MainStay MacKay Convertible Fund

MainStay MacKay Convertible Fund

Investment Objective

The Fund seeks capital appreciation together with current income.

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 MacKay Convertible 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 MacKay Convertible Fund SIMPLE CLASS
Management Fees (as an annual percentage of the Fund's average daily net assets)	0.57%	[1]
Distribution and/or Service (12b-1) Fees	0.50%
Other Expenses	0.35%	[2]
Acquired (Underlying) Fund Fees and Expenses	0.01%
Total Annual Fund Operating Expenses	1.43%

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 MacKay Convertible Fund SIMPLE CLASS USD ($)
1 Year	$ 146
3 Years	452
5 Years	782
10 Years	$ 1,713

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 23% of the average value of its portfolio.

Principal Investment Strategies

The Fund, under normal circumstances, invests at least 80% of its assets (net assets plus any borrowings for investment purposes) in "convertible securities" such as bonds, debentures, corporate notes, and preferred stocks or other securities that are convertible into common stock or the cash value of a stock or a basket or index of equity securities. The balance of the Fund may be invested or held in non-convertible debt, equity securities that do not pay regular dividends, U.S. government securities, and cash or cash equivalents.

Investment Process: The Fund takes a flexible approach by investing in a broad range of securities of a variety of companies and industries. The Fund invests in investment grade and below investment grade debt securities. Below investment grade securities are generally securities that receive low ratings from a nationally recognized statistical rating organization (“NRSRO”), or if unrated, are determined to be of equivalent quality by MacKay Shields LLC, the Fund's Subadvisor. Securities that are rated below investment grade by independent rating agencies are commonly referred to as “high-yield securities” or "junk bonds." The Subadvisor may also invest without restriction in securities with lower ratings from a NRSRO. If NRSROs assign different ratings to the same security, the Fund will use the higher rating for purposes of determining the security's credit quality.

In selecting convertible securities for purchase or sale, the Subadvisor takes into account a variety of investment considerations, including the potential return of the common stock into which the convertible security is convertible, credit risk, projected interest return, and the premium for the convertible security relative to the underlying common stock.

The Fund may also invest in "synthetic" convertible securities, which are derivative positions composed of two or more securities whose investment characteristics, taken together, resemble those of traditional convertible securities. Unlike traditional convertible securities whose conversion values are based on the common stock of the issuer of the convertible security, "synthetic" and "exchangeable" convertible securities are preferred stocks or debt obligations of an issuer which are structured with an embedded equity component whose conversion value is based on the value of the common stocks of one or more different issuers or a particular benchmark (which may include indices, baskets of domestic stocks, commodities, a foreign issuer or basket of foreign stocks, or a company whose stock is not yet publicly traded). The value of a synthetic convertible is the sum of the values of its preferred stock or debt obligation component and its convertible component.

The Fund may invest in foreign securities, which are securities issued by companies organized outside the United States or that trade primarily in non-U.S. securities markets.

The Subadvisor may sell a security if it believes the security will no longer contribute to meeting the investment objective of the Fund. In considering whether to sell a security, the Subadvisor may evaluate, among other things, the condition of the economy, meaningful changes in the issuer's financial condition, changes in credit risk, and changes in projected interest return.

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.

Yield Risk: There can be no guarantee that the Fund will achieve or maintain any particular level of yield.

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.

Synthetic Convertible Securities Risk: The values of a synthetic convertible and a true convertible security may respond differently to market fluctuations. In addition, in purchasing a synthetic convertible security, the Fund may have counterparty (including counterparty credit) risk with respect to the financial institution or investment bank that offers the instrument.

Debt Securities Risk: The risks of investing in debt or fixed-income securities include (without limitation): (i) credit risk, e.g., the issuer or guarantor of a debt security may be unable or unwilling (or be perceived as unable or unwilling) to make timely principal and/or interest payments or otherwise honor its obligations, or changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may affect the value of the Fund’s investments; (ii) maturity risk, e.g., a debt security with a longer maturity may fluctuate in value more than one with a shorter maturity; (iii) market risk, e.g., low demand for debt securities may negatively impact their price; (iv) interest rate risk, e.g., when interest rates go up, the value of a debt security generally goes down, and when interest rates go down, the value of a debt security generally goes up (long-term debt securities are generally more susceptible to interest rate risk than short-term debt securities); and (v) call or prepayment risk, e.g., during a period of falling interest rates, the issuer may redeem a security by repaying it early, which may reduce the Fund’s income if the proceeds are reinvested at lower interest rates.

Interest rate risk is the risk that the value of the Fund’s investments in fixed income or debt securities will change because of changes in interest rates. There is a risk that interest rates across the financial system may change, possibly significantly and/or rapidly. Changes in interest rates or a lack of market participants may lead to decreased liquidity and increased volatility in the fixed-income or debt markets, making it more difficult for the Fund to sell its fixed-income or debt holdings. Decreased liquidity in the fixed-income or debt markets also may make it more difficult to value some or all of the Fund’s fixed-income or debt holdings. For most fixed-income investments, when market interest rates fall, prices of fixed-rate debt securities rise. However, when market interest rates fall, prices of certain variable and fixed-rate debt securities may be adversely affected (i.e., falling interest rates bring the possibility of prepayment risk, as an instrument may be redeemed before maturity).

Not all U.S. government debt securities are guaranteed by the U.S. government—some are backed only by the issuing agency, which must rely on its own resources to repay the debt. The Fund's yield will fluctuate with changes in short-term interest rates.

High-Yield Securities Risk: Investments in high-yield securities or non-investment grade securities (commonly referred to as "junk bonds") are considered speculative because investments in such securities present a greater risk of loss than investments in higher quality securities. Such securities may, under certain circumstances, be less liquid than higher rated securities. These securities pay investors a premium (a high interest rate or yield) because of the potential illiquidity and increased risk of loss. These securities can also be subject to greater price volatility. In times of unusual or adverse market, economic or political conditions, these securities may experience higher than normal default rates.

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 manager's ability to anticipate such changes that can adversely affect the value of the Fund's holdings.

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.

Liquidity and Valuation Risk: The Fund’s investments may be illiquid at the time of purchase or liquid at the time of purchase and subsequently become illiquid due to, among other things, events relating to the issuer of the securities, market events, operational issues, economic conditions, investor perceptions or lack of market participants. The lack of an active trading market may make it difficult to sell or obtain an accurate price for a security. If market conditions or issuer specific developments make it difficult to value securities, the Fund may value these securities using more subjective methods, such as fair value pricing. In such cases, the value determined for a security could be different than the value realized upon such security's sale. As a result, an investor could pay more than the market value when buying shares or receive less than the market value when selling shares. This could affect the proceeds of any redemption or the number of shares an investor receives upon purchase.

The Fund is subject to the risk that it could not meet redemption requests within the allowable time period without significant dilution of remaining investors' interests in the Fund. To meet redemption requests or to raise cash to pursue other investment opportunities, the Fund may be forced to sell securities at an unfavorable time and/or under unfavorable conditions, which may adversely affect the Fund.

Money Market/Short-Term Securities Risk: To the extent the Fund holds cash or invests in money market or short-term securities, the Fund may be less likely to achieve its investment objective. In addition, it is possible that the Fund's investments in these instruments could lose money.

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 ICE BofA Merrill Lynch U.S. Convertible Indexas its primary benchmark. The ICE BofA Merrill Lynch U.S. Convertible Index is a market-capitalization weighted index of domestic corporate convertible securities. In order to be included in the ICE BofA Merrill Lynch U.S. Convertible Index, bonds and preferred stocks must be convertible only to common stock.

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
1Q/19	12.33	%
Worst Quarter
3Q/11	-16.90	%

As of June 30, 2020, the Class I shares of the Fund had a year to date return of 6.22%.

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

Average Annual Returns - MainStay MacKay Convertible Fund	1 Year	5 Years	10 Years	Inception Date
Class I	22.61%	8.06%	9.39%	Nov. 28, 2008
Class A	15.42%	6.50%	8.46%	Jan. 03, 1995
INVESTOR CLASS	15.22%	6.32%	8.26%	Feb. 28, 2008
Class B	16.05%	6.42%	8.06%	May 01, 1986
Class C	19.93%	6.73%	8.05%	Sep. 01, 1998
After Taxes on Distributions | Class I	21.63%	6.29%	7.49%
After Taxes on Distributions and Sale of Fund Shares | Class I	13.84%	5.78%	6.96%
ICE BofA Merrill Lynch U.S. Convertible Index (reflects no deductions for fees, expenses, or taxes)	23.15%	8.48%	10.09%

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: 0.60% on assets up to $500 million; 0.55% on assets from $500 million up to $1 billion; 0.50% on assets from $1 billion up to $2 billion; and 0.49% on assets over $2 billion, plus a fee for fund accounting services previously provided by New York Life Investment Management LLC ("New York Life Investments") under a separate fund accounting agreement. This fund accounting services fee amounted to 0.01% of the Fund's average daily net assets.

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