I’m not sure the original post I quoted fully explained what they saw.
I don’t doubt Schwab’s liquidity. They’re held in high regard and are generally conservative. I just met with my local branch last week. I dont use margin and don’t trade individual stonks (mostly ETFs and 1/2 in their own MM fund with monthly reallocation) so my funds aren’t typically in limbo.
I know that a lot of brokerages were dealing with traders caught short the past two days with heavy margin calls, thought it was an odd statement. Haven’t seen anymore on it.