What is FINRA?

FINRA is the self-regulatory organisation that watches over US broker-dealers and investment advisers. Finding it listed next to an account tells you that a federal regulator and a membership body stand behind the firm.

Betterment is registered with FINRA through its broker-dealer arm, alongside the SEC and SIPC, and Cash App Cash Card lists FINRA and SIPC. Ally Bank names SEC, FINRA and FDIC and publishes the FINRA licence number 136131, which you can search in the regulator's own records.