Visa’s processing network is called the VisaNET Integrated Payment System (VIP). VIP is comprised of a number of different components including an authorization system, called Base I, and a settlement system, called Base II.
Visa charges financial institutions a small transaction fee each time they access the VIP to authorize or settle a transaction. An acquirer processing fee is charged each time an authorization request is submitted to the VIP Base I system, and a settlement network access fee is charged each time a settlement request is submitted to the VIP Base II system.
Visa does not charge merchants directly to access the VIP, but financial institutions pass Visa’s charges to merchants along with processing fees.
The fee of $0.0018 charged for settlement requests is referred to as a settlement network access fee or a Base II fee.