This may be a perfectly good explanation, but if this is the case, why doesn't the Robinhood people release a statement explaining this instead of the puff piece the CEO did for PR.
That's a dubious way to refer to people. There are 7.5 million users in the sub at the moment.
Doing so would have likely pissed people of more.
"New sign up to Robinhood? Just started a transfer? Awesome! I know all our marketting material says 'trade right away', but actually you have to wait 2 days right now."
"Just sell a bunch of other stock in order to buy GME? Well, unfortunately right now you can't use that money for 2 days. See you next week! Ps: thanks for the taxable event that you probably wouldn't have done if you understood that you'd have to wait!"
The problem was clearing house margins. It went from a few percentage points every buy of GME to 100%. You cannot use customer money for these deposits, it must come from the brokerage firm's funds itself.
I think it really needs to be discussed that there were multiple "liquidity" crunches for RH here, one far more significant than the other.
You could have had every single buyer of GME locked and loaded with $100k of cash in their account for a month, but if they all bought GME last week for cash RH would still have the same exact margin requirement problem they have now with their clearing house. That they still had hundreds of billions of their customer's capital on deposit would have been irrelevant.
The other explanation is that they are running a b-book that is underwater due to the runaway success of GME and have big losses from that.
But that's something of a slog to read. The closest I've found is footnote 13 in this rule change, which notes that it was requested to change this requirement. I haven't found anything contradictory.