Exhibit 10.3

Option Amendment Agreement

This Option Amendment Agreement (this “Agreement”) is entered into as of
February 27, 2007 by and between American Tower Corporation, a Delaware
corporation (together with its affiliates, collectively, the “Company”), and J.
Michael Gearon, Jr. (“Optionee”).

WHEREAS, pursuant to the terms of the Amended and Restated American Tower
Systems Corporation 1997 Stock Option Plan, as amended (the “Plan”), the Company
has granted to Optionee options to purchase shares of the Company’s Class A
Common Stock, certain of which options are currently outstanding, as specified
on Exhibit A hereto (each, an “Option”), and has agreed, pursuant to a certain
letter dated February 12, 2004 (the “2004 Letter”), to certain provisions
potentially affecting the Option;

WHEREAS, the Optionee has notified the Company of his intention to resign from
all positions he currently holds with the Company and its affiliates;

WHEREAS, the parties wish, among other things, generally to have all of the
Options become exercisable upon termination of Optionee’s employment and be
subject to the rules under the Plan, pursuant to which the Options would be
exercisable for not more than three months after such termination;

WHEREAS, concurrently with this Agreement, the parties have entered into that
certain Option Pledge Agreement that provides for, among other things, certain
limitations on Optionee with respect to the transfer of shares received upon
exercise of the Options and/or the proceeds of any sales of shares received upon
exercise of the Options; and

WHEREAS, the Company and Optionee therefore now wish to agree as set forth below
with respect to the Options, and with respect to certain other matters;

NOW, THEREFORE, in consideration of the foregoing premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the Company and Optionee hereby agree as follows:

1. Rescission of Prior Agreement. The 2004 Letter is hereby rescinded in its
entirety, and shall be null and void and of no force or effect, both with
respect to the matters set forth herein and otherwise.

2. Termination of Employment; Certain Positions. Optionee hereby expressly
resigns with immediate effect as an officer and employee of the Company and from
any and all other positions with the Company and its affiliates, including
without limitation all positions on boards and committees of the Company and its
affiliates. Optionee acknowledges that his resignation does not constitute a
termination for Cause or Good Reason as such terms are defined in the 2004
Letter.

3. Option Vesting. Each outstanding Option held by Optionee is hereby amended so
as to become immediately exercisable (to the extent not otherwise exercisable),
as set forth on Exhibit A. Except for Section 1 above and the foregoing
sentence, and as otherwise provided herein, each Option held by Optionee will
continue to remain subject to the same terms and conditions as in effect for
that Option immediately prior to the date hereof. Accordingly, in accordance
with Section 12 of the Plan, each Option will in no event be exercisable for
more than three months following the date of this Agreement.

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4. Amendment; Waiver. This Agreement may be amended, modified or supplemented by
the parties hereto only by a written instrument signed by the Company and
Optionee. The terms and conditions of this Agreement may be waived only by a
written instrument signed by the party waiving compliance.

5. Governing Law. This Agreement shall be governed by, and construed and
enforced in accordance with, the substantive laws of the Commonwealth of
Massachusetts, without regard to its principles of conflicts of laws.

6. Entire Agreement, Assignment, etc. This Agreement supersedes all prior
written and oral negotiations, discussions, communications, understandings,
arrangements and agreements (including without limitation the 2004 Letter)
between the parties with respect to the subject matter hereof. This Agreement
constitutes the entire agreement between the parties with respect to the subject
matter hereof. This Agreement shall be binding upon and inure to the benefit of
the parties hereto and their respective successors and permitted assigns. This
Agreement is personal to Optionee and shall not be assignable by Optionee, by
operation of law or otherwise.

7. Counterparts. This Agreement may be executed in one or more counterparts, all
of which together shall constitute one and the same Agreement.

8. Riverwood Office Lease. The parties agree to negotiate in good faith the
assignment by March 31, 2007, of the Office Building Lease By and Between
Riverwood 100 Building LP and American Tower International, Inc. (the “Lease”)
to Optionee, pursuant to which Optionee would assume all of the Company’s rights
and obligations under the Lease in exchange for, among other things, the
Company’s agreement to transfer certain equipment, furniture and fixtures owned
by the Company and located in the office space subject to the Lease.

 

2

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In Witness Whereof, the parties have caused this Agreement to be executed as an
agreement under seal as of the date first written above.

 

AMERICAN TOWER CORPORATION By:  

/s/ James D. Taiclet, Jr.

Name:   James D. Taiclet, Jr. Title:  

Chairman, President and Chief Executive

    Officer

OPTIONEE:

/s/ J. Michael Gearon, Jr.

J. Michael Gearon, Jr.

 

3

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Exhibit A

Schedule of Options

 

Option

Number

 

Option

Grant

Date

 

Option

Exercise

Price

 

Shares Vested

and Exercisable
at 2/20/07

 

Shares

Unvested

as of 2/20/07*

00000218   12/1/1998   $ 28.25   100,000   0 000029   1/22/1998   $ 13.00  
195,991   0 00003453   11/11/1999   $ 53.62   4,199   0 00003454   11/11/1999  
$ 53.62   95,801   0 00009445   9/21/2000   $ 30.625   200,000   0 00015245  
12/9/2002   $ 3.60   50,004   0 00015246   12/9/2002   $ 3.60   49,996   0
00017579   11/17/2003   $ 10.50   2,285   9,523 00017580   11/17/2003   $ 10.50
  182,930   52,977 00017739   3/4/2004   $ 12.11   290,000   0 00019821  
4/1/2005   $ 18.15   0   11,018 00019822   4/1/2005   $ 18.15   31,250   82,732
00020150   3/1/2006   $ 31.50   0   3,174 00020151   3/1/2006   $ 31.50   0  
121,826                   1,202,456   281,250            

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* In accordance with Section 3 of this Agreement, the Options covering such
shares shall be amended so as to become immediately exercisable with respect to
all shares subject to such Options.