I'm not from a trained background, so let's use my actual combat experience to express it. Default option refers to futures option. Let's start with futures 1. Futures take up a lot of money and take up a certain amount of capital risk. 2。 Futures trading is generally not as big as futures options, so there is a certain liquidity risk. Option a. Option buyer 1. Although the risk borne by the buyer is relatively limited, the risk of market fluctuation of royalty change is greater than that of futures. There is the possibility of "losing everything" 2. There is a stricter time expiration risk B than the buyer. Option seller 1. The seller's income is limited and the risk is huge. When the price changes in a favorable direction, the income is limited, but when it changes in an unfavorable direction, the risk is infinite.