- -------- UNITED STATES SECURITIES AND EXCHANGE COMMISSION ----------------------------- FORM 4 WASHINGTON, D.C. 20549 OMB APPROVAL - -------- ----------------------------- / / CHECK THIS BOX IF NO STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OMB NUMBER: 3235-0287 LONGER SUBJECT TO EXPIRES: SEPTEMBER 30, 1998 SECTION 16. FORM 4 OR Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, ESTIMATED AVERAGE BURDEN FORM 5 OBLIGATIONS MAY Section 17(a) of the Public Utility Holding Company Act of 1935 or HOURS PER RESPONSE .... 0.5 CONTINUE. SEE Section 30(f) of the Investment Company Act of 1940 ----------------------------- INSTRUCTION 1(b). (Print or Type Responses) - ------------------------------------------------------------------------------------------------------------------------------------ 1. Name and Address of Reporting Person* 2. Issuer Name AND Ticker or Trading Symbol 6. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director 10% Owner Mack William L. Mack-Cali Realty Corporation (CLI) ---- ---- - --------------------------------------------------------------------------------------------- Officer (give Other (Last) (First) (Middle) 3. IRS or Social Security 4. Statement for ---- title ---- (specify Number of Reporting Month/Year below) below c/o Mack-Cali Realty Corporation Person (Voluntary) ----------------- ------------------ 11 Commerce Drive 9/00 - -------------------------------------------- --------------------- 7. Individual or Joint/Group Filing (Street) 5. If Amendment, (Check Applicable Line) Date of Original X Form filed by One Reporting Person (Month/Year) --- Form filed by More than One Reporting Person Cranford, New Jersey 07016 --- - ------------------------------------------------------------------------------------------------------------------------------------ (City) (State) (Zip) TABLE I - NON-DERIVATIVE SECURITIES ACQUIRED, DISPOSED OF, OR BENEFICIALLY OWNED - ------------------------------------------------------------------------------------------------------------------------------------ 1. Title of Security 2. Trans- 3. Trans- 4. Securities Acquired (A) 5. Amount of 6. Owner- 7. Nature (Instr. 3) action action or Disposed of (D) Securities ship of In- Date Code (Instr. 3, 4 and 5) Beneficially Form: direct (Month/ (Instr. 8) Owned at Direct Bene- Day/ End of (D) or ficial Year) ------------------------------------------- Month Indirect Owner- Code V Amount (A) or Price (Instr. 3 (I) ship (D) and 4) (Instr. 4) (Instr. 4) - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------------------ * If the form is filed by more than one reporting person, SEE Instruction 4(b)(v). (Over) Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1474 (7-97) POTENTIAL PERSONS WHO ARE TO RESPOND TO THE COLLECTION OF INFORMATION CONTAINED IN THIS FORM ARE NOT REQUIRED TO RESPOND UNLESS THE FORM DISPLAYS A CURRENTLY VALID OMB CONTROL NUMBER.

FORM 4 (CONTINUED) TABLE II - DERIVATIVE SECURITIES ACQUIRED, DISPOSED OF, OR BENEFICIALLY OWNED (E.G., PUTS, CALLS, WARRANTS, OPTIONS, CONVERTIBLE SECURITIES) - ------------------------------------------------------------------------------------------------------------------------ 1. Title of Derivative Security 2. Conver- 3. Trans- 4. Transac- 5. Number of Deriv- 6. Date Exer- (Instr. 3) sion or action tion Code ative Securities Ac- cisable and Ex- Exercise Date (Instr. 8) quired (A) or Dis- piration Date Price of (Month/ posed of (D) (Month/Day/ Deriv- Day/ (Instr. 3, 4, and 5) Year) ative Year) Security -------------------------------------- -------------------- Code V (A) (D) Date Expira- Exer- tion cisable Date - ------------------------------------------------------------------------------------------------------------------------ Director Stock Option (Right to Buy) $26.25 9/7/00 A V 5,000 9/7/01 9/7/10 - ------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------------------------------

- ------------------------------------------------------------------------------------------ 7. Title and Amount of Under- 8. Price 9. Number 10. Owner- 11. Nature lying Securities of of Deriv- ship of In- (Instr. 3 and 4) Deriv- ative Form direct ative Securi- of De- Bene- Secur- ties rivative ficial ity Bene- Secu- Own- (Instr. ficially rity: ership 5) Owned Direct (Instr. 4) at End (D) or Title Amount or of Indi- Number of Month rect (I) Shares (Instr. 4) (Instr. 4) - ------------------------------------------------------------------------------------------ Common Stock 5,000 5,000 D - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------ Explanation of Responses: /s/ William L. Mack 10/10/00 ----------------------------------- ----------- **Intentional misstatements or omissions of facts constitute **Signature of Reporting Person Date Federal Criminal Violations. SEE 18 U.S.C. 1001 and 15 U.S.C. 78ff(a). Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, SEE Instruction 6 for procedure. Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number. Page 2 SEC 1474 (7-97)