SCHEDULE 13D/A 0000769317 XXXXXXXX LIVE 1 Common Stock 02/04/2026 false 0001287498 27828V104 Eaton Vance Short Duration Diversified Income Fund

One Post Office Square Boston MA 02109

Paul E. Rasmussen 612-332-3223 80 South Eighth Street Suite 3300 Minneapolis MN 55402-4130 0000769317 N Sit Investment Associates, Inc. b OO N MN 0.00 693390.00 0.00 693390.00 693390.00 N 5.2 IA 0001053046 N Sit Fixed Income Advisors II, LLC b OO N DE 0.00 693390.00 0.00 693390.00 693390.00 N 5.2 IA Common Stock Eaton Vance Short Duration Diversified Income Fund One Post Office Square Boston MA 02109 This statement is filed by: Sit Investment Associates, Inc., a Minnesota corporation (SIA), and Sit Fixed Income Advisors II, LLC, a Delaware limited liability company (SFI). Both SIA and SFI are parties to a Joint Filing Agreement as filed on October 20, 2025 as exhibit B to the Original Schedule 13D. The business address of each of the Sit Entities is 80 South Eighth Street, Suite 3300. Minneapolis, MN 55402 SIA is a registered investment adviser. SFI is a registered investment adviser and subsidiary of SIA. SIA or SFI serves as investment adviser on behalf of its clients. SIA and SFI have entered into investment management agreements with each of its clients pursuant to which SIA or SFI has full discretionary authority to direct the investments of its client in accordance with the investment objectives and restrictions of the client. The investment management agreements also provide that SIA or SFI has assumed the responsibility to vote on behalf of its clients all shares held by its clients in accounts managed by SIA or SFI. Roger J. Sit is chairman and CEO of SIA and SFI. Ronald D. Sit is a director of SIA. Raymond E. Sit is a vice president and director of SIA. By virtue of these positions, each of SIA, SFI, Roger J. Sit, Ronald D. Sit, and Raymond E. Sit may be deemed to beneficially own the Shares held in SIA and SFI client accounts. SIA, SFI, Roger J. Sit, Ronald D. Sit, and Raymond E. Sit together are the "Sit Entities." During the last five years, Roger J. Sit, Ronald D. Sit, and Raymond E. Sit have not been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors). During the last five years, none of the Sit Entities have been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree, or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws. Roger J. Sit, Ronald D. Sit, and Raymond E. Sit are United States citizens. The aggregate percentage of Shares reported owned by Sit Entities herein is based upon 13,456,906 Shares outstanding as of October 31, 2025, which is the total number of Shares outstanding as reported in the Issuer's Form N-CSR. As of the date hereof, the Sit Entities may be deemed to be the beneficial owner of 693,390 Shares held in client accounts which represent 5.2% of the Issuer's outstanding Shares. Each of the Sit Entities may be deemed to have shared power to vote and dispose of such Shares. However, none of SIA's or SFI's client accounts own more than 5% of the shares outstanding, and none of SIA's or SFI's directors or executive officers own shares directly. Transactions in Shares effected during the past 60 days by the Sit Entities are set forth in Exhibit A. The clients of SIA and SFI have the right to participate in the receipt of dividends from, or proceeds from the sales of, the Shares held for their respective accounts. Not applicable. Exhibit A: Schedule of Transactions in Shares by Sit Entities during the past 60 days Sit Investment Associates, Inc. /s/ Roger J. Sit 02/05/2026 Sit Fixed Income Advisors II, LLC /s/ Roger J. Sit 02/05/2026