n. An investment scam in which a stockbroker, analyst, or shareholder encourages investors to buy a particular stock in an effort to raise its share price, and then to sell what he owns of the stock at the higher price.
1998
The goal of such con artists is to create a "pump and dump" stock-rigging scheme by controlling the bulk of the company's shares and working in concert to exaggerate the stock's investment potential to investors.
1988
Some of the promoters charged Wednesday allegedly engaged in "pump-and-dump" schemes in which they spread falsely positive information about stocks. As small investors piled into the stocks, sending the prices up, the promoters sold the shares they owned.
1988 (earliest)
For most promoters, the preferred scam is "pump and dump"—pump up the per-share price with hot air and hype, then dump the stock on duped investors for immense profits.