This article originally appeared on informed-merchant.com, a blog started by one of our founders, Sean, before he started FeeFighters.

Here is a list of the largest merchant acquirers in the U.S.  as estimated by the Nilson Report.  In this context the definition of Acquirer is a little bit strained, because it includes ISOs and processors at multiple levels of the value chain.  For example, EVO Merchant Services (#14) is known to be an ISO that sells processing provided by Global Payments Inc (#5).  I am not sure what methodology Nilson used to make these estimates, they are probably directionally correct, but there is a chance that some double-counting is involved.

Rank	Company	Volume ($B)
1	First Data and Alliances(1)	842
2	Bank of America	273
3	NOVA (US Bank) and Key Merchant Services(2)	138
4	Fifth Third Bank	115
5	Global Payments	56
6	Heartland Payment Systems	34
7	First National Merchant Solutions	34
8	iPayment	26
9	TransFirst	22
10	First Horizon Merchant Services	19
11	RBS Lynk	19
12	Alliance Data	12
13	Moneris Solutions	12
14	EVO Merchant Services	10
15	Verus Financial Management	8
16	Merchant E-Solutions	8
17	Innovative Merchant Solutions	8
18	Retriever Payment Systems	7
19	Branch Banking and Trust	7
20	First American Payment Systems	7

(1) First Data alliances include Chase Paymentech, Wells Fargo, SunTrust, PNC Merchant Services and CardService International

(2) NOVA owns part of Key Merchant Services

Source: Nilson Report