UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 6)*

The Macerich Company

(Name of Issuer)

Common Stock, Par Value $0.01 Per Share

(Title of Class of Securities)

554382101

(CUSIP Number)

Jeff Davis

Chief Legal & Corporate Affairs Officer

Ontario Teachers’ Pension Plan Board

5650 Yonge Street, 3rd Floor

Toronto, Ontario M2M 4H5

Canada

(416) 228-5900

With a Copy to:

William G. Farrar

Sullivan & Cromwell LLP

125 Broad Street

New York, New York 10004

(212) 558-4940

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

January 27, 2021

(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.  ☐

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See § 240.13d-7 for other parties to whom copies are to be sent.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (the “Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13D

SCHEDULE 13D

This Amendment No. 6 (this “Amendment No. 6”) amends and supplements the statement on Schedule 13D filed with the Securities and Exchange Commission (the “SEC”) on November 24, 2014 (the “Original Schedule 13D”), Amendment No. 1 to the Original Schedule 13D filed with the SEC on May 8, 2015 (“Amendment No. 1”), Amendment No. 2 to the Original Schedule 13D filed with the SEC on May 15, 2015 (“Amendment No. 2”), Amendment No. 3 to the Original Schedule 13D filed with the SEC on March 9, 2016 (“Amendment No. 3”), Amendment No. 4 to the Original Schedule 13D filed with the SEC on August 9, 2016 (“Amendment No. 4”) and Amendment No. 5 to the Original Schedule 13D filed with the SEC on February 1, 2018 (“Amendment No. 5”) (the Original Schedule 13D, together with Amendment No. 1, Amendment No. 2, Amendment No. 3, Amendment No. 4, Amendment No. 5 and this Amendment No. 6, collectively, the “Schedule 13D”), with respect to the common stock, par value $0.01 per share (the “Common Stock”), of The Macerich Company, a Maryland corporation (the “Issuer”), filed by Ontario Teachers’ Pension Plan Board, an Ontario, Canada corporation (“Teachers’”), and 1700480 Ontario Inc., an Ontario, Canada corporation (“1700480”), wholly owned by Teachers’. Capitalized terms used herein and not otherwise defined have the meanings assigned to such terms in the Original Schedule 13D. All items or responses not described herein remain as previously reported in the Original Schedule 13D, as amended and supplemented by Amendment No. 1, Amendment No. 2, Amendment No. 3, Amendment No. 4 and Amendment No. 5.

All calculations with respect to beneficial ownership of the Issuer’s Common Stock set forth in this Amendment No. 6 are based on 149,472,431 shares of Common Stock outstanding as of November 5, 2020, as reported on to the cover page of the Issuer’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2020, filed with the SEC by the Issuer on November 6, 2020.

Item 2 of the Schedule 13D is hereby amended solely with respect to Schedule A and B attached hereto.

As of January 27, 2021 (after giving effect to the transactions described in Item 5(c) below), the Reporting Persons beneficially own no shares of Common Stock. The first sentence of paragraphs (a) and (b) of Item 5 of the Schedule 13D is hereby amended and restated to read in its entirety as follows:

See the rows numbered 7, 8, 9, 10, 11 and 13 on each of pages 2 and 3 of this Amendment No. 6, which are incorporated in this Item 5 by reference.

Item 5(c) of the Schedule 13D is hereby amended by adding the following information:

On January 27, 2021, 7,000,000 shares of Common Stock beneficially owned by the Reporting Persons were sold in a block trade at a price of $19.25 per share, 4,951,814 shares of Common Stock beneficially owned by the Reporting Persons were sold in multiple open market transactions at a weighted average price per share of $19.09, at prices ranging from $18.60 through $19.59 per

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share, 6,201,597 shares of Common Stock beneficially owned by the Reporting Persons were sold in multiple open market transactions at a weighted average price per share of $20.26, at prices ranging from $19.60 through $20.59 per share, 4,080,364 shares of Common Stock beneficially owned by the Reporting Persons were sold in multiple open market transactions at a weighted average price per share of $21.21, at prices ranging from $20.60 through $21.59 per share, 706,959 shares of Common Stock beneficially owned by the Reporting Persons were sold in multiple open market transactions at a weighted average price per share of $22.03, at prices ranging from $21.60 through $22.59 per share, 372,230 shares of Common Stock beneficially owned by the Reporting Persons were sold in multiple open market transactions at a weighted average price per share of $22.75, at prices ranging from $22.60 through $23.59 per share, 400,000 shares of Common Stock beneficially owned by the Reporting Persons were sold in multiple open market transactions at a weighted average price per share of $24.93, at prices ranging from $24.60 through $25.59 per share and 850,000 shares of Common Stock beneficially owned by the Reporting Persons were sold in multiple open market transactions at a weighted average price per share of $25.75, at prices ranging from $25.60 through $26.59 per share. The Reporting Persons undertake to provide the staff of the SEC, upon request, full information regarding the number of shares sold at each separate price.

Except for the arrangements described in this Amendment No. 6, neither Reporting Person has, and to the knowledge of the Reporting Persons, without independent verification, no person named in Schedule A or Schedule B has, effected any transactions in the class of securities reported since the date that is 60 days before the date of this Amendment No. 6.

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Signatures

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

January 28, 2021

SCHEDULE A

CERTAIN INFORMATION REGARDING THE BOARD MEMBERS AND OFFICERS OF ONTARIO TEACHERS’ PENSION PLAN BOARD

Set forth in the table below are the name, current business address and current occupation or employment of each of the board members and officers of Ontario Teachers’ Pension Plan Board, an Ontario, Canada corporation (“Teachers’”). Each director and officer is a citizen of Canada with the exception of Andrew Jonathan Mark Taylor and Nicholas Jansa, who are citizens of the United Kingdom, Karen-Ann Frank, who is a citizen of the United States and Wei Beng Chan, who is a citizen of Malaysia.

SCHEDULE B

CERTAIN INFORMATION REGARDING THE DIRECTORS AND EXECUTIVE OFFICERS OF 1700480 ONTARIO INC.

Set forth in the table below are the name, current business address and current occupation or employment of each of the directors and executive officers of 1700480 Ontario Inc., an Ontario, Canada corporation. Each director and officer is a citizen of Canada with the exception of Cintia Guimaraes, who is a citizen of Brazil.

EXHIBIT INDEX