SSGA ACTIVE TRUST

Supplement dated April 18, 2019 to the currently effective

Prospectus, as may be supplemented from time to time

Securities Lending Risk. Each Fund may lend portfolio securities in an amount not to exceed 40% of the value of its net assets. For these purposes, net assets shall exclude the value of all assets received as collateral for the loan. Such loans may be terminated at any time. Any such loans must be continuously secured by collateral maintained on a current basis in an amount at least equal to the market value of the securities loaned by a Fund, marked to market each trading day. In a loan transaction, as compensation for lending its securities, a Fund will receive a portion of the dividends or interest accrued on the securities held as collateral or, in the case of cash collateral, a portion of the income from the investment of such cash. In addition, a Fund will receive the amount of all dividends, interest and other distributions on the loaned securities. However, the borrower has the right to vote the loaned securities. A Fund will call loans to vote proxies if a material issue affecting the investment is to be voted upon. Efforts to recall such securities promptly may be unsuccessful, especially for foreign securities or thinly traded securities, and may involve expenses to a Fund. Securities lending involves the risk that the Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. Should the borrower of the securities fail financially, a Fund may experience delays in recovering the securities or exercising its rights in the collateral. Loans are made only to borrowers that are deemed by the securities lending agent to be of good financial standing. In a loan transaction, a Fund will also bear the risk of any decline in value of securities provided as collateral or acquired with cash collateral. A Fund will attempt to minimize this risk by limiting the investment of cash collateral to high quality instruments of short maturity either directly on behalf of the lending Fund or through one or more joint accounts or funds, which may include those managed by the Adviser. To the extent the collateral provided or investments made with cash collateral differ from securities included in an Index, such collateral or investments may have a greater risk of loss than the securities included in the Index. In addition, a Fund will be subject to the risk that any income generated by lending its securities or reinvesting cash collateral is lower than any fees the Fund has agreed to pay a borrower.

PLEASE RETAIN THIS SUPPLEMENT FOR FUTURE REFERENCE

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SSGA ACTIVE TRUST

Supplement dated April 18, 2019 to the currently effective

Statement of Additional Information, as may be supplemented from time to time

Effective immediately, the following replaces the “Lending Portfolio Securities” discussion in the “INVESTMENT POLICIES” section:

Each Fund may lend portfolio securities to certain creditworthy borrowers in U.S. and non-U.S. markets in an amount not to exceed 40% of the value of its net assets. The borrowers provide collateral that is marked to market daily in an amount at least equal to the current market value of the securities loaned. A Fund may terminate a loan at any time and obtain the securities loaned. A Fund receives the value of any interest or cash or non-cash distributions paid on the loaned securities. A Fund cannot vote proxies for securities on loan, but may recall loans to vote proxies if a material issue affecting the Fund’s economic interest in the investment is to be voted upon. Efforts to recall such securities promptly may be unsuccessful, especially for foreign securities or thinly traded securities, and may involve expenses to a Fund. Distributions received on loaned securities in lieu of dividend payments (i.e., substitute payments) would not be considered qualified dividend income.

With respect to loans that are collateralized by cash, the borrower will be entitled to receive a fee based on the amount of cash collateral. A Fund is compensated by the difference between the amount earned on the reinvestment of cash collateral and the fee paid to the borrower. In the case of collateral other than cash, a Fund is compensated by a fee paid by the borrower equal to a percentage of the market value of the loaned securities. Any cash collateral may be reinvested in certain high quality short-term instruments either directly on behalf of the lending Fund or through one or more joint accounts or funds, which may include those managed by the Adviser. A Fund could lose money due to a decline in the value of collateral provided for loaned securities or any investments made with cash collateral. Certain non-cash collateral or investments made with cash collateral may have a greater risk of loss than other non-cash collateral or investments.

A Fund may pay a portion of the interest or fees earned from securities lending to a borrower as described above, and to one or more securities lending agents approved by the Board of Trustees of the Trust (the “Board”) who administer the lending program for the Funds in accordance with guidelines approved by the Board. In such capacity, the lending agent provides the following services to the Funds in connection with the Funds’ securities lending activities: (i) locating borrowers among an approved list of prospective borrowers; (ii) causing the delivery of loaned securities from a Fund to borrowers; (iii) monitoring the value of loaned securities, the value of collateral received, and other lending parameters; (iv) seeking additional collateral, as necessary, from borrowers; (v) receiving and holding collateral from borrowers, and facilitating the investment and reinvestment of all or substantially all cash collateral in an investment vehicle designated by the Funds; (vi) returning collateral to borrowers; (vii) facilitating substitute dividend, interest, and other distribution payments to the Funds from borrowers; (viii) negotiating the terms of each loan of securities, including but not limited to the amount of any loan premium, and monitoring the terms of securities loan agreements with prospective borrowers for consistency with the requirements of the Funds’ Securities Lending Authorization Agreement; (ix) selecting securities, including amounts (percentages), to be loaned; (x) recordkeeping and accounting servicing; and (xi) arranging for return of loaned securities to the Fund in accordance with the terms of the Securities Lending Authorization Agreement. State Street Bank and Trust Company (“State Street”), an affiliate of the Trust, has been approved by the Board to serve as

securities lending agent for a Fund and the Trust has entered into an agreement with State Street for such services. Among other matters, the Trust has agreed to indemnify State Street for certain liabilities. State Street has received an order of exemption from the SEC under Sections 17(a) and 12(d)(1) under the 1940 Act to serve as the lending agent for affiliated investment companies such as the Trust and to invest the cash collateral received from loan transactions to be invested in an affiliated cash collateral fund.

Securities lending involves exposure to certain risks, including operational risk (i.e., the risk of losses resulting from problems in the settlement and accounting process especially so in certain international markets such as Taiwan), “gap” risk (i.e., the risk of a mismatch between the return on cash collateral reinvestments and the fees a Fund has agreed to pay a borrower), risk of loss of collateral, credit, legal, counterparty and market risk. If a securities lending counterparty were to default, a Fund would be subject to the risk of a possible delay in receiving collateral or in recovering the loaned securities, or to a possible loss of rights in the collateral. In the event a borrower does not return a Fund’s securities as agreed, the Fund may experience losses if the proceeds received from liquidating the collateral do not at least equal the value of the loaned security at the time the collateral is liquidated, plus the transaction costs incurred in purchasing replacement securities. Although State Street has agreed to provide a Fund with indemnification in the event of a borrower default, a Fund is still exposed to the risk of losses in the event a borrower does not return a Fund’s securities as agreed. For example, delays in recovery of lent securities may cause a Fund to lose the opportunity to sell the securities at a desirable price.

PLEASE RETAIN THIS SUPPLEMENT FOR FUTURE REFERENCE

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