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S000038895 [Member] Investment Strategy - CORE BOND FUND
Mar. 31, 2026
Prospectus [Line Items]  
Strategy [Heading] PRINCIPAL INVESTMENT STRATEGIES
Strategy Narrative [Text Block]
The Fund will seek capital appreciation and current income in its attempt to maximize total return. In doing so, the Fund will invest, under normal circumstances, at least 80% of its net assets in bonds and other fixed-income securities. These may include:
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Obligations of the U.S. government or its agencies, instrumentalities or sponsored enterprises, including obligations issued by private issuers that are guaranteed as to principal and interest by the U.S. government, its agencies or instrumentalities;
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Obligations of U.S. state and local governments, and foreign governments;
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Obligations of domestic and foreign banks and corporations;
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Zero coupon bonds and debentures;
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Mortgage and other asset-backed securities;
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Inflation-indexed securities; and
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Stripped securities evidencing ownership of future interest or principal payments on debt obligations.
The Fund invests primarily in the investment grade debt obligations of domestic issuers. Investment grade debt obligations are obligations rated within the top four rating categories by a Nationally Recognized Statistical Rating Organization (“NRSRO”) or determined by NTI to be of comparable quality. Credit ratings are determined at the time of purchase. The Fund also may invest up to 25% of its total assets in U.S. dollar denominated investment grade obligations of foreign issuers.
The Fund may also invest in securities that are subject to resale restrictions such as those contained in Rule 144A promulgated under the Securities Act of 1933.
In buying and selling securities for the Fund, NTI uses a relative value approach. This approach involves an analysis of general economic and market conditions. It also involves the use of models that analyze and compare expected returns and assumed risks. Under the relative value approach, NTI will emphasize particular securities and types of securities (such as treasury, agency, asset-backed, mortgage-related and corporate securities) that the team believes will provide a favorable total return in light of these risks.
The Fund may seek to obtain exposure to mortgage-backed and mortgage-related securities (collectively, “MBS”) through to‑be‑announced (“TBA”) transactions. Most transactions in MBS occur through TBA transactions, which are standardized contracts for future delivery in which the exact mortgage pools to be delivered are not specified until a few days prior to settlement.
The Fund’s dollar-weighted average maturity, under normal circumstances, will range between three and fifteen years.
From time to time the Fund may have a focused investment (i.e., investment exposure comprising more than 15% of its total assets) in one or more particular sectors.
NTI may engage in active trading, and will not consider portfolio turnover a limiting factor in making decisions for the Fund.
In seeking to achieve its investment objective, the Fund may invest in U.S. Treasury futures, which are considered to be derivative instruments, for various purposes, including to manage duration, credit and interest rate risks, and for cash management. Derivatives instruments that provide investment exposure to investments in the Fund’s 80% investment policy and derivatives instruments that provide investment exposure to one or more of the market risk factors associated with such securities may be counted towards the Fund’s 80% investment policy.