

              [Letterhead of McDonald & Company Securities. Inc.]



As of August 3, 1995

PERSONAL & CONFIDENTIAL

Board of Directors
Ross Roy Communications, Inc.
100 Bloomfield Hills Parkway
Bloomfield Hills, Michigan 48304

Ladies and Gentlemen:

   
You have  requested  our opinion as to the fairness,  from a financial  point of
view as of the date hereof,  to the holders of the outstanding  shares of common
stock,  par value $1.00 per share of Ross Roy  Communications,  Inc., a Michigan
corporation  ("Ross Roy" or the "Company"),  of the  consideration to be paid by
Omnicom Group, Inc., a New York corporation ("Omnicom"),  to the holders of Ross
Roy common stock in connection  with the proposed  merger (the "Merger") of Ross
Roy with and into  Omnicom  pursuant to the  Agreement  and Plan of Merger dated
June 15, 1995 between Ross Roy and Omnicom (the "Agreement").

You have advised us that under the terms of the Agreement,  upon consummation of
the Merger (the "Closing"),  the issued and outstanding aggregate shares of Ross
Roy common stock will be converted into the equivalent of $52 million of Omnicom
common stock (as described in the  Agreement),  subject to adjustment in certain
events as provided in the Agreement (the "Conversion Price").
    

McDonald & Company Securities,  Inc., as part of its investment banking business
is  customarily  engaged in the  valuation of business and their  securities  in
connection with mergers and acquisitions, negotiated underwritings,  competitive
biddings,  secondary  distributions of listed and unlisted  securities,  private
placements and valuations for estate, corporate and other purposes.

In connection with rendering this opinion, we have reviewed and analyzed,  among
other  things,  the  following:  (i) the  Agreement,  including the exhibits and
schedules thereto;  (ii) certain information  concerning the Company,  including
its audited financial statements for fiscal years ending December 31, 1992, 1993
and 1994;  (iii)  certain other  internal  information,  primarily  financial in
nature  concerning the business and operations of the Company furnished to us by

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the Company for  purposes  of our  analysis;  (iv)  certain  publicly  available
information  regarding  Omnicom,  including  the  Annual  Report on Form 10-K of
Omnicom,  for the year ended December 31, 1994 and the Quarterly  Report on Form
10-Q of Omnicom  for the  quarter  ended March 31,  1995;  (v) certain  publicly
available information with respect to certain other companies that we believe to
be comparable  to the Company or to Omnicom and the trading  markets for certain
of such  other  companies'  securities;  and  (vi)  certain  publicly  available
information  concerning the nature and terms of certain other  transactions that
we consider relevant to our inquiry.  We have also met with certain officers and
employees of the Company to discuss the business and prospects of the Company as
well as other matters that we believe to be relevant to our inquiry.

In our review and  analysis  and in arriving at our opinion we have  assumed and
relied upon the accuracy and  completeness  of all of the financial  information
and other  information  provided us or publicly  available  and have assumed and
relied  upon the  representations  and  warranties  of the  Company  and Omnicom
contained  in the  Agreement.  We  have  not  been  engaged  to,  and  have  not
independently  attempted  to, verify any such  information.  We have also relied
upon the  management  of the Company and  Omnicom as to the  reasonableness  and
acheivability  of the financial and operating  projections  (and the assumptions
and bases  therefor)  associated  with the Merger  provided to us and, with your
consent,  we have  assumed  that such  projections,  reflect the best  currently
available  estimates and judgments of management.  We express no view as to such
projections or the assumptions on which they are based. In addition, we have not
conducted a physical inspection or appraisal of any of the assets, properties or
facilities of either the Company or Omnicom nor have we been  furnished with any
such  evaluation or appraisal.  We have also assumed that the  conditions to the
Merger as set forth in the Agreement  would be  consummated on a timely basis in
the manner contemplated by the Agreement.

It should be noted that this opinion is based on economic and market  conditions
and other  circumstances  existing on, and information made available as of, the
date hereof and does not address any matters subsequent to such date,  including
the value of the Omnicom  Common  Stock at the time of  issuance  thereof to the
holders of the  Company's  common  stock.  In  addition,  our opinion is, in any
event,  limited to the fairness,  from a financial point of view, as of the date
hereof,  of the Conversion  Price to be received by the holders of the Company's
common  stock  pursuant  to the  Merger  and  does  not  address  the  Company's
underlying  business  decision to effect the  Merger,  or any other terms of the
Merger (including,  without  limitation,  the covenants and agreements set forth
in, or contemplated  by, the Agreement and the related  effects,  if any, on the
value of the Conversion  Price to be received in connection with the Merger,  as
to which we express no opinion).

We have acted as financial  advisor to the Company in connection with the Merger
and will receive from the Company a fee for our services upon  completion of the
Merger, and the Company has agreed to indemnify us under certain circumstances.
       

   
Our opinion is  directed to the Board of  Directors  and does not  constitute  a
recommendation  to any  shareholder  of the  Company as to how such  shareholder
should vote at the shareholders' meeting held in connection with the Merger.
    


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Based upon and  subject to the  foregoing  in such other  matters as we consider
relevant,  it is our opinion that as of the date hereof, the Conversion Price to
be received by the holders of the Company common stock is fair to the holders of
the Company common stock, from a financial point of view.

Very truly yours,




McDONALD & COMPANY SECURITIES, INC.
