Pink Sheets LLC is actually a privately owned comp

Pink Sheets LLC is actually a privately owned company based in the state of New York. Pink Sheets are not the same type of marketplace as many of the other exchanges, rather they offer a real-time quotation service for stocks in the OTCBB as well as stocks that are unlisted at any other exchange because of rules and regulations. Most frequently a company will offer their shares on the Pink Sheets market if they are unwilling to disclose financial information. In recent years, some large foreign companies have made the move to list their shares on Pink Sheets. Pink Sheets has seen its popularity grow quite a bit over the last few years because of their move to a more high-tech QTCQX marketplace. 

Over-The-Counter-Bulletin Board (OTCBB) Explained 

The OTCBB is an electronic quotation system that displays real-time quotes, sale prices, and volume information for thousands of over-the-counter securities that are not listed on the NASDAQ or the NYSE. Companies who go public on the OTCBB must adhere to the Sarbanes-Oxley Bill, and they must be audited on a yearly basis. In general, stocks that trade on the OTCBB are typically penny stocks and the bid/ask spread can be quite large because of the low volume.