MainStay Epoch U.S. All Cap Fund

MainStay Epoch U.S. All Cap Fund

Investment Objective

The Fund seeks long-term capital appreciation.

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 be required to pay a commission or other transaction charge to your financial intermediary for effecting transactions in a class of shares of the Fund that has no initial sales charge, contingent deferred sales charge, or other asset-based fee for sales or distribution, such as SIMPLE Class. These commissions are not reflected in the fee and expense table or expense example below.

Shareholder Fees (fees paid directly from your investment)

Shareholder Fees	MainStay Epoch U.S. All Cap Fund SIMPLE Class
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	none
Maximum Deferred Sales Charge (Load) (as a percentage of the lesser of the original offering price or redemption proceeds)	none

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses	MainStay Epoch U.S. All Cap Fund SIMPLE Class
Management Fees (as an annual percentage of the Fund's average daily net assets)	0.84%	[1]
Distribution and/or Service (12b-1) Fees	0.50%
Other Expenses	0.44%	[2]
Total Annual Fund Operating Expenses	1.78%
Waivers / Reimbursements	(0.03%)	[3]
Total Annual Fund Operating Expenses After Waivers / Reimbursements	1.75%	[3]

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 whether or not you redeem all of your shares at the end of those periods. 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:

Expense Example	MainStay Epoch U.S. All Cap Fund SIMPLE Class USD ($)
1 Year	$ 178
3 Years	557
5 Years	962
10 Years	$ 2,092

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 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 51% of the average value of its portfolio.

Principal Investment Strategies

The Fund invests primarily in a diversified portfolio consisting of equity securities of U.S. companies. Under normal circumstances, the Fund will invest at least 80% of its assets (net assets plus any borrowings for investment purposes) in equity securities of U.S. companies across all market capitalizations. Generally, U.S. companies are companies organized in the United States or companies that issue securities that trade primarily in U.S. securities markets. Equity securities include common stocks and securities convertible into common stock, such as warrants, rights, convertible bonds, debentures and convertible preferred stock. Convertible preferred stocks and debentures must be rated investment grade by a nationally recognized statistical rating organization when purchased, or if unrated, considered by Epoch Investment Partners, Inc., the Fund’s Subadvisor, to be of comparable quality.

Investment Process: The Subadvisor invests primarily in companies that generate increasing levels of free cash flow and have management teams that the Subadvisor believes allocate free cash flow effectively to create shareholder value.

The security selection process focuses on free-cash-flow analytics as opposed to traditional accounting-based metrics. The Subadvisor seeks to identify companies with a consistent, straightforward ability to both generate free cash flow and to intelligently allocate it among internal reinvestment opportunities, acquisitions, dividends, share repurchases and/or debt reduction.

The Subadvisor may sell or reduce a position in a security when it believes its investment objectives have been met or if the investment thesis is failing to materialize. The Subadvisor may also sell or reduce a position in a security when the security is deemed less attractive relative to another security on a return/risk basis.

Although the Fund may invest in securities of companies across all market capitalizations, it may invest a significant portion of its assets in companies of one particular market capitalization category when the Subadvisor believes such companies offer attractive opportunities. The Fund may also invest up to 15% of its net assets in foreign securities. Generally, foreign securities are issued by companies organized outside the United States or that trade primarily in non-U.S. securities markets.

Principal Risks

You can lose money by investing in the Fund. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. The investments selected by the Subadvisor may underperform the market in which the Fund invests or other investments. The Fund may receive large purchase or redemption orders which may have adverse effects on performance if the Fund were required to sell securities, invest cash or hold a relatively large amount of cash at times when it would not otherwise do so.

The principal risks of investing in the Fund are summarized below.

Market 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 investment objectives and strategies. Such changes 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 of Fund shares. 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 analyses used by the Subadvisor may not produce the desired results.

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.

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.

Value Stock Risk: Value stocks may never reach what the Subadvisor believes is their full value or they may go down in value. In addition, different types of stocks tend to shift in and out of favor depending on market and economic conditions, and therefore the Fund's performance may be lower or higher than that of funds that invest in other types of equity securities.

Market Capitalization Risk: To the extent the Fund invests in securities issued by small-, mid-, or large-cap companies, the Fund will be subject to the risks associated with securities issued by companies of the applicable market capitalization.  Securities of small-cap and mid-cap companies may be subject to greater price volatility, significantly lower trading volumes, cyclical, static or moderate growth prospects and greater spreads between their bid and ask prices than securities of larger companies. Smaller capitalization companies frequently rely on narrower product lines and niche markets and may be more vulnerable to adverse business or market developments.  Securities issued by larger companies may have less growth potential and may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods.  In addition, larger companies may be less capable of responding quickly to competitive challenges and industry changes, including those resulting from improvements in technology, and may suffer sharper price declines as a result of earnings disappointments.  There is a risk that the securities issued by companies of a certain market capitalization may underperform the broader market at any given time.

Convertible Securities Risk: Convertible securities are typically subordinate to an issuer’s other debt obligations. In part, the total return for a convertible security depends upon the performance of the underlying stock into which it can be converted. Also, issuers of convertible securities are often not as strong financially as those issuing securities with higher credit ratings, are more likely to encounter financial difficulties and typically are more vulnerable to changes in the economy, such as a recession or a sustained period of rising interest rates, which could affect their ability to make interest and principal payments. If an issuer stops making interest and/or principal payments, the Fund could lose its entire investment.

Foreign Securities Risk: Investments in foreign (non-U.S.) securities may be riskier than investments in U.S. securities. Foreign regulatory regimes and securities markets can have less stringent investor protections and disclosure standards and less liquid trading markets than U.S. regulatory regimes and securities markets, and can experience political, social and economic developments that 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. Changes in the value of foreign currencies may make the return on an investment increase or decrease, unrelated to the quality or performance of the investment itself. 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.

Rights and Warrants Risk: Rights and warrants may provide a greater potential for profit or loss than an equivalent investment in the underlying securities. Prices of these investments do not necessarily move in tandem with the prices of the underlying securities, and warrants are speculative investments. If a right or warrant is not exercised by the date of its expiration, the Fund will lose its entire investment in such right or warrant.

Past Performance

SIMPLE Class shares have not commenced operations as of the date of this Prospectus. The following chart and table reflect the performance for the other share classes of the Fund, which are not offered in this Prospectus. The performance of SIMPLE Class shares would be similar to the other share classes because all share classes are invested in the same portfolio of securities and would differ only to the extent that SIMPLE Class shares have different expenses. Because SIMPLE Class shares have higher expenses than all other share classes of the Fund, except Class B and Class C shares, the performance of SIMPLE Class shares would be lower than that of the other share classes, except Class B and Class C shares.

The following bar chart and table 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 time. Sales loads, if any, 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) compare to those of a broad-based securities market index. The Fund has selected the Russell 3000^® Indexas its primary benchmark. The Russell 3000^® Index measures the performance of the largest 3,000 U.S. companies representing approximately 98% of the investable U.S. equity market.

Performance data for the classes varies based on differences in their fee and expense structures. Performance data is not shown for classes with less than one calendar year of performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Please visit nylinvestments.com/funds for more recent performance information.

Annual Returns, Class I Shares (by calendar year 2010-2019)

Best Quarter
4Q/11	13.75	%
Worst Quarter
3Q/11	-18.50	%

As of June 30, 2020, the Class I shares of the Fund had a year to date return of -12.40%.

Average Annual Total Returns (for the periods ended December 31, 2019)

Average Annual Returns - MainStay Epoch U.S. All Cap Fund	1 Year	5 Years or Since Inception	10 Years	Inception Date
Class I	31.44%	8.92%	11.89%	Jan. 02, 1991
Class A	23.89%	7.42%	10.99%	Jan. 02, 2004
Investor Class	23.60%	7.13%	10.60%	Feb. 28, 2008
Class B	24.85%	7.30%	10.39%	Jan. 02, 2004
Class C	28.83%	7.52%	10.38%	Jan. 02, 2004
Class R6	31.55%	8.22%		Feb. 28, 2018
After Taxes on Distributions | Class I	28.25%	6.56%	9.97%
After Taxes on Distributions and Sale of Fund Shares | Class I	20.78%	6.67%	9.52%
Russell 3000® Index (reflects no deductions for fees, expenses, or taxes)	31.02%	11.24%	13.42%

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 I shares. After-tax returns for the other share classes may vary.

[1] The management fee is as follows: 0.85% on assets up to $500 million; 0.825% on assets from $500 million to $1 billion; and 0.80% on assets over $1 billion.

[2] Based on amounts expected to be incurred during the current fiscal year.

[3] New York Life Investment Management LLC ("New York Life Investments") has contractually agreed to limit the transfer agency expenses charged to each of the Fund's share classes to a maximum of 0.35% of that share class's average daily net assets on an annual basis after deducting any applicable Fund or class-level expense reimbursements or small account fees. This agreement will remain in effect until August 31, 2021, 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.