Under normal circumstances, the Fund will invest substantially all (and at least 80%) of its net assets in equity securities included in the S&P MidCap 400^® Index, in weightings that approximate the relative composition of securities contained in the Index, and in S&P MidCap 400^® Index futures approved by the Commodity Futures Trading Commission.

The Index is a free float-adjusted market capitalization index consisting of 400 mid‑capitalization stocks. As of May 29, 2026, the approximate market capitalization of the companies in the Index was between $980.4 million and $55.4 billion. It is rebalanced quarterly. The Fund generally rebalances its portfolio in accordance with the Index.

NTI uses a “passive” or indexing approach to try to achieve the Fund’s investment objective. Unlike many investment companies, the Fund does not try to “beat” the index it tracks and does not seek temporary defensive positions when markets decline or appear overvalued. NTI will buy and sell securities in response to changes in the Index as well as in response to subscriptions and redemptions.

The Fund generally invests in substantially all of the securities in the Index in approximately the same proportion as the Index (i.e., replication). In certain circumstances, however, the Fund may not hold every security in the Index or in the same proportion as the Index, such as to improve tax efficiency or when it may not be practicable to fully implement a replication strategy. Rather, it will use an optimization strategy to seek to construct a portfolio that minimizes tracking error versus the Index while managing transaction costs and realized capital gains and losses.

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.

The Fund intends to be diversified in approximately the same proportion as the Index is diversified. The Fund may become “non‑diversified,” as defined in the Investment Company Act of 1940 (the “1940 Act”), solely as a result of a change in relative market capitalization or index weighting of one or

more constituents of the Index. A “non‑diversified” fund can invest a greater percentage of its assets in a small group of issuers or in any one issuer than a diversified fund can. Shareholder approval will not be sought if the Fund becomes non‑diversified due solely to a change in the relative market capitalization or index weighting of one or more constituents of the Index.

In seeking to track the performance of the Index, 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. As of March 31, 2026, the Fund had a focused investment in the industrials sector.

NTI expects that, under normal circumstances, the quarterly performance of the Fund, before fees and expenses, will track the performance of the Index within a 0.95 correlation coefficient.