What's the point of allowing them at all? Going public is really pretty easy.
If you don't want to report to the SEC, all you have to do is prepare the necessary information, and then find a sponsoring MM willing to submit a Form 211. Once FINRA approves and assigns a ticker, you're ready to trade. You'll need a lawyer's help, but it's quick and relatively inexpensive.
If you do--as you should--want to report to the SEC, you file an S-1 or a Form 10. That's more complicated, and will involve interaction with the SEC. But it isn't necessarily more expensive than doing a reverse merger, as you don't have to buy a shell.
Market Data 
Markets 
AI
