Facebook Wants Your Banking Data

The social network’s negotiating stance with institutions evolved

Facebook Inc. had been haggling with financial firms over its access to users’ sensitive financial information for years, well before the social-media company came under fire for its handling of personal data.

As recently as last year, the social-media company pressed financial firms for the ability to use customer data flowing through its Messenger platform for a range of purposes, including advertising, according to people familiar with the matter and documents reviewed by The Wall Street Journal. Concerned about privacy,...