Pump and dump (P&D) is a form of securities fraud that involves artificially inflating the price of an owned stock through false and misleading positive statements, in order to sell the cheaply purchased stock at a higher price. Once the operators of the scheme "dump" (sell) their overvalued shares, the price falls and investors lose their money. This is most common with small-cap cryptocurrencies and very small corporations/companies, i.e. "microcaps".

While fraudsters in the past relied on cold calls, the Internet now offers a cheaper and easier way of reaching large numbers of potential investors through spam email, investment research websites, social media, and misinformation.