Originally Posted by
freecia
Might you be thinking of Google Voice, the virtual phone forwarding service, and not Google Fi, Google's prepaid cellular offering? Google Fi (mostly) operates on T-Mobile and roams on US Cellular. Fi used to also work with Sprint's carrier network. Fi technically had three carrier networks which might have made carrier account linking look a bit odd ("secret" phone number may not match one in details of a credit report?). T-Mobile and Sprint merged.
Yes, I think I'm mostly thinking of Google Voice, which I did check out, but the ability to open a Google Fi account and obtain a cell phone number by anyone from outside the US should also make it unacceptable as a number for opening a Schwab account, regardless of whether it operates on T-Mobile or not. I believe you need to open an account directly with a major carrier such as T-Mobile (and not through Google Fi) so that you are on file in their customer database for the number to be verifiable by Schwab.
Originally Posted by
freecia
I believe Schwab brokerage accounts have a US residency requirement. Schwab High Yield checking is from Schwab bank and requires opening a linked brokerage account.
I'm pretty sure that if a US expat had a verifiable mobile phone number, SSN, and US address, they would qualify for the Schwab account, except for the question of residency. Morgan Stanley too requires US residency on their account application forms. My credit card companies, Amex and Chase, both see me as a US resident based on the data I submitted (US mailing address, SSN, US telephone number, etc.) to open my credit card accounts, but even so, US residency is not required to open those accounts, but US citizenship usually, but not always, is.