That is very surprising. I'm not sure why they wouldn't? On Stocktwits there were people saying they bought there. I bought on ETrade yesterday morning at the bell so I know that's possible - and obviously a lot of others did too, by putting in limit orders premarket. This is why the volume was explosive in the first minute of trading yesterday (I believe 360 million shares).
So you went to Ameritrade, put in a limit order and it just refused you? Maybe you should open an ETrade or Fidelity account. It's stunning there would be that much volume (well over 2 billion in one day) and Ameritrade was blocked out. Seems incredibly strange.
News 
Market Data 
Discover 
