UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 ----------------------------- FORM N-17f-2 OMB Approval ----------------------------- Certificate of Accounting of Securities and OMB Number: 3235-0360 Similar Investments in the Custody Expires: Dec 31, 2026 of Management Investment Companies Estimate average burden hours per response . . . . . 2.00 Pursuant to Rule 17f-2 [17 CFR 270.17f-2] ----------------------------- ----------------------------------------------------------------------------- 1. Investment Company Act File Number: Date examination completed: 811-03605 November 30, 2025 ----------------------------------------------------------------------------- 2. State Identification Number: IL AL AK AZ AR CA CO CT DE DC FL GA HI ID IL IN IA KS KY LA ME MD MA MI MN MS MO MT NE NV NH NJ NM NY NC ND OH OK OR PA RI SC SD TN TX UT VT VA WA WV WI WY PUERTO RICO Other (specify): ----------------------------------------------------------------------------- 3. Exact name of investment company as specified in registration statement: Northern Institutional Funds ----------------------------------------------------------------------------- 4. Address of principal executive office (number,street,city,state,zip code): 50 South LaSalle, Chicago, IL 60603 ----------------------------------------------------------------------------- INDEPENDENT ACCOUNTANTS' REPORT To the Board of Trustees of Northern Institutional Funds We have examined management of the Northern Institutional Funds' assertion, included in the accompanying Management's Assertion Regarding Northern Institutional Funds' Compliance with Rule 17f-2 Under the Investment Company Act of 1940, that the Northern Institutional Funds (collectively, the "Company"), comprised of the funds listed in Appendix A, complied with the requirements of subsections (b) and (c) of Rule 17f-2 under the Investment Company Act of 1940 (the "specified requirements") as of November 30, 2025. The Company's management is responsible for its assertion. Our responsibility is to express an opinion on management's assertion about the Company's compliance with the specified requirements based on our examination. Our examination was conducted in accordance with attestation standards established by the American Institute of Certified Public Accountants. Those standards require that we plan and perform the examination to obtain reasonable assurance about whether management's assertion about compliance with the specified requirements is fairly stated, in all material respects. An examination involves performing procedures to obtain evidence about whether management's assertion is fairly stated, in all material respects. The nature, timing, and extent of the procedures selected depend on our judgment, including an assessment of the risks of material misstatement of management's assertion, whether due to fraud or error. We believe that the evidence we obtained is sufficient and appropriate to provide a reasonable basis for our opinion. We are required to be independent and to meet our other ethical responsibilities in accordance with relevant ethical requirements relating to the engagement. Included among our procedures were the following tests performed as of November 30, 2025, and with respect to agreement of security purchases and sales, for the period from August 31, 2025 (the date of our last examination) through November 30, 2025: 1. Confirmation of all securities held by institutions in book entry form on behalf of Northern Trust by the Federal Reserve Bank of Kansas City and The Depository Trust Company. 2. Confirmation of all securities hypothecated, pledged, placed in escrow, or out for transfer with brokers, pledgees, and/or transfer agents. 3. Reconciliation of all such securities to the books and records of the Company and Northern Trust. 4. Confirmation of 33 out of 50 repurchase agreements with brokers/banks and agreement of underlying collateral with Northern Trust records. For confirmations not received, agreed to the cash records provided by Northern Trust. 5. Agreement of 5 security purchases and 5 security sales or maturities since our last report from the books and records of the Company to the subsequent settlement in cash records provided by Northern Trust. Our examination does not provide a legal determination on the Company's compliance with specified requirements. In our opinion, management's assertion that each of the Northern Institutional Funds (listed in the attached Appendix A) complied with the requirements of subsections (b) and (c) of Rule 17f-2 of the Investment Company Act of 1940 as of November 30, 2025, with respect to securities reflected in the investment accounts of the Company is fairly stated, in all material respects. This report is intended solely for the information and use of management and the Board of Trustees of Northern Institutional Funds and the U.S. Securities and Exchange Commission and is not intended to be, and should not be, used by anyone other than the specified parties. /s/ DELOITTE & TOUCHE LLP Chicago, Illinois March 10, 2026 APPENDIX A Northern Institutional Funds: Liquid Assets Portfolio Treasury Portfolio U.S. Government Portfolio U.S. Government Select Portfolio Treasury Instruments Portfolio Management Assertion Regarding Northern Institutional Funds' Compliance with Rule 17f-2 Under the Investment Company Act of 1940 We, as members of management of Northern Institutional Funds (collectively, the "Company"), comprised of the funds listed in the attached Appendix A, are responsible for complying with the requirements of subsections (b) and (c) of Rule 17f-2, "Custody of Investments by Registered Management Investment Companies," of the Investment Company Act of 1940. We are also responsible for establishing and maintaining effective internal controls over compliance with those requirements. We have performed an evaluation of the Company's compliance with the requirements of subsections (b) and (c) of Rule 17f-2 as of November 30, 2025, and from August 31, 2025 (the date of your last examination) through November 30, 2025. Based on this evaluation, we assert that the Company was in compliance with the requirements of subsections (b) and (c) of Rule 17f-2 of the Investment Company Act of 1940 as of November 30, 2025, with respect to securities reflected in the investment accounts of the Company. Northern Institutional Funds By: /s/ Kevin O'Rourke Kevin O'Rourke President, Northern Institutional Funds /s/ Randal Rein Randal Rein Treasurer, Northern Institutional Funds March 10,2026 APPENDIX A Northern Institutional Funds: Liquid Assets Portfolio Treasury Portfolio U.S. Government Portfolio U.S. Government Select Portfolio Treasury Instruments Portfolio