US stock options are contracts established between buyers and sellers, which stipulate the right to sell or buy stocks at a specific price. In the transaction, both parties only need to determine when to buy at what price. Then on the day when the contract expires, the buyer of the stock option can choose to continue to exercise the option or choose to void the stock option.

Option trading guide: The person who buys the put has the right to sell the underlying asset when it expires, and the opposite is true when selling the put; if the person who buys the put exercises the right on expiration, the person who sells the put must Buy the corresponding underlying assets at the finalized price. In the past, the person who bought the put was actually the seller of the underlying asset, and the person who sold the put was actually the buyer of the underlying asset.

The specific rules for U.S. stock options trading are as follows:

1. Trading unit and price increase or decrease. The minimum trading unit for U.S. stocks is 1 share, and like Hong Kong stocks, there is no single-day limit on the rise or fall of U.S. stocks.

2. Intraday trading. T+0 trading: If the total amount of the cash account is less than 2,000 US dollars, intraday trading can only be carried out if the funds have been delivered, otherwise the user will be prohibited from trading for 90 days. When the account's net assets are greater than $25,000, the account can conduct unlimited intraday transactions.

3. Funding threshold. Some U.S. stocks are very expensive, ranging from hundreds to thousands of shares. But the minimum trading unit is 1 share, which is basically affordable for most people.

4. Short selling mechanism. Basically, for stocks with a stock price higher than $5 and good liquidity, you can choose to sell first and then buy.