Base II

Base II is a data processing system operated by Visa USA for the clearing and settlement of bank card transactions between card-honoring financial institutions and card issuers. It is part of Visa's processing network, called VisaNET Integrated Payment System (VIP), together with its transaction authorization system, Base I.

Base II was created along with the Base I standard in 1976 by Bank of America's IT staff. BASE stands for Bank of America System Engineering, because prior to 1973, Visa was known as BankAmericard.

Visa charges financial institutions a transaction fee each time they access the VIP to authorize or settle a transaction. Additionally, 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 is submitted to the VIP Base II system.

Visa does not charge merchants to access the VIP, but financial institutions pass on Visa's charges and processing fees to them. The fee charged for settlement requests is referred to as a settlement network access fee or Base II fee.