EIRF is the acronym for "Electronic Interchange Reimbursement Fee."  It was the first interchange fee developed by Visa.  Most electronic transactions should be charged at the interchange level of the merchant based upon card brand, card type, industry type and processing method.  EIRF is now a "down grade" in interchange level because the merchant did not perform specific functions when processing the transaction (i.e., CVV verification; address verification; invoice number; delayed deposit; etc.).  It can cause an increase of as much as 79 basis points (0.79%) on a single transaction.