To say that gains and losses in futures trading are the result of price changes is an accurate explanation but by no means a complete explanation. Perhaps more so than in any other form of speculation or investment, gains and losses in futures trading are highly leveraged. An understanding of leverage--and of how it can work to your advantage or disadvantage--is crucial to an understanding of futures trading.
As mentioned in the introduction, the leverage of futures trading stems from the fact that only a relatively small amount of money (known as initial margin) is required to buy or sell a futures contract. On a particular day, a margin deposit of only $1,000 might enable you to buy or sell a futures contract covering $25,000 worth of soybeans. Or for $10,000, you might be able to purchase a futures contract covering common stocks worth $260,000. The smaller the margin in relation to the value of the futures contract, the greater the leverage.
If you speculate in futures contracts and the price moves in the direction you anticipated, high leverage can produce large profits in relation to your initial margin. Conversely, if prices move in the opposite direction, high leverage can produce large losses in relation to your initial margin. Leverage is a two-edged sword.
For example, assume that in anticipation of rising stock prices you buy one June S&P 500 stock index futures contract at a time when the June index is trading at 1000. And assume your initial margin requirement is $10,000. Since the value of the futures contract is $250 times the index, each 1 point change in the index represents a $250 gain or loss.
Thus, an increase in the index from 1000 to 1040 would double your $10,000 margin deposit and a decrease from 1000 to 960 would wipe it out. That's a 100% gain or loss as the result of only a 4% change in the stock index!
Said another way, while buying (or selling) a futures contract provides exactly the same dollars and cents profit potential as owning (or selling short) the actual commodities or items covered by the contract, low margin requirements sharply increase the percentage profit or loss potential. For example, it can be one thing to have the value of your portfolio of common stocks decline from $100,000 to $96,000 (a 4% loss) but quite another (at least emotionally) to deposit $10,000 as margin for a futures contract and end up losing that much or more as the result of only a 4% price decline. Futures trading thus requires not only the necessary financial resources but also the necessary financial and emotional temperament.