Good question.

I looked everywhere I could (including their FAQ and Terms of Use) and didn’t see anything about length of time/how far back they look to analyze spending. Where it’s proprietary, I’m not sure they disclose it and they presumably make up for any errors with their overdraft protection clauses (i.e. they’ll pay any overdraft fees if they accidentally transfer too much).

Where I assume they’re not in the business of wanting to pay too many fees, I’d bet on them being pretty conservative.

Digit uses Axos and Opus (both local to where Digit is headquartered out of in California). They may have recently added more banks to the mix but those are the two primary ones they’ve used since inception.

Deposits through Digit are closed-loop, so if the company folds, deposits made into those accounts are reverted back to the originating account.