Exhibit 10.51

FIRST AMENDMENT TO LOAN AGREEMENT

This First Amendment to Loan Agreement (this “Amendment”) is made as of
February 5, 2015, by and among AMERICAN TOWER CORPORATION, as Borrower (the
“Borrower”), TORONTO DOMINION (TEXAS) LLC, as Administrative Agent (the
“Administrative Agent”), and the financial institutions whose names appear as
lenders on the signature page hereof.

WHEREAS, the Borrower and the Administrative Agent are party to that certain
Amended and Restated Loan Agreement, dated as of September 19, 2014 (as amended,
restated, extended, supplemented or otherwise modified in writing from time to
time, the “Loan Agreement”) among the Borrower, the Administrative Agent and the
Lenders from time to time party thereto.

WHEREAS, the Borrower, the Administrative Agent and the Lenders who are
signatories hereto and who constitute Majority Lenders have agreed to amend the
Loan Agreement pursuant to Section 12.12 of the Loan Agreement.

NOW, THEREFORE, for good and valuable consideration, the receipt and sufficiency
of which are hereby acknowledged by each of the parties hereto, the parties
hereby agree as follows:

1. DEFINED TERMS. Unless otherwise defined herein, capitalized terms used herein
shall have the meanings given to them in the Loan Agreement.

2. AMENDMENT. Section 7.6 of the Loan Agreement is hereby amended by deleting
the text thereof and inserting in its place the following:

“As of the end of each fiscal quarter, the Company shall not permit the ratio of
(a) Total Debt on such calculation date to (b) Adjusted EBITDA, as of the last
day of such fiscal quarter to be greater than (i) for the fiscal quarter ended
December 31, 2014, 6.00 to 1.00, (ii) for the fiscal quarters ended March 31,
2015 and June 30, 2015, 8.00 to 1.00, (iii) for the fiscal quarters ended
September 30, 2015 and December 31, 2015, 7.00 to 1.00 and (iv) thereafter, 6.00
to 1.00.”

3. BRING-DOWN OF REPRESENTATIONS. The Borrower hereby certifies that, as of the
date of this Amendment, (i) the representations and warranties contained in
Section 4.1 of the Loan Agreement are true and correct in all material respects,
except for those representations and warranties that are qualified by
materiality or Materially Adverse Effect, which shall be true and correct, both
before and after giving effect to this Amendment, and after giving effect to any
updates to information provided to the Lenders in accordance with the terms of
the Loan Agreement except to the extent stated to have been made as of the
Agreement Date, and (ii) no Default exists.

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4. EFFECTIVENESS. This Amendment shall become effective upon the Administrative
Agent receiving this Amendment duly executed by the Borrower and the Majority
Lenders.

5. NO OTHER AMENDMENTS. Except as provided herein, each of the other provisions
of the Loan Agreement shall remain in full force and effect.

6. COUNTERPARTS. This Amendment may be executed in any number of counterparts,
each of which shall be deemed to be an original, but all such separate
counterparts shall together constitute one and the same instrument. Delivery of
an executed counterpart of a signature page to this Amendment by telecopier or
electronic transmission shall be effective as delivery of a manually executed
counterpart.

7. GOVERNING LAW. This Amendment shall be construed in accordance with and
governed by the internal laws of the State of New York applicable to agreements
made and performed in the State of New York.

8. MISCELLANEOUS.

(a) On and after the effective date of this Amendment, each reference in the
Loan Agreement to “this Agreement,” “hereunder,” “hereof” or words of like
import referring to the Loan Agreement shall mean and be a reference to the Loan
Agreement, as amended by this Amendment.

(b) The execution, delivery and effectiveness of this Amendment shall not,
except as expressly provided herein, operate as a waiver of any right, power or
remedy of any Lender or the Administrative Agent under any of the Loan
Documents, nor constitute a waiver of any provision of any of the Loan
Documents.

(c) On and after the effectiveness of this Amendment, this Amendment shall for
all purposes constitute a Loan Document.

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IN WITNESS WHEREOF, the parties hereto have executed this Amendment or caused it
to be executed by their duly authorized officers, all as of the day and year
above written.

 

BORROWER: AMERICAN TOWER CORPORATION By:

/S/ THOMAS A. BARTLETT

Name: Thomas A. Bartlett Title: Executive Vice President and Chief Financial
Officer

 

[Signature Page to First Amendment to Loan Agreement]

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LENDERS TORONTO DOMINION (TEXAS) LLC, as Administrative Agent and a Lender By:

/S/ ROBIN ZELLER

Name: Robin Zeller Title: Senior Vice President Bank of America, N.A. as a
Lender By:

/S/ MARIE FORURIA

Name: Marie Foruria Title: Vice President Barclays PLC, as a Lender By:

/S/ CRAIG J. MALLOY

Name: Craig J. Malloy Title: Director BNP PARIBAS, as a Lender By:

/S/ BARBARA NASH

Name: Barbara Nash Title: Managing Director By:

/S/ JENNY SHUM

Name: Jenny Shum Title: Vice President Citibank, N.A., as a Lender By:

/S/ ROBERT F. PARR

Name: Robert F. Parr Title: Managing Director & Vice President

 

[Signature Page to First Amendment to Loan Agreement]

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JP MORGAN CHASE BANK, N.A. as a Lender By:

/S/ DONALD R. BENSON

Name: Donald R. Benson Title: Managing Director Morgan Stanley Bank, N.A. as a
Lender By:

/S/ SCOTT JENSEN

Name: Scott Jensen Title: Authorized Signatory THE BANK OF TOKYO-MITSUBISHI UFJ,
LTD., as a Lender By:

/S/ MATTHEW ANTIOCO

Name: Matthew Antioco Title: Vice President THE ROYAL BANK OF SCOTLAND PLC, as a
Lender By:

/S/ TYLER J. MCCARTHY

Name: Tyler J. McCarthy Title: Director THE ROYAL BANK OF CANADA, as a Lender
By:

/S/ SCOTT JOHNSON

Name: Scott Johnson Title: Authorized Signatory

 

[Signature Page to First Amendment to Loan Agreement]

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SUNTRUST BANK, as a Lender By:

/S/ BRIAN GUFFIN

Name: Brian Guffin Title: Director BANCO BILBAO VIZCAYA ARGENTARIA, S.A., as a
Lender By:

/S/ VERÓNICA INCERA

Name: Verónica Incera Title: Managing Director By:

/S/ MAURICIO BENITEZ

Name: Mauricio Benitez Title: Director The Bank of Novia Scotia, as a Lender By:

/S/ BRAD JARMAN

Name: Brad Jarman Title: Associate Director By:

/S/ PAULA J. CZACH

Name: Paula J. Czach Title: Managing Director & Head CREDIT AGRICOLE CORPORATE
AND INVESTMENT BANK, as a Lender By:

/S/ TANYA CROSSLEY

Name: Tanya Crossley Title: Director By:

/S/ JILL WONG

Name: Jill Wong Title: Director

 

[Signature Page to First Amendment to Loan Agreement]

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GOLDMAN SACHS BANK USA, as a Lender By:

/S/ JAMIE MINIERI

Name: Jamie Minieri Title: Authorized Signatory MIZUHO BANK LTD., as a Lender
By:

/S/ BERTRAM H. TANG

Name: Bertram H. Tang Title: Authorized Signatory SANTANDER BANK, N.A., as a
Lender By:

/S/ PALOMA DEL VALLE

Name: Paloma Del Valle Title: Vice President Sumitomo Mitsui Banking
Corporation, as a Lender By:

/S/ SHUJI YABE

Name: Shuji Yabe Title: Managing Director

 

[Signature Page to First Amendment to Loan Agreement]