A type of speculation that involves taking a bet on the price movement of a security. A spread betting company quotes two prices, the bid and offer price (also called the spread), and investors bet whether the price of the underlying stock will be lower than the bid or higher than the offer. The investor does not own the underlying stock in spread betting, they simply speculate on the price movement of the stock.
For example, assume that a spread-betting company quotes a bid of $200 and an offer of $203 for ABC stock and you believe that the price for ABC will be lower than $200. Since you believe that the price of the stock would be go below $200, you could "bet" $2 for every dollar that ABC falls below $200. Therefore, if the stock price after a week came to $190 you would receive $20, but if the price was $215 you would end up losing $30.