May 1, 2024

SHORT DURATION BOND PORTFOLIO

SUMMARY PROSPECTUS

Class I

The Fund is offered to certain life insurance companies to serve as an investment vehicle for premiums paid under their variable annuity and variable life insurance contracts (each, a “variable contract”) and to certain qualified pension and other retirement plans (each, a “qualified plan”). 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, reports to shareholders, and other information about the Fund (including the Fund’s SAI) online at http://www.nb.com/amtportfolios/i. You can also get this information at no cost by calling 800-877-9700 or by sending an e-mail request to fundinfo@nb.com. You can also get this information from your investment provider or any investment provider authorized to sell the Fund’s shares. The Fund’s prospectus and SAI, each dated May 1, 2024 (as each may be amended or supplemented), are incorporated herein by reference.

GOAL

The Fund seeks the highest available current income consistent with liquidity and low risk to principal; total return is a secondary goal.

FEES AND EXPENSES

These tables describe the fees and expenses that you may pay if you buy, hold or sell shares of the Fund. These tables do not reflect any fees and expenses charged by your insurance company under your variable contract or by your qualified plan. If the tables did reflect such fees and expenses, the overall expenses would be higher than those shown. Please refer to the prospectus for your variable contract or your qualified plan documentation for information on their separate fees and expenses.

Expense Example

The expense example can help you compare costs among mutual funds. The example assumes that you invested $10,000 for the periods shown, that you redeemed all of your shares at the end of those periods, that the Fund earned a hypothetical 5% total return each year, and that the Fund’s expenses were those in the table. Actual performance and expenses may be higher or lower.

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. These costs, which are not reflected in annual operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 53% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES

To pursue its goals, the Fund invests mainly in fixed and floating rate investment-grade bonds and other debt securities issued by domestic and foreign governments, corporate entities, and trusts. These may include mortgage- and asset-backed securities, collateralized debt obligations (“CDOs”), including collateralized loan obligations (“CLOs”), and credit risk transfer securities. The Fund considers debt securities to be investment grade if, at the time of investment, they are rated within the four highest categories by at least one independent credit rating agency or, if unrated, are determined by the Portfolio Managers to be of comparable quality.

The Portfolio Managers monitor trends in the corporate and government securities markets, as well as a range of economic and financial factors utilizing internally generated data that are produced by specialty sector investment teams in conjunction with asset allocation tools. If particular sectors of the bond market appear relatively inexpensive, the Portfolio Managers may increase the Fund’s exposure in those sectors and decrease exposure in other sectors. The Portfolio Managers look for securities that appear under-priced compared to securities of similar structure and credit quality. The Fund may sell securities if the Portfolio Managers find an opportunity they believe is more compelling or if the Portfolio Managers’ outlook on the investment or the market changes.

To enhance yield and add diversification, the Fund may invest up to 20% of its net assets in securities that are below investment grade (commonly known as “junk bonds”). In choosing lower-rated securities, the Portfolio Managers generally look for bonds from issuers whose financial health appears comparatively strong, and that may have their credit ratings raised. The Fund does not normally invest in or continue to hold securities that are in default or have defaulted with respect to the payment of interest or repayment of principal, but may do so depending on market or other conditions.

The Fund may invest in foreign securities, including obligations of issuers in emerging market countries, denominated in any currency, but the Fund normally will not invest more than 20% of its total assets at the time of investment in non-US dollar denominated securities. The Fund considers emerging market countries to be countries included in the JPMorgan Emerging Markets Bond Index - Global Diversified, the JPMorgan Corporate Emerging Markets Bond Index - Diversified, the JPMorgan Emerging Local Markets Index or the JPMorgan Government Bond Index - Emerging Markets Global Diversified, as well as those countries which are not defined as High Income Organization for Economic Cooperation and Development (OECD) member countries by the World Bank.

The Fund may also invest in derivative instruments as a means of hedging risk and/or for investment or efficient portfolio management purposes, which may include altering the Fund’s exposure to interest rates, currencies, sectors and individual issuers. These derivative instruments may include futures, forward foreign currency contracts, and swaps.

The Fund may also invest a significant amount of its assets in U.S. Treasury securities or other money market instruments depending on market conditions. Additionally, the Fund may invest in restricted securities. The Fund may also engage in whenissued and forward-settling securities (such as to-be-announced (“TBA”) mortgage-backed securities), which involve a commitment by the Fund to purchase securities that will be issued or settled at a later date.

The Fund seeks to reduce credit risk by diversifying among many issuers and different types of securities. As part of the investment process, the Portfolio Managers analyze individual issues (including an analysis of cash flows, ability to pay principal and interest, balance sheet composition, and market positioning). As part of their fundamental investment analysis the Portfolio Managers consider Environmental, Social and Governance (ESG) factors they believe are financially material to individual investments, where applicable, as described below. While this analysis is inherently subjective and may be informed by internally generated and third-party metrics, data and other information, the Portfolio Managers believe that the consideration of financially material ESG factors, alongside traditional financial metrics, may improve credit analysis, security selection, relative value analysis and enhance the Fund’s overall investment process. The specific ESG factors considered and scope and application of integration may vary depending on the specific investment and/or investment type. The consideration of ESG factors does not apply to certain instruments, such as certain derivative instruments, other registered investment companies, cash and cash equivalents. The consideration of ESG factors as part of the investment process does not mean that the Fund pursues a specific “impact” or “sustainable” investment strategy.

Although it may invest in securities of any maturity, the Fund normally seeks to maintain an average portfolio duration of three years or less.

The Fund may invest in other investment companies, including exchange-traded funds (“ETFs”), if the investment companies invest principally in the types of investments in which the Fund may invest directly.

In an effort to achieve its goal, the Fund may engage in frequent and active trading.

The Fund normally invests at least 80% of its net assets in bonds and other debt securities and other investment companies that provide investment exposure to such debt securities. The Fund will not alter this policy without providing shareholders at least 60 days’ notice. This test is applied at the time the Fund invests; later percentage changes caused by a change in Fund assets, market values or company circumstances will not require the Fund to dispose of a holding.

PRINCIPAL INVESTMENT RISKS

Most of the Fund’s performance depends on what happens in the market for debt instruments, the Portfolio Managers’ evaluation of those developments, and the success of the Portfolio Managers in implementing the Fund’s investment strategies. The Fund’s use of derivative instruments will result in leverage, which amplifies the risks that are associated with these markets. The market’s behavior can be difficult to predict, particularly in the short term. There can be no guarantee that the Fund will achieve its goal. The Fund may take temporary defensive and cash management positions; to the extent it does, it will not be pursuing its principal investment strategies.

The actual risk exposure taken by the Fund in its investment program will vary over time, depending on various factors including the Portfolio Managers’ evaluation of issuer, political, regulatory, market, or economic developments. There can be no guarantee

that the Portfolio Managers will be successful in their attempts to manage the risk exposure of the Fund or will appropriately evaluate or weigh the multiple factors involved in investment decisions, including issuer, market and/or instrument-specific analysis, valuation and ESG factors.

The Fund is a mutual fund, not a bank deposit, and is not guaranteed or insured by the Federal Deposit Insurance Corporation or any other government agency. The value of your investment may fall, sometimes sharply, and you could lose money by investing in the Fund. While this Fund may have a shorter duration than many other income funds, this Fund is not intended to operate like a money market fund.

Each of the following risks, which are described in alphabetical order and not in order of any presumed importance, can significantly affect the Fund’s performance. The relative importance of, or potential exposure as a result of, each of these risks will vary based on market and other investment-specific considerations.

Call Risk. Upon the issuer’s desire to call a security, or under other circumstances where a security is called, including when interest rates are low and issuers opt to repay the obligation underlying a “callable security” early, the Fund may have to reinvest the proceeds in an investment offering a lower yield and may not benefit from any increase in value that might otherwise result from declining interest rates.

Collateralized Debt Obligations Risk. CDOs, which include collateralized loan obligations (CLOs), issue classes or “tranches” of securities that vary in risk and yield and may experience substantial losses due to interest rate fluctuations, actual defaults, collateral defaults, disappearance of subordinate tranches, market anticipation of defaults, and investor aversion to CDO securities as a class. The risks of investing in CDOs depend largely on the quality and type of the underlying debt, which may include loans, bonds and mortgages, and the tranche of the CDO in which the Fund invests. In addition, CDOs that obtain their exposure through derivative instruments entail the additional risks associated with such instruments. CDOs can be difficult to value, may at times be illiquid, may be highly leveraged (which could make them highly volatile), and may produce unexpected investment results due to their complex structure. In addition, CDOs involve many of the same risks of investing in debt securities and assetbacked securities including, but not limited to, interest rate risk, credit risk, liquidity risk, and valuation risk.

Credit Risk. Credit risk is the risk that issuers, guarantors, or insurers may fail, or become less able or unwilling, to pay interest and/or principal when due. Changes in the actual or perceived creditworthiness of an issuer or a downgrade or default affecting any of the Fund’s securities could affect the Fund’s performance by affecting the credit quality or value of the Fund’s securities. Generally, the longer the maturity and the lower the credit quality of a security, the more sensitive it is to credit risk.

Currency Risk. Currency risk is the risk that foreign currencies will decline in value relative to the U.S. dollar. To the extent that the Fund invests in securities or other instruments denominated in or indexed to foreign currencies, changes in currency exchange rates could adversely impact investment gains or add to investment losses. Currency exchange rates may fluctuate significantly over short periods of time and can be affected unpredictably by various factors, including investor perception and changes in interest rates; intervention, or failure to intervene, by U.S. or foreign governments, central banks, or supranational entities; or by currency controls or political developments in the U.S. or abroad.

Derivatives Risk. Use of derivatives is a highly specialized activity that can involve investment techniques and risks different from, and in some respects greater than, those associated with investing in more traditional investments, such as stocks and bonds. Derivatives can be highly complex and highly volatile and may perform in unanticipated ways. Derivatives can create leverage, and the Fund could lose more than the amount it invests; some derivatives can have the potential for unlimited losses. Derivatives may at times be highly illiquid, and the Fund may not be able to close out or sell a derivative at a particular time or at an anticipated price. Derivatives can be difficult to value and valuation may be more difficult in times of market turmoil. The value of a derivative instrument depends largely on (and is derived from) the value of the reference instrument underlying the derivative. There may be imperfect correlation between the behavior of a derivative and that of the reference instrument underlying the derivative. An abrupt change in the price of a reference instrument could render a derivative worthless. Derivatives may involve risks different from, and possibly greater than, the risks associated with investing directly in the reference instrument. Suitable derivatives may not be available in all circumstances, and there can be no assurance that the Fund will use derivatives to reduce exposure to other risks when that might have been beneficial. Derivatives involve counterparty risk, which is the risk that the other party to the derivative will fail to make required payments or otherwise comply with the terms of the derivative. That risk is generally thought to be greater with over-the-counter (OTC) derivatives than with derivatives that are exchange traded or centrally cleared. When the Fund uses derivatives, it will likely be required to provide margin or collateral; these practices are intended to satisfy contractual undertakings and regulatory requirements and will not prevent the Fund from incurring losses on derivatives. The need to provide margin or collateral could limit the Fund’s ability to pursue other opportunities as they arise. Ongoing changes to regulation of the derivatives markets and actual and potential changes in the regulation of funds using derivative

instruments could limit the Fund’s ability to pursue its investment strategies. New regulation of derivatives may make them more costly, or may otherwise adversely affect their liquidity, value or performance.

Additional risks associated with certain types of derivatives are discussed below:

Forward Contracts. There are no limitations on daily price movements of forward contracts. Changes in foreign exchange regulations by governmental authorities might limit the trading of forward contracts on currencies.

Futures. Futures contracts are subject to the risk that an exchange may impose price fluctuation limits, which may make it difficult or impossible for a fund to close out a position when desired. In the absence of such limits, the liquidity of the futures market depends on participants entering into offsetting transactions rather than taking or making delivery. To the extent a Fund enters into futures contracts requiring physical delivery (e.g., certain commodities contracts), the inability of the Fund to take or make physical delivery can negatively impact performance.

Swaps. The risk of loss with respect to swaps generally is limited to the net amount of payments that the Fund is contractually obligated to make or, in the case of the other party to a swap defaulting, the net amount of payments that the Fund is contractually entitled to receive. If the Fund sells a credit default swap, however, the risk of loss may be the entire notional amount of the swap.

Some swaps are now executed through an organized exchange or regulated facility and cleared through a regulated clearing organization. The absence of an organized exchange or market for swap transactions may result in difficulties in trading and valuation, especially in the event of market disruptions. The use of an organized exchange or market for swap transactions is expected to result in swaps being easier to trade or value, but this may not always be the case.

Foreign and Emerging Market Risk. Foreign securities, including those issued by foreign governments, involve risks in addition to those associated with comparable U.S. securities. Additional risks include exposure to less developed or less efficient trading markets; social, political, diplomatic, or economic instability; trade barriers and other protectionist trade policies (including those of the U.S.); imposition of economic sanctions against a particular country or countries, organizations, companies, entities and/or individuals; significant government involvement in an economy and/or market structure; fluctuations in foreign currencies or currency redenomination; potential for default on sovereign debt; nationalization or expropriation of assets; settlement, custodial or other operational risks; higher transaction costs; confiscatory withholding or other taxes; and less stringent auditing and accounting, corporate disclosure, governance, and legal standards. As a result, foreign securities may fluctuate more widely in price, and may also be less liquid, than comparable U.S. securities. Regardless of where a company is organized or its stock is traded, its performance may be affected significantly by events in regions from which it derives its profits or in which it conducts significant operations.

Investing in emerging market countries involves risks in addition to and greater than those generally associated with investing in more developed foreign countries. The governments of emerging market countries may be more unstable and more likely to impose capital controls, nationalize a company or industry, place restrictions on foreign ownership and on withdrawing sale proceeds of securities from the country, intervene in the financial markets, and/or impose burdensome taxes that could adversely affect security prices. To the extent a foreign security is denominated in U.S. dollars, there is also the risk that a foreign government will not let U.S. dollar-denominated assets leave the country. In addition, the economies of emerging market countries may be dependent on relatively few industries that are more susceptible to local and global changes. Emerging market countries may also have less developed legal and accounting systems, and their legal systems may deal with issuer bankruptcies and defaults differently than U.S. law would. Securities markets in emerging market countries are also relatively small and have substantially lower trading volumes. Securities of issuers in emerging market countries may be more volatile and less liquid than securities of issuers in foreign countries with more developed economies or markets and the situation may require that the Fund fair value its holdings in those countries.

Securities of issuers traded on foreign exchanges may be suspended, either by the issuers themselves, by an exchange, or by governmental authorities. The likelihood of such suspensions may be higher for securities of issuers in emerging or less-developed market countries than in countries with more developed markets. Trading suspensions may be applied from time to time to the securities of individual issuers for reasons specific to that issuer, or may be applied broadly by exchanges or governmental authorities in response to market events. Suspensions may last for significant periods of time, during which trading in the securities and in instruments that reference the securities, such as derivative instruments, may be halted. In the event that the Fund holds material positions in such suspended securities or instruments, the Fund’s ability to liquidate its positions or provide liquidity to investors may be compromised and the Fund could incur significant losses.

High Portfolio Turnover Risk. The Fund may engage in active and frequent trading and may have a high portfolio turnover rate, which may increase the Fund’s transaction costs and may adversely affect the Fund’s performance.

Interest Rate Risk. The Fund’s yield and share price will fluctuate in response to changes in interest rates. In general, the value of investments with interest rate risk, such as debt securities, will move in the direction opposite to movements in interest rates. If interest rates rise, the value of such securities may decline. Typically, the longer the maturity or duration of a debt security, the greater the effect a change in interest rates could have on the security’s price. Thus, the sensitivity of the Fund’s debt securities to interest rate risk will increase with any increase in the duration of those securities.

Issuer-Specific Risk. An individual security may be more volatile, and may perform differently, than the market as a whole.

Leverage Risk. Leverage amplifies changes in the Fund’s net asset value and may make the Fund more volatile. Derivatives and when-issued and forward-settling securities may create leverage and can result in losses to the Fund that exceed the amount originally invested and may accelerate the rate of losses or magnify the risks of other portfolio investments. There can be no assurance that the Fund’s use of any leverage will be successful and the Fund may need to dispose of some of its holdings at unfavorable times or prices. The Fund’s investment exposure can exceed its net assets, sometimes by a significant amount.

Liquidity Risk. From time to time, the trading market for a particular investment in which the Fund invests, or a particular type of instrument in which the Fund is invested, may become less liquid or even illiquid. Illiquid investments frequently can be more difficult to purchase or sell at an advantageous price or time, and there is a greater risk that the investments may not be sold for the price at which the Fund is carrying them. Certain investments that were liquid when the Fund purchased them may become illiquid, sometimes abruptly. Additionally, market closures due to holidays or other factors may render a security or group of securities (e.g., securities tied to a particular country or geographic region) illiquid for a period of time. An inability to sell a portfolio position can adversely affect the Fund’s value or prevent the Fund from being able to take advantage of other investment opportunities. Market prices for such securities or other investments may be volatile. During periods of substantial market volatility, an investment or even an entire market segment may become illiquid, sometimes abruptly, which can adversely affect the Fund’s ability to limit losses.

Unexpected episodes of illiquidity, including due to market or political factors, instrument or issuer-specific factors and/or unanticipated outflows or other factors, may limit the Fund’s ability to pay redemption proceeds within the allowable time period. To meet redemption requests during periods of illiquidity, the Fund may be forced to sell securities at an unfavorable time and/or under unfavorable conditions.

Lower-Rated Debt Securities Risk. Lower-rated debt securities (commonly known as “junk bonds”) and unrated debt securities determined to be of comparable quality involve greater risks than investment grade debt securities. Such securities may fluctuate more widely in price and yield and may fall in price, sometimes abruptly, due to changes in interest rates, market activity, economic conditions, such as when economic conditions are deteriorating or are expected to deteriorate, or other factors. These securities may be less liquid, may require a greater degree of judgment to establish a price and may be difficult to sell at the time and price the Fund desires. Lower-rated debt securities are considered by the major rating agencies to be predominantly speculative with respect to the issuer’s continuing ability to pay principal and interest and carry a greater risk that the issuer of such securities will default in the timely payment of principal and interest. Issuers of securities that are in default or have defaulted may fail to resume principal or interest payments, in which case the Fund may lose its entire investment. The creditworthiness of issuers of these securities may be more complex to analyze than that of issuers of investment grade debt securities, and the overreliance on credit ratings may present additional risks.

Market Volatility Risk. Markets may be volatile and values of individual securities and other investments, including those of a particular type, may decline significantly in response to adverse issuer, political, regulatory, market, economic or other developments that may cause broad changes in market value, public perceptions concerning these developments, and adverse investor sentiment or publicity. Geopolitical and other risks, including environmental and public health risks may add to instability in world economies and markets generally. Changes in value may be temporary or may last for extended periods. If the Fund sells a portfolio position before it reaches its market peak, it may miss out on opportunities for better performance.

Mortgage- and Asset-Backed Securities Risk. The value of mortgage- and asset-backed securities, including collateralized mortgage instruments, will be influenced by the factors affecting the housing market or the assets underlying the securities. These securities tend to be more sensitive to changes in interest rates than other types of debt securities. In addition, investments in mortgage- and asset-backed securities may be subject to prepayment risk and extension risk, call risk, credit risk, valuation risk, and illiquid investment risk, sometimes to a higher degree than various other types of debt securities. These securities are also

subject to the risk of default on the underlying mortgages or assets, particularly during periods of market downturn, and an unexpectedly high rate of defaults on the underlying assets will adversely affect the security’s value.

Other Investment Company Risk. To the extent the Fund invests in other investment companies, including money market funds and exchange-traded funds (ETFs), its performance will be affected by the performance of those other investment companies. Investments in other investment companies are subject to the risks of the other investment companies’ investments, as well as to the other investment companies’ expenses.

An ETF may trade in the secondary market at a price below the value of its underlying portfolio, may not be liquid and may be halted by the listing exchange. An actively managed ETF’s performance will reflect its adviser’s ability to make investment decisions that are suited to achieving the ETF’s investment objectives. A passively managed ETF may not replicate the performance of the index it intends to track.

Prepayment and Extension Risk. The Fund’s performance could be affected if borrowers pay back principal on certain debt securities, such as mortgage- or asset-backed securities, before (prepayment) or after (extension) the market anticipates such payments, shortening or lengthening their duration. Due to a decline in interest rates or an excess in cash flow into the issuer, a debt security might be called or otherwise converted, prepaid or redeemed before maturity. As a result of prepayment, the Fund may have to reinvest the proceeds in an investment offering a lower yield, may not benefit from any increase in value that might otherwise result from declining interest rates, and may lose any premium it paid to acquire the security. Conversely, rising market interest rates generally result in slower payoffs or extension, which effectively increases the duration of certain debt securities, heightening interest rate risk and increasing the magnitude of any resulting price declines.

Private Placements and Other Restricted Securities Risk. Private placements and other restricted securities, including securities for which Fund management has material non-public information, are securities that are subject to legal and/or contractual restrictions on their sales. These securities may not be sold to the public unless certain conditions are met, which may include registration under the applicable securities laws. As a result of the absence of a public trading market, the prices of these securities may be more difficult to determine than publicly traded securities and these securities may involve heightened risk as compared to investments in securities of publicly traded companies. Private placements and other restricted securities may be illiquid, and it frequently can be difficult to sell them at a time when it may otherwise be desirable to do so or the Fund may be able to sell them only at prices that are less than what the Fund regards as their fair market value. Transaction costs may be higher for these securities. In addition, the Fund may get only limited information about the issuer of a private placement or other restricted security.

Recent Market Conditions. Both U.S. and international markets have experienced significant volatility in recent months and years. As a result of such volatility, investment returns may fluctuate significantly. National economies are substantially interconnected, as are global financial markets, which creates the possibility that conditions in one country or region might adversely impact issuers in a different country or region. However, the interconnectedness of economies and/or markets may be diminishing or changing, which may impact such economies and markets in ways that cannot be foreseen at this time.

Although interest rates were unusually low in recent years in the U.S. and abroad, recently, the Federal Reserve and certain foreign central banks raised interest rates as part of their efforts to address rising inflation. It is difficult to accurately predict the pace at which interest rates might increase or start decreasing, the timing, frequency or magnitude of any such changes in interest rates, or when such changes might stop or reverse course. Additionally, various economic and political factors could cause the Federal Reserve or other foreign central banks to change their approach in the future and such actions may result in an economic slowdown both in the U.S. and abroad. Unexpected changes in interest rates could lead to significant market volatility or reduce liquidity in certain sectors of the market. Deteriorating economic fundamentals may, in turn, increase the risk of default or insolvency of particular issuers, negatively impact market value, cause credit spreads to widen, and reduce bank balance sheets. Any of these could cause an increase in market volatility, or reduce liquidity across various markets or decrease confidence in the markets.

Some countries, including the U.S., have adopted more protectionist trade policies. Slowing global economic growth, the rise in protectionist trade policies, changes to some major international trade agreements, risks associated with the trade agreement between the United Kingdom and the European Union, and the risks associated with trade negotiations between the U.S. and China, could affect the economies of many nations in ways that cannot necessarily be foreseen at the present time. In addition, if the U.S. dollar continues to be strong, it may decrease foreign demand for U.S. assets, which could have a negative impact on certain issuers and/or industries.

Regulators in the U.S. have proposed and adopted a number of changes to regulations involving the markets and issuers, some of which apply to the Fund. The full effect of various newly adopted regulations is not currently known. Additionally, it is not currently known whether any of the proposed regulations will be adopted. However, due to the scope of regulations being proposed and adopted, certain of these changes to regulation could limit the Fund’s ability to pursue its investment strategies or make certain investments, may make it more costly for it to operate, or adversely impact performance.

Tensions, war, or open conflict between nations, such as between Russia and Ukraine, in the Middle East, or in eastern Asia could affect the economies of many nations, including the United States. The duration of ongoing hostilities and any sanctions and related events cannot be predicted. Those events present material uncertainty and risk with respect to markets globally and the performance of the Fund and its investments or operations could be negatively impacted.

High public debt in the U.S. and other countries creates ongoing systemic and market risks and policymaking uncertainty. There is no assurance that the U.S. Congress will act to raise the nation’s debt ceiling; a failure to do so could cause market turmoil and substantial investment risks that cannot now be fully predicted. Unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy.

There is widespread concern about the potential effects of global climate change on property and security values. Certain issuers, industries and regions may be adversely affected by the impact of climate change in ways that cannot be foreseen. The impact of legislation, regulation and international accords related to climate change may negatively impact certain issuers and/or industries.

Redemption Risk. The Fund may experience periods of large or frequent redemptions that could cause the Fund to sell assets at inopportune times, which could have a negative impact on the Fund’s overall liquidity, or at a loss or depressed value. Redemption risk is greater to the extent that one or more investors or intermediaries control a large percentage of investments in the Fund and the risk is heightened during periods of declining or illiquid markets. Large redemptions could hurt the Fund’s performance, increase transaction costs, and create adverse tax consequences. A general rise in interest rates has the potential to cause investors to move out of fixed income securities on a large scale, which may increase redemptions from mutual funds that hold large amounts of fixed income securities; such a move, coupled with a reduction in the ability or willingness of dealers and other institutional investors to buy or hold fixed income securities, may result in decreased liquidity and increased volatility in the fixed income markets.

Sector Risk. From time to time, based on market or economic conditions, the Fund may have significant positions in one or more sectors of the market. To the extent the Fund invests more heavily in particular sectors, its performance will be especially sensitive to developments that significantly affect those sectors. Individual sectors or sub-sectors may be more volatile, and may perform differently, than the broader market. The industries that constitute a sector may all react in the same way to economic, political or regulatory events.

Sovereign Debt Risk. Sovereign debt securities are subject to the risk that a governmental entity may delay or refuse to pay interest or principal on its sovereign debt, due, for example, to cash flow problems, insufficient foreign currency reserves, political considerations, the size of the governmental entity’s debt position in relation to the economy, its policy toward international lenders or the failure to put in place economic reforms required by multilateral agencies. If a governmental entity defaults, it may ask for more time in which to pay or for further loans. There may be no legal process for collecting sovereign debt that a government does not pay nor are there bankruptcy proceedings through which all or part of the sovereign debt that a governmental entity has not repaid may be collected. Sovereign debt risk is increased for emerging market issuers.

U.S. Government Securities Risk. Although the Fund may hold securities that carry U.S. government guarantees, these guarantees do not extend to shares of the Fund itself and do not guarantee the market prices, including due to changes in interest rates, of the securities. Furthermore, not all securities issued by the U.S. government and its agencies and instrumentalities are backed by the full faith and credit of the U.S. Treasury. Securities not backed by the full faith and credit of the U.S. Treasury carry at least some risk of non-payment or default.

Variable and Floating Rate Instruments Risk. The market prices of instruments with variable and floating interest rates are generally less sensitive to interest rate changes than are the market prices of instruments with fixed interest rates. Variable and floating rate instruments may decline in value if market interest rates or interest rates paid by such instruments do not move as expected. Certain types of floating rate instruments, such as interests in bank loans, may be subject to greater liquidity risk than other debt securities, may have restrictions on resale and may lack an active market.

When-Issued and Forward-Settling Securities Risk. When-issued and forward-settling securities can have a leverage-like effect on the Fund, which can increase fluctuations in the Fund’s share price; may cause the Fund to liquidate positions when it may not

be advantageous to do so, in order to satisfy its purchase obligations; and are subject to the risk that the security will not be issued or that a counterparty will fail to complete the sale or purchase of the security in which case the Fund may lose the opportunity to purchase or sell the security at the agreed upon price and any gain in the security’s price.

A summary of the Fund’s additional principal investment risks is as follows:

Risk of Increase in Expenses. A decline in the Fund’s average net assets during the current fiscal year due to market volatility or other factors could cause the Fund’s expenses for the current fiscal year to be higher than the expense information presented in “Fees and Expenses.”

Operational and Cybersecurity Risk. The Fund and its service providers, and your ability to transact with the Fund, may be negatively impacted due to operational matters arising from, among other problems, human errors, systems and technology disruptions or failures, or cybersecurity incidents. Cybersecurity incidents may allow an unauthorized party to gain access to fund assets, customer data, or proprietary information, or cause the Fund or its service providers, as well as the securities trading venues and their service providers, to suffer data corruption or lose operational functionality. Cybersecurity incidents can result from deliberate attacks or unintentional events. It is not possible for the Manager or the other Fund service providers to identify all of the cybersecurity or other operational risks that may affect the Fund or to develop processes and controls to completely eliminate or mitigate their occurrence or effects. Most issuers in which the Fund invests are heavily dependent on computers for data storage and operations, and require ready access to the internet to conduct their business. Thus, cybersecurity incidents could also affect issuers of securities in which the Fund invests, leading to significant loss of value.

Risk Management. Risk is an essential part of investing. No risk management program can eliminate the Fund’s exposure to adverse events; at best, it may only reduce the possibility that the Fund will be affected by such events, and especially those risks that are not intrinsic to the Fund’s investment program. The Fund could experience losses if judgments about risk prove to be incorrect.

Valuation Risk. The Fund may not be able to sell an investment at the price at which the Fund has valued the investment. Such differences could be significant, particularly for illiquid securities and securities that trade in relatively thin markets and/or markets that experience extreme volatility. If market or other conditions make it difficult to value an investment, the Fund may be required to value such investments using more subjective methods, known as fair value methodologies. Using fair value methodologies to price investments may result in a value that is different from an investment’s most recent price and from the prices used by other funds to calculate their NAVs. The Fund uses pricing services to provide values for certain securities and there is no assurance that the Fund will be able to sell an investment at the price established by such pricing services. The Fund’s ability to value its investments in an accurate and timely manner may be impacted by technological issues and/or errors by third party service providers, such as pricing services or accounting agents.

PERFORMANCE

The following bar chart and table provide an indication of the risks of investing in the Fund. The bar chart shows how the Fund’s performance has varied from year to year. The table below the bar chart shows what the returns would equal if you averaged out actual performance over various lengths of time and compares the returns with the returns of a broad-based market index. The index, which is described in “Description of Index” in the prospectus, has characteristics relevant to the Fund’s investment strategy. The performance information does not reflect variable contract or qualified plan fees and expenses. If such fees and expenses were reflected, returns would be less than those shown. Please refer to the prospectus for your variable contract or your qualified plan documentation for information on their separate fees and expenses.

Returns would have been lower if Neuberger Berman Investment Advisers LLC had not reimbursed certain expenses and/or waived a portion of the investment management fees during certain of the periods shown.

Past performance is not a prediction of future results. Visit www.nb.com or call 800-877-9700 for updated performance information.

YEAR-BY-YEAR % RETURNS AS OF 12/31 EACH YEAR

AVERAGE ANNUAL TOTAL % RETURNS AS OF 12/31/23

INVESTMENT MANAGER

Neuberger Berman Investment Advisers LLC (“Manager”) is the Fund’s investment manager.

PORTFOLIO MANAGERS

The Fund is managed by Michael Foster (Managing Director of the Manager), Matthew McGinnis (Senior Vice President of the Manager), Ashok Bhatia, CFA (Managing Director and Co-Chief Investment Officer of Fixed Income of the Manager) and David M. Brown, CFA (Managing Director and Co-Head of Global Investment Grade Fixed Income of the Manager). Mr. Foster has managed the Fund since 2008. Mr. McGinnis has managed the Fund since February 2017. Mr. Brown has managed the Fund since May 2021. Mr. Bhatia has managed the Fund since July 2022.

BUYING AND SELLING SHARES

The Fund is designed as a funding vehicle for certain variable contracts and qualified plans. Because shares of the Fund are held by the insurance companies or qualified plans involved, you will need to follow the instructions provided by your insurance company or qualified plan administrator for matters involving allocations to the Fund.

When shares of the Fund are bought and sold, the share price is the Fund’s net asset value per share. When shares are bought or sold, the share price will be the next share price calculated after the order has been received in proper form. Shares of the Fund may be purchased or redeemed (sold) on any day the New York Stock Exchange is open.

TAX INFORMATION

Distributions made by the Fund to an insurance company separate account or a qualified plan, and exchanges and redemptions of Fund shares made by a separate account or qualified plan, ordinarily do not cause the contract holder or plan participant to recognize income or gain for federal income tax purposes. Please see your variable contract prospectus or the governing documents of your qualified plan for information regarding the federal income tax treatment of the distributions to the applicable separate account or qualified plan and the holders of the contracts or plan participants, respectively.

PAYMENTS TO FINANCIAL INTERMEDIARIES

Neuberger Berman BD LLC and/or its affiliates may pay insurance companies or their affiliates, qualified plan administrators, broker-dealers or other financial intermediaries, for services to current and prospective variable contract owners and qualified plan participants who choose the Fund as an investment option. These payments may create a conflict of interest by influencing the financial intermediary and its employees to recommend the Fund over another investment or make the Fund available to their current or prospective variable contract owners and qualified plan participants. Ask your financial intermediary or visit its website for more information.

The “Neuberger Berman” name and logo and “Neuberger Berman Investment Advisers LLC” are registered service marks of Neuberger Berman Group LLC. The individual Fund name in this prospectus is either a service mark or a registered service mark of Neuberger Berman Investment Advisers LLC. ©2024 Neuberger Berman BD LLC, distributor. All rights reserved.

SEC File Number: 811-4255
K0047 05/24