The Dark Markets are terrible places to trade penny stocks, and most shares are bad investments.
Always avoid trading Dark Market penny stocks. This includes the Pink Sheets, the OTC-X, and OTC-QB.
These are technically not even real stock markets, but rather are more akin to a garage sale negotiation.
Since there are very minimal listing requirements to trade on the Dark Markets, they become like a magnet for unprofessional or low-quality businesses. There is also a lot of fraud and illegalities which surround dark market penny stocks, such as pump & dump schemes.
However, IF the company is ALSO listed on another international exchange, which is a solid, legitimate exchange, then it is OK if they also have a dark market listing. Usually, they only do the dark market listing to make it easier to trades the shares in US dollars, without having to suffer the currency exchange rates each transaction.
The best market to trade penny stocks is the OTC-BB – which is the bulletin board – because it is owned by the NASDAQ. There are thousands of good-quality penny stocks trading on the bulletin board, and there are plenty of reporting requirements, fees, and investor visibility regulations, so the shares which find their home on the bulletin board are generally fine companies.
This is all opinion, not trading advice.