Merchant accepts ₦10,000 from a Visa card. They receive ₦9,725. Where did the ₦275 go? Five buckets: INTERCHANGE (paid to the card's issuer, set by scheme, typically 1.5-2.0%), SCHEME FEE (paid to Visa/Mastercard/Verve, ~0.13-0.20%), ACQUIRER PROCESSING FEE (your processor's per-transaction cost), MDR MARKUP (what your acquirer keeps on top), and sometimes a separate PAYMENT FACILITATOR FEE (Stripe / Paystack's take). This lesson breaks down the entry on the acquirer side so every basis point is named and booked to its own GL account. Without this discipline you cannot reconcile to your scheme statement and you cannot prove your MDR pricing to a sponsor bank.