NEW YORK (AP) — Visa is purchasing the financial technology company Plaid for $5.3 billion, a major push by the payment processing giant into other types of money transfer systems outside of Visa's traditional credit and debit card business.

Plaid allows consumers to link their bank accounts to financial services apps like Venmo, PayPal, Betterment and Transferwise. The company is an important but unknown middle man between the banks, who hold consumers's cash, and the dozens of platforms who vie to be the platform of choice to send that cash. Bankers refer to companies like Plaid as "the plum...