Futures are leveraged because futures have a futures margin system: the futures margin trading system has certain leverage, and investors do not need to pay the full contract value, but only need to pay a certain percentage of margin to trade. The leverage effect of the margin system not only magnifies the income, but also magnifies the risk. In case of extreme market, the loss of investors may even exceed the principal invested.

Take your example: you spent 10 yuan to buy a futures contract of 100 yuan, and the contract rose to 105 yuan, and your cash withdrawal became 15 yuan, making a net profit in 5 yuan. It can be understood as: 10 yuan bought something at 100 yuan, and the goods went up and down at 100 yuan.