The Hidden Code in Your Wallet: Visa's '4' Unlocks Global Riches!

The '4' Secret Decoded

In a recent discussion, Visa's India & South Asia Group Country Manager T Rabi Sankar demystified credit card anatomy, noting the first digit—called the Major Industry Identifier (MII)—defines the card network. Visa secured '4' during 1970s standardization, distinguishing it from Mastercard ('5'), Amex ('3'), and Discover ('6').​

This prefix, part of the Bank Identification Number (BIN/IIN—first 6 digits), routes transactions efficiently across 200+ countries, supports fraud detection via Luhn algorithm, and powers rewards. Visa's 16-digit format (4 + BIN + account + check digit) ensures universal compatibility.​

Key Highlights

MII Magic: '4' = Airlines/Financial (Visa); contrasts '5' (Mastercard), '3' (Amex).​

BIN Power: First 6 digits pinpoint issuer (e.g., 4400 = Visa debit/credit).​

Global Glue: Enables instant network recognition for secure, fast payments.​

Security Layer: Luhn check validates numbers before authorization.​

Sources: KNIru, Wikipedia, Privacy.com, Lloyds Bank.