Exhibit 10.12

THIRD AMENDMENT TO LEASE

I. PARTIES AND DATE.

     This Third Amendment to Lease (the “Amendment”) dated December 19, 2003, is
by and between THE IRVINE COMPANY (“Landlord”), and BROADCOM CORPORATION, a
California corporation (“Tenant”).

II. RECITALS.

     On August 7, 1998, Landlord and Tenant entered into a lease for space in
buildings located at 16215 Alton Parkway (“Building A”) and 16205 Alton Parkway
(“Building B”) (collectively, the ‘Premises”), which Lease was amended by a
First Amendment to Lease dated August 27, 1999, wherein approximately 39,134
rentable square feet of space located at 16225 Alton Parkway (“Suite 200”) was
added to the Premises, and by a Second Amendment to Lease dated December 10,
1999 wherein approximately 39,134 rentable square feet of space located at 16225
Alton Parkway (“Suite 100”) was added to the Premises (as amended, the “Lease”).

     Landlord and Tenant each desire to modify the Lease to extend the Lease
Term, to adjust the Basic Rent, and to make such other modifications as are set
forth in “III. MODIFICATIONS” next below.

III. MODIFICATIONS.

     A. Basic Lease Provisions. The Basic Lease Provisions are hereby amended as
follows:

     1. Item 5 is hereby deleted in its entirety and substituted therefore shall
be the following:

“5. Lease Term: The Term of this Lease shall expire at midnight on June 30,
2006”

     2. Item 6 is hereby amended by adding the following:

“Basic Rent: Commencing January 1, 2006, the Basic Rent shall be Three Hundred
Eighty Thousand Five Hundred Twenty-Six Dollars ($380,526.00) per month, based
on $1.65 per rentable square foot.

     3. Item 12 is hereby amended by deleting Landlord’s address for payments
and notices and substituted therefor shall be the following:

“12. Address for Payments and Notices:

 

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  LANDLORD
 
THE IRVINE COMPANY
dba Office Properties
8105 Irvine Center Drive, Suite 300
Irvine, CA 92618
Attn: Vice President, Operations, Technology Portfolio

   
 
  with a copy of notices to:

   
     
  THE IRVINE COMPANY
dba Office Properties
8105 Irvine Center Drive, Suite 300
Irvine, CA 92618
Attn: Senior Vice President, Operations Office Properties”

     B. Acceptance of Premises. Tenant acknowledges that the lease of the
Premises pursuant to this Amendment shall be on an “as-is” basis without further
obligation on Landlord’s part as to improvements whatsoever, except for
Landlord’s maintenance and repair obligations set forth in the Lease.

IV. GENERAL.

     A. Effect of Amendments. The Lease shall remain in full force and effect
except to the extent that it is modified by this Amendment.

     B. Entire Agreement. This Amendment embodies the entire understanding
between Landlord and Tenant with respect to the modifications set forth in “III.
MODIFICATIONS” above and can be changed only by a writing signed by Landlord and
Tenant.

     C. Counterparts. If this Amendment is executed in counterparts, each is
hereby declared to be an original; all, however, shall constitute but one and
the same amendment. In any action or proceeding, any photographic, photostatic,
or other copy of this Amendment may be introduced into evidence without
foundation.

     D. Defined Terms. All words commencing with initial capital letters in this
Amendment and defined in the Lease shall have the same meaning in this Amendment
as in the Lease, unless they are otherwise defined in this Amendment.

     E. Corporate and Partnership Authority. If Tenant is a corporation or
partnership, or is comprised of either or both of them, the individual executing
this Amendment for the corporation or partnership represents that he or she is
duly authorized to execute and deliver this Amendment on behalf of the
corporation or partnership and that this Amendment is binding upon the
corporation or partnership in accordance with its terms.

     F. Attorneys’ Fees. The provisions of the Lease respecting payment of
attorneys’ fees

 

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shall also apply to this Amendment.

V. EXECUTION.

     Landlord and Tenant executed this Amendment on the date as set forth in “I.
PARTIES AND DATE.” above.

      LANDLORD:   TENANT:

   
THE IRVINE COMPANY
  BROADCOM CORPORATION,
a California corporation

   
By /s/ CLARENCE W. BARKER
  By /s/ WILLIAM J. RUEHLE
Name Clarence W. Barker
Title Executive Vice President
Officer
  Name William J Ruehle
Title Vice President & Chief Financial
Officer

   
By: /s/ DONALD S. MCNUTT
Name Donald S. NcNutt, Senior Vice President
Title Leasing, Office Properties
  By:
Name
Title