Individual stock option refers to an option contract with a single stock as the underlying asset. Its intrinsic value depends on the change of the underlying stock price. By buying and selling a single stock option contract, investors can buy and sell the underlying stock at a specific price when the option expires.

On-market and off-market refer to two market forms of option trading. On-site option trading refers to standardized option trading in exchanges, such as Shanghai Stock Exchange and Shenzhen Stock Exchange. OTC options trading refers to non-standardized and personalized OTC options trading, which is usually provided by brokers or futures companies.

There are some differences between on-site and off-site trading of individual stock options. On-site option trading is standardized, contract specifications and deadlines are fixed, and trading processes and liquidation methods are also unified. On-site option trading usually requires investors to open a specific account in the exchange and abide by the trading rules and restrictions of the exchange.

OTC options trading is more flexible and personalized. Investors can customize the contract specifications and duration according to their own needs and risk tolerance, and the price and cost are relatively more flexible. OTC options trading usually requires investors to sign trading agreements with securities companies or futures companies and provide a certain margin.

There are usually risks in OTC options trading, because the non-standardized and personalized characteristics of contracts may lead to problems such as insufficient liquidity and high trading risks.