BUYING AND SELLING FUND SHARES

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

When you buy and sell shares of the Fund, the share price is the Fund’s net asset value per share. When you buy shares, you will receive the next share price to be calculated after your order has been accepted. The Fund is open for business every day the New York Stock Exchange (“Exchange”) is open.

TAX INFORMATION

Distributions made by the Fund to a variable annuity or variable life insurance separate account or a qualified pension or retirement plan, and exchanges and redemptions of Fund shares made by a separate account or qualified plan ordinarily do not cause the corresponding 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 separate accounts or qualified plans and the holders of the contracts or plan participants.

PAYMENTS TO FINANCIAL INTERMEDIARIES

NBM and/or its affiliates may pay insurance companies or their affiliates, qualified plan administrators, broker-dealers or other financial intermediaries, for services they provide respecting the Fund 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 as they may be made to the intermediaries to render services to variable contract owners and qualified plan participants, and may also provide incentive for the intermediaries to recommend the Fund’s shares or make them available to current or prospective variable contract owners and qualified plan participants, and therefore promote distribution of the Fund’s shares.

5    Advisers Management Trust Guardian Portfolio (Class I)

Descriptions of Certain Practices and Security Types

Mid- and Large-Cap Stocks. Mid-cap stocks have historically performed more like small-caps than like large-caps. Their prices can rise and fall substantially, although many have the potential to offer attractive long-term returns.

Large-cap companies are usually well established. Compared to mid-cap companies, they may be less responsive to change, but their returns have sometimes led those of mid-cap companies, often with lower volatility.

Foreign Stocks. There are many promising opportunities for investment outside the United States. Foreign markets often respond to different factors and therefore may follow cycles that are different from each other.

For this reason, many investors put a portion of their portfolios in foreign investments as a way of gaining further diversification. While foreign stock markets can be risky, investors gain an opportunity to add potential long-term growth, while diversifying their portfolio.

Valuation Sensitive Investing. In addition to traditional value investing—i.e., looking for value among companies whose stock prices are below their historical average, based on earnings, cash flow, or other financial measures—we may also buy a company’s shares if they look more fully priced based on Wall Street consensus estimates of earnings, but still inexpensive relative to our estimates. We look for these companies to rise in price as they outperform Wall Street’s expectations, because some aspects of the business have not been fully appreciated or appropriately priced by other investors.

Change of Goal. The Fund may change its goal without shareholder approval, although it does not currently intend to do so.

Additional Information about Principal Investment Risks

This section provides additional information about the Fund’s principal investment risks described in the Fund Summary section.

Concentration Risk. The Fund holds a relatively concentrated portfolio that may contain fewer securities than the portfolios of other mutual funds. Holding a relatively concentrated portfolio may increase the risk that the value of the Fund could go down because of the poor performance of one or a few investments.

Value Investing Risk. With a valuation sensitive approach, there is also the risk that stocks may remain undervalued during a given period. This may happen because value stocks, as a category, lose favor with investors compared to growth stocks, or because of a failure to anticipate which stocks or industries would benefit from changes market or economic conditions.

Market Capitalization Risk. To the extent the Fund emphasizes mid- or large-cap stocks, it takes on the associated risks. Mid- cap stocks tend to be more volatile than large-cap stocks and are usually more sensitive to economic, political, regulatory and market factors. At any given time, one or both groups of stocks may be out of favor with investors.

Foreign Risk. Foreign securities 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 or economic instability; fluctuations in foreign currencies; nationalization or expropriation of assets; settlement, custodial or other operational risks; and less stringent auditing and legal standards. In addition, key information about the issuer, the markets or the local government or economy may be unavailable, incomplete or inaccurate. As a result, foreign securities can fluctuate more widely in price than comparable U.S. securities, and they may also be less liquid. Although foreign securities offer added diversification potential, world markets may all react in similar fashion to important economic or political developments.

In addition, foreign markets can perform differently than the U.S. market. Over a given period of time, foreign securities may underperform U.S. securities—sometimes for years. A Fund could also underperform if the Fund’s Portfolio Managers invest in countries or regions whose economic performance falls short. To the extent that a Fund invests a portion of its assets in one country, state, region or currency, an adverse economic, business or political development may affect the value of the Fund’s investments more than if its investments were not so concentrated.

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Arbitrage Risk. Investing in foreign securities may also involve a greater risk for excessive trading due to “time-zone arbitrage”. If an event occurring after the close of a foreign market, but before the time the Fund computes its current net asset value, causes a change in the price of the foreign securities and such price is not reflected in the Fund’s current net asset value, investors may attempt to take advantage of anticipated price movements in securities held by the Fund based on such pricing discrepancies. This could be harmful to long-term shareholders. Similar arbitrage opportunities may occur in a fund which invests in thinly-traded securities, such as the securities of certain mid- or small-capitalization companies. The Board of Trustees has adopted fair valuation policies and procedures intended to reduce the Fund’s exposure to such arbitrage opportunities and other potential pricing discrepancies.

Currency Risk. Changes in currency exchange rates bring an added dimension of risk. Currency fluctuations could erase investment gains or add to investment losses.

Information about Additional Risks

The Fund may use certain practices and invest in certain securities involving additional risks. Borrowing, securities lending, and using derivatives could create leverage, meaning that certain gains or losses could be amplified, increasing share price movements. If the Fund were to use certain derivatives to gain stock market exposure for excess cash holdings, it would increase its risk of loss.

When the Fund anticipates adverse market, economic, political, or other conditions, or it receives large cash inflows, it may temporarily depart from its goal and invest substantially in high-quality short-term investments. This could help the Fund avoid losses, but may mean lost opportunities.

Description of Index

The S&P 500 Index is an unmanaged index of U.S. stocks.

Management of the Fund

Investment Managers

Neuberger Berman Management LLC (the “Manager”) is the Fund’s investment manager, administrator, and distributor. Pursuant to an investment advisory agreement, the Manager is responsible for choosing the Fund’s investments and handling its day-to-day business. The Manager carries out its duties subject to the policies established by the Board of Trustees. The investment advisory agreement establishes the fees the Fund pays to the Manager for its services as the Fund’s investment manager and the expenses paid directly by the Fund. The Manager engages Neuberger Berman LLC as sub-adviser to provide investment research and related services. Together, the Neuberger Berman affiliates manage approximately $173 billion in total assets (as of 12/31/2009) and continue an asset management history that began in 1939. For the 12 months ended 12/31/2009, the management/administration fees paid to the Manager were 0.85% of the Funds’ average net assets.

A discussion regarding the basis for the approval of the investment advisory and sub-advisory agreements by the Board of Trustees is available in the Fund’s annual report to shareholders dated December 31, 2008.

Portfolio Managers

Arthur Moretti, CFA , is a Managing Director of Neuberger Berman Management LLC and Neuberger Berman LLC. Mr. Moretti joined each firm in 2001 and has managed the fund since December 2002. He was a portfolio manager and fund analyst at two other firms since 1991.

Ingrid S. Dyott is a Managing Director of Neuberger Berman Management LLC and Neuberger Berman LLC. She has been an Associate Manager of the Fund since December 2003 and has been a Portfolio Manager at Neuberger Berman since 1997. She was a research analyst and the project director for a social research group from 1995 to 1997.

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Sajjad S. Ladiwala , CFA, is a Managing Director of Neuberger Berman Management LLC and Neuberger Berman LLC. He has been an Associate Manager of the Fund since December 2003. He held various positions as a financial analyst at two other firms since 1994.

Mamundi Subhas , CFA, is a Senior Vice President of Neuberger Berman Management LLC and Neuberger Berman LLC. Mr. Subhas is an Associate Portfolio Manager on the Socially Responsive Equity Team. He has been an Associate Manager of the Fund since December 2008. He joined the firm in 2001.

Please see the Statement of Additional Information for additional information about the Portfolio Managers’ compensation, other accounts managed by the Portfolio Managers, and the Portfolio Managers’ ownership of Fund shares.

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Financial Highlights

Neuberger Berman Advisers Management Trust Guardian Portfolio — I Class Shares

The financial highlights table is intended to help you understand the Fund’s financial performance for the past 5 years.

Certain information reflects financial results for a single Fund share. The total returns in the table represent the rate that an investor would have earned (or lost) on an investment in the Fund (assuming reinvestment of all dividends and distributions). The above figures have been audited by Ernst & Young LLP, the Fund’s independent registered public accounting firm. Their report, along with full financial statements, appears in the Fund’s most recent shareholder report (see back cover).

This information does not reflect insurance product or qualified plan expenses. If such expenses were reflected, returns would be less than those shown.

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Your Investment

Buying and Selling Fund Shares

The Fund described in this prospectus is designed for use with certain variable insurance contracts and qualified plans. Because shares of the Fund are held by the insurance company or qualified plans involved, you will need to follow the instructions provided by your insurance company or qualified plan for matters involving allocations to this Fund.

Under certain circumstances, the Fund reserves the right to:

Frequent purchases, exchanges and redemptions in fund shares (“market-timing activities”) can interfere with Fund management and affect costs and performance for other shareholders. To discourage market-timing activities by Fund shareholders, the Board of Trustees has adopted market-timing policies and has approved the procedures of the Fund’s principal underwriter for implementing those policies. Pursuant to such policies, the exchange privilege can be withdrawn from any investor that is believed to be “timing the market” or is otherwise making exchanges judged to be excessive. In furtherance of these policies, under certain circumstances, the Fund reserves the right to reject any exchange or purchase order; or change, suspend or revoke the exchange privilege. These policies and procedures are applied consistently to all shareholders.

Neuberger Berman Management LLC applies the Fund’s policies and procedures with respect to market-timing activities by monitoring trading activity in the Fund, identifying excessive trading patterns, and warning or prohibiting shareholders who trade excessively from making further purchases or exchanges of Fund shares. The Fund generally requires insurance companies and qualified plan administrators to enter into agreements with the Fund to enable the Fund to implement and enforce its market-timing policies and procedures. Although the Fund makes efforts to monitor for market-timing activities, the ability of the Fund and Neuberger Berman Management LLC to monitor exchange or purchase orders by individual variable contract owners or qualified plan participants that are submitted to the Fund on an aggregated basis by insurance companies or qualified plans may be limited. Accordingly, there can be no assurance that the Fund or Neuberger Berman Management LLC will be able to mitigate or eliminate all market-timing activities.

Because the Fund is offered to different insurance companies and for different types of variable contracts — annuities, life insurance and qualified plans — groups with different interests will share the Fund. Due to differences of tax treatment and other considerations among these shareholders, it is possible (although not likely) that the interests of the shareholders might sometimes be in conflict. For these reasons, the trustees of the Fund watch for the existence of any material irreconcilable conflicts and will determine what action, if any, should be taken in the event of a conflict. If there is a conflict, it is possible that to resolve it, one or more insurance company separate accounts or qualified plans might be compelled to withdraw its investment in the Fund. While this might resolve the conflict, it also might force the Fund to sell securities at disadvantageous prices.

Share Prices

When you buy and sell shares of the Fund, the share price is the Fund’s net asset value per share.

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The Fund is open for business every day the New York Stock Exchange (“Exchange”) is open. The Exchange is closed on all national holidays and Good Friday; Fund shares will not be priced on those days or other days on which the Exchange is closed. The Fund may decide to remain open on a day when the Exchange is closed for unusual reasons. In such a case, the Fund would post a notice on www.nb.com. In general, every buy or sell request you place will go through at the next share price to be calculated after your request has been accepted; check with your insurance company or qualified plan administrator to find out by what time your transaction request must be received in order to be processed the same day. The Fund normally calculates its share price as of the end of regular trading on the Exchange on business days, usually 4:00 p.m. Eastern time. Depending on when your insurance company or qualified plan accepts transaction requests, it is possible that the Fund’s share price could change on days when you are unable to buy or sell shares. Because foreign markets may be open on days when U.S. markets are closed, the value of foreign securities owned by the Fund could change on days when you can’t buy or sell Fund shares. The Fund’s share price, however, will not change until the next time it is calculated.

Share Price Calculations

The price of a share of the Fund is the total value of the Fund’s assets minus its liabilities, divided by the total number of Fund shares outstanding. Because the value of the Fund’s securities changes every business day, the share price usually changes as well.

The Fund values equity securities by using market prices, and values debt securities using bid quotations from independent pricing services or principal market markers. The Fund may value short-term securities with remaining maturities of less than 60 days at cost; these values, when combined with interest earned, approximate market value.

In certain cases, events that occur after markets have closed may render certain prices unreliable or reliable market quotes may not be available. When a market price is not available or the Fund believes a market price does not reflect the amount that the Fund would receive on a current sale of that security, the Fund may substitute for the market price a fair-value estimate made according to methods approved by the Board of Trustees. The Fund may also use these methods to value certain types of illiquid securities.

Fair value pricing generally will be used if the exchange on which a portfolio security is traded closes early or if trading in a particular security was halted during the day and did not resume prior to a Fund’s net asset value calculation. The Fund may also use these methods to value securities that trade in a foreign market, especially if significant events that appear likely to affect the value of these securities occur between the time that the foreign market closes and the time the New York Stock Exchange closes. Significant events may include (1) those impacting a single issuer; (2) governmental actions that affect securities in one sector or country; (3) natural disasters or armed conflicts affecting a country or region; or (4) significant domestic or foreign market fluctuations.

The use of fair value estimates could affect the Fund’s share price. Estimated fair value may involve greater reliance on the manager’s judgment and available data bearing on the value of the security and the state of the markets, which may be incomplete. The estimated fair value of a security may differ from the value that would have been assigned to a security had other sources, such as the last trade price, been used and, because it is an estimate, it may not reflect the price that the Fund would actually obtain if it were to sell the security.

Because foreign markets may be open on days when U.S. markets are closed, the value of foreign securities owned by a Fund could change on days when you can’t buy or sell Fund shares. Remember, though, any purchase or sale takes place at the next share price calculated after your order is accepted.

Fund Structure

While Neuberger Berman Management LLC and Neuberger Berman LLC may serve as the adviser or sub-adviser of other mutual funds that have similar names, goals, and strategies as the Fund, there may be certain differences between the Fund and these other mutual funds in matters such as size, cash flow patterns and tax matters, among others. As a result, there could also be differences in performance.

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The Fund uses a “multiple class” structure. The Fund offers Class I and Class S shares that have identical investment programs but different arrangements for distribution and shareholder servicing and, consequently, different expenses. This prospectus relates only to Class I shares of the Fund.