Amendment to Underwriting Agreement dated July 28, 2005



 Exhibit 10.1 
  
 17,620,000 Shares 
  
 SYNIVERSE HOLDINGS, INC. 
  
 Common Stock 
  
 AMENDMENT TO UNDERWRITING AGREEMENT 
  
 July 28, 2005 
  
 LEHMAN BROTHERS INC. 
 GOLDMAN, SACHS & CO.

 BEAR, STEARNS & CO. INC. 
 DEUTSCHE BANK SECURITIES INC. 
 ROBERT W.
BAIRD & CO. INCORPORATED 
 FRIEDMAN, BILLINGS, RAMSEY &
CO., INC. 
 RAYMOND JAMES & ASSOCIATES, INC., 
  
 As Representatives of the several Underwriters named in Schedule 1 to the Underwriting
Agreement, 
 c/o Lehman Brothers Inc. 
 605 Third Avenue

 New York, New York 10158 
  
 Dear Sirs: 
  
 Reference is made to that certain Underwriting Agreement, dated February 9, 2005 (the “Underwriting Agreement”), by and among Syniverse Holdings, Inc., a Delaware corporation (the
“Company”), Syniverse Technologies, Inc., a Delaware corporation and a wholly owned subsidiary of the Company (the “Principal Subsidiary”), certain stockholders of the Company named in Schedule 2 to the
Underwriting Agreement (the “Selling Stockholders”), and the several Underwriters listed in Schedule 1 to the Underwriting Agreement (the “Underwriters”), pursuant to which the Company sold an aggregate of
17,620,000 shares of the Company’s common stock, par value $0.001 per share, to the Underwriters. The Company, the Principal Subsidiary, the Selling Stockholders and the Underwriters wish to amend the Underwriting Agreement in accordance with
the terms of this amendment to the Underwriting Agreement (this “Amendment”). Capitalized terms used and not defined in this Amendment shall have the respective meanings ascribed to them in the Underwriting Agreement. 
  
 In consideration for good and valuable consideration, the receipt of which is
hereby acknowledged, the parties to this Amendment hereby agree that the phrase “For a period of 180 days from the date of the Prospectus” that appears at the beginning of Section 6(i) of the Underwriting Agreement shall be deleted in its
entirety and replaced with the phrase “Until 11:59 p.m., Eastern Daylight Time, on August 21, 2005”. 







 Except as expressly modified by this Amendment, the Underwriting Agreement is unmodified and this
Amendment shall not impair the full force and effect of the Underwriting Agreement. 
  
 [Signature pages follow] 
  

 2 








 If the foregoing correctly sets forth the Amendment to the Underwriting Agreement among the Company, the
Principal Subsidiary, the Selling Stockholders and the Underwriters, please indicate your acceptance in the space provided for that purpose below. 
  

			
	Very truly yours,
	
	SYNIVERSE HOLDINGS, INC.
		
	By:	 	 /S/ Raymond L. Lawless


	
	SYNIVERSE TECHNOLOGIES, INC.
		
	By:	 	 /S/ Raymond L. Lawless


	
	The Selling Stockholders named in Schedule 2 to the Underwriting Agreement
		
	By:	 	 /S/ Robert F. Garcia


	 	 	Attorney-in-Fact









 Accepted: 
  
 LEHMAN BROTHERS INC. 
 GOLDMAN, SACHS & CO. 
 BEAR, STEARNS & CO.
INC. 
 DEUTSCHE BANK SECURITIES INC. 
 ROBERT W. BAIRD & CO. INCORPORATED 
 FRIEDMAN, BILLINGS, RAMSEY & CO., INC. 
 RAYMOND JAMES & ASSOCIATES, INC. 
  
 For themselves and as Representatives of the several Underwriters named in Schedule 1 to the Underwriting Agreement 
  

			
	By:	 	LEHMAN BROTHERS INC.
		
	By:	 	 /s/ Joseph P. Coleman


	
	GOLDMAN, SACHS & CO.
		
	By:	 	 /s/ Goldman, Sachs & Co.


	 	 	(Goldman, Sachs & Co.)