[j4ustin]

They connect to your account using a service like Yodlee, Intuit Aggcat, or Plaid.io. So all they really have access to are your transactions. (I worked with these API's for over 1 year, and can spot that sign up flow a mile away)

They then pull in the transactions for you to round up manually (through a simple select process), and if you choose to round up, they ACH that amount of money over.

Makes sense for people who are not used to saving money or budgeting for financial services.

[kolev]

I understand how they do it and I doubt they will reinvent the wheel (at least I know about Yodlee that's been around for over a decade), but it's still not worthy of exposing my financials for some questionable benefit. If they add a feature to allow automatic investment of predefined small (or big) amounts, they will have my business.