Hi @AndrewAMD. I spent a bunch of time today on Ally chat with "Stephen". With his permission, the relevant parts of the chat are ("our team" is the API team):

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Thank you for your patience. I spoke with our team and confirmed that the data would be free now. There used to be charges with MBTrading for market data services, but these are no longer charged unless you are a professional user.
Stephen
- 8:11 PM
what's "MBTrading"?

- 8:12 PM
That is a trading platform that we were partnered with, but it merged with us around the beginning of the year.
Stephen
- 8:13 PM
ok. please let me recap to be sure i have the facts correct:
a) in 2017 market data came via mbtrading who charged for it and these charges were passed on to all users
b) in early 2020 ally merged mbtrading in and these charges no longer apply
c) unless the user is a professional
all correct?

- 8:15 PM
It is a bit more complicated regarding a), as MBTrading was a separate platform linked with us but, but correct, these charges are no longer applicable unless you are a professional user.
Stephen
- 8:17 PM
so as a non-professional user, i can trade via any mechanism, including api via 3rd party software, without incurring any data charges, correct?

- 8:18 PM
Correct. The 3rd party may charge a fee for this but we would not.
Stephen
- 8:19 PM


Does "MBTrading" ring any bells? If all of this is true and complete, Ally would seem to be a usable broker again... "usable" meaning no worse than the rest...

At least I have something in writing from them if they decide to try and charge me later...