Savvy investors want choice. The ability to choose between several kinds of investments can turn your portfolio into a well-oiled machine. Want lots of growth with a little income? Prefer safety over growth? Willing to risk that safety? No matter what you're looking for, there's an investment to match your style. That choice means you can assemble a portfolio to exactly match your preferences.

The investing market is made up of two kinds of markets: Auction markets and dealer markets. Most basic-to-intermediate investors are aware of auction markets, where stocks are traded on an exchange in an auction-style transaction which are the stock markets we're most familiar with.

Dealer markets, also known as "unlisted" or "over-the-counter" ("OTC") markets, are not traded on an exchange. Bidding and asking prices are posted but the order is not sent to an exchange floor. Instead, the transaction is carried out between dealers. According to the Securities Industry Association, the NASDAQ is actually an OTC market but several additional rules make it function like an auction market.

Over The Counter investments are investments that either cannot meet the listing requirements of a stock exchange (such as capitalization requirements) or choose not to be listed on a stock exchange. These investments also have reporting requirements that are less strict than listed stocks. As a result, OTC investing is usually classified as a higher risk investment.

The OTC market has been around for a long time and was highly fragmented. Over the past century, efforts to unify this market (so that buyers and sellers could find each other and know what price they could buy investments at) resulted in two quoting systems. Today, the two key players in this dealer market are the Over The Counter Bulletin Board (OTCBB) and Pink Sheets.

The OTCBB (www.otcbb.com) is operated by the NASDAQ (which also writes the rules for OTC trading). Investments that don't appear on the NASDAQ can appear on the OTCBB.

Pink Sheets is a privately owned company based in New York offering competing services to the OTCBB. Although it has been around for decades, it has only been operating as Pink Sheets LLC since June of 2000. Its website, www.pinksheets.com, offers quotation services for unlisted stocks, as well as stocks that cannot be listed on OTCBB because the investment does not meet the SEC reporting requirements.

What does this mean for the average OTC investor? OTCBB, while quoting unlisted investments, has slightly stricter rules, including financial reporting rules. Pink Sheets continues to quote investments that may be listed on the OTCBB but also investments that do not qualify to be posted there. For investors who love the excitement of higher risk investments but want slightly more safety that comes from stricter reporting requirements, the OTCBB is the quotation service to use. For investors who love the excitement of higher risk investments and want greater access should look at investments found on Pink Sheets.