Yes, I'm sure Robinhood or Schwab will allow me to open a $2M short position when my portfolio is $[sufficiently small that I'm debating the costs of a couple of thousand for a helicopter charter].
It's easy enough to synthesize 100x leverage by synthesis through options. If you have $25k for a margin account you could do it no problem. Of course, your funds would be rapidly vaporized if you were even a little bit wrong on timing or you needed more margin for volatility to keep it from getting called before it dips.
