Document ID: ./input/supremecourt_opinions/opinions/17pdf/16-1454_5h26.pdf
Page Number: 18

14 

OHIO v. AMERICAN EXPRESS CO. 

Opinion of the Court 

Evaluating  both  sides  of  a  two-sided  transaction  plat-
form  is  also  necessary  to  accurately  assess  competition. 
Only  other  two-sided  platforms  can  compete  with  a  two-
sided  platform  for  transactions.  See  Filistrucchi  301.  A 
credit-card  company  that  processed  transactions  for  mer-
chants, but that had no cardholders willing to use its card, 
could not compete with Amex.  See ibid.  Only a company
that had both cardholders and merchants willing to use its
network could sell transactions and compete in the credit-
card  market.    Similarly,  if  a  merchant  accepts  the  four 
major  credit  cards,  but  a  cardholder  only  uses  Visa  or 
Amex, only those two cards can compete for the particular
transaction.  Thus,  competition  cannot  be  accurately
assessed  by  looking  at  only  one  side  of  the  platform  in 
isolation.9 

For  all  these  reasons,  “[i]n  two-sided  transaction  mar-
kets, only one market should be defined.”  Id., at 302; see 
also  Evans  &  Noel  671  (“[F]ocusing  on  one  dimension  of 
. . . competition tends to distort the competition that actu-
ally  exists  among  [two-sided  platforms]”).    Any  other
analysis  would  lead  to  “ ‘ “mistaken  inferences” ’ ”  of  the 
kind that could “ ‘ “chill the very conduct the antitrust laws 
are designed to protect.” ’ ”  Brooke Group Ltd. v. Brown & 
Williamson  Tobacco  Corp.,  509  U. S.  209,  226  (1993);  see 
also Matsushita Elec. Industrial Co. v. Zenith Radio Corp., 

—————— 

tary  products,  in  which  both  products  are  bought  by  the  same  buyers,
who,  in  their  buying  decisions,  can  therefore  be  expected  to  take  into
account both prices”).  As already explained, credit-card companies are 
best understood as supplying only one product—transactions—which is 
jointly  consumed  by  a  cardholder  and  a  merchant.    See  Klein  580. 
Merchant services and cardholder services are both inputs to this single 
product.  See ibid. 

9 Nontransaction  platforms,  by  contrast,  often  do  compete  with  com-
panies that do not operate on both sides of their platform.  A newspaper
that  sells  advertising,  for  example,  might  have  to  compete  with  a 
television  network,  even  though  the  two  do  not  meaningfully  compete
for viewers.  See Filistrucchi 301.