Exhibit
4.1

     

    SECOND SUPPLEMENTAL
INDENTURE

     

    This
Second Supplemental Indenture, dated as of October 23, 2010 (this “Supplemental
Indenture”), among MF+P Acquisition Co., a Delaware Corporation (“MF+P”), Crispin
Porter + Bogusky Canada Inc., a Canadian corporation (“CPB Canada” and
together with MF+P, each a “New Note Guarantor”),
MDC Partners Inc., a corporation continued under the laws of Canada (together
with its successors and assigns, the “Company”), each other
Note Guarantor under the Indenture referred to below, and The Bank of New York
Mellon, a New York banking corporation, as Trustee under the Indenture referred
to below.

     

    WITNESSETH:

     

    WHEREAS,
the Company, the Note Guarantors and the Trustee have heretofore executed and
delivered an Indenture, dated as of October 23, 2009 (as amended by that certain
First Supplemental Indenture dated as of May 14, 2010 and as may be further
amended, supplemented, waived or otherwise modified, the “Indenture”),
providing for the issuance of 11% Senior Notes due 2016 of the Company (the
“Notes”);

     

    WHEREAS,
pursuant to Section 10.7 of the Indenture, the Company is required to cause each
Wholly Owned Subsidiary created or acquired by the Company to execute and
deliver to the Trustee an Additional Note Guarantee; and

     

    WHEREAS,
pursuant to Section 9.1 of the Indenture, the Trustee, the Company and
existing Note Guarantors are authorized to execute and deliver this Supplemental
Indenture to supplement the Indenture, without the consent of any
Holder;

     

    NOW,
THEREFORE, in consideration of the foregoing and for other good and valuable
consideration, the receipt of which is hereby acknowledged, each New Note
Guarantor, the Company, each other Note Guarantor and the Trustee mutually
covenant and agree for the equal and ratable benefit of the holders of the Notes
as follows:

     

    ARTICLE
I

    DEFINITIONS

     

    Section
1.1.  Defined
Terms.  Unless otherwise defined in this Supplemental
Indenture, terms defined in the Indenture are used herein as therein
defined.

     

    ARTICLE
II

    AGREEMENT TO BE BOUND;
GUARANTEE

     

    Section
2.1.  Agreement to be
Bound.  Each New Note Guarantor hereby becomes a party to the
Indenture as a Note Guarantor and as such will have all of the rights and be
subject to all of the obligations and agreements of a Note Guarantor under the
Indenture.  Each New Note Guarantor hereby agrees to be bound by all
of the provisions of the Indenture applicable to a Note Guarantor and to perform
all of the obligations and agreements of a Note Guarantor under the
Indenture.


    
      
         


      

      
        
        

        
          

        

      

      
         


      

    

     

    Section
2.2.  Guarantee.  Each
New Note Guarantor hereby fully, unconditionally and irrevocably guarantees, as
primary obligor and not merely as surety, jointly and severally with each other
Note Guarantor, to each Holder of the Notes and the Trustee, the full and
punctual payment when due, whether at maturity, by acceleration, by redemption
or otherwise, of the Obligations, all as more fully set forth in Article X of the
Indenture.

     

    ARTICLE
III

    MISCELLANEOUS

     

    Section
3.1.  Notices.   Any
notice or communication delivered to the Company under the provisions of the
Indenture shall constitute notice to each New Note Guarantor.

     

     Section
3.2.  Parties.  Nothing
expressed or mentioned herein is intended or shall be construed to give any
Person, firm or corporation, other than the Holders and the Trustee, any legal
or equitable right, remedy or claim under or in respect of this Supplemental
Indenture or the Indenture or any provision herein or therein
contained.

     

    Section
3.3.  Governing Law
etc.  This Supplemental Indenture shall be governed by the
provisions set forth in Section 11.7 of
the Indenture.

     

    Section
3.4.  Severability.  In
case any provision in this Supplemental Indenture shall be invalid, illegal or
unenforceable, the validity, legality and enforceability of the remaining
provisions shall not in any way be affected or impaired thereby and such
provision shall be ineffective only to the extent of such invalidity, illegality
or unenforceability.

     

    Section
3.5.  Ratification of Indenture;
Supplemental Indenture Part of Indenture.  Except as expressly
amended hereby, the Indenture is in all respects ratified and confirmed and all
the terms, conditions and provisions thereof shall remain in full force and
effect.  This Supplemental Indenture shall form a part of the
Indenture for all purposes, and every Holder of Notes heretofore or hereafter
authenticated and delivered shall be bound hereby.  The Trustee makes
no representation or warranty as to the validity or sufficiency of this
Supplemental Indenture.  The recitals contained herein shall be taken
as statements of the Company, and the Trustee assumes no responsibility for
their correctness.

     

    Section
3.6.  Duplicate and Counterpart
Originals. The parties may sign any number of copies of this Supplemental
Indenture.  One signed copy is enough to prove this Supplemental
Indenture.  This Supplemental Indenture may be executed in any number
of counterparts, each of which so executed shall be an original, but all of them
together represent the same agreement.

     

    Section
3.7.  Headings.  The
headings of the Articles and Sections in this Supplemental Indenture have been
inserted for convenience of reference only, are not intended to be considered as
a part hereof and shall not modify or restrict any of the terms or provisions
hereof.

     

    [Signature Pages
Follow]


    
      
         


      

      
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    IN
WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture to
be duly executed as of the date first above written.


     

    
      
        
          
            
              
                
                  
                    
                      
                        	 
      	
                                MDC
      PARTNERS INC.

                              
	 
      	 
      	 
      
	 
      	
                                By:

                              	/s/
      Michael Sabatino
	 
      	 
      	
                                Name:
      Michael Sabatino

                              
	 
      	 
      	
                                Title:  
      Authorized Signatory

                              
	 
      	 
      	 
      
	 
      	
                                MF+P ACQUISITION
      CO.,

                              
	 
      	
                                as
      a Note Guarantor

                              
	 
      	 
      	 
      
	 
      	
                                By:

                              	      
                                /s/
      Michael Sabatino

                              
	 
      	 
      	
                                Name:
      Michael Sabatino

                              
	 
      	 
      	
                                Title:  
      Authorized Signatory

                              
	 
      	 
      	 
      
	 
      	
                                CRISPIN PORTER + BOGUSKY CANADA
      INC.,

                              
	 
      	
                                as
      a Note Guarantor

                              
	 
      	 
      	 
      
	 
      	
                                By:

                              	      
                                /s/
      Michael Sabatino

                              
	 
      	 
      	
                                Name:
      Michael Sabatino

                              
	 
      	 
      	
                                Title:  
      Authorized
Signatory

                              


                      

                    

                  

                

              

            

          

        

      

    


    
      
         


      

      
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                                                                    ACCENT
      MARKETING SERVICES, LLC

                                                                  
	 
      	
                                                                    ASHTON
      POTTER CANADA INC.

                                                                  
	 
      	
                                                                    COMPUTER
      COMPOSITION OF CANADA INC.

                                                                  
	 
      	
                                                                    MDC/
      CPB HOLDINGS INC.

                                                                  
	 
      	
                                                                    CRISPIN
      PORTER & BOGUSKY LLC

                                                                  
	 
      	
                                                                    DOTGLU
      LLC

                                                                  
	 
      	
                                                                    HELLO
      ACQUISITION INC.

                                                                  
	 
      	
                                                                    KBP
      HOLDINGS LLC

                                                                  
	 
      	
                                                                    KIRSHENBAUM
      BOND SENECAL & PARTNERS LLC

                                                                  
	 
      	
                                                                    MAXXCOM
      (USA) HOLDINGS INC.

                                                                  
	 
      	
                                                                    MAXXCOM
      INC. (ON)

                                                                  
	 
      	
                                                                    MAXXCOM
      INC. (US)

                                                                  
	 
      	
                                                                    MDC
      ACQUISITION INC.

                                                                  
	 
      	
                                                                    MDC
      CORPORATE (US) INC.

                                                                  
	 
      	
                                                                    MDC/KBP
      ACQUISITION INC.

                                                                  
	 
      	
                                                                    TARGETCOM
      LLC

                                                                  
	 
      	
                                                                    TC
      ACQUISITION INC.

                                                                  
	 
      	
                                                                    YAMAMOTO
      MOSS MACKENZIE, INC.

                                                                  
	 
      	
                                                                    ZG
      ACQUISITION INC.,

                                                                  
	 
      	
                                                                    each
      as Note Guarantor

                                                                  
	 
      	 
      	 
      
	 
      	
                                                                    By:

                                                                  	      
                                                                    /s/
      Michael Sabatino

                                                                  
	 
      	 
      	
                                                                    Name:
      Michael Sabatino

                                                                  
	 
      	 
      	
                                                                    Title:  
      Authorized Signatory

                                                                  
	 
      	 
      	 
      
	 
      	
                                                                    THE
      BANK OF NEW YORK MELLON,

                                                                  
	 
      	
                                                                    as
      Trustee

                                                                  
	 
      	 
      	 
      
	 
      	
                                                                    By:

                                                                  	/s/
      Latoya Elvin
	 
      	 
      	
                                                                    Name:
      Latoya Elvin

                                                                  
	 
      	 
      	
                                                                    Title:  
      Associate

                                                                  


                                                          

                                                        

                                                      

                                                    

                                                  

                                                

                                              

                                            

                                          

                                        

                                      

                                    

                                  

                                

                              

                            

                          

                        

                      

                    

                  

                

              

            

          

        

      

    

     

    
      
        
        

      

      
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