If only Ally allowed non-citizens and non-Green Card holders to open accounts. I've got my emergency fund in Robin Hood. They pay 3% on cash in the brokerage account.
Robinhood requires a $5/month subscription to go from 1.5% to 3% interest. Only starts being relatively worth it at $7k cash, assuming ~40% marginal tax bracket. And since others are paying 2.3% currently, really it's only worth it at like $15k. Like another commenter said though, 3-month US treasuries are paying 4% and exempt from state tax.
> With the brokerage cash sweep program, the uninvested cash in your brokerage account (cash intended for investing but that you have not yet invested or spent) is swept to program banks, where it becomes eligible for FDIC insurance up to $1.5 million or $250,000 per program bank,