In seeking high current income exempt from regular federal income tax, the Fund will invest in municipal instruments. A municipal instrument is a fixed-income obligation issued by a state, territory or possession of the United States (including the District of Columbia) or a political subdivision, agency or instrumentality thereof. Interest income received by holders of municipal instruments is often exempt from the federal income tax and from the income tax of the state in which they are issued, although municipal instruments issued for certain purposes may not be tax-exempt. The municipal instruments in which the Fund invests may include:

The Fund primarily invests in investment grade debt obligations (i.e., obligations rated within the top four rating categories by a Nationally Recognized Statistical Rating Organization (“NRSRO”) or of comparable quality as

determined by NTI). However, it may invest up to 15% of its net assets in obligations that are rated below-investment grade (commonly referred to as “junk bonds”). Credit ratings are determined at the time of purchase.

Except in extraordinary circumstances, at least 80% of the Fund’s net assets will be invested in debt instruments that pay interest that is exempt from regular federal income tax. Alternative minimum tax (“AMT”) obligations (also known as “private activity bonds”), which pay interest that may be treated as an item of tax preference to shareholders under the federal AMT, will not be deemed to be eligible debt instruments for the purposes of determining whether the Fund meets this policy. For shareholders subject to AMT, a portion of the Fund’s dividends may be subject to federal tax.

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 general obligation bonds, corporate-backed municipal bonds and revenue obligation bonds) that NTI believes will provide a favorable return in light of these risks. NTI may engage in active trading, and will not consider portfolio turnover a limiting factor in making decisions for the Fund.

The Fund’s dollar-weighted average maturity, under normal circumstances, will range from at least one year to less than six years.

In seeking to achieve its investment objective, the Fund may make significant investments in structured securities and also may invest, to a lesser extent, in futures contracts, options and swaps, all of which are considered to be derivative instruments, for both hedging and non-hedging purposes.