X0306 4 2015-05-18 0 0000912242 MACERICH CO MAC 0000937567 ONTARIO TEACHERS PENSION PLAN BOARD 5650 YONGE STREET, 3RD FLOOR TORONTO, ONTARIO Z4 M2M 4H5 CANADA (FEDERAL LEVEL) 1 0 1 0 0001625247 1700480 ONTARIO INC 20 QUEEN STREET WEST TORONTO A6 M5H 3R4 ONTARIO, CANADA 1 0 1 0 Common Stock, par value $0.01 per share 2015-05-18 4 P 0 496500 83.45 A 22569055 I See Note Common Stock, par value $0.01 per share 2015-05-19 4 P 0 689500 83.05 A 23258555 I See Note Common Stock, par value $0.01 per share 27682 D The price reported in Column 4 is a weighted average price. These shares of Common Stock were purchased in multiple transactions at prices ranging from $83.42 to $83.46, inclusive. The reporting persons undertake to provide The Macerich Company, any security holder of The Macerich Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the ranges set forth in footnotes (1) and (3) to this Form 4. 23,258,555 shares of Common Stock are owned directly by 1700480 Ontario Inc., which is a wholly owned subsidiary of Ontario Teachers' Pension Plan. Ontario Teachers' Pension Plan is an indirect beneficial owner of such reported securities. The price reported in Column 4 is a weighted average price. These shares of Common Stock were purchased in multiple transactions at prices ranging from $82.97 to $83.07, inclusive. Ontario Teachers' Pension Plan and 1700480 Ontario Inc. are directors by deputization for purposes of Section 16 of the Securities Exchange Act of 1934. /s/ Sandra Hardy, Authorized Person on behalf of 1700480 Ontario Inc. 2015-05-20 /s/ Rossana Di Lieto, Chief Compliance Officer on behalf of Ontario Teachers' Pension Plan 2015-05-20