APP. E4 REGULATION OF INVESTMENT ADVISORS CUSIP No. 554382101 Page 1 of 3 Pages ________________________________________________________________________ 1. NAME OF REPORTING PERSON S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON ING Clarion Real Estate Securities, L.P. 232802869 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a)____ (b)____ 3. SEC USE ONLY 4. CITIZENSHIP OR PLACE OF ORGANIZATION 201 King of Prussia Rd, Suite 600, Radnor, PA 19087 NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH 5. SOLE VOTING POWER 4,790,219 shares, sole voting power 6. SHARED VOTING POWER 3,700 shares, shared voting power 7. SOLE DISPOSITIVE POWER 8,124,549 shares, sole dispositive power 8. SHARED DISPOSITIVE POWER No shares under shared dispositive power 9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 8,124,549 shares 10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* 11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 10.67% 12. TYPE OF REPORTING PERSON* IA SCHEDULE 13G APP. E4 UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No _______)* The Macerich Co (Name of Issuer) Ordinary Shares (Title of Class of Securities) 554382101 (Cusip Number) Sec 1745 (6-88) E4-1 Items Item 1 (a) The Macerich Co (b) 401 Wilshire Blvd, Suite 700, Santa Monica, CA 90401 Item 2 (a) ING Clarion Real Estate Securities, L.P. (b) 201 King of Prussia Rd, Suite 600, Radnor, PA 19087 (c) N/A (d) Ordinary Shares (e) 554382101 Item 3 (a) Investment Adviser registered under section 203 of the Investment Advisers Act of 1940 Item 4 (a) 8,124,549 shares (b) 10.67% (c) (i.) 4,790,219 shares, sole voting power (ii.) 3,700 shares, shared voting power (iii.) 8,124,549 shares, sole dispositive power (iv.) No shares, shared dispositive power Item 5 N/A Item 6 N/A Item 7 N/A Item 8 N/A Item 9 N/A Item 10 William E. Zitelli, Chief Compliance Officer