Document ID: ./input/supremecourt_opinions/opinions/17pdf/16-1454_5h26.pdf
Page Number: 41

Cite as:  585 U. S. ____ (2018) 

17 

BREYER, J., dissenting 

the  relevant  question.  The  relevant  question  is  whether
merchant-related  and  shopper-related  services  are substi-
tutes, one for the other, so that customers can respond to a 
price  increase  for  one  service  by  switching  to  the  other 
service.  As I have explained, the two types of services are 
not substitutes in this way.  Supra, at 11–12.  And so the 
question  remains,  just  as  before:  What  is  it  about  the 
economic  relationship  between  merchant-related  and 
shopper-related  services  that  would  justify  the  majority’s
novel approach to market definition?

What  about  the  last  two  features—that  the  company 
connects  the  two  groups  of  customers  to  each  other,  in
simultaneous  transactions?  That,  too,  is  commonplace.
Consider  a  farmers’  market.    It  brings  local  farmers  and
local shoppers together, and transactions will occur only if
a farmer and a shopper simultaneously agree to engage in 
one.  Should courts abandon their ordinary step 1 inquiry
if several competing farmers’ markets in a city agree that
only certain kinds of farmers can participate, or if a farm­
ers’  market  charges  a  higher  fee  than  its  competitors  do
and  prohibits  participating  farmers  from  raising  their
prices to cover it?  Why?  If farmers’ markets are special, 
what  about  travel  agents  that  connect  airlines  and  pas­
sengers?  What  about  internet  retailers,  who,  in  addition 
to  selling  their  own  goods,  allow  (for  a  fee)  other  goods-
producers to sell over their networks?  Each of those busi­
nesses seems to meet the majority’s four-prong definition. 

Apparently  as  its  justification  for  applying  a  special 

market-definition  rule  to  “two-sided  transaction  plat­
forms,”  the  majority  explains  that  such  platforms  “often 
exhibit” what it calls “indirect network effects.”  Ante, at 3. 
By this, the majority means that sales of merchant-related 
card services and (different) shopper-related card services 
are  interconnected,  in  that  increased  merchant-buyers 
mean  increased  shopper-buyers  (the  more  stores  in  the
card’s network, the more customers likely to use the card),