Last time it happened on a listed stock. Got a message in ticket center from compliance and had to confirm i am not affiliated with company and stuff like that. Was no big issue, never heard back and was able to trade them all the time (i think it said answer required within 48 hours or something).
No, it’s based on trading volume. I’ve had a compliance review trigger for trading 1000 shares at less than $10 each. The stock had 7M shares outstanding as of their last annual report. Average volume for the stock was about 1000 shares daily. there’s a separate >1% outstanding shares threshold that causes outstanding the margin requirements start going up rapidly, but that’s a separate problem (and not relevant to OTC, where you don’t get margin anyway).
I’m sure it’s based on average volume over a few weeks or months. Either way, if you’re trading a stock like that, expect to run into these compliance issues. the bad part is that even after you address their concerns, the trading permissions are only restored for two weeks (to allow you to exit your position), and if you keep holding it, it gets re-restricted until you do the compliance thing again and again. PITA.