Practice of buying stock with money borrowed from the broker. In this arrangement, the investor makes a cash down payment (called the margin) with the broker and can purchase stocks worth about twice the cash amount. The broker charges interest on this loan (in addition to the commission on each buy/sell trade) and the investor has to keep the entire stockholding with the broker as collateral. Also, the investor has to put up additional cash in case the value of the stockholding falls below a certain amount. Margin trading is a double-edged sword - it cuts both ways. If the stock price rises, the investor makes twice as much profit as with his own cash only. Similarly, if the stock price falls, the investor loses twice the amount. In slang, this practice is called 'investing on steroids.'