Document:

Exhibit 4.2

                               OMNICOM GROUP INC.

                              OMNICOM CAPITAL INC.

                              OMNICOM FINANCE INC.

                                   as Issuers

                          FIRST SUPPLEMENTAL INDENTURE

                           Dated as of March 29, 2006

                            JPMORGAN CHASE BANK, N.A.

                                   as Trustee

                             Senior Debt Securities

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      First Supplemental Indenture dated as of March 29, 2006 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 together with the Company and OCI, collectively referred to as the
"Issuers," and each, individually, an "Issuer"), and JPMorgan Chase Bank, N.A.,
a national banking association, as Trustee (the "Trustee").

                              W I T N E S S E T H:

      WHEREAS, the Issuers and the Trustee executed and delivered an indenture
dated as of March 29, 2006 (the "Indenture") to provide for the issuance by the
Issuers from time to time of Securities to be issued in one or more series as
provided in the Indenture;

      WHEREAS, the issuance and sale of up to $1,000,000,000 aggregate principal
amount of a series of the Issuers' 5.90% Senior Notes due 2016 (the
"Securities") have been authorized by the boards of directors of each of the
Issuers;

      WHEREAS, the Issuers desire to issue and sell $1,000,000,000 aggregate
principal amount of the Securities on the date hereof;

      WHEREAS,  the  Issuers  desire to enter into this  Supplemental  Indenture
pursuant to Sections  2.2,  2.14.1 and 9.1 of the  Indenture to  supplement  the
Indenture to establish the form and terms of the Securities; and

      NOW, THEREFORE, THIS INDENTURE WITNESSETH, that, for and in
consideration of the above premises, it is mutually covenanted and agreed, for
the equal and proportionate benefit of all Holders of the Securities, as
follows:

                                   ARTICLE ONE
                                   DEFINITIONS

      Section 1.1  Relation to Base Indenture.

      This Supplemental Indenture constitutes an integral part of the
Indenture. In the event of inconsistencies between the Indenture and this
Supplemental Indenture, the terms hereof shall govern.

      Section 1.2  Definitions.

      All of the terms used in this Supplemental Indenture which are defined
in the Indenture shall have the meanings specified in the Indenture, unless
otherwise provided herein or unless the context otherwise requires, and for the
purposes of this Supplemental Indenture, the following terms have the meanings
set forth in this Section:

      "Comparable Treasury Issue" means the United States Treasury security
selected by the Reference Treasury Dealer as having a maturity comparable to the
remaining term of the Securities, that would be utilized, at the time of
selection and in accordance with customary

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financial practice, in pricing new issues of corporate debt securities of
comparable maturity to the remaining term of the Securities.

      "Comparable Treasury Price" means, with respect to any redemption date,
the Reference Treasury Dealer Quotations for that redemption date.

      "Consolidated Net Worth" means the consolidated net worth of the
Company, as determined in accordance with GAAP.

      "Debt" of any Person means, without duplication: (a) all indebtedness
of such Person for borrowed money; (b) all obligations of such Person for the
deferred purchase price of property or services (other than earn-out payment
obligations of such Person in connection with the purchase of property or
services to the extent they are still contingent); (c) all obligations of such
Person evidenced by notes, bonds, debentures or other similar instruments; (d)
all obligations of such Person created or arising under any conditional sale or
other title retention agreement with respect to property acquired by such Person
(even though the rights and remedies of the seller or lender under such
agreement in the event of default are limited to repossession or sale of such
property); (e) all obligations of such Person as lessee under leases to the
extent that such leases have been or should be, in accordance with GAAP,
recorded as capital leases; (f) all obligations, contingent or otherwise, of
such Person in respect of acceptances, letters of credit or similar extensions
of credit; (g) all obligations of such Person in respect of Hedge Agreements;
(h) all Debt of others referred to in clauses (a) through (g) above or clause
(i) below and other payment obligations guaranteed, directly or indirectly, in
any manner by such Person, or in effect guaranteed, directly or indirectly, by
such Person through an agreement (1) to pay or purchase such Debt or to advance
or supply funds for the payment or purchase of such Debt, (2) to purchase, sell
or lease (as lessee or lessor) property, or to purchase or sell services,
primarily for the purpose of enabling the debtor to make payment of such Debt or
to assure the holder of such Debt against loss, (3) to supply funds to or in any
other manner invest in the debtor (including any agreement to pay for property
or services irrespective of whether such property is received or such services
are rendered) or (4) otherwise to assure a creditor against loss; and (i) all
Debt referred to in clauses (a) through (h) above secured by (or for which the
holder of such Debt has an existing right, contingent or otherwise, to be
secured by) any Lien on property (including, without limitation, accounts and
contract rights) owned by such Person, even though such Person has not assumed
or become liable for the payment of such Debt.

      "GAAP" means generally accepted accounting principles set forth in the
opinions and pronouncements of the Accounting Principles Board of the American
Institute of Certified Public Accountants, the opinions and pronouncements of
the Public Company Accounting Oversight Board and in the statements and
pronouncements of the Financial Accounting Standards Board or in such other
statements by such other entity as have been approved by a significant segment
of the accounting profession, which are in effect from time to time.

      "Hedge Agreements" means interest rate swap, cap or collar agreements,
interest rate future or option contracts, currency swap agreements, currency
future or option contracts and other similar agreements.

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      "Lien" means any lien, security interest or other charge or encumbrance
of any kind, or any other type of preferential arrangement intended to provide
security for the payment or performance of an obligation, including, without
limitation, the lien or retained security title of a conditional vendor and any
easement, right of way or other encumbrance on title to real property.

      "Permitted Liens" means such of the following as to which no enforcement,
collection, execution, levy or foreclosure proceeding shall have been commenced:
(a) Liens for taxes, assessments and governmental charges or levies to the
extent not yet due and payable, or being contested in good faith by appropriate
proceedings; (b) Liens imposed by law, such as materialmen's, mechanics',
carriers', workmen's and repairmen's Liens and other similar Liens arising in
the ordinary course of business securing obligations that are not overdue for a
period of more than 30 days or that are being contested in good faith and by
appropriate proceedings that prevent the forfeiture or sale of the asset subject
to such Lien; (c) pledges or deposits to secure obligations under workers'
compensation laws or similar legislation or to secure public or statutory
obligations or, in any such case, to secure reimbursement obligations under
letters of credit or bonds issued to support such obligations; and (d)
easements, rights of way and other encumbrances on title to real property that
do not render title to the property encumbered thereby unmarketable or
materially adversely affect the use of such property for its present purposes.

      "Reference Treasury Dealer" means Citigroup Global Markets Inc. and any
two other primary U.S. Government securities dealer selected by the Issuers and
their respective successors.

      "Reference Treasury Dealer Quotations" means, with respect to the
Reference Treasury Dealer and any redemption date, the average, as determined by
the Trustee, of the bid and asked prices for the Comparable Treasury Issue
(expressed in each case as a percentage of its principal amount) quoted in
writing to the Trustee by the Reference Treasury Dealer at 3:30 p.m., New York
City time, on the third business day preceding that redemption date.

      "Remaining Scheduled Payments" means the remaining scheduled payments of
principal of and interest on the Securities that would be due after the related
redemption date but for that redemption. If that redemption date is not an
interest payment date with respect to the Securities, the amount of the next
succeeding scheduled interest payment on the Securities will be reduced by the
amount of interest accrued on the Securities to such redemption date. On and
after the redemption date, interest will cease to accrue on the Securities or
any portion of the Securities called for redemption (unless the Issuers default
in the payment of the redemption price and accrued interest). On or before the
redemption date, the Issuers will deposit with a paying agent (or the Trustee)
money sufficient to pay the redemption price of and accrued interest on the
Securities to be redeemed on that date. If less than all of the Securities are
to be redeemed, the Securities to be redeemed shall be selected by the Trustee
by a method the Trustee deems to be fair and appropriate.

      "Subsidiary" of any Person means any corporation, partnership, joint
venture, limited liability company, trust or estate of which (or in which) more
than 50% of: (a) the issued and outstanding voting stock of such Person; (b) the
interest in the capital or profits of such limited liability company,
partnership or joint venture; or (c) the beneficial interest in such trust or
estate

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is at the time, directly or indirectly, owned or controlled by such Person, by
such Person and one or more of its other subsidiaries or by one or more of such
Person's other subsidiaries.

      "Treasury Rate" means, with respect to any redemption date, the rate per
annum equal to the semiannual equivalent yield to maturity (computed as of the
third business day immediately preceding that redemption date) of the Comparable
Treasury Issue, assuming a price for the Comparable Treasury Issue (expressed as
a percentage of its principal amount) equal to the Comparable Treasury Price for
that redemption date.

                                   ARTICLE TWO
                                    THE NOTES

      Section 2.1.  Title of the Notes.

      The Notes shall have the following terms, established pursuant to
Section 2.2 of the Indenture:

      2.1.1. Pursuant to Section 2.2.1 of the Indenture, the title of the Notes
to be issued as a series of Securities under the Indenture shall be the "5.90%
Senior Notes due 2016";

      2.1.2. Pursuant to Section 2.2.2 of the Indenture, the price or prices at
which the Securities of the Series will be issued shall be 99.51% of the
aggregate principal amount thereof;

      2.1.3. Pursuant to Section 2.2.3 of the Indenture, the aggregate principal
amount of the Notes that may be authenticated and delivered under this
Supplemental Indenture shall be limited to $1,000,000,000;

      2.1.4. Pursuant to Section 2.2.4 of the Indenture, 100% of the Notes shall
be payable on April 15, 2016;

      2.1.5. Pursuant to Section 2.2.5 of the Indenture, the Notes shall bear
interest at a rate equal to 5.90% per annum; interest on the Notes shall accrue
from March 29, 2006 until the principal thereof is paid or duly provided for;
interest on the Notes shall be payable semi-annually in arrears in cash on April
15 and October 15 of each year to Holders of record on April 1 and October 1
(whether or not a Business Day) immediately preceding the applicable interest
payment date. Interest on the Notes shall be computed from and including the
prior interest payment date (or, in the case of the first interest payment date,
from and including March 29, 2006) to but excluding the next interest payment
date on the basis of a 360-day year consisting of twelve 30-day months. In the
event that any principal or interest on the Notes is not paid when due, whether
at Maturity or otherwise, then except to the extent permitted by law such
overdue principal and interest shall bear interest until paid at the rate of
interest set forth in Section 2.1.5 of this Supplemental Indenture, compounded
semi-annually;

      2.1.6. Pursuant to Section 2.2.6 of the Indenture, the place or places
where the principal of and interest in the Notes shall be payable shall be as
set forth in the Notes, the form of which is attached hereto as Exhibit A;

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      2.1.7. Pursuant to Section 2.2.7 of the Indenture, the Notes shall be
subject to redemption at the option of the Issuers as set forth in Section 3.1
of this Supplemental Indenture;

      2.1.8. Pursuant to Section 2.2.8 of the Indenture, the Issuers shall not
be obligated to redeem or purchase the Notes pursuant to any sinking fund or at
the option of a Holder thereof prior to the maturity;

      2.1.9. Pursuant to Section 2.2.9 of the Indenture, the Issuers shall not
be obligated to redeem or purchase the Notes pursuant to any repurchase
obligations or at the option of a Holder thereof prior to the maturity;

      2.1.10. Pursuant to Section 2.2.11 of the Indenture, the Securities shall
be issued as Global Securities; and 2.1.11.

      Pursuant to Section 2.2.15 of the Indenture, the covenant contained in
Section 4.7 of the Indenture shall be changed so that the Issuers shall instead
be subject the restrictions as set forth to Section 4.1 of this Supplemental
Indenture.

                                  ARTICLE THREE
                         ADDITIONAL REDEMPTION PROVISION

      Section 3.1.  Optional Redemption.

      The Securities will be redeemable, as a whole or in part, at the Issuers'
option, at any time or from time to time, upon mailed notice to the registered
address of each Holder of Securities at least 30 days but not more than 60 days
prior to the redemption. The redemption price will be equal to the greater of
(1) 100% of the principal amount of the Securities to be redeemed and (2) the
sum of the present values of the Remaining Scheduled Payments on the Securities
discounted to the date of redemption, on a semiannual basis (assuming a 360-day
year consisting of twelve 30-day months), at a rate equal to the sum of the
applicable Treasury Rate plus 25 basis points, plus accrued and unpaid interest
thereon to the redemption date.

                                  ARTICLE FOUR
                               LIMITATION ON LIENS

      Section 4.1.  Limitation on Liens.

      The Company will not, and will not permit any of its Subsidiaries to,
create or suffer to exist any Lien on or with respect to any of the Company's
properties, whether now owned or hereafter acquired, to secure any Debt of the
Company, any direct or indirect subsidiary or any other person, or to assign or
permit any of its Subsidiaries to assign, without securing the notes equally and
ratably with such Debt to which such Liens relate for so long as such debt shall
be so secured, other than:

            (a) Permitted Liens;

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            (b) purchase money Liens upon or in any real property or equipment
      acquired or held by the Company or any Subsidiary in the ordinary course
      of business to secure the purchase price of such property or equipment or
      to secure Debt incurred solely for the purpose of financing the
      acquisition of such property or equipment, or Liens existing on such
      property or equipment at the time of its acquisition (other than any such
      Liens created in contemplation of such acquisition that were not incurred
      to finance the acquisition of such property) or extensions, renewals or
      replacements of any of the foregoing for the same or a lesser amount,
      provided, however, that no such Lien shall extend to or cover any
      properties of any character other than the real property or equipment
      being acquired and fixed improvements thereon or accessions thereto, and
      no such extension, renewal or replacement shall extend to or cover any
      properties not theretofore subject to the Lien being extended, renewed or
      replaced;

            (c) Liens existing on March 24, 2006;

            (d) Liens on property of a Person existing at the time such Person
      is merged into, consolidated with, or acquired by the Company or any
      Subsidiary of the Company or becomes a Subsidiary of the Company; provided
      that such Liens were not created in contemplation of such merger,
      consolidation or acquisition and do not extend to any assets other than
      those of the Person so merged into or consolidated with the Company or
      such Subsidiary or acquired by the Company or such Subsidiary;

            (e) Liens granted by Subsidiaries of the Company (other than OFI and
      OCI) to secure Debt owed to the Company or a wholly owned Subsidiary of
      the Company;

            (f) Liens arising out of judgment, decree or order of court being
      contested in good faith by appropriate proceedings, provided that adequate
      reserves with respect thereto are maintained on the books of the Company
      or the books of its Subsidiaries, as the case may be, in conformity with
      GAAP;

            (g) Debt of a Person existing at the time such Person is merged into
      or consolidated with the Company or becomes a Subsidiary of the Company
      provided that such Debt was not created in contemplation of such merger,
      consolidation or acquisition and provided further that the aggregate
      principal amount of such Debt shall not exceed $50,000,000 at any time
      outstanding;

            (h) Liens to secure any extension, renewal, refinancing or refunding
      (or successive extensions, renewals, refinancings or refundings), in whole
      or in part, of any Debt secured by Liens referred to above or Liens
      created in connection with any amendment, consent or waiver relating to
      such Debt, so long as such Lien does not extend to any other property, the
      amount of Debt secured is not increased (other than by the amount equal to
      any costs and expenses incurred in connection with any extension, renewal,
      refinancing or refunding) and the Debt so secured does not exceed the fair
      market value (as determined by the Company's Board of Directors) of the
      assets subject to such Liens at the time of such extension, renewal,
      refinancing or refunding, or such amendment, consent or waiver, as the
      case may be; or

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            (i) Liens otherwise prohibited by this covenant, securing Debt,
      provided that the aggregate principal amount of such secured Debt shall
      not exceed 20% of the Consolidated Net Worth of the Company and its
      Subsidiaries at any time.

                                  ARTICLE FIVE
                                COMPANY GUARANTEE

      5. Company Guarantee.

      5.1. 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 Holder 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 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.

      5.2. 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 rescission, amendment or modification to any of the
      terms or provisions of the Securities or the Indenture;

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            (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 Holder
      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 Holder 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 Holder 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.

      5.3. 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,
in its capacity as guarantor, none of the Holders shall be under any obligation
to marshal 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.

      5.4. 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 Holder that in any manner impairs,
reduces, releases or otherwise adversely affects the subrogation, reimbursement,
exoneration, contribution or indemnification rights of the

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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.

      5.5. 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, OFI 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 Holder or the Trustee to any security held
for payment of the Guaranteed Obligations.

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

      5.7. The Company's obligations under its Guarantee shall not be affected
if any Holder 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 Holder, 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.

      5.8. 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 Holder 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
Holder; 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

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the case may be). The Company further agrees that, in its capacity as guarantor,
as between the Company, on the one hand, and the Holders 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 5, 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.

      5.9. Except as otherwise specifically provided in Section 5.12 of this
Supplemental Indenture 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 Holders 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.

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

      5.11. The Company shall pay all reasonable costs and expenses (including
reasonable attorneys' fees and expenses) paid or incurred by the Trustee or any
Holder in connection with the enforcement of the Guarantee or any other rights
of the Trustee or such Holder under this Supplemental Indenture with respect to
such Guarantee and the prosecution or defense of any action by or against any of
the Holders 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 Holder
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).

      5.12. 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 Holder. 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 5.12. Any actions taken pursuant to this Section
5.12 shall not release the Company, OCI or OFI as a primary obligor under the
Indenture or the Securities.

                                   ARTICLE SIX
                              LIABILITY OF TRUSTEE

                                       10
<PAGE>

      Section 6.1  Trustee Not Responsible for Recitals.

      The Trustee shall not be responsible in any matter whatsoever for or in
respect of the validity or sufficiency of this First Supplemental Indenture or
for or in respect of the recitals contained herein, all of which are made solely
by the Issuers.

                                  ARTICLE SEVEN
                                  MISCELLANEOUS

      Section 7.1. Ratification and Effect.

      Except as hereby expressly amended, the Indenture is in all respects
ratified and confirmed and all the terms, provisions and conditions thereof
shall be and remain in full force and effect.

      Upon and after the execution of this Supplemental Indenture, each
reference in the Indenture to "this Indenture," "hereunder," "hereof" or words
of like import referring to the Indenture shall mean and be a reference to the
Indenture as modified hereby.

      Section 7.2  Governing Law.

      THIS INDENTURE AND THE SECURITIES SHALL BE GOVERNED BY THE LAWS OF THE
STATE OF NEW YORK APPLICABLE TO AGREEMENTS MADE AND TO BE PERFORMED IN SUCH
STATE, WITHOUT REGARD TO THE CONFLICT OF LAWS PROVISIONS THEREOF.

      Section 7.3  Counterpart Originals.

      This Indenture may be executed in any number of counterparts and by the
parties hereto in separate counterparts, each of which when so executed shall be
deemed to be an original and all of which taken together shall constitute one
and the same agreement.

      Section 7.4  Effect of Headings.

      The Table of Contents, the Cross-Reference Table, and headings of the
Articles and Sections of this Indenture have been inserted for convenience of
reference only, are not to be considered a part hereof, and shall in no way
modify or restrict any of the terms or provisions hereof.

      Section 7.5.      Severability.

      In case any provision in this Supplemental Indenture or in the Securities
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.

                                       11
<PAGE>

      Section 7.6.      Modification, Amendment and Waiver.

      The provisions of this Supplemental Indenture may not be amended,
supplemented, modified or waived except by an execution of a Supplemental
Indenture executed by OCI, OFI, the Company and the Trustee. Any such amendment
shall comply with Article 9 of the Indenture. Until an amendment, waiver or
other action by Holders becomes effective, a consent thereto by a Holder of a
Security hereunder is a continuing consent by the Holder and every subsequent
Holder of that Security or portion of the Security that evidences the same
obligation as the consenting Holder's Security, even if notation of the consent,
waiver or action is not made on the Security. However, any such Holder or
subsequent Holder may revoke the consent, waiver or action as to such Holder'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
Holder.

      Section 7.7. 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. 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.

      Section 7.8.  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 (the
"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.

                         (Signatures on following page)

                                       12
<PAGE>

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

                                          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/ Eric Huttner
                                             -----------------------------------
                                             Name: Eric Huttner
                                             Title: Executive Vice President

                                          OMNICOM FINANCE INC.

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

                                          JPMORGAN CHASE BANK, N.A., as
                                            Trustee

                                          By: /s/ Carol Ng
                                             -----------------------------------
                                             Name: Carol Ng
                                             Title: Vice President

First Supplemental IndentureExhibit 4.3

                                 [Form of Note]

UNLESS THIS  CERTIFICATE  IS PRESENTED BY AN  AUTHORIZED  REPRESENTATIVE  OF THE
DEPOSITORY  TRUST  COMPANY  TO THE  COMPANY  OR ITS  AGENT FOR  REGISTRATION  OF
TRANSFER,  EXCHANGE OR PAYMENT,  AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO. OR TO SUCH  OTHER  ENTITY AS IS  REQUESTED  BY AN  AUTHORIZED
REPRESENTATIVE  OF THE DEPOSITORY  TRUST COMPANY (AND ANY PAYMENT HEREON IS MADE
TO CEDE & CO.), ANY TRANSFER,  PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE
BY OR TO ANY PERSON IS WRONGFUL SINCE THE REGISTERED  OWNER HEREOF,  CEDE & CO.,
HAS AN INTEREST HEREIN.

TRANSFERS OF THIS GLOBAL NOTE SHALL BE LIMITED TO TRANSFERS, IN WHOLE BUT NOT IN
PART, TO NOMINEES OF THE DEPOSITORY  TRUST COMPANY OR TO A SUCCESSOR  THEREOF OR
SUCH SUCCESSOR'S  NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL NOTE SHALL BE
LIMITED TO  TRANSFERS  MADE IN  ACCORDANCE  WITH THE  RESTRICTIONS  SET FORTH IN
ARTICLE 2 OF THE  SUPPLEMENTAL  INDENTURE AND THE  INDENTURE  REFERRED TO ON THE
REVERSE HEREOF.

<PAGE>

                       Form of 5.90% Senior Notes due 2016

CUSIP No. 681919 AS 5
$500,000,000

      OMNICOM  GROUP INC.,  a New York  corporation,  OMNICOM  CAPITAL  INC.,  a
Connecticut  corporation and OMNICOM FINANCE INC. a Delaware corporation (herein
collectively  referred to as the  "Issuers",  which term  includes any successor
person to any of them under the  Indenture  hereinafter  referred to), for value
received,  hereby  promises to pay to CEDE & CO.,  or  registered  assigns,  the
principal  sum of  $500,000,000  Dollars on April 15,  2016 and to pay  interest
thereon  from March 29, 2006 or from the most recent  interest  payment  date to
which interest has been paid or duly provided for, semi-annually on April 15 and
October 15 in each year , commencing  October 15, 2006, at the rate of 5.90% per
annum,  set forth below.  The interest so payable,  and punctually  paid or duly
provided for, on any interest  payment date will, as provided in such Indenture,
be paid to the person in whose name this  Security  (or one or more  Predecessor
Securities)  is registered  at the close of business on the regular  record date
for such  interest,  which  shall be the April 1 or October 1 (whether  or not a
Business Day), as the case may be, next  preceding  such interest  payment date.
Any such  interest not so punctually  paid or duly  provided for will  forthwith
cease to be payable to the Holder on such regular  record date and may either be
paid to the  person in whose  name  this  Security  (or one or more  Predecessor
Securities)  is registered at the close of business on a special record date for
the  payment  of such  defaulted  interest  to be fixed by the  Trustee,  notice
whereof  shall be given to Holders of Securities of this Series not less than 10
days  prior to such  special  record  date,  or be paid at any time in any other
lawful manner not inconsistent with the requirements of any securities  exchange
on which the  Securities  of this Series may be listed,  and upon such notice as
may be required by such exchange, all as more fully provided in said Indenture).

      Payment of the  principal  of (and  premium,  if any) and interest on this
Security will be made at the office or agency of the Issuers maintained for that
purpose in The City of New York,  New York, in accordance  with the terms of the
Indenture  referred  to or the  reverse  hereof in such coin or  currency of the
United  States of America as at the time of payment is legal  tender for payment
of public  and  private  debts;  provided,  however,  that at the  option of the
Issuers  payment of interest  may be made by check  mailed to the address of the
person entitled thereto as such address shall appear in the Security register).

      Reference is hereby made to the further  provisions  of this  Security set
forth on the reverse  hereof,  which further  provisions  shall for all purposes
have the same effect as if set forth at this place.

      This Security  shall be deemed to be a contract made under the laws of the
State of New York,  and for all purposes  shall be construed in accordance  with
and governed by the laws of said state.

<PAGE>

      Unless the certificate of  authentication  hereon has been executed by the
Trustee  referred to on the reverse  hereof by manual  signature,  this Security
shall  not be  entitled  to any  benefit  under  the  Indenture  or be  valid or
obligatory for any purpose.

<PAGE>

      IN WITNESS  WHEREOF,  the Issuers have caused this  instrument  to be duly
executed.

Dated:                                     OMNICOM GROUP INC.

                                           By___________________________________

                                           By___________________________________

                                           OMNICOM CAPITAL INC.

                                           By___________________________________

                                           By___________________________________

                                           OMNICOM FINANCE INC.

                                           By___________________________________

                                           By___________________________________

<PAGE>

                Form of Trustee's Certificate of Authentication.

      The Trustee's  certificate of authentication shall be in substantially the
following form:

      This is one of the Securities of the Series designated therein referred to
in the within-mentioned Indenture.

                                                       JPMorgan Chase Bank, N.A.
                                                                      As Trustee

                                            By _________________________________
                                                              Authorized Officer

<PAGE>

                              Reverse of Security.

                               OMNICOM GROUP INC.
                              OMNICOM CAPITAL INC.
                              OMNICOM FINANCE INC.

                           5.90% Senior Notes due 2016

      This  Security  is one of a duly  authorized  issue of  securities  of the
Issuers,  designated  as their 5.90% Senior  Notes due 2016  (herein  called the
"Securities"), issued and to be issued in one or more Series under an Indenture,
dated as of March 29, 2006 (herein called the "Indenture"),  between the Issuers
and JPMorgan Chase Bank,  N.A., as Trustee  (herein called the "Trustee",  which
term includes any successor trustee under the Indenture), to which Indenture and
all indentures  supplemental thereto reference is hereby made for a statement of
the respective rights,  limitations of rights,  duties and immunities thereunder
of the Issuers,  the Trustee and the Holders of the  Securities and of the terms
upon which the Securities are, and are to be, authenticated and delivered.  This
Security  is  one of the  series  designated  on the  face  hereof,  limited  in
aggregate  principal amount to  $1,000,000,000.  Capitalized  terms used in this
Security  and not  defined  herein  have the  meaning  ascribed  thereto  in the
Indenture.

      JPMorgan  Chase Bank,  N.A.,  the  Trustee  under the  Indenture  has been
appointed by the Issuers as paying agent,  Securities registrar,  with regard to
the Securities.

      In case an Event of Default  shall have  occurred and be  continuing,  the
principal of and accrued  interest on all Securities  may be declared,  and upon
said declaration,  shall become due and payable,  in the manner, with the effect
and subject to the conditions provided for in the Indenture.

      The Securities will be redeemable,  as a whole or in part, at the Issuers'
option,  at any time or from time to time,  upon mailed notice to the registered
address of each Holder of  Securities at least 30 days but not more than 60 days
prior to the  redemption.  The redemption  price will be equal to the greater of
(1) 100% of the  principal  amount of the  Securities to be redeemed and (2) the
sum of the present values of the Remaining  Scheduled Payments on the Securities
discounted to the date of redemption,  on a semiannual basis (assuming a 360-day
year  consisting  of twelve  30-day  months),  at a rate equal to the sum of the
applicable  Treasury Rate plus 25 basis points, plus accrued and unpaid interest
thereon to the redemption date.

      "Comparable  Treasury  Issue" means the United  States  Treasury  security
selected by the Reference Treasury Dealer as having a maturity comparable to the
remaining  term of the  Securities,  that  would  be  utilized,  at the  time of
selection and in accordance with customary  financial  practice,  in pricing new
issues of corporate debt securities of comparable maturity to the remaining term
of the Securities.

      "Comparable  Treasury Price" means,  with respect to any redemption  date,
the Reference Treasury Dealer Quotations for that redemption date.

      "Reference  Treasury  Dealer" means Citigroup  Global Markets Inc. and any
two other primary U.S. Government  securities dealer selected by the Issuers and
their respective successors.

                                      A-5
<PAGE>

      "Reference   Treasury  Dealer  Quotations"  means,  with  respect  to  the
Reference Treasury Dealer and any redemption date, the average, as determined by
the  Trustee,  of the bid and asked  prices for the  Comparable  Treasury  Issue
(expressed  in each case as a  percentage  of its  principal  amount)  quoted in
writing to the Trustee by the Reference  Treasury  Dealer at 3:30 p.m., New York
City time, on the third business day preceding that redemption date.

      "Remaining  Scheduled  Payments" means the remaining scheduled payments of
principal of and interest on the Securities  that would be due after the related
redemption  date  but for that  redemption.  If that  redemption  date is not an
interest  payment  date with respect to the  Securities,  the amount of the next
succeeding  scheduled  interest payment on the Securities will be reduced by the
amount of interest  accrued on the  Securities to such  redemption  date. On and
after the  redemption  date,  interest will cease to accrue on the Securities or
any portion of the Securities called for redemption  (unless the Issuers default
in the payment of the redemption price and accrued  interest).  On or before the
redemption  date,  the Issuers will deposit with a paying agent (or the Trustee)
money  sufficient  to pay the  redemption  price of and accrued  interest on the
Securities to be redeemed on that date. If less than all of the  Securities  are
to be redeemed,  the  Securities to be redeemed shall be selected by the Trustee
by a method the Trustee deems to be fair and appropriate.

      "Treasury Rate" means,  with respect to any redemption  date, the rate per
annum equal to the semiannual  equivalent yield to maturity  (computed as of the
third business day immediately preceding that redemption date) of the Comparable
Treasury Issue, assuming a price for the Comparable Treasury Issue (expressed as
a percentage of its principal amount) equal to the Comparable Treasury Price for
that redemption date.

      In the event of  redemption  of this Security in part only, a new Security
or Securities of this Series and of like tenor for the unredeemed portion hereof
will be issued in the name of the Holder hereof upon the cancellation hereof.

      The Indenture contains  provisions that permit the Issuers to elect either
(1) to defease and be discharged  from the entire  indebtedness of this Security
or (2) to be released from their obligations under certain restrictive covenants
and Events of Default with respect to this  Security,  in each case upon payment
in full of the Securities and  compliance  with certain  conditions set forth in
the Indenture.

      If an Event of Default  with  respect to  Securities  of this Series shall
occur and be  continuing,  the principal of the Securities of this Series may be
declared  due and  payable in the manner  and with the  effect  provided  in the
Indenture.

      The Indenture  permits the amendment  thereof and the  modification of the
rights and  obligations  of the  Issuers  and the  rights of the  Holders of the
Securities of each Series to be affected  under the Indenture at any time by the
Issuers  and the  Trustee  with the  consent of the  Holders  of a  majority  in
principal  amount of the Securities at the time outstanding of each Series to be
affected,  with certain  exceptions as therein  provided with respect to certain
modifications  or  amendments  which may not be made without the consent of each
Holder of such Security  affected  thereby.  The Indenture also permits  certain
amendments  and  modifications  thereto from time to

                                      A-6
<PAGE>

time by the Issuers  and the  Trustee  without the consent of the Holders of any
Series of the Securities to be affected thereby for certain specified  purposes,
including curing  ambiguities,  defects or  inconsistencies  and making any such
change that does not adversely affect the rights of any Holder of such series of
the Securities, as provided therein.

      The  Indenture  contains  provisions  permitting  the Holders of specified
percentages  in principal  amount of the  Securities  of each Series at the time
outstanding, on behalf of the Holders of all Securities of such Series, to waive
compliance  by the Issuers with certain  provisions of the Indenture and certain
past defaults  under the Indenture and their  consequences.  Any such consent or
waiver by the Holder of this Security  shall be conclusive and binding upon such
Holder and upon all future  Holders of this Security and of any Security  issued
upon the  registration  of  transfer  hereof  or in  exchange  hereof or in lieu
hereof,  whether  or not  notation  of such  consent or waiver is made upon this
Security.

      No reference  herein to the Indenture and no provision of this Security or
of the Indenture  shall alter or impair the obligation of the Issuers,  which is
absolute and unconditional, to pay the principal of and any premium and Interest
on this  Security  at the times,  place and rate,  and in the coin or  currency,
herein prescribed.

      As provided in the  Indenture and subject to certain  limitations  therein
set  forth,  the  transfer  of this  Security  is  registrable  in the  security
register,  upon surrender of this Security for  registration  of transfer at the
office or agency of the  Issuers  in any place  where the  principal  of and any
premium  and  interest  on this  Security  are  payable,  duly  endorsed  by, or
accompanied  by a written  instrument  of transfer in form  satisfactory  to the
Issuers and the security  Registrar  duly  executed by, the Holder hereof or his
attorney duly authorized in writing, and thereupon one or more new Securities of
this  Series and of like tenor,  of  authorized  denominations  and for the same
aggregate  principal  amount,  will be issued to the  designated  transferee  or
transferees.

      The Securities of this Series are issuable only in registered form without
coupons  in  denominations  of $1,000  and any  integral  multiple  thereof.  As
provided in the Indenture and subject to certain  limitations therein set forth,
Securities of this Series are exchangeable for a like aggregate principal amount
of  Securities  of this  series  and of like  tenor  of a  different  authorized
denomination, as requested by the Holder surrendering the same.

      No service charge shall be made for any such  registration  of transfer or
exchange,  but the Issuers may require  payment of a sum sufficient to cover any
tax or other governmental charge payable in connection therewith.

      Prior to due  presentment of this Security for  registration  of transfer,
the  Issuers,  the Trustee and any agent of the Issuers or the Trustee may treat
the person in whose name this Security is registered as the owner hereof for all
purposes,  whether or not this Security is overdue, and neither the Issuers, the
Trustee nor any such agent shall be affected by notice to the contrary.

      No recourse shall be had for the payment of the principal of (and premium,
if any) or  interest  on  this  Security,  or for any  claim  based  hereon,  or
otherwise in respect  hereof,  or based on or in respect of the Indenture or any
indenture supplemental thereto, against any incorporator,  stockholder,  officer
or  director,  as such,  past,  present  or  future,  of the  Issuers  or of any
successor

                                      A-7
<PAGE>

corporation,  whether by virtue of any constitution,  statute or rule of law, or
by the enforcement of any assessment or penalty or otherwise, all such liability
being, by the acceptance  hereof and as part of the  consideration for the issue
hereof, expressly waived and released.

      All terms used in this Security  which are defined in the Indenture  shall
have the meanings assigned to them in the Indenture.

                                      A-8

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