"Pink sheets" is an outdated term used to describe stocks that trade over-the-counter (OTC) rather than on a major U.S. stock exchange. These companies cannot or do not want to meet the requirements for listing on a major U.S. stock exchange like the New York Stock Exchange (NYSE). They could be too small, foreign, or choose not to file the necessary paperwork with the Securities and Exchange Commission (SEC) and avoid all the extra costs that entails.

The term "pink sheet" arose as price quotes for these unlisted stocks used to appear on pink-colored sheets of paper.