Exhibit 4.3
                                                               Execution Version

                          FIRST SUPPLEMENTAL INDENTURE

            This FIRST  SUPPLEMENTAL  INDENTURE (the  "Supplemental  Indenture")
dated as of February 13, 2004 among OMNICOM  GROUP INC., a New York  corporation
(the  "Company"),  OMNICOM  CAPITAL  INC., a  Connecticut  corporation  ("OCI"),
OMNICOM FINANCE INC., a Delaware  corporation  ("OFI"), and JPMORGAN CHASE BANK,
f/k/a The Chase Manhattan Bank, as trustee under the indenture referred to below
(the "Trustee").

                              W I T N E S S E T H:

            WHEREAS,  the Company and the Trustee have  heretofore  executed and
delivered to the Trustee an Indenture dated February 7, 2001 (the  "Indenture"),
providing  for  the  issuance  of  an  aggregate   principal  amount  of  up  to
$850,000,000 of Liquid Yield Option(TM) Notes due 2031 (the  "Securities"),  all
of which have been issued and  $847,031,000 of which are outstanding on the date
hereof;

            WHEREAS,  the Company desires to cause each of OCI and OFI to become
a co-issuer and co-obligor  under the Indenture and the Securities,  jointly and
severally with each other and with the Company;

            WHEREAS,  it is in the  best  interests  of  each  of OCI and OFI to
become a  co-issuer  and  co-obligor  under  the  Indenture  and the  Securities
inasmuch  as each of OCI and OFI will  derive  substantial  direct and  indirect
benefits from so becoming a co-issuer and co-obligor under the Indenture and the
Securities;

            WHEREAS, it is in the best interests of the Company to guarantee the
obligations  of each  of OCI  and OFI  with  respect  to the  Indenture  and the
Securities;

            WHEREAS,  Section 9.01(4) of the Indenture provides that the Company
and the Trustee may amend or supplement the Indenture without the consent of any
Securityholder  to make any change that does not, as  evidenced by an Opinion of
Counsel delivered to the Trustee,  materially adversely affect the rights of any
Securityholder;

            WHEREAS,  an Opinion of Counsel  has been  delivered  to the Trustee
under Section 9.01(4); and

            WHEREAS,  pursuant to Sections 9.01 and 9.06 of the  Indenture,  the
Trustee and the Company are authorized to execute and deliver this  Supplemental
Indenture;

            NOW THEREFORE,  for good and valuable consideration,  the receipt of
which is hereby  acknowledged,  the Company,  OCI, OFI and the Trustee  mutually
covenant  and agree for the equal and  ratable  benefit  of the  holders  of the
Securities as follows:

      1.  Definitions.  All capitalized  terms used but not defined herein shall
have the meanings given to such terms set forth in the Indenture.

      2. Agreement to Become  Co-Obligor.  By its signature hereto,  each of OCI
and OFI agrees to become a co-issuer of the  Securities  and a co-obligor  under
the Indenture and the
<PAGE>

Securities,  jointly  and  severally  with  each  other  and with  the  Company.
Notwithstanding  anything to the contrary contained in the Indenture, as amended
by this  Supplemental  Indenture,  each of OCI and OFI  may,  by  execution  and
delivery to the Trustee of a supplemental indenture satisfactory to the Trustee,
be released from their respective  obligations hereunder and under the Indenture
and the  Securities  upon (a) the sale or other transfer of its capital stock or
of all or  substantially  all of its assets to an entity that is not the Company
or a Subsidiary  of the Company and which sale is otherwise in  compliance  with
the Indenture,  which release shall be effective  without any action on the part
of the Trustee or any  Securityholder  or (b) with the prior written  consent of
each  applicable  Rating Agency  (which prior written  consent will be deemed to
have been given if each  applicable  Rating  Agency  approves a revised  list of
subsidiaries  of the Company  that are  required  to  guarantee  the  Guaranteed
Obligations  (as defined  below) or otherwise  become an "obligor" in respect of
the  Indenture  and  the  Securities  that  does  not  include  OCI or  OFI,  as
applicable), any such release to become effective upon receipt of notice of such
consent (and, if any  Subsidiary of the Company is required to become  guarantor
of the  Guaranteed  Obligations  or an "obligor" in respect of the Indenture and
the  Securities  in  connection  with the release of OCI or OFI, as  applicable,
pursuant to this Section 2, receipt of the required  guarantee)  by the Trustee.
Upon any such  release,  the Trustee  shall  deliver an  appropriate  instrument
evidencing  such release  upon  receipt of a request by the Company,  OCI or OFI
accompanied by an Officers'  Certificate  certifying as to compliance  with this
Section 2. Any actions  taken  pursuant to this  Section 2 shall not release the
Company as a primary obligor under the Indenture or the Securities.

      3. Amendments. The Indenture be and hereby is amended as follows:

      3.1 The preamble to the Indenture is hereby amended to add each of OCI and
OFI as a party to the Indenture as an issuer of the Securities.

      3.2 Article 1 of the Indenture is hereby amended as follows:

            (a) Section 1.01 of the  Indenture  is hereby  amended to insert the
      following new definition in its proper alphabetic place:

                  "Issuers"  means  each  of the  parties  named  as such in the
            preamble to this Indenture until a successor replaces it pursuant to
            the applicable  provisions of this Indenture and, thereafter,  shall
            mean such successor.  The foregoing sentence shall likewise apply to
            any subsequent such successor or successors.

            (b)  Section  1.01 of the  Indenture  is  amended  by  amending  and
      restating the following  definitions in their entirety  (changes are shown
      in bold italicized text; where only a deletion has been made, the deletion
      is shown in strikethrough italicized text):

                  "Board of Directors" means, with respect to any Issuer, either
            the  board  of  directors  of such  Issuer  or any  duly  authorized
            committee of such board.

                  "Company  Request" or "Company  Order" means,  with respect to
            any Issuer,  a written  request or order  signed in the name of such
            Issuer by any two Officers of such Issuer.


                                      -2-
<PAGE>

                  "Corporate  Trust Office"  means the  principal  office of the
            Trustee at which at any time its corporate  trust  business shall be
            administered,  which  office at the date  hereof is located at 4 New
            York Plaza, 15th Floor, New York, NY 10004, Attention: Institutional
            Trust  Services,  or such other address as the Trustee may designate
            from  time  to time  by  notice  to the  Issuers,  or the  principal
            corporate  trust  office of any  successor  Trustee  (or such  other
            address as a successor  Trustee may  designate  from time to time by
            notice to the Issuers).

                  "Indebtedness"  means, with respect to any Issuer at any date,
            without   duplication,   obligations  of  such  Issuer  (other  than
            nonrecourse  obligations)  for borrowed money or evidenced by bonds,
            debentures, notes or similar instruments of such Issuer.

                  "Officer" means,  with respect to any Issuer,  the Chairman of
            the Board,  the Vice  Chairman,  the Chief  Executive  Officer,  the
            President,  any Executive Vice President, any Senior Vice President,
            any Vice President,  the Treasurer or the Secretary or any Assistant
            Treasurer or Assistant Secretary of such Issuer.

                  "Officers'  Certificate"  means, with respect to any Issuer, a
            written certificate containing the information specified in Sections
            12.04(1)  and  12.05,  signed in the name of such  Issuer by any two
            Officers of such Issuer and  delivered to the Trustee.  An Officers'
            Certificate  given  pursuant to Section 4.03 needs only to be signed
            by the principal, executive, financial or accounting Officer of such
            Issuer and need not contain the  information  specified  in Sections
            12.04 and 12.05.

                  "Opinion of Counsel"  means a written  opinion  containing the
            information  specified  in  Sections  12.04 and  12.05,  from  legal
            counsel who is reasonably acceptable to the Trustee. The counsel may
            be an employee of, or counsel to, the Issuers or the Trustee.

                  "Securities"  means any of the Liquid Yield  Option(TM)  Notes
            due 2031 issued under this Indenture.

                  "Subsidiary"   means,  with  respect  to  any  Issuer,  (i)  a
            corporation,  a majority of whose  Capital  Stock with voting power,
            under ordinary circumstances,  to elect directors is, at the date of
            determination,  directly or indirectly owned by such Issuer,  by one
            or more  Subsidiaries  of such  Issuer or by such  Issuer and one or
            more  Subsidiaries of such Issuer,  (ii) a partnership in which such
            Issuer or a Subsidiary  of such Issuer holds a majority  interest in
            the equity  capital or  profits  of such  partnership,  or (iii) any
            other person (other than a corporation or partnership) in which such
            Issuer,  a Subsidiary  of such Issuer or such Issuer and one or more
            Subsidiaries of such Issuer, directly or indirectly,  at the date of
            determination, has (x) at least a majority equity ownership interest
            or (y) the power to elect or direct the  election  of a majority  of
            the directors or other governing body of such person.


                                      -3-
<PAGE>

            (c) The  definition of "obligor" in Section 1.03 of the Indenture is
      hereby  amended and restated in its  entirety to read as follows  (changes
      are shown in bold italicized text):

                  "obligor" on the indenture securities means each of Issuers.

            (d) Section  1.05(e) of the  Indenture is hereby  amended to replace
      each reference in said Section to the "Company"  with the term  "Issuers";
      and all  singular  pronouns  which  referred to the  "Company"  are hereby
      amended to be plural pronouns  referring to the "Issuers" and all singular
      verb forms used in a clause in which the  "Company"  was the sole  subject
      are  hereby  amended  to be in the  plural  verb  forms  referring  to the
      "Issuers" as the subject.

      3.3 Article 2 of the Indenture is hereby amended to replace each reference
in said Article to (i) the "Company" with the term "Issuers",  (ii) all singular
pronouns which referred to the "Company" with plural  pronouns  referring to the
"Issuers", (iii) all singular verb forms used in a clause in which the "Company"
was the sole subject with a plural verb forms  referring to the "Issuers" as the
subject and (iv) the phrase "either of them" with the phrase "any of them".

      3.4 With the  exception  of  Section  3.08(d)(iv),  Section  3.08(f),  the
definition of "Change of Control" in Section 3.09 and the paragraph  immediately
following  that  definition  (none of which shall be amended),  Article 3 of the
Indenture is hereby amended to replace each reference in said Article to (i) the
"Company" with the term "Issuers",  (ii) all singular pronouns which referred to
the  "Company"  with  plural  pronouns  referring  to the  "Issuers",  (iii) all
singular verb forms used in a clause in which the "Company" was the sole subject
with a plural verb forms  referring to the "Issuers" as the subject and (iv) the
phrase "either of them" with the phrase "any of them".

      3.5 With the exception of Section 4.02 (which shall not be amended  except
for the last sentence  thereof)  Article 4 of the Indenture is hereby amended to
replace  each  reference  in said  Article  to (i) the  "Company"  with the term
"Issuers",  (ii) all singular  pronouns  which  referred to the  "Company"  with
plural pronouns  referring to the "Issuers",  (iii) all singular verb forms used
in a clause in which the "Company" was the sole subject with a plural verb forms
referring to the  "Issuers" as the subject and (iv) the phrase  "either of them"
with the phrase "any of them".  Section 4.05 of the Indenture is hereby  further
amended to change the address of JPMorgan  Chase Bank,  the new address  being 4
New York Plaza, 15th Floor, New York, NY 10004.

      3.6 Section 5.01 of the  Indenture is hereby  amended and restated to read
in its entirety as follows (changes are shown in bold italicized text):

            "SECTION  5.01 When the  Issuers May Merge or  Transfer  Assets.  An
            Issuer  shall not  consolidate  with or merge with or into any other
            person or  convey,  transfer  or lease  its  properties  and  assets
            substantially  as an entirety  to any person  (except in the case of
            OCI or OFI,  with,  into or to the Company,  each other or any other
            Subsidiary of the Company), unless:


                                      -4-
<PAGE>

            (a) either (1) such Issuer shall be the  continuing  corporation  or
            (2)  the  person  (if  other  than  the  Company)   formed  by  such
            consolidation  or into which the such Issuer is merged or the person
            which acquires by  conveyance,  transfer or lease the properties and
            assets of such  Issuer  substantially  as an  entirety  (i) shall be
            organized and validly  existing  under the laws of the United States
            or any State  thereof or the  District  of  Columbia  and (ii) shall
            expressly assume, by an indenture supplemental hereto,  executed and
            delivered to the Trustee,  in form satisfactory to the Trustee,  all
            of the  obligations  of such Issuer  under the  Securities  and this
            Indenture;

            (b) immediately after giving effect to such transaction,  no Default
            shall have occurred and be continuing; and

            (c) the Company  shall have  delivered  to the Trustee an  Officers'
            Certificate  and an  Opinion  of  Counsel,  each  stating  that such
            consolidation,  merger,  conveyance,  transfer  or lease  and,  if a
            supplemental   indenture  is  required  in   connection   with  such
            transaction, such supplemental indenture, comply with this Article 5
            and that all conditions  precedent  herein  provided for relating to
            such transaction have been satisfied.

      For purposes of the foregoing,  the  conveyance,  transfer or lease of the
      properties and assets of one or more Subsidiaries of an Issuer (other than
      to the Company or another  Subsidiary  of any of the Issuers),  which,  if
      such  assets  were  owned  by  such  Issuer,   would   constitute  all  or
      substantially  all of the properties  and assets of such Issuer,  shall be
      deemed to be the transfer of all or  substantially  all of the  properties
      and assets of such Issuer, but a bona fide pledge or hypothecation will be
      deemed not to be prohibited by this Indenture.

      The  successor  person  formed by such  consolidation  or into  which such
      Issuer  is  merged  or the  successor  person  to which  such  conveyance,
      transfer or lease is made shall  succeed to, and be  substituted  for, and
      may exercise  every right and power of, such Issuer  under this  Indenture
      with the same  effect  as if such  successor  had been  named as an Issuer
      herein; and thereafter, except in the case of a lease and obligations such
      Issuer may have under a supplemental  indenture pursuant to Section 10.14,
      such Issuer shall be discharged  from all  obligations and covenants under
      this Indenture and the  Securities.  Subject to Section 9.06, such Issuer,
      the  Trustee and the  successor  person  shall  enter into a  supplemental
      indenture to evidence the  succession and  substitution  of such successor
      person and such discharge and release of such Issuer."

      3.7 Article 6 of the Indenture is hereby amended to replace each reference
in said Article to (i) the "Company" with the term "Issuers",  (ii) all singular
pronouns which referred to the "Company" with plural  pronouns  referring to the
"Issuers", (iii) all singular verb forms used in a clause in which the "Company"
was the sole subject with a plural verb forms  referring to the "Issuers" as the
subject and (iv) the phrase "either of them" with the phrase "any of them".

      3.8 Article 7 of the Indenture is hereby amended to replace each reference
in said Article to (i) the "Company" with the term "Issuers",  (ii) all singular
pronouns which referred to


                                      -5-
<PAGE>

the  "Company"  with  plural  pronouns  referring  to the  "Issuers",  (iii) all
singular verb forms used in a clause in which the "Company" was the sole subject
with a plural verb forms  referring to the "Issuers" as the subject and (iv) the
phrase "either of them" with the phrase "any of them".

      3.9 Article 8 of the Indenture is hereby amended to replace each reference
in said Article to (i) the "Company" with the term "Issuers",  (ii) all singular
pronouns which referred to the "Company" with plural  pronouns  referring to the
"Issuers", (iii) all singular verb forms used in a clause in which the "Company"
was the sole subject with a plural verb forms  referring to the "Issuers" as the
subject and (iv) the phrase "either of them" with the phrase "any of them".

      3.10 With the  exception  of Section  9.02 (which  shall not be  amended),
Article 9 of the Indenture is hereby  amended to replace each  reference in said
Article to (i) the "Company" with the term "Issuers", (ii) all singular pronouns
which referred to the "Company" with plural pronouns referring to the "Issuers",
(iii) all singular  verb forms used in a clause in which the  "Company"  was the
sole subject with a plural verb forms  referring to the "Issuers" as the subject
and (iv) the phrase "either of them" with the phrase "any of them".

      3.11 With the exception of Sections 10.05,  10.06,  10.07,  10.08,  10.11,
10.12, 10.13,  10.14, 10.15 and 10.19 (none of which shall be amended),  Article
10 of the Indenture is hereby  amended to replace each reference in said Article
to (i) the "Company" with the term "Issuers",  (ii) all singular  pronouns which
referred to the "Company" with plural pronouns referring to the "Issuers", (iii)
all  singular  verb forms used in a clause in which the  "Company"  was the sole
subject with a plural verb forms  referring to the  "Issuers" as the subject and
(iv) the phrase  "either of them" with the phrase  "any of them".  In  addition,
references in Article 10 to the term "Board of Directors"  shall be deemed to be
to the Board of Directors of the Company only, and not the Board of Directors of
any other Issuer.

      3.12  Article  11 of the  Indenture  is hereby  amended  to  replace  each
reference in said Article to (i) the "Company" with the term "Issuers", (ii) all
singular pronouns which referred to the "Company" with plural pronouns referring
to the  "Issuers",  (iii) all singular  verb forms used in a clause in which the
"Company"  was the  sole  subject  with a plural  verb  forms  referring  to the
"Issuers"  as the subject  and (iv) the phrase  "either of them" with the phrase
"any of them".

      3.13  Article  12 of the  Indenture  is hereby  amended  to  replace  each
reference in said Article to (i) the "Company" with the term "Issuers", (ii) all
singular pronouns which referred to the "Company" with plural pronouns referring
to the  "Issuers",  (iii) all singular  verb forms used in a clause in which the
"Company"  was the  sole  subject  with a plural  verb  forms  referring  to the
"Issuers"  as the subject  and (iv) the phrase  "either of them" with the phrase
"any of them".  Additionally,  Section  12.02 of the  Indenture  is  amended  by
amending  and  restating  the  notice  information  for the  Trustee  as follows
(changes are shown in bold italicized text):

            JPMorgan Chase Bank
            4 New York Plaza, 15th Floor
            New York, New York  10004

            Telephone No.  (212) 623-6794


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<PAGE>

            Facsimile No.  (212) 623-6167
            Attention:  Institutional Trust Services

      3.14 Exhibit A-1 to the Indenture is hereby amended as follows:

            (a) Each reference to "The Chase  Manhattan Bank" is hereby replaced
      with "JPMorgan Chase Bank."

            (b) The fifth  paragraph of the legend  contained  therein is hereby
      amended to replace the words "ON WHICH OMNICOM GROUP INC. (THE  "COMPANY")
      OR ANY  AFFILIATE OF THE COMPANY"  with the words "ON WHICH  OMNICOM GROUP
      INC. (THE "COMPANY"),  OMNICOM CAPITAL INC. ("CAPITAL") OR OMNICOM FINANCE
      INC. ("FINANCE" AND TOGETHER WITH THE COMPANY AND CAPITAL,  THE "ISSUERS")
      OR ANY AFFILIATE OF ANY OF THEM".

            (c) With the exception of the second and third paragraphs of Section
      5 of said Exhibit,  the definitions of "Five-Day Period" and "Regular Cash
      Dividends"  in Section 5 of said  Exhibit,  the first,  fourth and seventh
      paragraphs  of Section  9(d) of said  Exhibit  and the  Conversion  Notice
      contained  in said  Exhibit  (none of which  shall be  amended  except  as
      otherwise  set forth in  paragraph  (c)  below),  said  Exhibit  is hereby
      amended to replace each  reference  in said  Exhibit to (i) the  "Company"
      with the term "Issuers",  (ii) all singular pronouns which referred to the
      "Company"  with plural  pronouns  referring  to the  "Issuers",  (iii) all
      singular  verb forms used in a clause in which the  "Company" was the sole
      subject with a plural verb forms referring to the "Issuers" as the subject
      and (iv) the phrase "either of them" with the phrase "any of them".

            (d)  References to the term "Board of Directors" in the  definitions
      of "Five-Day  Period" and "Regular Cash  Dividends" in paragraph 5 of said
      Exhibit  shall be deemed to be to the Board of  Directors  of the  Company
      only, and not the Board of Directors of any other Issuer.

            (e)  The  third  page of  said  Exhibit  is  hereby  amended  to add
      additional  signature  blocks for Omnicom Capital Inc. and Omnicom Finance
      Inc. and the first  paragraph on said page is hereby  amended and restated
      to read in its entirety as follows  (changes are shown in bold  italicized
      text):

            "Each of OMNICOM GROUP INC., a New York corporation, OMNICOM CAPITAL
            INC.,  a  Connecticut  corporation,  and  OMNICOM  FINANCE  INC.,  a
            Delaware corporation, jointly and severally, promises to pay to Cede
            & Co.  or  registered  assigns,  the  Initial  Principal  Amount  at
            Maturity of  [_______________________________  ($_________)],  or if
            greater, the Principal Amount at Maturity, on February 7, 2031."

      3.15 Exhibit A-2 to the Indenture is hereby amended as follows:

            (a) Each reference to "The Chase  Manhattan Bank" is hereby replaced
      with "JPMorgan Chase Bank."


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<PAGE>

            (b) The fourth paragraph of the legend  contained  therein is hereby
      amended to replace the words "ON WHICH OMNICOM GROUP INC. (THE  "COMPANY")
      OR ANY  AFFILIATE OF THE COMPANY"  with the words "ON WHICH  OMNICOM GROUP
      INC. (THE "COMPANY"),  OMNICOM CAPITAL INC. ("CAPITAL") OR OMNICOM FINANCE
      INC. ("FINANCE" AND TOGETHER WITH THE COMPANY AND CAPITAL,  THE "ISSUERS")
      OR ANY AFFILIATE OF ANY OF THEM".

            (c) Said Exhibit is hereby amended to replace each reference in said
      Exhibit to (i) the "Company"  with the term  "Issuers",  (ii) all singular
      pronouns which referred to the "Company" with plural pronouns referring to
      the "Issuers", (iii) all singular verb forms used in a clause in which the
      "Company"  was the sole subject with a plural verb forms  referring to the
      "Issuers"  as the  subject  and (iv) the phrase  "either of them" with the
      phrase "any of them".

            (d)  The  third  page of  said  Exhibit  is  hereby  amended  to add
      additional  signature  blocks for Omnicom Capital Inc. and Omnicom Finance
      Inc. and the first  paragraph on said page is hereby  amended and restated
      to read in its entirety as follows  (changes are shown in bold  italicized
      text):

            "Each of OMNICOM GROUP INC., a New York corporation, OMNICOM CAPITAL
            INC.,  a  Connecticut  corporation,  and  OMNICOM  FINANCE  INC.,  a
            Delaware corporation, jointly and severally, promises to pay to Cede
            & Co.  or  registered  assigns,  the  Initial  Principal  Amount  at
            Maturity of  [_______________________________  ($_________)],  or if
            greater, the Principal Amount at Maturity, on February 7, 2031."

      3.16  Exhibit  B-1 to the  Indenture  is hereby  amended to  replace  each
reference in said Exhibit to the term "Company" with the term "Issuers".

      3.17 Exhibit B-2 to the Indenture is hereby amended as follows:

            (a) The  address of The Chase  Manhattan  Bank is  amended,  the new
      address being JPMorgan Chase Bank, 4 New York Plaza, 15th Floor, New York,
      NY 10004,

            (b) The  first  paragraph  of said  Exhibit  is hereby  amended  and
      restated  to read in its  entirety as follows  (changes  are shown in bold
      italicized text):

            "We are  delivering  this  letter in  connection  with the  proposed
            transfer of  $_____________  Initial Principal Amount at Maturity of
            the Liquid Yield  Option(TM) Notes due 2031 (the "Notes") of Omnicom
            Group Inc. (the "Company"), Omnicom Finance Inc. and Omnicom Finance
            Inc.,  as  co-issuers  and  co-obligors  on  the  Notes,  which  are
            convertible  into shares of the Company's  Common  Stock,  $0.15 par
            value per share (the "Common Stock") as specified in the Indenture."

            (c) Each  reference in said Exhibit to the term  "Company" is hereby
      replaced with the term "Issuers".


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<PAGE>

      3.18 Any and all Securities  issued and outstanding as of the date of this
First  Supplemental  Indenture  shall be deemed  amended as follows  without any
further  action (and the Company,  OCI, OFI and the Trustee  expressly so agree)
with the same effect as if a new Security expressly including such provisions as
so  amended  had been  issued  in  exchange  for  such  issued  and  outstanding
securities:

            (a) The fifth  paragraph of the legend  contained  thereon is hereby
      amended to replace the words "ON WHICH OMNICOM GROUP INC. (THE  "COMPANY")
      OR ANY  AFFILIATE OF THE COMPANY"  with the words "ON WHICH  OMNICOM GROUP
      INC. (THE "COMPANY"),  OMNICOM CAPITAL INC. ("CAPITAL") OR OMNICOM FINANCE
      INC. ("FINANCE" AND TOGETHER WITH THE COMPANY AND CAPITAL,  THE "ISSUERS")
      OR ANY AFFILIATE OF ANY OF THEM".

            (b) With the exception of the  definitions of "Five-Day  Period" and
      "Regular Cash  Dividends" in Section 5 of each said  Security,  the first,
      fourth and seventh  paragraphs  of Section 9(d) of each said  Security and
      the Conversion Notice contained in each said Security (none of which shall
      be amended  except as otherwise  set forth in paragraph  (c) below),  each
      said Security is hereby amended to replace each  reference  therein to (i)
      the "Company" with the term  "Issuers",  (ii) all singular  pronouns which
      referred to the "Company" with plural pronouns referring to the "Issuers",
      (iii) all singular  verb forms used in a clause in which the "Company" was
      the sole  subject with a plural verb forms  referring to the  "Issuers" as
      the subject  and (iv) the phrase  "either of them" with the phrase "any of
      them".

            (c)  References to the term "Board of Directors" in the  definitions
      of "Five-Day  Period" and "Regular Cash  Dividends" in paragraph 5 of each
      said  Security  shall be  deemed to be to the  Board of  Directors  of the
      Company only, and not the Board of Directors of any other Issuer.

            (d) Each of OCI and OFI shall be deemed,  by their signature hereto,
      to have signed each of the outstanding  Securities as if their  signatures
      appeared thereon.

      4. Company Guarantee.

      4.1 The Company  hereby,  jointly and severally  with any other Person who
may  also   guarantee   the   Guaranteed   Obligations   (as   defined   below),
unconditionally  and  irrevocably  guarantees  (the  "Guarantee"),  on a  senior
unsecured   basis,  as  a  primary  obligor  and  not  as  a  surety,   to  each
Securityholder  and to the Trustee and its  successors  and assigns the full and
punctual payment when due, whether at maturity,  by acceleration,  redemption or
otherwise,  of the  principal of and interest  on, if any,  the  Securities,  if
lawful,  and all  other  monetary  obligations  of each of OCI and OFI under the
Indenture  (as so amended by this  Supplemental  Indenture)  and the  Securities
(collectively, the "Guaranteed Obligations"). The Company further agrees, in its
capacity as a  guarantor,  that the  Guaranteed  Obligations  may be extended or
renewed, in whole or in part, without notice or further assent from the Company,
and the Company  shall remain bound under its Guarantee  and the  Indenture,  as
amended hereby,  notwithstanding any such extension or renewal.  Failing payment
when due of any amount so


                                      -9-
<PAGE>

guaranteed for whatever reason, the Company will be obligated to pay the same in
full,  or cause to be duly and  punctually  paid in full,  without any demand or
notice whatsoever.

      4.2 In its capacity as guarantor,  the Company hereby waives  presentation
to, demand of payment from and protest to OCI or OFI, as the case may be, of any
of the Guaranteed  Obligations and also waives notice of protest for nonpayment.
In its  capacity as  guarantor,  the Company  also hereby  waives  notice of any
default  by OCI or  OFI,  as the  case  may  be,  under  the  Securities  or the
Indenture.  The Company agrees that its obligations under its Guarantee shall be
continuing, absolute, full and unconditional under any and all circumstances, to
the fullest  extent  permitted by  applicable  law, and shall not be  discharged
except by payment in full of the Securities, irrespective of:

            (a) the value, genuineness,  regularity,  validity,  enforceability,
      avoidance,  subordination,  discharge  or  disaffirmance  of  any  of  the
      Guaranteed Obligations, the Securities or the Indenture, or the absence of
      any action to enforce the same;

            (b) any  extension  or  waiver,  at any  time or from  time to time,
      without  notice to the Company,  of the time for compliance by OCI or OFI,
      as the case may be, with any of its  obligations  under the  Securities or
      the Indenture;

            (c) any substitution,  release or exchange of any other guarantee of
      or security for any  obligations  of OCI or OFI, as the case may be, under
      the Securities or the Indenture;

            (d) any recission,  amendment or modification to any of the terms or
      provisions of the Securities or the Indenture;

            (e) any law,  regulation or order of any jurisdiction  affecting any
      term  of any of the  Securities  or the  Indenture  or the  rights  of any
      Securityholder or the Trustee with respect thereto;

            (f) any failure to obtain any  authorization  or approval  from,  or
      other action by, to notify,  or to file anything  with,  any  governmental
      authority or regulatory  body required in connection  with the performance
      of the Guarantee by the Company;

            (g) the failure by any  Securityholder  or the Trustee to assert any
      claim or demand or to exercise any right or remedy  against OCI or OFI, as
      the case may be, or any other  guarantor of the Guaranteed  Obligations or
      any other Person;

            (h) the failure by any Securityholder or the Trustee to exercise any
      right or remedy  against any  collateral  securing  any of the  Guaranteed
      Obligations; or

            (i)  any  other   circumstance   whatsoever   that  might  otherwise
      constitute a defense to or a legal or equitable discharge of the Company's
      obligations,  in its capacity as guarantor,  under its Guarantee or of the
      Company's obligations,  in its capacity as guarantor, under the Securities
      and the Indenture.


                                      -10-
<PAGE>

      4.3 The Company's  obligations  under its Guarantee and the Indenture,  as
amended by this Supplemental Indenture, and the Securities,  in each case in its
capacity as  guarantor,  shall not be limited by any  valuation,  estimation  or
disallowance  made in connection  with any  proceedings  filed by or against the
Company or the  Company  under the United  States  Bankruptcy  Code of 1978,  as
amended  (the  "Bankruptcy  Code"),  whether  pursuant  to  Section  502  of the
Bankruptcy Code or any other section  thereof.  The Company further agrees that,
it its capacity as  guarantor,  none of the  Securityholders  shall be under any
obligation to marshall any assets in favor of or against or in payment of any or
all of the  Guaranteed  Obligations  or the  Securities.  To the extent that the
Company makes a payment or payments on any or all of the Guaranteed  Obligations
and such  payment  or  payments  (or any part  thereof)  is or are  subsequently
invalidated, declared to be fraudulent or preferential, set aside or required to
be repaid to the  Company,  its estate,  trustee or receiver or any other party,
including,  without limitation,  the Company, under any bankruptcy law, state or
federal law, common law or equitable  cause,  then to the extent of such payment
or repayment,  the Guaranteed Obligations (or, if applicable,  such part thereof
as had been paid, reduced or satisfied by such amount),  shall be reinstated and
revived  and  continued  in full  force and  effect as of the date such  initial
payment, reduction or satisfaction occurred. The Company waives, in its capacity
as guarantor,  all set-offs,  counterclaims,  reductions and  diminutions of any
obligation,  and any defense of any kind or nature  (other than,  payment of the
Guaranteed Obligations), that the Company may have or assert against OCI, OFI or
any other Person,  and all  presentments,  demands for  performance,  notices of
nonperformance, protests, notices of protest, notices of dishonor and notices of
acceptance of its Guarantee.

      4.4 The Company, in its capacity as guarantor,  hereby unconditionally and
irrevocably  waives  (i) any  defense  arising by reason of any claim or defense
based upon an  election of  remedies  by any  Securityholder  that in any manner
impairs,  reduces,  releases or  otherwise  adversely  affects the  subrogation,
reimbursement,  exoneration,  contribution  or  indemnification  rights  of  the
Company or other rights of the Company to proceed  against  OCI,  OFI, any other
guarantor or any other Person or collateral,  if any, and (ii) any defense based
on any right of set-off or counterclaim  against or in respect of the Guaranteed
Obligations or the Securities of the Company under the Indenture, the Securities
or this Supplemental Indenture.

      4.5 The Company, in its capacity as guarantor,  hereby waives any right to
which it may be entitled to have its  obligations  under the  Guarantee  and the
Indenture divided among it and other guarantor of the Guaranteed Obligations, if
any,  such that the  Company's  obligations  would be less than the full  amount
claimed.  The Company, in its capacity as guarantor,  hereby waives any right to
which it may be entitled to have the assets of OCI,  OFI or any other Person who
became an "obligor"  under the  Securities  or the  Indenture  first be used and
depleted  as  payment  of the  obligations  of OCI,  OPI or such  other  Person,
respectively,  under the Securities and the Indenture prior to any amounts being
claimed from or paid by the Company  under its  Guarantee.  The Company,  in its
capacity as  guarantor,  hereby  waives any right to which it may be entitled to
require that suit be instituted  against OCI, OFI or any other  guarantor of the
Guaranteed  Obligations or "obligor" under the Securities or the Indenture prior
to an action being  initiated  against the Company.  The Company  further agrees
that the  Guarantee  constitutes  a  guarantee  of  payment  when due (and not a
guarantee of collection) and waives any right, in its capacity as guarantor,  to
require  that any  resort be had by any  Securityholder  or the  Trustee  to any
security held for payment of the Guaranteed Obligations.


                                      -11-
<PAGE>

      4.6 The failure to endorse the Guarantee on any Security  shall not affect
or impair the validity thereof.

      4.7 The Company's obligations under its Guarantee shall not be affected if
any Securityholder is precluded for any reason (including,  without  limitation,
the application of the automatic stay under Section 362 of the Bankruptcy  Code)
from enforcing or exercising any right or remedy with respect to the Securities,
and the Company  shall pay to each  affected  Securityholder,  upon demand,  the
amount that would  otherwise  have been due and payable had the exercise of such
rights and remedies been permitted.  In the event of any such application of the
automatic  stay under Section 362 of the Bankruptcy  Code, the Securities  shall
forthwith become due and payable by the Company for purposes of the Guarantee.

      4.8 The Company hereby agrees that,  unless and until all obligations with
respect to the  Securities and the  Indenture,  as amended by this  Supplemental
Indenture,  have been paid in full, in its capacity as guarantor,  it shall have
no right (whether direct or indirect) of subrogation (whether contractual, under
Section  509  of  the  Bankruptcy  Code  or  otherwise)  to  the  claims  of any
Securityholder or the Trustee against OCI, OFI or any other Person who became an
"obligor"  under the  Securities or the  Indenture in respect of any  obligation
with respect to the Securities or the Indenture,  notwithstanding any payment or
payments made by the Company hereunder or any set-off or application of funds of
the  Company  by  the   Securityholder;   and  the  Company  hereby  waives  all
contractual,  statutory and common law rights of reimbursement,  contribution or
indemnity  it may have against OCI, OFI or any other such Person as the case may
be, and any and all other  rights of payment or  recovery  from OCI,  OFI or any
other such Person, as the case may be, that it may now have or hereafter acquire
until all Securities and all  obligations  under the Indenture have been paid in
full (in which event such rights of payment or recovery shall be deemed to be in
the form of a loan or loans made from the Company to OCI,  OFI or any other such
Person,  as the case may be. The Company further agrees that, in its capacity as
guarantor,  as between the Company, on the one hand, and the Securityholders and
the Trustee,  on the other hand, (1) the maturity of the  Securities  guaranteed
hereby may be  accelerated  as  provided in Article 6 of the  Indenture  for the
purposes  of  the  Company's  Guarantee  hereunder,  notwithstanding  any  stay,
injunction or other  prohibition  preventing such acceleration in respect of the
Securities  guaranteed  pursuant to this  Section 4, and (2) in the event of any
declaration of  acceleration  of such Securities as provided in Article 6 of the
Indenture,  such  Securities  (whether or not due and  payable)  will  forthwith
become  due  and  payable  by the  Company  for  the  purpose  of its  Guarantee
hereunder.

      4.9 Except as otherwise  specifically provided in Section 4.12 hereof with
respect  to the  release  of the  Company  from its  Guarantee  hereunder,  such
Guarantee  shall  remain in full force and  effect and be binding in  accordance
with and to the extent of its terms upon the Company and the successors thereof,
and shall  inure to the benefit of (and be  enforceable  by) the Trustee and the
Securityholders from time to time, or their respective  successors or assignees,
until  the  Indenture  shall  have  been  terminated  and the  principal  of and
interest,  if any,  on the  Securities,  and the  obligations  of the Company in
respect of the Guaranteed Obligations, have been satisfied by payment in full.


                                      -12-
<PAGE>

      4.10 Payments made by the Company pursuant to its Guarantee hereunder will
be made to each Securityholder in the same manner, and to the same location,  as
payments  to  such  Securityholder  are  required  to be  made  pursuant  to the
provisions of the Indenture.

      4.11 The Company shall pay all  reasonable  costs and expenses  (including
reasonable  attorneys' fees and expenses) paid or incurred by the Trustee or any
Securityholder  in connection with the enforcement of the Guarantee or any other
rights of the Trustee or such Securityholder  under this Supplemental  Indenture
with respect to such  Guarantee and the  prosecution or defense of any action by
or against any of the  Securityholders  in connection with the Guarantee or this
Supplemental  Indenture with respect to such  Guarantee,  whether  involving the
Company  or any other  Person,  including  a trustee  in  bankruptcy;  provided,
however,  that the Company shall have no such  obligation in connection with any
action brought by any Securityholder  against the Company to the extent that the
Company is the prevailing party in the judgment rendered in any such action; and
provided  further  that the Company  shall not be  responsible  for the fees and
expenses of more than one firm of attorneys  (in addition to any required  local
counsel).

      4.12 The  Company  may,  by  execution  and  delivery  to the Trustee of a
supplemental  indenture  satisfactory  to the  Trustee,  be  released  from  its
Guarantee  upon the sale or other  transfer  of its  capital  stock or of all or
substantially  all of its  assets  to an  entity  that is not the  Company  or a
subsidiary  of the Company and which sale is  otherwise in  compliance  with the
Indenture,  which release  shall be effective  without any action on the part of
the Trustee or any  Securityholder.  Upon any such  release,  the Trustee  shall
deliver an  appropriate  instrument  evidencing  such  release upon receipt of a
request by the Company or the Company  accompanied  by an Officers'  Certificate
certifying as to compliance  with this Section 4.12.  Any actions taken pursuant
to this  Section  4.12 shall not  release the  Company,  OCI or OFI as a primary
obligor under the Indenture or the Securities.

      5.  Separability  Clause.  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.

      6. Modification, Amendment and Waiver. The provisions of this Supplemental
Indenture  may not be  amended,  supplemented,  modified  or waived  except by a
execution of a Supplemental  Indenture executed by OCI, OFI, the Company and, to
the extent such amendment,  supplement or waiver limits or impairs the rights of
any Securityholder, by such Securityholder. Any such amendment shall comply with
Article  9 of the  Indenture.  Until an  amendment,  waiver  or other  action by
Securityholders  becomes  effective,  a consent thereto by a Securityholder of a
Security  hereunder  is a  continuing  consent by the  Securityholder  and every
subsequent  Securityholder  of that  Security  or portion of the  Security  that
evidences the same obligation as the consenting  Securityholder's Security, even
if  notation  of the  consent,  waiver or  action  is not made on the  Security.
However,  any such  Securityholder or subsequent  Securityholder  may revoke the
consent, waiver or action as to such Securityholder's Security or portion of the
Security if the Trustee  receives the notice of  revocation  before the date the
amendment,  waiver or action becomes  effective.  After an amendment,  waiver or
action becomes effective, it shall bind every Securityholder.


                                      -13-
<PAGE>

      7.  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.  In the event of a  conflict  between  the terms and
conditions of the Indenture  and the terms and  conditions of this  Supplemental
Indenture,  then the terms and conditions of this  Supplemental  Indenture shall
prevail. This Supplemental  Indenture shall form a part of the Indenture for all
purposes,  and every holder of Securities heretofore or hereafter  authenticated
and delivered shall be bound hereby.

      8. Trust  Indenture Acts Controls.  If any provision of this  Supplemental
Indenture  limits,  qualifies  or  conflicts  with any  provision  of the  Trust
Indenture Act of 1939, as amended ("TIA"),  that is required under the TIA to be
part of and govern any provision of this Supplemental  Indenture,  the provision
of the TIA  shall  control.  If any  provision  of this  Supplemental  Indenture
modifies  or  excludes  any  provisions  of the TIA that may be so  modified  or
excluded, the provisions of the TIA shall be deemed to apply to the Indenture as
so modified or to be excluded by this  Supplemental  Indenture,  as the case may
be.

      9. Governing  Law. THIS  SUPPLEMENTAL  INDENTURE  SHALL BE GOVERNED BY AND
CONSTRUED IN  ACCORDANCE  WITH THE LAWS OF THE STATE OF NEW YORK,  AS APPLIED TO
CONTRACTS MADE AND PERFORMED  WITHIN THE STATE OF NEW YORK WITHOUT GIVING EFFECT
TO THE PRINCIPLES OF CONFLICTS OF LAW.

      10. Trustee Makes No  Representation.  The statements herein are deemed to
be those  of the  Company,  OCI or OFI,  as  applicable.  The  Trustee  makes no
representation as to the validity or sufficiency of this Supplemental Indenture.

      11. Multiple Originals.  The parties may sign any number of copies of this
Supplemental  Indenture.  Each signed copy shall be an original, but all of them
together  represent the same agreement.  One signed copy is enough to prove this
Supplemental Indenture.

      12. Effect of Headings.  The Section  headings  herein are for convenience
only and shall not effect the construction thereof.

      13. Notices. Any request, demand,  authorization,  notice, waiver, consent
or  communication  to any of the  parties  shall be made as set forth in Section
12.02 of the Indenture, as said Section may be amended hereby.

      14.  Successors.  All agreements of each of OCI and OFI in respect of this
Supplemental Indenture shall bind its successor.


                                      -14-
<PAGE>

            IN  WITNESS  WHEREOF,  this  Supplemental  Indenture  has been  duly
executed by the Company, OCI and the Trustee as of the date first written above.

                                      OMNICOM GROUP INC.

                                       By:    /s/ Randall J. Weisenburger
                                           -------------------------------------
                                           Name:  Randall J. Weisenburger
                                           Title: Executive Vice President and
                                                  Chief Financial Officer

                                       OMNICOM CAPITAL INC.

                                       By:    /s/ Dennis E. Hewitt
                                           -------------------------------------
                                           Name:  Dennis E. Hewitt
                                           Title: Chief Executive Officer

                                       OMNICOM FINANCE INC.

                                       By:    /s/ Randall J. Weisenburger
                                           -------------------------------------
                                           Name:  Randall J. Weisenburger
                                           Title: Chief Executive Officer

                                       JPMORGAN CHASE BANK, as Trustee

                                       By:    /s/ William G. Keenan
                                           -------------------------------------
                                           Name:  William G. Keenan
                                           Title: Vice President


                                      -15-