MainStay Large Cap Growth Fund		Summary Prospectus February 29, 2016
Class/Ticker	A MLAAXInvestor MLINXB MLABXC MLACXI MLAIXR1 MLRRXR2 MLRTXR3 MLGRXR6 MLRSX

To Statutory ProspectusTo Statement of Additional Information

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 by going online to mainstayinvestments.com/documents, by calling 800-MAINSTAY (624-6782) or by sending an e-mail to MainStayShareholderServices@nylim.com. The Fund's Prospectus and Statement of Additional Information, both dated February 29, 2016, as may be amended from time to time, are incorporated by reference into this Summary Prospectus.

Investment Objective

The Fund seeks long-term growth of capital.

Fees and Expenses of the Fund

The table below 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 MainStay Funds. This amount may vary depending on the MainStay Fund in which you invest. More information about these and other discounts is available from your financial professional and in the "Information on Sales Charges" section starting on page 100 of the Prospectus and in the "Alternative Sales Arrangements" section on page 111 of the Statement of Additional Information.

		Class A		Investor  Class		Class B		Class C		Class I		Class R1		Class R2		Class R3		Class R6
Shareholder Fees (fees paid directly from your investment)
	Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	5.50	%	5.50	%	None		None		None		None		None		None		None
	Maximum Deferred Sales Charge (Load) (as a percentage of the lesser of the original offering price or redemption proceeds)	None	1	None	1	5.00	%	1.00	%	None		None		None		None		None
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
	Management Fees (as an annual percentage of the Fund's average daily net assets)2	0.60	%	0.60	%	0.60	%	0.60	%	0.60	%	0.60	%	0.60	%	0.60	%	0.60	%
	Distribution and/or Service (12b-1) Fees	0.25	%	0.25	%	1.00	%	1.00	%	None		None		0.25	%	0.50	%	None
	Other Expenses	0.14	%	0.19	%	0.19	%	0.19	%	0.14	%	0.24	%	0.24	%	0.24	%	0.02	%
	Total Annual Fund Operating Expenses	0.99	%	1.04	%	1.79	%	1.79	%	0.74	%	0.84	%	1.09	%	1.34	%	0.62	%
	Waivers / Reimbursements2	(0.02	)%	(0.02	)%	(0.02	)%	(0.02	)%	(0.02	)%	(0.02	)%	(0.02	)%	(0.02	)%	(0.02	)%
	Total Annual Fund Operating Expenses After Waivers / Reimbursements2	0.97	%	1.02	%	1.77	%	1.77	%	0.72	%	0.82	%	1.07	%	1.32	%	0.60	%

1.A contingent deferred sales charge of 1.00% may be imposed on certain redemptions made within one year of the date of purchase on shares that were purchased without an initial sales charge.

2.The management fee is as follows: 0.75% on assets up to $500 million; 0.725% on assets from $500 million to $750 million; 0.71% on assets from $750 million to $1 billion; 0.70% on assets from $1 billion to $2 billion; 0.66% on assets from $2 billion to $3 billion; 0.61% on assets from $3 billion to $7 billion; 0.585% on assets from $7 billion to $9 billion; and 0.575% on assets in excess of $9 billion. New York Life Investment Management LLC (“New York Life Investments”) has contractually agreed to waive a portion of its management fee so that the management fee does not exceed 0.550% on assets from $11 billion to $13 billion; and 0.525% on assets over $13 billion. This agreement will remain in effect until March 1, 2017, and shall renew automatically for one-year terms unless New York Life Investments provides written notice of termination prior to the start of the next term or upon approval of the Board of Trustees of the Fund.

Example

The 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 as indicated with respect to Class B and Class C shares). The Example reflects Class B shares converting into Investor Class shares in years 9-10; fees could be lower if you are eligible to convert to Class A shares instead. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. The Example reflects the contractual fee waiver and/or expense reimbursement arrangement, if applicable, for the current duration of the arrangement only. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expenses After	Class A	Investor	Class B		Class C		Class I	Class R1	Class R2	Class R3	Class R6
		Class	Assuming no redemption	Assuming redemption at end of period	Assuming no redemption	Assuming redemption at end of period
1 Year	$       644	$       648	$       180	$       680	$       180	$       280	$         74	$         84	$       109	$       134	$         61
3 Years	$       846	$       861	$       561	$       861	$       561	$       561	$       235	$       266	$       345	$       423	$       197
5 Years	$    1,065	$    1,091	$       968	$    1,168	$       968	$       968	$       410	$       464	$       599	$       732	$       344
10 Years	$    1,695	$    1,749	$    1,906	$    1,906	$    2,104	$    2,104	$       917	$    1,035	$    1,327	$    1,611	$       772

(NYLIM) NL244 MSLG01-02/16

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 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 66% of the average value of its portfolio.

Principal Investment Strategies

Under normal circumstances, the Fund invests at least 80% of its assets (net assets plus any borrowings for investment purposes) in large capitalization companies, which are companies having a market capitalization in excess of $4 billion at the time of purchase. Typically, Winslow Capital Management, LLC, the Fund's Subadvisor, invests substantially all of the Fund's investable assets in domestic securities. However, the Fund is permitted to invest up to 20% of its net assets in foreign securities, which are generally securities issued by companies organized outside the U.S. and traded primarily in markets outside the U.S.

Investment Process: The Fund invests in those companies that the Subadvisor believes will provide an opportunity for achieving superior portfolio returns (i.e., returns in excess of the returns of the average stock mutual fund) over the long term. The Subadvisor seeks to invest in companies that have the potential for above-average future earnings and cash flow growth with management focused on shareholder value.

When purchasing stocks for the Fund, the Subadvisor looks for companies typically having some or all of the following attributes: addressing markets with growth opportunities; leads or gains in market share; identifiable and sustainable competitive advantages; managed by a team that can perpetuate the firm's competitive advantages; high, and preferably rising, returns on invested capital and deploys excess cash flow to enhance shareholder return.

The Subadvisor takes a "bottom-up" investment approach when selecting investments. This means it bases investment decisions on company specific factors, not general economic conditions.

Under normal market conditions, the Subadvisor employs a sell discipline pursuant to which it may sell some or all of its position in a stock when a stock becomes fully valued, the fundamental business prospects are deteriorating, or the position exceeds limits set by the Subadvisor.

Principal Risks

Loss of Money Risk: Before considering an investment in the Fund, you should understand that you could lose money.

Market Changes Risk: The value of the Fund's investments may fluctuate because of changes in the markets in which the Fund invests, which could cause the Fund to underperform other funds with similar objectives. Changes in these markets may be rapid and unpredictable. From time to time, markets may experience periods of stress for potentially prolonged periods that may result in (i) increased market volatility; (ii) reduced market liquidity; and (iii) increased redemptions. Such conditions may add significantly to the risk of volatility in the net asset value of the Fund's shares.

Portfolio Management Risk: The investment strategies, practices and risk analysis used by the Subadvisor may not produce the desired results. In addition, the Fund may not achieve its investment objective if the Subadvisor takes temporary positions in response to unusual or adverse market, economic or political conditions, or other unusual or abnormal circumstances.

Selection Risk: The investments selected by the Fund's Subadvisor may underperform the market or other investments.

Equity Securities Risk: Investments in common stocks and other equity securities are particularly subject to the risk of changing economic, stock market, industry and company conditions and the risks inherent in the portfolio managers' ability to anticipate such changes that can adversely affect the value of the Fund's holdings. Opportunity for greater gain often comes with greater risk of loss.

Growth Stock Risk: If growth companies do not increase their earnings at a rate expected by investors, the market price of the stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can cushion stock prices in market downturns.

Foreign Securities Risk: Investments in foreign securities may be riskier than investments in U.S. securities. Differences between U.S. and foreign regulatory regimes and securities markets, including less stringent investor protections and disclosure standards of some foreign markets, less liquid trading markets and political and economic developments in foreign countries, may affect the value of the Fund's investments in foreign securities. Foreign securities may also subject the Fund's investments to changes in currency rates. These risks may be greater with respect to securities of companies that conduct their business activities in emerging markets or whose securities are traded principally in emerging markets.

Past Performance

The following bar chart and tables indicate some of the risks of investing in the Fund. The bar chart shows you how the Fund's calendar year performance has varied over the last ten years. Sales loads are not reflected in the bar chart. If they were, returns would be less than those shown. The average annual total returns table shows how the Fund's average annual total returns (before and after taxes) for the one-, five- and ten-year periods compare to those of two broad-based securities market indices. The Fund has selected the Russell 1000^® Growth Indexas its primary benchmark. The Russell 1000^® Growth Index measures the performance of the large-cap growth segment of the U.S. equity universe. It includes those Russell 1000^® Index companies with higher price-to-book ratios and higher forecasted growth values. The Fund has selected the Standard & Poor’s 500^® Index (“S&P 500^® Index”) as a secondary benchmark. The S&P 500^® Index is widely regarded as the standard index for measuring large-cap U.S. stock market performance.

Performance data for the classes varies based on differences in their fee and expense structures. Performance figures for Class R3 shares which were first offered on April 28, 2006, include the historical performance of Class A shares through April 27, 2006. Performance figures for Investor Class shares, first offered on February 28, 2008, include the historical performance of Class A shares through February 27, 2008. Performance figures for Class R6 shares, first offered on June 17, 2013, include the historical performance of Class I shares through June 16, 2013. Performance for these newer share classes is adjusted for differences in certain fees and expenses. Unadjusted, the performance shown for these newer share classes would likely have been different.

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Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Please visit mainstayinvestments.com for more recent performance information.

Annual Returns, Class A Shares

(by calendar year 2006-2015)

Best Quarter
1Q/12	17.20	%
Worst Quarter
4Q/08	-22.57	%

Average Annual Total Returns (for the periods ended December 31, 2015)

	1 Year		5 Years		10 Years
Return Before Taxes
Class A	0.10	%	11.12	%	7.96	%
Investor Class	-0.07	%	11.06	%	7.89	%
Class B	0.51	%	11.22	%	7.70	%
Class C	4.18	%	11.50	%	7.69	%
Class I	6.17	%	12.67	%	8.95	%
Class R1	6.16	%	12.56	%	8.86	%
Class R2	5.82	%	12.28	%	8.60	%
Class R3	5.57	%	12.01	%	8.29	%
Class R6	6.25	%	12.73	%	8.98	%
Return After Taxes on Distributions
Class A	-2.76	%	9.63	%	7.24	%
Return After Taxes on Distributions and Sale of Fund Shares
Class A	2.41	%	8.79	%	6.47	%
Russell 1000® Growth Index (reflects no deductions for fees, expenses, or taxes)	5.67	%	13.53	%	8.53	%
S&P 500® Index (reflects no deductions for fees, expenses, or taxes)	1.38	%	12.57	%	7.31	%

After-tax returns are calculated using the highest individual federal marginal income tax rates in effect at the time of each distribution or capital gain or upon the sale of fund shares, and do not reflect the impact of state and local taxes. In some cases, the return after taxes may exceed the return before taxes due to an assumed tax benefit from any losses on a sale of shares at the end of the measurement period. Actual after-tax returns depend on your tax situation and may differ from those shown. After-tax returns are not relevant if you hold your shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns shown are for Class A shares. After-tax returns for the other share classes may vary.

Management

New York Life Investment Management LLC serves as the Fund's Manager. Winslow Capital Management, LLC serves as the Fund's Subadvisor.

Subadvisor	Portfolio Managers	Service Date
Winslow Capital Management, LLC	Clark J. Winslow, Founder*	Since 2005
	Justin H. Kelly, Chief Executive Officer & Chief Investment Officer	Since 2005
	Patrick M. Burton, Managing Director	Since 2013

* Clark J. Winslow will continue to serve as a portfolio manager for the Fund until December 31, 2016.

How to Purchase and Sell Shares

You may purchase or sell shares of the Fund on any day the Fund is open for business by contacting your financial adviser or financial intermediary firm, or by contacting the Fund by telephone at 800-MAINSTAY (624-6782), by mail at MainStay Funds, P.O. Box 8401, Boston, MA 02266-8401 or by accessing our website at mainstayinvestments.com. Class R6 shares are generally available only to certain retirement plans, including Section 401(a) and 457 plans, certain 403(b)(7) plans, 401(k), profit sharing, money purchase pension and defined benefit plans and non-qualified deferred compensation plans, in each case provided that the plan trades on an omnibus level. Class R6 shares are generally not available to retail accounts. Generally, an initial investment minimum of $1,000 applies if you invest in Investor Class, Class B, or Class C shares, $25,000 for Class A shares, $5,000,000 for individual investors in Class I shares investing directly (i) with the Fund; or (ii) through certain private banks and trust companies that have an agreement with NYLIFE Distributors

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LLC, the Fund’s principal underwriter and distributor, or its affiliates, and $250,000 for Class R6 shares. A subsequent investment minimum of $50 applies to investments in Investor Class, Class B and Class C shares. However, for Investor Class, Class B, or Class C shares purchased through AutoInvest, MainStay’s systematic investment plan, a $500 initial investment minimum and a $50 minimum for subsequent purchases applies. Class R6 shares have no subsequent investment minimum. Class R1 shares, Class R2 shares, Class R3 shares and institutional shareholders in Class I shares have no initial or subsequent investment minimums.

Tax Information

The Fund's distributions are generally taxable to you as ordinary income, capital gains, or a combination of the two, unless you are investing through a tax-deferred arrangement, such as a 401(k) plan or an individual retirement account.

Compensation to Financial Intermediary Firms

If you purchase Fund shares through a financial intermediary firm (such as a broker/dealer or bank), the Fund and its related companies may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the financial intermediary firm or your financial adviser to recommend the Fund over another investment. Ask your financial adviser or visit your financial intermediary firm's website for more information. No compensation, administrative payments, sub-transfer agency payments or service payments are paid to broker/dealers or other financial intermediaries from Fund assets or the Distributor’s or an affiliate’s resources on sales of or investments in Class R6 shares. Class R6 shares do not carry sales commissions or pay Rule 12b-1 fees, or make payments to financial intermediaries to assist in, or in connection with, the sale of the Fund’s shares. For additional information about compensation to financial intermediaries, please see the section entitled "Compensation to Financial Intermediary Firms" in the "Shareholder Guide" section starting on page 106 of the Prospectus.

To Statutory ProspectusTo Statement of Additional Information

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