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        <ExplanationTxt>B)NILSSON IS CHAIR OF SEI,US AND IS THE EXECUTIVE DIRECTOR OF SEI INTERNATIONAL D) SEI INTERNATIONAL GAVE A GRANT TO SEI US IN 2018.</ExplanationTxt>
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    </IRS990ScheduleL>
    <IRS990ScheduleO documentId="RetDoc7">
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990 - ORGANIZATION'S MISSION</FormAndLineReferenceDesc>
        <ExplanationTxt>SEI US SUPPORTS DECISION-MAKING AND INDUCING CHANGE TOWARDS SUSTAINABLE DEVELOPMENT AROUND THE WORLD BY PROVIDING KNOWLEDGE THAT BRIDGES SCIENCE AND POLICY IN THE FIELDS OF ENVIRONMENT AND DEVELOPMENT, AND BY CONDUCTING INNOVATIVE, INTEGRATED APPLIED SYSTEMS RESEARCH, WHICH FORMS THE BASIS FOR POLICY ADVICE, CAPACITY BUILDING, DECISION SUPPORT, AND POLICY IMPLEMENTATION.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PAGE 6, PART VI, LINE 4</FormAndLineReferenceDesc>
        <ExplanationTxt>AT ITS OCTOBER 24, 2018 BOARD MEETING, SEI CHANGED ITS BYLAWS AS FOLLOWS: TO CLARIFY THAT THE PROPERTY OF SEI WOULD BE DEDICATED TO NONPROFIT PURPOSES (ARTICLE 2); TO EXPAND ON THE TREATMENT OF BOARD COMPENSATION AND TO STATE THAT NO LOANS WOULD BE MADE TO BOARD MEMBERS (ARTICLE 4); TO ADD AN AUDIT COMMITTEE (ARTICLE 4); AND TO STATE RESTRICTIONS ON INTERESTED PARTY TRANSACTIONS (ARTICLE 9).</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PAGE 6, PART VI, LINE 11B</FormAndLineReferenceDesc>
        <ExplanationTxt>THE BOARD IS GIVEN THE 990 TO REVIEW AND APPROVE PRIOR TO FILING THE 990.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PAGE 6, PART VI, LINE 12C</FormAndLineReferenceDesc>
        <ExplanationTxt>THE FINANCIAL CONTROLLER REGULARLY REVIEWS ALL BUSINESS TRANSACTIONS TO DETERMINE IF CONFLICTS OF INTEREST MAY EXIST FOR BOARD MEMBERS, OFFICERS, KEY EMPOYEES, AND ALL OTHER EMPLOYEES. ANY POTENTIAL CONFLICTS OF INTEREST ARE BROUGHT TO THE ATTENTION OF THE PRESIDENT, MICHAEL LAZARUS, WHO THEN BRINGS THE ISSUE BEFORE THE BOARD OR REQUESTS THAT THE INTERESTED PERSON PRESENT THE ISSUE TO THE BOARD FOR REVIEW.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PAGE 6, PART VI, LINE 15A</FormAndLineReferenceDesc>
        <ExplanationTxt>THE COMPENSATION OF THE PRESIDENT IS APPROVED BY THE COMPENSATION COMMITTEE OF THE BOARD AFTER A REVIEW OF A COMPENSATION SURVEY DETAILING COMPENSATION OF OTHER SENIOR SCIENTISTS OF SIMILAR ORGANIZATIONS AND OTHER COMPARABLE 990S. THE PRESIDENT'S PAY IS COMPARABLE TO SENIOR SCIENTISTS IN THE INDUSTRY.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PAGE 6, PART VI, LINE 18</FormAndLineReferenceDesc>
        <ExplanationTxt>THE ORGANIZATION'S FORM 990 IS AVAILABLE TO THE PUBLIC UPON REQUEST.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PAGE 6, PART VI, LINE 19</FormAndLineReferenceDesc>
        <ExplanationTxt>GOVERNING DOCUMENTS, CONFLICT OF INTEREST POLICY, AND FINANCIAL STATEMENTS ARE AVAILABLE TO THE PUBLIC UPON REQUEST.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART IX, LINE 11G</FormAndLineReferenceDesc>
        <ExplanationTxt>OTHER FEES 1,113,217 31,211 0</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART XI, LINE 9</FormAndLineReferenceDesc>
        <ExplanationTxt>LOSSES REPORTED ON RETURN -600 RENTAL EXPENSES 17,319 LOSS ON SALE OF ASSET 600 RENTAL EXPENSES -17,319</ExplanationTxt>
      </SupplementalInformationDetail>
    </IRS990ScheduleO>
  </ReturnData>
</Return>