Summary Prospectus
May 1, 2014

ASG Tactical U.S. Market Fund

Ticker Symbol: Class A (USMAX), Class C (USMCX) and Class Y (USMYX)

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 May 1, 2014 are incorporated by reference into this Summary Prospectus.

Fund Summary

Investment Goal

The Fund seeks long-term capital appreciation, with emphasis on the protection of capital during unfavorable market conditions.

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 $50,000 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 75 of the Prospectus and on page 118 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 Y
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	5.75	%	None		None
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, as applicable)	None		1.00	%	None
Redemption fees	None		None		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 Y
Management fees	0.80	%	0.80	%	0.80	%
Distribution and/or service (12b-1) fees	0.25	%	1.00	%	0.00	%
Other expenses (estimated for the current fiscal year)	0.70	%	0.70	%	0.70	%
Acquired fund fees and expenses (estimated for the current fiscal year)	0.03	%	0.03	%	0.03	%
Total annual fund operating expenses	1.78	%	2.53	%	1.53	%
Fee waiver and/or expense reimbursement1	0.35	%	0.35	%	0.35	%
Total annual fund operating expenses after fee waiver and/or expense reimbursement	1.43	%	2.18	%	1.18	%

¹ AlphaSimplex Group, LLC ("AlphaSimplex" 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 1.40%, 2.15% and 1.15% of the Fund's average daily net assets for Class A, Class C and Class 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 April 30, 2015 and may be terminated before then only with the consent of the Fund's Board of Trustees. The Fund's investment 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 1.40%, 2.15% and 1.15% of the Fund's average daily net assets for Class A, Class C and Class 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 fee/expense was waived/reimbursed.

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 years. 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
Class A	$	712	$	1,071
Class C	$	321	$	754
Class Y	$	120	$	449

If shares are not redeemed:	1 year		3 years
Class C	$	221	$	754

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 from September 30, 2013 (the Fund's inception date) through December 31, 2013, the Fund's portfolio turnover rate was 13% of the average value of its portfolio.

Investments, Risks and Performance

Principal Investment Strategies

The Fund pursues its investment goal primarily through investments in equity securities that broadly represent the U.S. equities market (including common stocks, preferred stocks and exchange-traded funds ("ETFs") related to equity investments); derivative instruments related to the U.S. equities market (primarily futures contracts on U.S. equity indices); and fixed-income securities (including money market and other short-term or variable-rate, high quality securities and related ETFs). Under normal market conditions, the Fund will invest at least 80% of its net assets (plus any borrowings made for investment purposes) in investments that are tied economically to the U.S. The Adviser considers an investment to be tied economically to the U.S. if the investment is included in an index representative of the U.S., the investment's returns are linked to the performance of such an index, or the investment is exposed to the economic risks and returns of the U.S. The Adviser may use quantitative models to determine when to magnify the Fund's exposure to the U.S. equity market, for example, through the purchase of futures contracts, or, alternatively, when to decrease such exposure, for example, through the sale of futures contracts or through the purchase of ETFs that it believes may effectively hedge equity investments. The Adviser may increase the Fund's exposure to the U.S. equity market to up to 130% of the Fund's total assets when it believes that the risk of loss is justified by potential returns. The Adviser may decrease such exposure to as little as 0% of the Fund's total assets, in an attempt to limit the effects of extreme market drawdowns, when it believes that the risk of loss is not offset by potential returns. Such increases and decreases may lag changes in the market, and there is no guarantee that the Adviser's models will accurately predict market movement. Additionally, while the Fund's increased exposure to equity investments may magnify the Fund's potential for gains, it also may magnify the potential for loss. For these reasons, the Fund is intended for long-term investors.

Equity Securities Investments. The equity securities portion of the Fund is managed by NGAM Advisors, L.P. (through its division, Active Investment Advisors) ("NGAM Advisors"), with the exception of any investments in ETFs, which are selected by the Adviser. NGAM Advisors utilizes a proprietary sampling system when deciding which securities to purchase, with the goal of tracking the performance of the large-capitalization U.S. equity market. In an attempt to reduce adverse tax consequences, the portion of the Fund managed by NGAM Advisors may hold securities that are not considered to represent the large-capitalization U.S. equity market, or hold securities in amounts disproportionate to their weights within the large-capitalization U.S. equity market. The portfolio may experience tracking error and is not guaranteed to replicate exactly the large-capitalization U.S. equity market.

Derivative Investments. As discussed above, the Adviser seeks to complement the equity portion of the Fund with investments in derivative instruments intended to enhance return and, during times of significant market decline, mitigate losses. In addition, the Adviser uses futures contracts to manage volatility and adjusts the Fund's exposure to equity investments in times of significantly increased volatility (including, when volatility is more than double the long-term average volatility of the U.S. equity markets). As of March 31, 2014, the long-term average annualized volatility of the U.S. equity markets was 18.2%. The Fund's actual or realized volatility during certain periods or over time may materially exceed its target volatility, for various reasons, including changes in market levels of volatility and because the Fund's portfolio may include instruments that are inherently volatile. The Fund may have both "short" and "long" exposures to equity investments simultaneously. The Fund will benefit from a "short" exposure when equity and equity-related investments decrease in price, and will benefit from a "long" exposure when equity and equity-related investments increase in price.

Fixed-Income Investments. The fixed-income portion of the Fund is managed by Reich & Tang Asset Management, LLC ("Reich & Tang"), with the exception of any investments in ETFs, which are selected by the Adviser. The assets allocated to the fixed-income portion will be used primarily to support the Fund's investments in derivatives and, secondarily, to provide the Fund with incremental income and liquidity. The portion of the Fund managed by Reich & Tang will only invest in high-quality securities that are denominated in U.S. dollars, and will select securities for investment based on various factors, including the security's maturity and rating. Reich & Tang will invest primarily in (i) short-term obligations issued or guaranteed by the United States government, its agencies or instrumentalities; (ii) securities issued by foreign governments, their political subdivisions or agencies or instrumentalities; (iii) certificates of deposit, time deposits and bankers' acceptances issued by domestic and foreign banks, including domestic or foreign branches or subsidiaries of such banks; (iv) variable amount master demand notes; (v) participation interests in loans extended by banks to companies; (vi) commercial paper or similar debt obligations; and (vii) repurchase agreements.

When buying and selling securities and other instruments for the Fund, and when allocating assets to NGAM Advisors or Reich & Tang, the Adviser may consider: (i) the Adviser's proprietary quantitative models, including the outlook on volatility and market decline; (ii) the Fund's obligations under its various derivative positions; (iii) redemption requests; (iv) yield management; (v) credit management; and (vi) volatility management.

The Fund will concentrate its investments in the financial services industry, which means it will normally invest at least 25% of its total assets in securities and other obligations (for example, bank certificates of deposit) of issuers in such industry.

The Fund may engage in active and frequent trading of securities and other instruments. Effects of frequent trading may include high transaction costs, which may lower the Fund's return, and realization of greater short-term capital gains, distributions of which are taxable as ordinary income to taxable shareholders. Trading costs and tax effects associated with frequent trading may adversely affect the Fund's performance. The Fund's trading in derivatives is active and frequent. Active and frequent trading of derivatives, like active and frequent trading of securities, will result in transaction costs that reduce Fund returns.

With the exception of the Fund's 80% policy, the percentage limitations set forth herein are not investment restrictions and the Fund may exceed these limits from time to time. In accordance with applicable requirements of the Securities and Exchange Commission (the "SEC"), the Fund will notify shareholders prior to any change to the 80% policy discussed above taking effect.

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.

Concentrated Investment Risk: The Fund is particularly vulnerable to events affecting companies in the financial services industry because the Fund concentrates its investments in securities and other obligations of issuers in such industry. Examples of risks affecting the financial services industry include changes in governmental regulation, issues relating to the availability and cost of capital, changes in interest rates and/or monetary policy and price competition. In addition, financial services companies are often more highly leveraged than other companies, making them inherently riskier. As a result, the Fund's shares may rise and fall in value more rapidly and to a greater extent than shares of a fund that does not concentrate or focus in a particular industry or economic sector. The risk associated with investing in the Fund may be increased as compared to a fund that does not concentrate in the financial services industry.

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.

Derivatives Risk: Derivative instruments (such as those in which the Fund may invest) can be used to acquire or to transfer the risk and returns of a security or other asset without buying or selling the security or asset. Derivatives are subject to changes in the value of the underlying assets or indices on which such transactions 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, such as futures contracts involves other risks, such as the credit risk relating to the other party to a derivative contract (which is greater for forward contracts and other OTC derivatives), the risk of difficulties in pricing and valuation, the risk that changes in the value of a derivative may not correlate perfectly 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. There is a risk that the Adviser's use of derivatives, such as futures and forward contracts, to manage the Fund's volatility may be ineffective or may exacerbate losses, for example, if the derivative and the underlying assets decrease in value over time.

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.  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.  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.

Index/Tracking Error Risk: This is the risk that, to the extent the Fund's principal investment strategies utilize indices, the Fund's performance may not track that of such indices. For example, the equity securities selected by the Fund may not provide investment performance matching that of broad-based large capitalization U.S. equity indices. Similarly, changes in the value of the derivatives in which the Fund invests may not correlate perfectly with the underlying assets or index associated with such derivatives. Moreover, the ETFs in which the Fund invests may not replicate the performance of the indices they track and may, therefore, result in loss to the Fund.

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.  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. A period of rising interest rates could negatively impact 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 in which it invests in addition to its own expenses. In addition, investments in ETFs have unique characteristics, including, but not limited to, the expense structure and additional expenses associated with investing in ETFs.

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 securities may also result 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 exists when particular investments are difficult to purchase or sell, possibly preventing the Fund from transacting in these illiquid securities at an advantageous price or time. A lack of liquidity also may cause the value of investments to decline.  Illiquid investments also may be difficult to value.

Management Risk:  A strategy used by the Fund's portfolio managers may fail to produce the intended result. The Adviser utilizes various proprietary quantitative models to identify investment opportunities. There is a possibility that one or all of the quantitative models may fail to identify profitable opportunities at any time. Furthermore, they may incorrectly identify opportunities and these misidentified opportunities may lead to substantial losses.

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. The Fund's Adviser will attempt to reduce this risk by implementing various volatility management strategies and techniques. However, there is no guarantee that such strategies and techniques will produce the intended result.

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.

U.S. Government Securities Risk: Investments in certain U.S. government securities may not be supported by the full faith and credit of the U.S. government. Accordingly, no assurance can be given that the U.S. government will provide financial support to U.S. government agencies, instrumentalities or sponsored enterprises if it is not obligated to do so by law. The maximum potential liability of the issuers of some U.S. government securities held by the Fund may greatly exceed their current resources, and it is possible that these issuers will not have the funds to meet their payment obligations in the future. In such a case, the Fund would have to look principally to the agency, instrumentality or sponsored enterprise issuing or guaranteeing the security for ultimate repayment, and the Fund may not be able to assert a claim against the U.S. government itself in the event the agency, instrumentality or sponsored enterprise does not meet its commitment. Concerns about the capacity of the U.S. government to meet its obligations may raise the interest rates payable on its securities, negatively impacting the price of such securities already held by the Fund.

Valuation Risk: This is the risk that the Fund has valued certain securities at a higher price than the price at which they can be sold. This risk may be especially pronounced for investments, such as derivatives, that may be illiquid or may become illiquid.

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

AlphaSimplex Group, LLC

Investment Subadvisers

NGAM Advisors, L.P. (through its division, Active Investment Advisors)

Reich & Tang Asset Management, LLC

Portfolio Managers

AlphaSimplex
Andrew W. Lo, Chief Investment Strategist of the Adviser, has served as co-portfolio manager of the Fund since 2013.

Alexander D. Healy, Director of Strategic Research of the Adviser, has served as co-portfolio manager of the Fund since 2013.

Peter A. Lee, Senior Research Scientist for the Adviser, has served as co-portfolio manager of the Fund since 2014.

Philippe P. Lüdi, CFA, Senior Research Scientist for the Adviser, has served as co-portfolio manager of the Fund since 2014.

Robert W. Sinnott, Research Scientist for the Adviser, has served as co-portfolio manager of the Fund since 2014.

NGAM Advisors
Kevin H. Maeda, Chief Investment Officer for the Active Investment Advisors division of NGAM Advisors, has served as co-portfolio manager of the Fund since 2013. 

Serena V. Stone, CFA, Assistant Vice President for the Active Investment Advisors division of NGAM Advisors, has served as co-portfolio manager of the Fund since 2013. 

Reich & Tang
Robert S. Rickard, Senior Vice President and head of Portfolio Management and Trading of Reich & Tang, has served as co-portfolio manager of the Fund since 2013.

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	$	500	$	100

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 NGAM Distribution, L.P. (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.

UATM77-0514