Visa takes zero from interchange but charges volume based service fees in the single-digit basis points (each) to the acquirer and issuer. Visa makes additional yield from cross-border payments and grosses up revenue from value-added services such as issuer or merchant processing (e.g Cybersource) and from other value add services like risk/fraud tools, consulting etc. Source: 12 years at Visa. Around 20something bps yield on volume averaged-out is correct math.