I did not believe it either when I heard the term... been in the industry a while myself.
It is a callable only market, no dissimenated quotes anywhere.
Sometimes in you do not see the market on OTCBB quotes and not on pinks you can still call a market maker to see if they trade it.
Here's a blurb from the web...
Other OTC
Or otherwise known as the "Grey Market" is the trading of a security that is not listed on any stock exchange or quoted on the Pink Sheets or the OTCBB. Other OTC trades are reported to the NASD so investors can track price and volume, however bids and offers are not collected in a central spot so Best Execution of orders is difficult.
OTC Bulletin Board
An electronic quotation medium for unlisted, non-Nasdaq, over-the-counter securities. The OTC Bulletin Board allows Market Makers to display firm prices for domestic securities, foreign securities, and ADRs that can be updated on a real-time basis.
Pink Sheets®
The Pink Sheets is a centralized quotation service that collects and publishes market maker quotes for OTC securities in real time. Pink Sheets is a nexus of OTC dealer markets that enhances price transparency in the OTC markets so investors can more efficiently buy and sell OTC securities.
