In the trading market, position K is the biggest risk of a single transaction based on the total available funds in the trading account. Usually, this value is a percentage. For example, if the total account fund is 10000 yuan and the position k is 1%, the risk of a single transaction should not exceed 100 yuan. The purpose of this restriction is to prevent traders from going bankrupt or suffering serious losses due to the high risk of trading.

In addition to the position limit of a single transaction, there is also a total position limit, which is the maximum risk that can be held at the same time. Some traders will limit their total positions to 3%~5%, so that when the market fluctuates violently, they can still maintain relatively stable position changes. The total position limit can also be adjusted according to the risk tolerance of traders, trading time and market fluctuations.

For some complex or high-risk trading varieties, such as options and futures, the calculation method of position K may be more complicated. In option trading, the size of position K depends on factors such as option price and remaining term. In futures trading, the calculation of position K needs to consider many factors such as market fluctuation, margin rate, contract value, trading account funds and so on. For different trading varieties, the calculation method of position K may be different, so it is necessary to know the specific trading rules and calculation formulas.