Prospectus by Investment Company (Form 497)

FLEXSHARES® TRUST

FlexShares® Credit-Scored US Corporate Bond Index Fund (SKOR)

FlexShares® Credit-Scored US Long Corporate Bond Index Fund (LKOR)

FlexShares® Developed Markets ex-US Quality Low Volatility Index Fund (QLVD)

FlexShares® Disciplined Duration MBS Index Fund (MBSD)

FlexShares® Emerging Markets Quality Low Volatility Index Fund (QLVE)

FlexShares® ESG & Climate Developed Markets ex-US Core Index Fund (FEDM)

FlexShares® ESG & Climate Investment Grade Corporate Core Index Fund (FEIG)

FlexShares® ESG & Climate US Large Cap Core Index Fund (FEUS)

FlexShares® Global Quality Real Estate Index Fund (GQRE)

FlexShares® High Yield Value-Scored Bond Index Fund (HYGV)

FlexShares® iBoxx® 3-Year Target Duration TIPS Index Fund (TDTT)

FlexShares® iBoxx® 5-Year Target Duration TIPS Index Fund (TDTF)

FlexShares® International Quality Dividend Dynamic Index Fund (IQDY)

FlexShares® International Quality Dividend Index Fund (IQDF)

FlexShares® Morningstar Developed Markets ex-US Factor Tilt Index Fund (TLTD)

FlexShares® Morningstar Emerging Markets Factor Tilt Index Fund (TLTE)

FlexShares® Morningstar Global Upstream Natural Resources Index Fund (GUNR)

FlexShares® Morningstar US Market Factor Tilt Index Fund (TILT)

FlexShares® STOXX® Global Broad Infrastructure Index Fund (NFRA)

FlexShares® STOXX® Global ESG Select Index Fund (ESGG)

FlexShares® STOXX® US ESG Select Index Fund (ESG)

FlexShares® US Quality Large Cap Index Fund (QLC)

FlexShares® US Quality Low Volatility Index Fund (QLV)

FlexShares® Quality Dividend Defensive Index Fund (QDEF)

FlexShares® Quality Dividend Index Fund (QDF)

SUPPLEMENT DATED AUGUST 3, 2026 TO THE STATEMENT OF ADDITIONAL INFORMATION DATED MARCH 1, 2026, AS SUPPLEMENTED (THE "SAI")

Capitalized terms used in this Supplement, unless otherwise defined in this Supplement, have the meanings assigned to them in the Funds' SAI. This Supplement updates certain information contained in the SAI of the Funds and should be read in conjunction with the SAI.

At a special meeting of shareholders held on July 24, 2026, shareholders of the Trust elected a new slate of Trustees to the Board of Trustees of the Trust (the "Board"). Accordingly, effective July 24, 2026, all references to the prior Board of Trustees are deleted in their entirety and replaced with the disclosure below.

TRUSTEES AND OFFICERS

The Board is responsible for the management and business and affairs of the Trust. Set forth below is information about the Trustees and the Officers of the Trust as of July 31, 2026. Each Trustee has served in that capacity since he or she was originally elected or appointed to the Board. As of July 31, 2026, each Trustee oversees a total of 94 portfolios in the Northern Funds Complex. The Northern Funds Complex consists of Northern Funds, Northern Institutional Funds, and the Trust. As of July 31, 2026, Northern Funds consists of 61 portfolios, Northern Institutional Funds consists of 6 portfolios, and the Trust consists of 27 portfolios.

INDEPENDENT TRUSTEES

(1) Each Trustee may be contacted by writing to the Trustee, c/o the Secretary of the Trust, The Northern Trust Company, 50 South LaSalle Street, Chicago, Illinois 60603.

INTERESTED TRUSTEE

(1) Each Trustee may be contacted by writing to the Trustee, c/o the Secretary of the Trust, The Northern Trust Company, 50 South LaSalle Street, Chicago, Illinois 60603.

(2) Each Trustee will hold office for an indefinite term until the earliest of: (i) the next meeting of shareholders, if any, called for the purpose

of considering the election or re-election of such Trustee and until the election and qualification of his or her successor, if any, elected at such meeting; (ii) the date a Trustee resigns or retires, or a Trustee is removed by the Board or shareholders, in accordance with the Trust's Agreement and Declaration of Trust; or (iii) in accordance with the current resolutions of the Board (which may be changed without shareholder vote) on the earlier of the completion of 15 years of service on the Board and the last day of the calendar year in which he or she attains the age of seventy-five years.

(3) This column includes only directorships of companies required to report to the SEC under the Exchange Act (i.e., public companies) or other investment companies registered under the 1940 Act.

(4) An "interested person," as defined by the 1940 Act. Ms. Kar is deemed to be an "interested" Trustee because she is an officer, director, employee, and a shareholder of Northern Trust Corporation and/ its affiliates.

STANDING BOARD COMMITTEES

The prior Board had established a standing Audit Committee and a Governance Committee to assist the Board in fulfilling its oversight responsibilities. The new Board has established four standing committees in connection with its governance of the Trust: Audit, Governance, Valuation and Executive Committees.

The Audit Committee consists of three members: Ms. Bobek (Chairperson), and Messrs. David Martin (ex officio), and Kloet (ex officio). The Audit Committee oversees the audit process and provides assistance to the full Board with respect to fund accounting, tax compliance and financial statement matters. In performing its responsibilities, the Audit Committee selects and recommends annually to the entire Board an independent registered public accounting firm to audit the books and records of the Trust for the ensuing year, and reviews with the firm the scope and results of each audit. The Audit Committee also is designated as the Qualified Legal Compliance Committee under the Sarbanes-Oxley Act of 2002. The Audit Committee will convene at least four times each year to meet with the independent registered public accounting firm to review the scope and results of the audit and to discuss other non-audit matters as requested by the Board's Chairperson, the Committee Chairperson or the independent registered public accounting firm. Prior to the replacement of the former Board, the Audit Committee convened twice during the last fiscal year ended October 31, 2025.

The Governance Committee consists of three members: Mses. Skinner (Chairperson), Plouché and Mr. Kloet. The functions performed by the Governance Committee include, among other things, selecting and nominating candidates to serve as Independent Trustees, reviewing and making recommendations regarding Trustee compensation, developing policies regarding Trustee education and, subject to Board oversight, supervising the Trust's CCO and reviewing information and making recommendations to the Board in connection with the Board's annual consideration of the Trust's management, custody and transfer agency and service agreements. Prior to the replacement of the former Board, the Governance Committee convened twice during the last fiscal year ended October 31, 2025.

As stated above, each Trustee holds office for an indefinite term until the occurrence of certain events. In filling Board vacancies, the Governance Committee will consider nominees recommended by shareholders. Nominee recommendations should be submitted to the Secretary of the Trust, The Northern Trust Company, 50 South LaSalle Street, Chicago, Illinois 60603.

The Valuation Committee consists of four members: Messrs. David Martin (Chairperson), Kloet (ex officio), and William Martin, and Ms. de Jongh. The Valuation Committee is authorized to act for the Board in connection with the valuation of portfolio securities of the Funds in accordance with the Trust's valuation procedures. The Valuation Committee was formed on July 24, 2026 and has not convened yet.

The Executive Committee consists of four members: Messrs. Kloet (Chairperson) and David Martin, and Mses. Bobek and Skinner. The Executive Committee is comprised of the Chairperson of the Board as well as the Chairpersons of the Governance, Valuation and Audit Committees, with the remaining Trustees each serving as an alternate in the event of an emergency. The Executive Committee is granted the power to act on behalf of the full Board in the management of the business and affairs of the Trust, to be exercised when circumstances impair the ability of the Board or its committees to conduct business. In particular, the Executive Committee may take action with respect to: (1) the valuation of securities; and (2) the suspension of redemptions. The Executive Committee was formed on July 24, 2026 and will convene as necessary upon notice by the Chairperson of the Committee.

LEADERSHIP STRUCTURE

The Board is currently composed of eight Trustees, seven of whom are not "interested persons" as defined in the 1940 Act ("Independent Trustee"), and one of whom is an "interested person" as defined in the 1940 Act ("Interested Trustee"). The Chairperson of the Board, Thomas A. Kloet, is an Independent Trustee. Paula Kar is considered an Interested Trustee because she is an officer, director, employee, and a shareholder of Northern Trust Corporation and/or its affiliates. Each Trustee was nominated to serve on the Board because of his or her experience, skills and qualifications. See "Trustee Experience." The Board believes that its leadership structure is consistent with industry practices and is appropriate in light of the size of the Trust and the nature and complexity of its business. In particular:

Board Composition. The Trustees believe that having a super-majority of Independent Trustees (at least 75%) is appropriate and in the best interest of shareholders. The Trustees also believe that having Ms. Kar serve as an Interested Trustee brings management and financial insight that is important to certain of the Board's decisions and is also in the best interest of shareholders.

Independent Trustee Meetings and Executive Sessions. The Trustees believe that meetings of the Independent Trustees and meetings in executive session, including with independent counsel, help prevent conflicts of interest from occurring. The Trustees also believe that these sessions allow the Independent Trustees to deliberate candidly and constructively, separately from management, in a manner that affords honest disagreement and critical questioning.

RISK OVERSIGHT

Risk oversight is a part of the Board's general oversight of the Funds and is addressed as part of various Board and committee activities, including throughout the year at regular Board and committee meetings and through regular reports provided to the Board and/or its committees that address, among other items, certain investment, valuation, liquidity, and compliance matters. The Board also may receive special reports or presentations on a variety of risk issues, either upon the Board's request or upon Northern Trust Investments, Inc.'s (the "Investment Adviser'") initiative. Day-to-day risk management functions are subsumed within the responsibilities of the Investment Adviser and other service providers (depending on the nature of the risk), which carry out the Funds' investment management and business affairs. Each of the Investment Adviser and other service providers employ a variety of processes, procedures and controls to identify various events or circumstances that may give rise to risks, to lessen the probability of their occurrence and/or to mitigate the effects of such events or circumstances if they occur. Each of the

Investment Adviser and other service providers have their own independent interests in risk management, and their policies and methods of risk management will depend on their functions and business models. The Investment Adviser has a dedicated risk management function that is headed by a Chief Risk Officer.

Currently, the Board receives and reviews risk reports on a quarterly basis from the Investment Adviser's Chief Risk Officer covering various risk areas, such as investment and market risk, operational risk, business continuity, cybersecurity risk, and regulatory compliance risk. These reports are intended to provide the Trustees with a forward-looking view of risk and the manner in which the Investment Adviser is managing various risks.

The Audit Committee, in addition to its risk management responsibilities, plays an important role in the Board's risk oversight. Working with the Funds' independent registered accountants, the Audit Committee reviews the Funds' annual audit scope and the results of the audit of the Funds' year-end financial statements.

The Valuation Committee reviews quarterly reports on fair valuation determinations, including the methodology used in making fair value determinations.

The Board also monitors and reviews the Funds' performance metrics and regularly confers with the Investment Adviser on performance-related issues. With respect to liquidity risk, the Board receives regular liquidity risk management reports under the Funds' Liquidity Risk Management (LRM) Program that include information concerning illiquid investments within the Fund's portfolio. The Board also reviews, no less frequently than annually, a written report prepared by the LRM Program administrator that addresses, among other items, the operation of the LRM Program and assesses its adequacy and effectiveness of implementation as well as any material changes to the LRM Program.

The Board has approved a derivatives risk manager, which is responsible for administering the Derivatives Risk Management (DRM) Program for the Funds that are required to implement a DRM Program. The Board meets with the derivatives risk manager on a periodic basis, including receiving quarterly and annual reports from the derivatives risk manager, to review the implementation of the DRM Program.

The Trust's CCO reports to the Board at least quarterly regarding compliance matters. In addition to providing quarterly reports, the CCO provides an annual report to the Board in accordance with the Funds' compliance policies and procedures. The CCO regularly discusses relevant compliance issues, including compliance risks affecting the Funds during meetings with the Independent Trustees and counsel. The Board adopts compliance policies and procedures for the Funds and approves such procedures for the Funds' service providers. The compliance policies and procedures are specifically designed to detect and prevent violations of the federal securities laws.

TRUSTEE EXPERIENCE

Each Trustee is required to possess certain qualities such as integrity, intelligence, the ability to critically discuss and analyze issues presented to the Board and an understanding of a trustee's fiduciary obligations with respect to a registered investment company. In addition to these qualities, the following is a description of certain other Trustee attributes, skills, experiences and qualifications.

INDEPENDENT TRUSTEES

Therese M. Bobek: Ms. Bobek retired in 2018 from a 35-year career with PricewaterhouseCoopers, LLP ("PwC"), having served a wide variety of public and privately held clients with external audits, internal

auditing and risk advisory services. Ms. Bobek's final role was to serve in PwC's national office, where she led a nationwide network of partners and managers whose main responsibility was to support audit quality in the field. After retirement from PwC, Ms. Bobek taught Advanced Auditing in the Masters of Accountancy program at the University of Iowa's Henry B. Tippie College of Business for five years. Since 2020, she has been a director and member of the audit and nominating and governance committees of the board of directors of Methode Electronics, Inc., a global developer of custom engineered and application-specific products and solutions. Ms. Bobek has been a Board Member of Metropolitan Family Services and a Board Member of the Illinois Society of CPAs. She has also served as a member and Chair of the University of Iowa Professional Accounting Council, a voluntary council of business leaders supporting accounting education. She has served as an Independent Trustee of Northern Institutional Funds and Northern Funds since 2019 and as an Independent Trustee of the Trust since July 2026.

Ingrid LaMae A. de Jongh: Ms. de Jongh served as a partner in the global financial services strategy at Accenture and was with the global management consulting and professional services firm from 1987 through 2012. While at Accenture, she helped global financial institutions improve their business performance by developing strategies and business models and implementing business change programs and systems. Since 2020 she has been the Chief Schooling Officer & Provost, and from 2016 to 2020 she was the Head of School Management and Technology at Success Academy Charter Schools, the largest network and highest-performing free, public charter schools in New York City. Ms. de Jongh is a former member of the Board of Carver Bancorp, Inc. in New York City, where she served as a member of the Nominating and Governance Committees and the Compensation Committee. She previously served on the Board of Directors of Bank Leumi USA from 2016 to 2022. Ms. de Jongh had previously served from 2011 to 2013 as a member of the U.S. Department of Commerce's National Advisory Council for Minority Business Enterprises. She has served as an Independent Trustee of Northern Institutional Funds and Northern Funds since 2019 and as an Independent Trustee of the Trust since July 2026.

Thomas A. Kloet: Mr. Kloet is a long-time financial industry executive and former Chief Executive Officer of TMX Group, Ltd., a financial services company and operator of stock, derivatives exchanges, their clearing operations and securities depository. As a result of this position, Mr. Kloet is familiar with financial, investment and business matters. He also understands the functions of a board through his service during the past twelve years on the Board of Nasdaq, Inc. (plus the Nasdaq Stock Market, LLC as well as certain other U.S. stock and option exchanges of Nasdaq, Inc. where he has served as Board Chair since 2016); and previous board experience with TMX Group, Ltd.; Box Options Exchange; FTSE-TMX Global Debt Capital Markets, Inc.; Bermuda Stock Exchange, Inc.; the Investment Industry Regulatory Organization of Canada and the World Federation of Exchanges. He is a certified public accountant, a member of the American Institute of Certified Public Accountants and is an emeritus member of the Board of Elmhurst College. He has served as an Independent Trustee of Northern Institutional Funds and Northern Funds since 2015 and as an Independent Trustee of the Trust since July 2026.

Mr. Kloet serves on the Board of Directors of Nasdaq, Inc. Northern Trust Corporation ("NTC"), parent company of NTI, and its affiliates (including affiliated fund complexes) pay listing fees, market data fees, GRC (governance risk and compliance) software fees and similar fees to Nasdaq, Inc. and its affiliates, The Nasdaq Stock Market LLC, Nasdaq OMX Nordic OY and Nasdaq CXC Ltd. (collectively, "Nasdaq"). The total of these payments were $6,509,143 and $10,756,134 in each of 2024 and 2025, respectively, which are immaterial to Nasdaq's total revenues. In consideration of the immaterial amounts involved in the foregoing transactions, Mr. Kloet is not considered to have a material business or professional relationship with NTI or its affiliates.

David R. Martin: Mr. Martin was Chief Financial Officer for Neo Tech, an electronics manufacturer, from 2019 to 2023. Mr. Martin was Vice President, Chief Financial Officer and Treasurer from 2007 to 2016 of Dimensional Fund Advisors LP, a global investment manager that provides its services largely to investment companies or their local equivalent (mutual funds in the U.S.). The funds are held primarily by clients of independent financial advisors but they are also held by institutional clients (who may invest in separate accounts), pensions and profit sharing plans, corporations, defined contribution plans, endowments, state and municipal entities, and sovereign wealth funds. Mr. Martin had oversight responsibilities for all finance and accounting, real estate and compliance functions while at Dimensional, including the implementation of a global transfer pricing methodology. He also served as a director on eight internal Dimensional boards. During his 35 year career in corporate finance, Mr. Martin also had senior management positions at Janus Capital Group, Inc. and Charles Schwab & Co., Inc. and senior level finance positions at First Interstate Bank of Texas, N.A. and Texas Commerce Bancshares, Inc. Mr. Martin is familiar with the functions of mutual fund boards and their oversight responsibilities and the operations of fund advisers and other service providers. He is also well versed in risk management and financial matters affecting mutual funds. He has served as an Independent Trustee of Northern Institutional Funds and Northern Funds since 2017 and as an Independent Trustee of the Trust since July 2026.

William Martin: Mr. Martin has extensive experience in fixed income portfolio management and in the financial industry. From 2004 to 2020, he held various portfolio manager positions at Nuveen / TIAA, most recently serving as a Senior Managing Director and the Chief Investment Officer of Global Fixed Income. Prior to his role as Nuveen's Chief Investment Officer of Global Fixed Income, Mr. Martin held various roles at Nuveen, which included being the Lead Portfolio Manager of fixed income mutual funds and leading sector portfolio management within structured finance. Prior to working at Nuveen, Mr. Martin held executive positions at Lewtan Technologies and Visible Markets, Inc. Mr. Martin is familiar with the oversight functions of mutual fund boards and the operations and investment risk management responsibilities of fund advisors. He currently serves as Chairperson for the Foundation for the Carolinas' Investment Committee, where he oversees asset allocation guidelines and management of the OCIO relationship for the fifth largest community foundation in the United States. Mr. Martin is also a board member for Social Venture Partners Charlotte, a venture philanthropy partnership focused on building capacity with select non-profits and innovative social entrepreneurs in the Charlotte region. He has served as an Independent Trustee of Northern Funds and Northern Institutional Funds since 2024 and as an Independent Trustee of the Trust since July 2026.

Cynthia R. Plouché: Ms. Plouché has an extensive background in the financial services industry. Until 2017, she served as lead Independent Trustee and chair of the Audit Committee of the board of trustees of AXA Premier VIP Trust, a registered investment company. She served as an Independent Trustee of Barings Fund Trust, a registered investment company and an Independent Trustee of Barings Global Short Duration High Yield Fund, a closed-end investment company, from 2017 to 2021. She also has served as portfolio manager and chief investment officer for other registered investment advisers. Ms. Plouché is therefore familiar with the functions of mutual fund boards and their oversight responsibilities and the operations of fund advisers and other service providers. She has served as an independent trustee of MassMutual open-end investment funds since 2022. In addition, Ms. Plouché served as Township Assessor for Moraine, Illinois, from 2014 to 2018. She has served as an Independent Trustee of Northern Institutional Funds and Northern Funds since 2014 and as an Independent Trustee of the Trust since July 2026.

Mary Jacobs Skinner: Ms. Skinner was a partner until 2015 at Sidley Austin LLP, a large international law firm, in which she managed a regulatory-based practice. As a result of this position, Ms. Skinner is familiar with legal, regulatory and financial matters. She was a Harvard Advanced Leadership Fellow in

2016. She also is familiar with the functions of the Board and its oversight responsibilities with respect to the Investment Adviser and other Portfolio service providers as a result of her service as an Independent Trustee of Northern Institutional Funds since 2000 and Northern Funds since 1998 and as an Independent Trustee of the Trust since July 2026.

INTERESTED TRUSTEE

Paula Kar: Ms. Kar is Executive Vice President and Chief Product Officer for Northern Trust Asset Management. Ms. Kar has oversight of product strategy, innovation, commercialization and governance for all investment products globally. She serves on the Asset Management Executive Group and on the Board of Directors for Northern Trust Investments. She represents Northern Trust as a Trustee on the Northern Funds Board (Mutual Funds and ETFs), FlexShares Board (ETFs) and Alpha Board (Alternatives). Ms. Kar joined Northern Trust Asset Management in 2019 as global head of product strategy & development. Ms. Kar has served as head of product management at ProShares Advisors; head of product management for iShares fixed income & commodities ETFs at BlackRock; and as a senior consultant with McKinsey & Company serving global financial institutions. She started her career in banking with Citigroup. Ms. Kar is a founding member of Women in ETFs, a non-profit organization, and served on their global governance board. She holds an MBA in finance from the Wharton School of the University of Pennsylvania. She has served as an Interested Trustee of Northern Institutional Funds, Northern Funds, and the Trust since 2024.

TRUSTEE OWNERSHIP OF FUND SHARES. The following table shows the dollar range of shares of the Funds owned by each Trustee in the Funds included in this SAI and other investment portfolios of the Northern Funds, Northern Institutional Funds and the Trust.

TRUSTEE AND OFFICER COMPENSATION. The Trust pays each Trustee who is not an officer, director or employee of Northern Trust Corporation or its subsidiaries annual fees for his or her services as a Trustee of the Trust and as a member of the respective Board committees. In recognition of their services, the fees paid to the Board and Committee chairpersons are larger than the fees paid to other members of the Board and Committees. The Trustees also are reimbursed for travel expenses incurred in connection with attending such meetings. The Trust also may pay the incidental costs of a Trustee to attend training or other types of conferences relating to the investment company industry.

The following tables set forth certain information with respect to the compensation of each Independent and Interested Trustee of the Trust for the year ended March 31, 2026:

Independent Trustees

Interested Trustee

The Trust does not provide pension or retirement benefits to its Trustees. The Trust's officers do not receive fees from the Trust for services in such capacities.

Please retain this Supplement for future reference.

FLEXSHARES® TRUST

FlexShares® Core Select Bond Fund (BNDC)

FlexShares® Ultra-Short Income Fund (RAVI)

SUPPLEMENT DATED AUGUST 3, 2026 TO THE STATEMENT OF ADDITIONAL INFORMATION DATED MARCH 1, 2026, AS SUPPLEMENTED (THE "SAI")

Capitalized terms used in this Supplement, unless otherwise defined in this Supplement, have the meanings assigned to them in the Funds' SAI. This Supplement updates certain information contained in the SAI of the Funds and should be read in conjunction with the SAI.

At a special meeting of shareholders held on July 24, 2026, shareholders of the Trust elected a new slate of Trustees to the Board of Trustees of the Trust (the "Board"). Accordingly, effective July 24, 2026, all references to the prior Board of Trustees are deleted in their entirety and replaced with the disclosure below.

TRUSTEES AND OFFICERS

The Board is responsible for the management and business and affairs of the Trust. Set forth below is information about the Trustees and the Officers of the Trust as of July 31, 2026. Each Trustee has served in that capacity since he or she was originally elected or appointed to the Board. As of July 31, 2026, each Trustee oversees a total of 94 portfolios in the Northern Funds Complex. The Northern Funds Complex consists of Northern Funds, Northern Institutional Funds, and the Trust. As of July 31, 2026, Northern Funds consists of 61 portfolios, Northern Institutional Funds consists of 6 portfolios, and the Trust consists of 27 portfolios.

INDEPENDENT TRUSTEES

(1) Each Trustee may be contacted by writing to the Trustee, c/o the Secretary of the Trust, The Northern Trust Company, 50 South LaSalle Street, Chicago, Illinois 60603.

INTERESTED TRUSTEE

(1) Each Trustee may be contacted by writing to the Trustee, c/o the Secretary of the Trust, The Northern Trust Company, 50 South LaSalle Street, Chicago, Illinois 60603.

(2) Each Trustee will hold office for an indefinite term until the earliest of: (i) the next meeting of shareholders, if any, called for the purpose

of considering the election or re-election of such Trustee and until the election and qualification of his or her successor, if any, elected at such meeting; (ii) the date a Trustee resigns or retires, or a Trustee is removed by the Board or shareholders, in accordance with the Trust's Agreement and Declaration of Trust; or (iii) in accordance with the current resolutions of the Board (which may be changed without shareholder vote) on the earlier of the completion of 15 years of service on the Board and the last day of the calendar year in which he or she attains the age of seventy-five years.

(3) This column includes only directorships of companies required to report to the SEC under the Exchange Act (i.e., public companies) or other investment companies registered under the 1940 Act.

(4) An "interested person," as defined by the 1940 Act. Ms. Kar is deemed to be an "interested" Trustee because she is an officer, director, employee, and a shareholder of Northern Trust Corporation and/ its affiliates.

STANDING BOARD COMMITTEES

The prior Board had established a standing Audit Committee and a Governance Committee to assist the Board in fulfilling its oversight responsibilities. The new Board has established four standing committees in connection with its governance of the Trust: Audit, Governance, Valuation and Executive Committees.

The Audit Committee consists of three members: Ms. Bobek (Chairperson), and Messrs. David Martin (ex officio), and Kloet (ex officio). The Audit Committee oversees the audit process and provides assistance to the full Board with respect to fund accounting, tax compliance and financial statement matters. In performing its responsibilities, the Audit Committee selects and recommends annually to the entire Board an independent registered public accounting firm to audit the books and records of the Trust for the ensuing year, and reviews with the firm the scope and results of each audit. The Audit Committee also is designated as the Qualified Legal Compliance Committee under the Sarbanes-Oxley Act of 2002. The Audit Committee will convene at least four times each year to meet with the independent registered public accounting firm to review the scope and results of the audit and to discuss other non-audit matters as requested by the Board's Chairperson, the Committee Chairperson or the independent registered public accounting firm. Prior to the replacement of the former Board, the Audit Committee convened twice during the last fiscal year ended October 31, 2025.

The Governance Committee consists of three members: Mses. Skinner (Chairperson), Plouché and Mr. Kloet. The functions performed by the Governance Committee include, among other things, selecting and nominating candidates to serve as Independent Trustees, reviewing and making recommendations regarding Trustee compensation, developing policies regarding Trustee education and, subject to Board oversight, supervising the Trust's CCO and reviewing information and making recommendations to the Board in connection with the Board's annual consideration of the Trust's management, custody and transfer agency and service agreements. Prior to the replacement of the former Board, the Governance Committee convened twice during the last fiscal year ended October 31, 2025.

As stated above, each Trustee holds office for an indefinite term until the occurrence of certain events. In filling Board vacancies, the Governance Committee will consider nominees recommended by shareholders. Nominee recommendations should be submitted to the Secretary of the Trust, The Northern Trust Company, 50 South LaSalle Street, Chicago, Illinois 60603.

The Valuation Committee consists of four members: Messrs. David Martin (Chairperson), Kloet (ex officio), and William Martin, and Ms. de Jongh. The Valuation Committee is authorized to act for the Board in connection with the valuation of portfolio securities of the Funds in accordance with the Trust's valuation procedures. The Valuation Committee was formed on July 24, 2026 and has not convened yet.

The Executive Committee consists of four members: Messrs. Kloet (Chairperson) and David Martin, and Mses. Bobek and Skinner. The Executive Committee is comprised of the Chairperson of the Board as well as the Chairpersons of the Governance, Valuation and Audit Committees, with the remaining Trustees each serving as an alternate in the event of an emergency. The Executive Committee is granted the power to act on behalf of the full Board in the management of the business and affairs of the Trust, to be exercised when circumstances impair the ability of the Board or its committees to conduct business. In particular, the Executive Committee may take action with respect to: (1) the valuation of securities; and (2) the suspension of redemptions. The Executive Committee was formed on July 24, 2026 and will convene as necessary upon notice by the Chairperson of the Committee.

LEADERSHIP STRUCTURE

The Board is currently composed of eight Trustees, seven of whom are not "interested persons" as defined in the 1940 Act ("Independent Trustee"), and one of whom is an "interested person" as defined in the 1940 Act ("Interested Trustee"). The Chairperson of the Board, Thomas A. Kloet, is an Independent Trustee. Paula Kar is considered an Interested Trustee because she is an officer, director, employee, and a shareholder of Northern Trust Corporation and/or its affiliates. Each Trustee was nominated to serve on the Board because of his or her experience, skills and qualifications. See "Trustee Experience." The Board believes that its leadership structure is consistent with industry practices and is appropriate in light of the size of the Trust and the nature and complexity of its business. In particular:

Board Composition. The Trustees believe that having a super-majority of Independent Trustees (at least 75%) is appropriate and in the best interest of shareholders. The Trustees also believe that having Ms. Kar serve as an Interested Trustee brings management and financial insight that is important to certain of the Board's decisions and is also in the best interest of shareholders.

Independent Trustee Meetings and Executive Sessions. The Trustees believe that meetings of the Independent Trustees and meetings in executive session, including with independent counsel, help prevent conflicts of interest from occurring. The Trustees also believe that these sessions allow the Independent Trustees to deliberate candidly and constructively, separately from management, in a manner that affords honest disagreement and critical questioning.

RISK OVERSIGHT

Risk oversight is a part of the Board's general oversight of the Funds and is addressed as part of various Board and committee activities, including throughout the year at regular Board and committee meetings and through regular reports provided to the Board and/or its committees that address, among other items, certain investment, valuation, liquidity, and compliance matters. The Board also may receive special reports or presentations on a variety of risk issues, either upon the Board's request or upon Northern Trust Investments, Inc.'s (the "Investment Adviser'") initiative. Day-to-day risk management functions are subsumed within the responsibilities of the Investment Adviser and other service providers (depending on the nature of the risk), which carry out the Funds' investment management and business affairs. Each of the Investment Adviser and other service providers employ a variety of processes, procedures and controls to identify various events or circumstances that may give rise to risks, to lessen the probability of their occurrence and/or to mitigate the effects of such events or circumstances if they occur. Each of the Investment Adviser and other service providers have their own independent interests in risk management,

and their policies and methods of risk management will depend on their functions and business models. The Investment Adviser has a dedicated risk management function that is headed by a Chief Risk Officer.

Currently, the Board receives and reviews risk reports on a quarterly basis from the Investment Adviser's Chief Risk Officer covering various risk areas, such as investment and market risk, operational risk, business continuity, cybersecurity risk, and regulatory compliance risk. These reports are intended to provide the Trustees with a forward-looking view of risk and the manner in which the Investment Adviser is managing various risks.

The Audit Committee, in addition to its risk management responsibilities, plays an important role in the Board's risk oversight. Working with the Funds' independent registered accountants, the Audit Committee reviews the Funds' annual audit scope and the results of the audit of the Funds' year-end financial statements.

The Valuation Committee reviews quarterly reports on fair valuation determinations, including the methodology used in making fair value determinations.

The Board also monitors and reviews the Funds' performance metrics and regularly confers with the Investment Adviser on performance-related issues. With respect to liquidity risk, the Board receives regular liquidity risk management reports under the Funds' Liquidity Risk Management (LRM) Program that include information concerning illiquid investments within the Fund's portfolio. The Board also reviews, no less frequently than annually, a written report prepared by the LRM Program administrator that addresses, among other items, the operation of the LRM Program and assesses its adequacy and effectiveness of implementation as well as any material changes to the LRM Program.

The Board has approved a derivatives risk manager, which is responsible for administering the Derivatives Risk Management (DRM) Program for the Funds that are required to implement a DRM Program. The Board meets with the derivatives risk manager on a periodic basis, including receiving quarterly and annual reports from the derivatives risk manager, to review the implementation of the DRM Program.

The Trust's CCO reports to the Board at least quarterly regarding compliance matters. In addition to providing quarterly reports, the CCO provides an annual report to the Board in accordance with the Funds' compliance policies and procedures. The CCO regularly discusses relevant compliance issues, including compliance risks affecting the Funds during meetings with the Independent Trustees and counsel. The Board adopts compliance policies and procedures for the Funds and approves such procedures for the Funds' service providers. The compliance policies and procedures are specifically designed to detect and prevent violations of the federal securities laws.

TRUSTEE EXPERIENCE

Each Trustee is required to possess certain qualities such as integrity, intelligence, the ability to critically discuss and analyze issues presented to the Board and an understanding of a trustee's fiduciary obligations with respect to a registered investment company. In addition to these qualities, the following is a description of certain other Trustee attributes, skills, experiences and qualifications.

INDEPENDENT TRUSTEES

Therese M. Bobek: Ms. Bobek retired in 2018 from a 35-year career with PricewaterhouseCoopers, LLP ("PwC"), having served a wide variety of public and privately held clients with external audits, internal auditing and risk advisory services. Ms. Bobek's final role was to serve in PwC's national office, where she

led a nationwide network of partners and managers whose main responsibility was to support audit quality in the field. After retirement from PwC, Ms. Bobek taught Advanced Auditing in the Masters of Accountancy program at the University of Iowa's Henry B. Tippie College of Business for five years. Since 2020, she has been a director and member of the audit and nominating and governance committees of the board of directors of Methode Electronics, Inc., a global developer of custom engineered and application-specific products and solutions. Ms. Bobek has been a Board Member of Metropolitan Family Services and a Board Member of the Illinois Society of CPAs. She has also served as a member and Chair of the University of Iowa Professional Accounting Council, a voluntary council of business leaders supporting accounting education. She has served as an Independent Trustee of Northern Institutional Funds and Northern Funds since 2019 and as an Independent Trustee of the Trust since July 2026.

Ingrid LaMae A. de Jongh: Ms. de Jongh served as a partner in the global financial services strategy at Accenture and was with the global management consulting and professional services firm from 1987 through 2012. While at Accenture, she helped global financial institutions improve their business performance by developing strategies and business models and implementing business change programs and systems. Since 2020 she has been the Chief Schooling Officer & Provost, and from 2016 to 2020 she was the Head of School Management and Technology at Success Academy Charter Schools, the largest network and highest-performing free, public charter schools in New York City. Ms. de Jongh is a former member of the Board of Carver Bancorp, Inc. in New York City, where she served as a member of the Nominating and Governance Committees and the Compensation Committee. She previously served on the Board of Directors of Bank Leumi USA from 2016 to 2022. Ms. de Jongh had previously served from 2011 to 2013 as a member of the U.S. Department of Commerce's National Advisory Council for Minority Business Enterprises. She has served as an Independent Trustee of Northern Institutional Funds and Northern Funds since 2019 and as an Independent Trustee of the Trust since July 2026.

Thomas A. Kloet: Mr. Kloet is a long-time financial industry executive and former Chief Executive Officer of TMX Group, Ltd., a financial services company and operator of stock, derivatives exchanges, their clearing operations and securities depository. As a result of this position, Mr. Kloet is familiar with financial, investment and business matters. He also understands the functions of a board through his service during the past twelve years on the Board of Nasdaq, Inc. (plus the Nasdaq Stock Market, LLC as well as certain other U.S. stock and option exchanges of Nasdaq, Inc. where he has served as Board Chair since 2016); and previous board experience with TMX Group, Ltd.; Box Options Exchange; FTSE-TMX Global Debt Capital Markets, Inc.; Bermuda Stock Exchange, Inc.; the Investment Industry Regulatory Organization of Canada and the World Federation of Exchanges. He is a certified public accountant, a member of the American Institute of Certified Public Accountants and is an emeritus member of the Board of Elmhurst College. He has served as an Independent Trustee of Northern Institutional Funds and Northern Funds since 2015 and as an Independent Trustee of the Trust since July 2026.

Mr. Kloet serves on the Board of Directors of Nasdaq, Inc. Northern Trust Corporation ("NTC"), parent company of NTI, and its affiliates (including affiliated fund complexes) pay listing fees, market data fees, GRC (governance risk and compliance) software fees and similar fees to Nasdaq, Inc. and its affiliates, The Nasdaq Stock Market LLC, Nasdaq OMX Nordic OY and Nasdaq CXC Ltd. (collectively, "Nasdaq"). The total of these payments were $6,509,143 and $10,756,134 in each of 2024 and 2025, respectively, which are immaterial to Nasdaq's total revenues. In consideration of the immaterial amounts involved in the foregoing transactions, Mr. Kloet is not considered to have a material business or professional relationship with NTI or its affiliates.

David R. Martin: Mr. Martin was Chief Financial Officer for Neo Tech, an electronics manufacturer, from 2019 to 2023. Mr. Martin was Vice President, Chief Financial Officer and Treasurer from 2007 to 2016 of Dimensional Fund Advisors LP, a global investment manager that provides its services largely to investment companies or their local equivalent (mutual funds in the U.S.). The funds are held primarily by clients of independent financial advisors but they are also held by institutional clients (who may invest in separate accounts), pensions and profit sharing plans, corporations, defined contribution plans, endowments, state and municipal entities, and sovereign wealth funds. Mr. Martin had oversight responsibilities for all finance and accounting, real estate and compliance functions while at Dimensional, including the implementation of a global transfer pricing methodology. He also served as a director on eight internal Dimensional boards. During his 35 year career in corporate finance, Mr. Martin also had senior management positions at Janus Capital Group, Inc. and Charles Schwab & Co., Inc. and senior level finance positions at First Interstate Bank of Texas, N.A. and Texas Commerce Bancshares, Inc. Mr. Martin is familiar with the functions of mutual fund boards and their oversight responsibilities and the operations of fund advisers and other service providers. He is also well versed in risk management and financial matters affecting mutual funds. He has served as an Independent Trustee of Northern Institutional Funds and Northern Funds since 2017 and as an Independent Trustee of the Trust since July 2026.

William Martin: Mr. Martin has extensive experience in fixed income portfolio management and in the financial industry. From 2004 to 2020, he held various portfolio manager positions at Nuveen / TIAA, most recently serving as a Senior Managing Director and the Chief Investment Officer of Global Fixed Income. Prior to his role as Nuveen's Chief Investment Officer of Global Fixed Income, Mr. Martin held various roles at Nuveen, which included being the Lead Portfolio Manager of fixed income mutual funds and leading sector portfolio management within structured finance. Prior to working at Nuveen, Mr. Martin held executive positions at Lewtan Technologies and Visible Markets, Inc. Mr. Martin is familiar with the oversight functions of mutual fund boards and the operations and investment risk management responsibilities of fund advisors. He currently serves as Chairperson for the Foundation for the Carolinas' Investment Committee, where he oversees asset allocation guidelines and management of the OCIO relationship for the fifth largest community foundation in the United States. Mr. Martin is also a board member for Social Venture Partners Charlotte, a venture philanthropy partnership focused on building capacity with select non-profits and innovative social entrepreneurs in the Charlotte region. He has served as an Independent Trustee of Northern Funds and Northern Institutional Funds since 2024 and as an Independent Trustee of the Trust since July 2026.

Cynthia R. Plouché: Ms. Plouché has an extensive background in the financial services industry. Until 2017, she served as lead Independent Trustee and chair of the Audit Committee of the board of trustees of AXA Premier VIP Trust, a registered investment company. She served as an Independent Trustee of Barings Fund Trust, a registered investment company and an Independent Trustee of Barings Global Short Duration High Yield Fund, a closed-end investment company, from 2017 to 2021. She also has served as portfolio manager and chief investment officer for other registered investment advisers. Ms. Plouché is therefore familiar with the functions of mutual fund boards and their oversight responsibilities and the operations of fund advisers and other service providers. She has served as an independent trustee of MassMutual open-end investment funds since 2022. In addition, Ms. Plouché served as Township Assessor for Moraine, Illinois, from 2014 to 2018. She has served as an Independent Trustee of Northern Institutional Funds and Northern Funds since 2014 and as an Independent Trustee of the Trust since July 2026.

Mary Jacobs Skinner: Ms. Skinner was a partner until 2015 at Sidley Austin LLP, a large international law firm, in which she managed a regulatory-based practice. As a result of this position, Ms. Skinner is familiar with legal, regulatory and financial matters. She was a Harvard Advanced Leadership Fellow in

2016. She also is familiar with the functions of the Board and its oversight responsibilities with respect to the Investment Adviser and other Portfolio service providers as a result of her service as an Independent Trustee of Northern Institutional Funds since 2000 and Northern Funds since 1998 and as an Independent Trustee of the Trust since July 2026.

INTERESTED TRUSTEE

Paula Kar: Ms. Kar is Executive Vice President and Chief Product Officer for Northern Trust Asset Management. Ms. Kar has oversight of product strategy, innovation, commercialization and governance for all investment products globally. She serves on the Asset Management Executive Group and on the Board of Directors for Northern Trust Investments. She represents Northern Trust as a Trustee on the Northern Funds Board (Mutual Funds and ETFs), FlexShares Board (ETFs) and Alpha Board (Alternatives). Ms. Kar joined Northern Trust Asset Management in 2019 as global head of product strategy & development. Ms. Kar has served as head of product management at ProShares Advisors; head of product management for iShares fixed income & commodities ETFs at BlackRock; and as a senior consultant with McKinsey & Company serving global financial institutions. She started her career in banking with Citigroup. Ms. Kar is a founding member of Women in ETFs, a non-profit organization, and served on their global governance board. She holds an MBA in finance from the Wharton School of the University of Pennsylvania. She has served as an Interested Trustee of Northern Institutional Funds, Northern Funds, and the Trust since 2024.

TRUSTEE OWNERSHIP OF FUND SHARES. The following table shows the dollar range of shares of the Funds owned by each Trustee in the Funds included in this SAI and other investment portfolios of the Northern Funds, Northern Institutional Funds and the Trust.

TRUSTEE AND OFFICER COMPENSATION. The Trust pays each Trustee who is not an officer, director or employee of Northern Trust Corporation or its subsidiaries annual fees for his or her services as a Trustee of the Trust and as a member of the respective Board committees. In recognition of their services, the fees paid to the Board and Committee chairpersons are larger than the fees paid to other members of the Board and Committees. The Trustees also are reimbursed for travel expenses incurred in connection with attending such meetings. The Trust also may pay the incidental costs of a Trustee to attend training or other types of conferences relating to the investment company industry.

The following tables set forth certain information with respect to the compensation of each Independent and Interested Trustee of the Trust for the year ended March 31, 2026:

Independent Trustees

Interested Trustee

The Trust does not provide pension or retirement benefits to its Trustees. The Trust's officers do not receive fees from the Trust for services in such capacities.

Please retain this Supplement for future reference.