SEC Form 4 

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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| Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b). | |

1. Name and Address of Reporting Person^*
GEARON J MICHAEL JR

(Last) | (First) | (Middle)
116 HUNTINGTON AVENUE

(Street) 
BOSTON | MA | 02116

(City) | (State) | (Zip)

2. Issuer Name and Ticker or Trading Symbol 
AMERICAN TOWER CORP /MA/ [ AMT ]

5. Relationship of Reporting Person(s) to Issuer 
(Check all applicable) 
| Director | | 10% Owner
X | Officer (give title below) | | Other (specify below)
Pres., American Tower Int'l.

3. Date of Earliest Transaction (Month/Day/Year)
11/11/2005

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line) 
X | Form filed by One Reporting Person
| Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3) | 2. Transaction Date (Month/Day/Year) | 2A. Deemed Execution Date, if any (Month/Day/Year) | 3. Transaction Code (Instr. 8) | 4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5) | 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) | 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) | 7. Nature of Indirect Beneficial Ownership (Instr. 4)
| | | Code | V | Amount | (A) or (D) | Price | | |
Class A Common Stock | 11/11/2005 | | S | | 1,600 | D | $26.15 | 1,496,007 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 3,300 | D | $26.16 | 1,492,707 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 15,100 | D | $26.17 | 1,477,607 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 6,500 | D | $26.18 | 1,471,107 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 7,800 | D | $26.19 | 1,463,307 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 52,400 | D | $26.2 | 1,410,907 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 38,500 | D | $26.21 | 1,372,407 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 11,000 | D | $26.22 | 1,361,407 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 42,900 | D | $26.23 | 1,318,507 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 44,700 | D | $26.24 | 1,273,807 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 83,000 | D | $26.25 | 1,190,807 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 6,200 | D | $26.27 | 1,184,607 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 2,700 | D | $26.29 | 1,181,907 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 4,300 | D | $26.3 | 1,177,607 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 10,000 | D | $26.33 | 1,167,607 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 10,000 | D | $26.34 | 1,157,607 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 67,400 | D | $26.35 | 1,090,207 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 70,900 | D | $26.36 | 1,019,307 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 18,300 | D | $26.37 | 1,001,007 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 28,500 | D | $26.38 | 972,507 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 9,400 | D | $26.39 | 963,107 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 260,500 | D | $26.4 | 702,607 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 13,000 | D | $26.41 | 689,607 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 23,100 | D | $26.42 | 666,507 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 27,400 | D | $26.43 | 639,107 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 7,300 | D | $26.44 | 631,807 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 13,900 | D | $26.45 | 617,907 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 300 | D | $26.46 | 617,607 | I | By partnership^(1)
Class A Common Stock | 11/11/2005 | | S | | 10,000 | D | $26.47 | 607,607 | I | By partnership^(1)
Class A Common Stock | 11/14/2005 | | S | | 66,800 | D | $26.1 | 540,807 | I | By partnership^(1)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3) | 2. Conversion or Exercise Price of Derivative Security | 3. Transaction Date (Month/Day/Year) | 3A. Deemed Execution Date, if any (Month/Day/Year) | 4. Transaction Code (Instr. 8) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) | 6. Date Exercisable and Expiration Date (Month/Day/Year) | 7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4) | 8. Price of Derivative Security (Instr. 5) | 9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) | 10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) | 11. Nature of Indirect Beneficial Ownership (Instr. 4)
| | | | Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | | | |
Explanation of Responses:
1. Shares of Class A Common Stock held by JMG Partners L.P.
Remarks:
This is the first of two (1 of 2) Forms 4 being filed by the reporting person on the same date (11/15/05).
| /s/ Nathaniel B. Sisitsky | 11/15/2005
| ** Signature of Reporting Person | Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute 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.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
LIMITED POWER OF ATTORNEY

FOR SECTION 16 REPORTING OBLIGATIONS

Know all by these presents, that the undersigned hereby makes, constitutes and appoints

each of William H. Hess, Bradley E. Singer and Nathaniel B. Sisitsky, signing singly

and each acting individually, as the undersigned's true and lawful attorney in fact with

full power and authority as hereinafter described to:

(1) execute for and on behalf of the undersigned, in the undersigned's capacity

as an officer of American Tower Corporation (the Company), Form ID, Forms 3, 4, and

5 (including any amendments thereto) in accordance with Section 16(a) of the Securities

Exchange Act of 1934 and the rules thereunder (the Exchange Act);

(2) do and perform any and all acts for and on behalf of the undersigned which may

be necessary or desirable to prepare, complete and execute any such Form ID, Form 3, 4,

or 5, prepare, complete and execute any amendment or amendments thereto, and timely

deliver and file such form with the United States Securities and Exchange Commission

and any stock exchange or similar authority;

(3) seek or obtain, as the undersigned's representative and on the undersigned's

behalf, information regarding transactions in the Company's securities from any third

party, including brokers, employee benefit plan administrators and trustees, and the

undersigned hereby authorizes any such person to release any such information to such

attorney in fact and approves and ratifies any such release of information; and

(4) take any other action of any type whatsoever in connection with the foregoing

which, in the opinion of such attorney in fact, may be of benefit to, in the best

interest of, or legally required by, the undersigned, it being understood that the

documents executed by such attorney in fact on behalf of the undersigned pursuant to

this Power of Attorney shall be in such form and shall contain such terms and conditions

as such attorney in fact may approve in such attorney in fact's discretion.

The undersigned hereby grants to each such attorney in fact full power and authority

to do and perform any and every act and thing whatsoever requisite, necessary, or proper

to be done in the exercise of any of the rights and powers herein granted, as fully to

all intents and purposes as the undersigned might or could do if personally present,

with full power of substitution or revocation, hereby ratifying and confirming all

that such attorney in fact, or such attorney in fact's substitute or substitutes, s

hall lawfully do or cause to be done by virtue of this power of attorney and the rights

and powers herein granted.  The undersigned acknowledges that the foregoing attorneys

in fact, in serving in such capacity at the request of the undersigned, are not assuming

nor relieving, nor is the Company assuming nor relieving, any of the undersigned's

responsibilities to comply with Section 16 of the Exchange Act.

The undersigned acknowledges that neither the Company nor the foregoing attorneys in

fact assume (i) any liability for the undersigned's responsibility to comply with the

requirement of the Exchange Act, (ii) any liability of the undersigned for any failure

to comply with such requirements, or (iii) any obligation or liability of the

undersigned for profit disgorgement under Section 16(b) of the Exchange Act.

This Power of Attorney shall remain in full force and effect until the undersigned is

no longer required to file Forms 3, 4, and 5 with respect to the undersigned's holdings

of and transactions in securities issued by the Company, unless earlier revoked by the

undersigned in a signed writing delivered to the foregoing attorneys in fact.

IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as

of this 14th day of November, 2005.

/s/ J. Michael Gearon, Jr.