Pink Quote, informally known as the Pink Sheets, is an electronic quotation system operated by Pink OTC Markets that displays quotes from broker-dealers for many over-the-counter securities. Market makers and other brokers can use Pink Quote to publish their bid and ask quotation prices. Starting in 1913, and prior to the creation of the electronic system in 2000, these quotes were printed on pink colored paper by the National Quotation Bureau. The term Pink Sheets is also used to refer to a market tier within the current Pink Quote system.

The Pink Sheets is not a stock exchange. To be quoted in the Pink Sheets, companies do not need to fulfill any requirements (e.g. filing financial statements with the SEC). With the exception of foreign issuers, mostly represented by ADRs, the companies quoted in the Pink Sheets tend to be closely held, extremely small, or thinly traded. Most do not meet the minimum U.S. listing requirements for trading on a stock exchange such as the New York Stock Exchange. Many of these companies do not file periodic reports or audited financial statements with the SEC, making it very difficult for investors to find reliable, unbiased information about those companies.

For these reasons the SEC views companies listed on Pink Sheets as "among the most risky investments" and advises potential investors to heavily research the companies in which they plan to invest.

Buying Pink Sheets shares is supposed to be difficult. Broker-dealers are enjoined to weed-out unsophisticated investors who may get an e-mail or word-of-mouth tip about a small stock. Many Pink Sheets stocks may only be registered for sale in one state so that the only way to purchase the stock is to make a DRIP/business/unsolicited/accredited or other sophisticated form of investment. Many registered representatives do not even know how or if they can sell them.