TD Ameritrade was the 1st broker to announce they're restricting trading. I reposted it here from a comment/screenie posted in Main
I think Interactive Brokers cracked down in the pre-Market today simultaneously with Robbing Hood.
Those to, at least, have almost certainly been caught with their hands in the 'naked shorting' cookie jar.
RBC in Toronto, Canada too. They also failed to deliver TSLA dividend shares back on Aug 31, 2020.
Not helpful for you, but BMO Investorline in Canada has been above board. Recommended for Canadians seeking an honest broker.
Cheers!
No issues here with TD Waterhouse in Canada.. Allowed to buy GME/NAKD