Visa is buying Plaid in a deal worth $5.3 billion — roughly double the start-up's last private valuation.
Plaid's API software lets start-ups connect to users' bank accounts and works with Venmo, mobile investing app Robinhood and cryptocurrency exchanges Coinbase and Gemini.
Plaid says 25% of people in the United States with bank accounts have connected to the fintech company through an app. Visa and rival Mastercard were early investors in the start-up, along with the venture arms of Goldman Sachs, Citi and American Express.