As filed with the U.S. Securities and Exchange Commission on August 3, 2026

File No. 333-123467
File No. 811-21732

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT

UNDER

and/or

REGISTRATION STATEMENT

UNDER

(Check appropriate box or boxes.)

MERCER FUNDS

(Exact Name of Registrant as Specified in Charter)

Registrant’s Telephone Number: (617) 747-9500

Caroline Hulme, Esq.

Mercer Investments LLC

99 High Street

Boston, Massachusetts 02110

(Name and Address of Agent for Service)

Please send copies of all communications to:

David F. Roeber, Esq.

Stradley Ronon Stevens & Young, LLP

2005 Market Street, Suite 2600

Philadelphia, PA 19103-7098

(856) 321-2411

It is proposed that this filing will become effective immediately upon filing pursuant to Rule 462(d).

EXPLANATORY NOTE: This Post-Effective Amendment No. 57 (the “Amendment”) to the Registration Statement on Form N-1A of Mercer Funds (the “Registration Statement”) is being filed pursuant to Rule 462(d) under the Securities Act of 1933, as amended (the “Securities Act”), solely for the purpose of filing exhibits to the Registration Statement. Accordingly, this Amendment consists only of a facing page, this explanatory note and Part C of the Registration Statement on Form N-1A setting forth the exhibits to the Registration Statement. This Amendment does not modify any other part of the Registration Statement. Pursuant to Rule 462(d) under the Securities Act, this Amendment shall become effective immediately upon filing with the Securities and Exchange Commission.

This Amendment incorporates by reference the information contained in Parts A and B of Post-Effective Amendment No. 56 to the Trust’s Registration Statement, which was filed on July 29, 2026.

MERCER FUNDS

PART C

OTHER INFORMATION

See Article III, “Shares,” and Article V, “Shareholders’ Voting Powers and Meetings,” of the Registrant’s Amended and Restated Agreement and Declaration of Trust, incorporated herein by reference to the Registrant’s Registration Statement on Form N-1A as filed with the SEC via EDGAR on August 5, 2005.

See also, Article II, “Meetings of Shareholders,” and Article VII, “General Matters,” of the Registrant’s Amended and Restated By-laws, incorporated herein by reference to the Registrant’s Registration Statement on Form N-1A as filed with the SEC via EDGAR on August 5, 2005.

Not Applicable.

Not Applicable.

None.

Under the terms of the Delaware Statutory Trust Act (“DSTA”) and the Registrant’s Amended and Restated Agreement and Declaration of Trust (“Declaration of Trust”), no officer or Trustee of the Registrant shall have any liability to the Registrant, its shareholders, or any other party for damages, except to the extent such limitation of liability is precluded by Delaware law, the Declaration of Trust or the By-Laws of the Registrant.

Subject to the standards and restrictions set forth in the Declaration of Trust, DSTA, Section 3817 permits a statutory trust to indemnify and hold harmless any Trustee, beneficial owner or other person from and against any and all claims and demands whatsoever. DSTA, Section 3803 protects Trustees, officers, managers and other employees, when acting in such capacity, from liability to any person other than the Registrant or beneficial owner for any act, omission or obligation of the Registrant or any Trustee thereof, except as otherwise provided in the Declaration of Trust.

Insofar as indemnification for liability arising under the Securities Act of 1933 (the “1933 Act”) may be permitted to Trustees, officers, and controlling persons of the Registrant pursuant to the provisions described in response to Item 30, or otherwise, the Registrant has been advised that, in the opinion of the Securities and Exchange Commission, such indemnification is against public policy as expressed in the 1933 Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the Registrant of expenses incurred or paid by a Trustee, officer, or controlling person of the Registrant in the successful defense of any action, suit or proceeding) is asserted by such Trustee, officer, or controlling person in connection with the securities being registered, the Registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the 1933 Act and will be governed by the final adjudication of such issue.

Mercer Investments LLC, a Delaware corporation, is a federally registered investment adviser and indirect, wholly-owned subsidiary of Marsh & McLennan Companies, Inc. Mercer Investments LLC has its principal place of business at 99 High Street, Boston, MA 02110. Mercer Investments LLC is primarily engaged in providing investment management services. Additional information regarding Mercer Investments LLC, and information as to the officers and directors of Mercer Investments LLC, is included in its Form ADV, as filed with the U.S. Securities and Exchange Commission (“SEC” or “Commission”) (File No. 801-63730) and is incorporated herein by reference.

Ares Capital Management II LLC (“Ares”), is a Subadviser for the Registrant’s Mercer Opportunistic Fixed Income Fund. Ares has its principal place of business at 1800 Avenue of the Stars, Suite 1400, Los Angeles, CA 90067. Additional information as to Ares and the directors and officers of Ares is included in Ares’ Form ADV filed with the Commission (File No. 801-72399), which is incorporated herein by reference and sets forth the officers and directors of Ares and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

Aristotle Pacific Capital, LLC (“Aristotle Pacific”), is a Subadviser for the Registrant’s Mercer Short Duration Fixed Income Fund. Aristotle Pacific has its principal place of business at 840 Newport Center Drive, Suite 700, Newport Beach, CA 92660. Additional information as to Aristotle Pacific and the directors and officers of Aristotle Pacific is included in Aristotle Pacific’s Form ADV filed with the Commission (File No. 801-117402), which is incorporated herein by reference and sets forth the officers and directors of Aristotle Pacific and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

Arrowstreet Capital, Limited Partnership (“Arrowstreet”), is a Subadviser for the Registrant’s Mercer Non-US Core Equity Fund. Arrowstreet has its principal place of business at 200 Clarendon Street, 30th Floor, Boston, Massachusetts 02116. Additional information as to Arrowstreet and the directors and officers of Arrowstreet is included in Arrowstreet’s Form ADV filed with the Commission (File No. 801-56633), which is incorporated herein by reference and sets forth the officers and directors of Arrowstreet and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

Baillie Gifford Overseas Limited (“Baillie Gifford”), is a Subadviser for the Registrant’s Mercer Emerging Markets Equity Fund. Baillie Gifford has its principal place of business at Calton Square, 1 Greenside Row, Edinburgh EH1 3AN. Additional information as to Baillie Gifford and the directors and officers of Baillie Gifford is included in Baillie Gifford’s Form ADV filed with the Commission (File No. 801-21051), which is incorporated herein by reference and sets forth the officers and directors of Baillie Gifford and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

Crescent Capital Group LP (“Crescent”), is a Subadviser for the Registrant’s Mercer Opportunistic Fixed Income Fund. Crescent has its principal place of business at Calton Square, 11100 Santa Monica Blvd, Suite 2000, Los Angeles, CA 90025. Additional information as to Crescent and the directors and officers of Crescent is included in Crescent’s Form ADV filed with the Commission (File No. 801-71747), which is incorporated herein by reference and sets forth the officers and directors of Crescent and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

GW&K Investment Management, LLC (“GWK”), is a Subadviser for the Registrant’s Mercer US Small/Mid Cap Equity Fund. GWK has its principal place of business at 222 Berkeley St., Boston, MA 02116. Additional information as to GWK and the directors and officers of GWK is included in GWK’s Form ADV filed with the Commission (File No. 801-61559), which is incorporated herein by reference and sets forth the officers and directors of GWK and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

Hardman Johnston Global Advisors LLC (“Hardman Johnston”), is a Subadviser for the Registrant’s Mercer Non-US Core Equity Fund. Hardman Johnston has its principal place of business at 300 Atlantic Street, Stamford, CT 06901. Additional information as to Hardman Johnston and the directors and officers of Hardman Johnston is included in Hardman Johnston’s Form ADV filed with the Commission (File No. 801-23854), which is incorporated herein by reference and sets forth the officers and directors of Hardman Johnston and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

Income Research & Management (“IR+M”), is a Subadviser for the Registrant’s Mercer Core Fixed Income Fund. IR+M has its principal place of business at 100 Federal Street, 30^th Floor, Boston, MA 02110. Additional information as to IR+M and the directors and officers of IR+M is included in IR+M’s Form ADV filed with the Commission (File No. 801-29482), which is incorporated herein by reference and sets forth the officers and directors of IR+M and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

Loomis, Sayles & Company, L.P. (“Loomis”), is a Subadviser for the Registrant’s Mercer US Small/Mid Cap Equity Fund. Loomis has its principal place of business at One Financial Center, Boston, Massachusetts 02111. Additional information as to Loomis and the directors and officers of Loomis is included in Loomis’ Form ADV with the Commission (File No. 801-170), which is incorporated herein by reference and sets forth the officers and directors

of Loomis and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

LSV Asset Management (“LSV”), is a Subadviser for the Registrant’s Mercer US Small/Mid Cap Equity Fund and Mercer Non-US Core Equity Fund. LSV has its principal place of business at 155 North Wacker Drive, Suite 4600, Chicago, IL 60606. Additional information as to LSV and the directors and officers of LSV is included in LSV’s Form ADV filed with the Commission (File No. 801-47689), which is incorporated herein by reference and sets forth the officers and directors of LSV and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

Manulife Investment Management (US) LLC (“Manulife”), is a Subadviser for the Registrant’s Mercer Core Fixed Income Fund. Manulife has its principal place of business at 197 Clarendon Street, Boston, Massachusetts 02116. Additional information as to Manulife and the directors and officers of Manulife is included in Manulife’s Form ADV filed with the Commission (File No. 801-42023), which is incorporated herein by reference and sets forth the officers and directors of Manulife and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

Massachusetts Financial Services Company (“MFS”), is a Subadviser for the Registrant’s Mercer Non-US Core Equity Fund. MFS has its principal place of business at 111 Huntington Avenue, Boston, Massachusetts 02199. Additional information as to MFS and the directors and officers of MFS is included in MFS’s Form ADV filed with the Commission (File No. 801-17352), which is incorporated herein by reference and sets forth the officers and directors of MFS and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

Merganser Capital Management, LLC (“Merganser”), is a Subadviser for the Registrant’s Mercer Short Duration Fixed Income Fund. Merganser has its principal place of business at 99 High Street, Boston, MA 02110. Additional information as to Merganser and the directors and officers of Merganser is included in Merganser’s Form ADV filed with the Commission (File No. 801-78733), which is incorporated herein by reference and sets forth the officers and directors of Merganser and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

Ninety One North America, Inc. (“Ninety One”), is a Subadviser for the Registrant’s Mercer Opportunistic Fixed Income Fund. Ninety One has its principal place of business at 65 East 55th Street, 30th floor, New York, New York 10022. Additional information as to Ninety One and the directors and officers of Ninety One is included in Ninety One’s Form ADV filed with the Commission (File No. 801-80153), which is incorporated herein by reference and sets forth the officers and directors of Ninety One and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

Pacific Investment Management Company LLC (“PIMCO”) is a Subadviser for the Registrant’s Mercer Opportunistic Fixed Income Fund. PIMCO has its principal place of business at 650 Newport Center Drive, Newport Beach, California 92660. Additional information as to PIMCO and the directors and officers of PIMCO is included in PIMCO’s Form ADV filed with the Commission (File No. 801-48187), which is incorporated herein by reference and sets forth the officers and directors of PIMCO and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

Parametric Portfolio Associates, LLC (“Parametric”) is a Subadviser for the Registrant’s Mercer US Small/Mid Cap Equity Fund, Mercer Non-US Core Equity Fund and Mercer Emerging Markets Equity Fund. Parametric has its principal place of business at 800 Fifth Avenue, Suite 2800, Seattle, Washington 98104. Additional information as to Parametric and the directors and officers of Parametric is included in Parametric’s Form ADV filed with the Commission (File No. 801-60485), which is incorporated herein by reference and sets forth the officers and directors of Parametric and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

PGIM, Inc. (“PGIM”), is a Subadviser for the Registrant’s Mercer Core Fixed Income Fund. PGIM has its principal place of business at 655 Broad Street, 8^th Floor, Newark, NJ 07102. Additional information as to PGIM and the directors and officers of PGIM is included in PGIM’s Form ADV filed with the Commission (File No. 801-22808),

which is incorporated herein by reference and sets forth the officers and directors of PGIM and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

Polen Capital Credit, LLC (“Polen Credit”), is a Subadviser for the Registrant’s Mercer Core Fixed Income Fund. Polen Credit has its principal place of business at 1075 Main Street, Suite 320, Waltham, MA 02451. Additional information as to PGIM and the directors and officers of Polen Credit is included in Polen Credit’s Form ADV filed with the Commission (File No. 801-55001), which is incorporated herein by reference and sets forth the officers and directors of Polen Credit and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

River Road Asset Management, LLC (“River Road”), is a Subadviser of Mercer US Small/Mid Cap Equity Fund. River Road has its principal place of business at 462 South Fourth Street, Suite 2000, Louisville, Kentucky 40202. Additional information as to River Road and the directors and officers of River Road is included in River Road’s Form ADV filed with the Commission (File No. 801-64175), which is incorporated by reference and sets forth the officers and directors of River Road and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

Robeco Institutional Asset Management US Inc. (“Robeco”) is a Subadviser of Mercer Emerging Markets Equity Fund. Robeco has its principal place of business at 230 Park Avenue, Suite 3330, New York, NY 10169. Additional information as to Robeco and the directors and officers of Robeco is included in Robeco’s Form ADV filed with the Commission (File No. 801-54142), which is incorporated by reference and sets forth the officers and directors of Robeco and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

Skerryvore Asset Management Ltd. (“Skerryvore”) is a Subadviser of Mercer Emerging Markets Equity Fund. Skerryvore has its principal place of business at 45 Charlotte Square, Edinburgh, EH2 4HQ, United Kingdom. Additional information as to Skerryvore and the directors and officers of Skerryvore is included in Skerryvore’s Form ADV filed with the Commission (File No. 801-129723), which is incorporated by reference and sets forth the officers and directors of Skerryvore and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

Voya Investment Management Co. LLC (“Voya IM”), is a Subadviser for the Registrant’s Mercer Short Duration Fixed Income Fund. Voya IM has its principal place of business at 230 Park Avenue, New York, New York, 101689. Additional information as to Voya IM and the directors and officers of Voya IM is included in Voya IM’s Form ADV filed with the Commission (File No. 801-9046), which is incorporated herein by reference and sets forth the officers and directors of Voya IM and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

WCM Investment Management, LLC (“WCM”), is a Subadviser for the Registrant’s Mercer Non-US Core Equity Fund. WCM has its principal place of business at 281 Brooks Street, Laguna Beach, CA 92651. Additional information as to WCM and the directors and officers of WCM is included in WCM’s Form ADV filed with the Commission (File No. 801-11916), which is incorporated herein by reference and sets forth the officers and directors of WCM and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

Wellington Management Company LLP (“Wellington”), is a Subadviser for the Registrant’s Mercer Opportunistic Fixed Income Fund. Wellington has its principal place of business at One Financial Center, 24^th Floor, Boston, MA, 02111. Additional information as to Wellington and the directors and officers of Wellington is included in Wellington’s Form ADV filed with the Commission (File No. 801-15908), which is incorporated herein by reference and sets forth the officers and directors of Wellington and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

Westfield Capital Management Company, L.P. (“Westfield”), is a Subadviser for the Registrant’s Mercer US Small/Mid Cap Equity Fund. Westfield has its principal place of business at One Financial Center, 24^th Floor, Boston, MA, 02111. Additional information as to Westfield and the directors and officers of Westfield is included in

Westfield’s Form ADV filed with the Commission (File No. 801-34350), which is incorporated herein by reference and sets forth the officers and directors of Westfield and information as to any business, profession, vocation or employment of a substantial nature engaged in by those officers and directors during the past two years.

The following is a list of the Officers and Managers of the Distributor:

All accounts, books and other documents required to be maintained by Section 31(a) [15 U.S.C. 80a-3-(a)] and rules under that section, are maintained by State Street Bank and Trust Company, with the exception of those maintained by the Registrant’s investment advisor, Mercer Investments LLC, 99 High Street, Boston, Massachusetts 02110 and 1166 Avenue of the Americas, New York, New York 10036.

State Street Bank and Trust Company provides general administrative, accounting, portfolio valuation, and custodian services to the Registrant, including the coordination and monitoring of any third-party service providers and maintains all such records relating to these services.

There are no management related service contracts not discussed in Part A or Part B.

None.

Pursuant to the requirements of the Securities Act of 1933, as amended, and the Investment Company Act of 1940, as amended, the Registrant has duly caused this Post-Effective Amendment to the Registration Statement to be signed on its behalf by the undersigned, duly authorized, in the City of Boston and Commonwealth of Massachusetts, on the 3^rd day of August, 2026.

Pursuant to the requirements of the Securities Act of 1933, as amended, this Post-Effective Amendment No. 57 has been signed below by the following persons in the capacities and on the dates indicated.

EXHIBITS INDEX

ATTACHMENTS / EXHIBITS

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