counterparty Risk: Credit risk is the risk that the issuer or the guarantor of a fixed-income security, or the counterparty to a derivatives or other transaction, will be unable or unwilling to make timely payments of interest or principal or to otherwise honor its obligations. The Fund will be subject to credit risks with respect to the counterparties of its derivative transactions. Many of the protections afforded to participants on organized exchanges, such as the performance guarantee of an exchange clearing house, are not available in connection with over-the-counter ("OTC") derivative transactions, such as foreign currency transactions. As a result, in instances when the Fund enters into OTC derivative transactions, the Fund will be subject to the risk that its direct counterparties will not perform their obligations under the transactions and that the Fund will sustain losses or be unable to realize gains.

Currency Risk: Fluctuations in the exchange rates between different currencies may negatively affect an investment. The Fund may be subject to currency risk because it may invest a significant portion of its assets in currency-related instruments and may invest in securities or other instruments denominated in, or receive revenues in, foreign currencies. The Adviser may elect not to hedge currency risk, or may hedge such risk imperfectly, which may cause the Fund to incur losses that would have not been incurred had the risk been hedged.

Derivatives Risk: Derivative instruments (such as those in which the Fund may invest, including futures contracts, forward contracts, options and swap transactions) are subject to changes in the value of the underlying assets or indices on which such instruments are based. There is no guarantee that the use of derivatives will be effective or that suitable transactions will be available. Even a small investment in derivatives may give rise to leverage risk and can have a significant impact on the Fund's exposure to securities markets values, interest rates or currency exchange rates. It is possible that the Fund's liquid assets may be insufficient to support its obligations under its derivatives positions. The use of derivatives for other than hedging purposes may be considered a speculative activity, and involves greater risks than are involved in hedging. The use of derivatives may cause the Fund to incur losses greater than those that would have occurred had derivatives not been used. The Fund's use of derivatives involves other risks, such as the credit risk relating to the other party to a derivative contract (which is greater for forward currency contracts, swaps and other over-the-counter traded derivatives), the risk of difficulties in pricing and valuation, the risk that changes in the value of a derivative may not correlate as expected with changes in the value of relevant assets, rates or indices, liquidity risk, allocation risk and the risk of losing more than the initial margin required to initiate derivatives positions. There is also the risk that the Fund may be unable to terminate or sell a derivatives position at an advantageous time or price. The Fund's derivative counterparties may experience financial difficulties or otherwise be unwilling or unable to honor their obligations, possibly resulting in losses to the Fund. 

Emerging Markets Risk: In addition to the risks of investing in foreign investments generally, emerging markets investments are subject to greater risks arising from political or economic instability, nationalization or confiscatory taxation, currency exchange restrictions, sanctions by the U.S. government and an issuer's unwillingness or inability to make principal or interest payments on its obligations.  Emerging markets companies may be smaller and have shorter operating histories than companies in developed markets.

Equity Securities Risk: The value of the Fund's investments in equity securities could be subject to unpredictable declines in the value of individual securities and periods of below-average performance in individual securities or in the equity market as a whole. Rule 144A securities may be less liquid than other equity securities. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of the issuer's bonds generally take precedence over the claims of those who own preferred stock or common stock.

Fixed-Income Securities Risk: Fixed-income securities are subject to credit risk, interest rate risk and liquidity risk. You may lose money on your investment due to unpredictable drops in a security's value or periods of below-average performance in a given security or in the securities market as a whole. Zero-coupon bonds may be subject to these risks to a greater extent than other fixed-income securities. Rule 144A securities may be less liquid than other fixed-income securities. In addition, an economic downturn or period of rising interest rates could adversely affect the market of these securities and reduce the Fund's ability to sell them.

Foreign Securities Risk: Investments in foreign securities may be subject to greater political, economic, environmental, credit and information risks. The Fund's investments in foreign securities also are subject to foreign currency fluctuations and other foreign currency-related risks. Foreign securities may be subject to higher volatility than U.S. securities, varying degrees of regulation and limited liquidity.

Interest Rate Risk: Interest rate risk is the risk that the value of the Fund's investments will fall if interest rates rise. Generally, the value of fixed-income securities rises when prevailing interest rates fall and falls when interest rates rise.  Interest rate risk generally is greater for funds that invest in fixed-income securities with relatively longer durations than for funds that invest in fixed-income securities with shorter durations. The value of zero-coupon bonds may be more sensitive to fluctuations in interest rates than other fixed-income securities. In addition, an economic downturn or period of rising interest rates could adversely affect the market of these securities and reduce the Fund's ability to sell them, negatively impacting the performance of the Fund.

Investments in Other Investment Companies Risk: The Fund will indirectly bear the management, service and other fees of any other investment companies, including ETFs, in which it invests in addition to its own expenses.

Issuer Risk: The value of the Fund's investments may decline for a number of reasons that directly relate to the issuer, such as management performance, financial leverage and reduced demand for the issuer's goods and services.

Large Investor Risk: Ownership of shares of the Fund may be concentrated in one or a few large investors. Such investors may redeem shares in large quantities or on a frequent basis. Redemptions by a large investor can affect the performance of the Fund, may increase realized capital gains, may accelerate the realization of taxable income to shareholders and may increase transaction costs. These transactions potentially limit the use of any capital loss carryforwards and certain other losses to offset future realized capital gains (if any). Such transactions may also increase the Fund's expenses.

Leverage Risk: Use of derivative instruments may involve leverage. Taking short positions in stocks also results in a form of leverage. Leverage is the risk associated with securities or practices that multiply small index, market or asset-price movements into larger changes in value. The use of leverage increases the impact of gains and losses on a fund's returns, and may lead to significant losses if investments are not successful.

Liquidity Risk: Liquidity risk is the risk that the Fund may be unable to find a buyer for its investments when it seeks to sell them or to receive the price it expects. Events that may lead to increased redemptions, such as market disruptions or increases in interest rates, may also negatively impact the liquidity of the Fund's investments when it needs to dispose of them. If the Fund is forced to sell its investments at an unfavorable time and/or under adverse conditions in order to meet redemption requests, such sales could negatively affect the Fund. Securities acquired in a private placement, such as Rule 144A securities, are generally subject to greater liquidity risk because they are subject to strict restrictions on resale and there may be no liquid secondary market or ready purchaser for such securities. Non-exchange traded derivatives are generally subject to greater liquidity risk as well. Liquidity issues may also make it difficult to value the Fund's investments.

Management Risk: A strategy used by the Fund's portfolio managers may fail to produce the intended result.

Market Risk: The market value of a security or portfolio will move up and down, sometimes rapidly and unpredictably, based upon a change in an issuer's financial condition, as well as overall market and economic conditions.

Non-Diversification Risk: Compared with other mutual funds, the Fund may invest a greater percentage of its assets in a particular issuer and may invest in fewer issuers. Therefore, the Fund may have more risk because changes in the value of a single security or the impact of a single economic, political or regulatory occurrence may have a greater adverse impact on the Fund's NAV.

Short Exposure Risk: A short exposure through a derivative may present various risks, including credit/counterparty risk and leverage risk. If the value of the asset, asset class or index on which the Fund has obtained a short investment exposure increases, the Fund will incur a loss. Unlike a direct cash investment such as a stock, bond or exchange-traded fund, where the potential loss is limited to the purchase price, the potential risk of loss from a short exposure is theoretically unlimited. Moreover, there can be no assurance that securities necessary to cover a short position will be available for purchase.

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 currency exchange when 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. Sovereign debt risk is increased for emerging market issuers.

Risk/Return Bar Chart and Table

Because the Fund has not yet completed a full calendar year, information related to Fund performance, including a bar chart showing annual returns, has not been included in this Prospectus. The performance information provided by the Fund in the future will give some indication of the risks of an investment in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns compare against those of a broad measure of market performance.

Management

Investment Adviser

Loomis, Sayles & Company, L.P. ("Loomis Sayles")

Portfolio Managers

Elisabeth Colleran, CFA^®, Vice President of the Adviser, has served as co-portfolio manager of the Fund since 2014.

Peter A. Frick, CFA^®, Vice President of the Adviser, has served as co-portfolio manager of the Fund since 2014.

Peter N. Marber, Vice President and Head of Emerging Markets Investments of the Adviser, has served as co-portfolio manager of the Fund since 2014.

David W. Rolley, CFA^®, Vice President of the Adviser, has served as co-portfolio manager of the Fund since 2014.

Edgardo Sternberg, Vice President of the Adviser, has served as co-portfolio manager of the Fund since 2014.

Purchase and Sale of Fund Shares

Class A and C Shares

The following chart shows the investment minimums for various types of accounts:

Type of Account	Minimum Initial Purchase			Minimum Subsequent Purchase
Any account other than those listed below	$	2,500	$	100
For shareholders participating in Natixis Funds' Investment Builder Program	$	1,000	$	50
For Traditional IRA, Roth IRA, Rollover IRA, SEP-IRA and Keogh plans using the Natixis Funds' prototype document (direct accounts, not held through intermediary)	$	1,000	$	100
Coverdell Education Savings Accounts using the Natixis Funds' prototype document (direct accounts, not held through intermediary)	$	500	$	100

Class N Shares

Class N shares of the Fund are intended primarily for employer-sponsored retirement plans held in an omnibus fashion and are not available for purchase by individual investors. Class N shares are also available to fund of funds that are distributed by NGAM Distribution, L.P. (the "Distributor").  There is no minimum initial or subsequent investment for these shares. Please see the section "How to Buy Shares" in the SAI for details.

Class Y Shares

Class Y shares of the Fund may be purchased by the following entities at the following investment minimums.

A minimum initial investment of $100,000 and the minimum subsequent investment of $100 for:

■

Other mutual funds, endowments, foundations, bank trust departments or trust companies.

There is no initial or subsequent investment minimum for:

■

Wrap Fee Programs of certain broker-dealers, the advisers or the Distributor. Please consult your financial representative to determine if your wrap fee program is subject to additional or different conditions or fees.

■

Retirement Plans such as 401(a), 401(k) or 457 plans.

■

Certain Individual Retirement Accounts if the amounts invested represent rollover distributions from investments by any of the retirement plans invested in the Fund.

■

Registered Investment Advisers investing on behalf of clients in exchange for an advisory, management or consulting fee.

■

Fund Trustees, former Fund trustees, employees of affiliates of the Natixis Funds and other individuals who are affiliated with any Natixis Fund (this also applies to any spouse, parents, children, siblings, grandparents, grandchildren and in-laws of those mentioned) and Natixis affiliate employee benefit plans.

Due to operational limitations at your financial intermediary, certain wrap fee programs, retirement plans, individual retirement accounts and accounts of registered investment advisers may be subject to the investment minimums described above.

The Fund's shares are available for purchase and are redeemable on any business day through your investment dealer, directly from the Fund by writing to the Fund at Natixis Funds, P.O. Box 219579, Kansas City, MO 64121-9579, by exchange, by wire, by internet at ngam.natixis.com, through the Automated Clearing House system, or, in the case of redemptions, by telephone at 800-225-5478 or by the Systematic Withdrawal Plan. 

Tax Information

Fund distributions are generally taxable to you as ordinary income or capital gains, except for distributions to retirement plans and other investors that qualify for tax-exempt treatment under U.S. federal income tax law generally. Investments in such tax-advantaged plans will generally be taxed only upon withdrawal of monies from the tax-exempt arrangement.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer or other financial intermediary (such as a bank), the Fund and its related companies may pay the intermediary for the sale of the Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary's website for more information.

UEM77-0415