Strategy. In seeking to track the performance of the ICE 1+ Year AMT-Free Broad Municipal Index ? (the Index), the Fund employs a sampling strategy, which means that the Fund is not required to purchase all of the securities represented in the Index. Instead, the Fund may purchase a subset of the securities in the Index in an effort to hold a portfolio of securities with generally the same risk and return characteristics of the Index. The quantity of holdings in the Fund will be based on a number of factors, including asset size of the Fund. Based on its analysis of these factors, Nuveen Asset Management, LLC (Nuveen Asset Management or the Sub-Adviser), the investment sub-adviser to the Fund, either … Show more… In seeking to track the performance of the ICE 1+ Year AMT-Free Broad Municipal Index ? (the Index), the Fund employs a sampling strategy, which means that the Fund is not required to purchase all of the securities represented in the Index. Instead, the Fund may purchase a subset of the securities in the Index in an effort to hold a portfolio of securities with generally the same risk and return characteristics of the Index. The quantity of holdings in the Fund will be based on a number of factors, including asset size of the Fund. Based on its analysis of these factors, Nuveen Asset Management, LLC (Nuveen Asset Management or the Sub-Adviser), the investment sub-adviser to the Fund, either may invest the Fund's assets in a subset of securities in the Index or may invest the Fund's assets in substantially all of the securities represented in the Index in approximately the same proportions as the Index, as determined by the Sub-Adviser to be in the best interest of the Fund in pursuing its objective. Under normal market conditions, the Fund generally invests substantially all, but at least 80%, of its total assets in the securities comprising the Index and in securities that the Sub-Adviser determines have economic characteristics that are substantially identical to the economic characteristics of the securities that comprise the Index. Additionally, the Fund intends to invest, under normal circumstances, at least 80% of its net assets, plus the amount of borrowings for investment purposes, in investments the income of which is exempt from Federal income tax. ? In addition, in seeking to track the Index, the Fund may invest in debt securities that are not included in the Index. The Fund may also invest in cash and cash equivalents or money market instruments (including money market funds advised by SSGA Funds Management, Inc. (SSGA FM or the Adviser), the investment adviser to the Fund) for cash management purposes. In seeking to track the Index, the Fund's assets may be concentrated in an industry or group of industries, but only to the extent that the Index concentrates in a particular industry or group of industries. The Index is designed to track the performance of U.S. dollar denominated investment grade tax-exempt debt publicly issued by U.S. states and territories, and their political subdivisions, in the U.S. domestic market. The Index includes state and local general obligation bonds, revenue bonds, pre-refunded bonds, and insured bonds. A general obligation bond is secured by the full faith and credit of its issuer. A revenue bond is payable from a specific source of revenue. A pre-refunded bond is a revenue bond that the issuer has allocated funds to fully retire. An insured bond is protected from issuer default or rating downgrade by an insurance company. The Index also includes municipal lease obligations, which are securities issued by state and local governments and authorities to finance the acquisition of equipment and facilities. They may take the form of a lease, an installment purchase contract, a conditional sales contract, or a participation interest in a lease or contract. The Index is a rules-based, market-capitalization weighted index engineered for the tax-exempt bond market. All bonds in the Index must be exempt from federal taxes, U.S. dollar denominated and have an average rating of Baa3/BBB- or higher by the following statistical ratings agencies: Moody's Investors Service, Inc., S&P Global Ratings, and Fitch Ratings Inc. In addition, to be included in the Index, a security must (i) not be subject to alternative minimum tax; (ii) have a fixed coupon schedule; (iii) have at least one year remaining term to final maturity; (iv) have at least 18 months to final maturity at the time of issuance; and (v) meet the following minimum size requirements: (a) have a minimum current amount outstanding of $5 million for bonds with an initial term to final maturity of less than 3 years; (b) have a minimum current amount outstanding of $7 million for bonds with an initial term to final maturity of 3 to 15 years; and (c) have a minimum current amount outstanding of $10 million for bonds with an initial term to final maturity of 15 or more years. Securities included in the Index may include when-issued securities and zero-coupon bonds. Secondarily insured bonds, Rule 144A bonds, bonds issued under the municipal liquidity facility or a municipal commercial paper program are excluded from the Index. The Index is rebalanced and reconstituted monthly on the last calendar day of the month. As of July 31, 2025, there were 60,390 securities in the Index. The Index is sponsored by ICE Data Indices, LLC (the Index Provider), which is not affiliated with the Fund, the Adviser or the Sub-Adviser. The Index Provider determines the composition of the Index, relative weightings of the securities in the Index and publishes information regarding the market value of the Index. Show less