Why is the frozen amount generated in pre-IPO market trading and how is it calculate

The frozen amount generated during the pre-IPO market trading process = the cumulative net selling amount of the pre-IPO market stocks.

For example:

1. If you buy 2000HKD pre-IPO stock A. The frozen amount at this time = 0HKD

2. Following the example above, if you sell another 3000HKD pre-IPO stock A. The frozen amount at this time = 1000HKD

3. Following the example above, if you buy 4000HKD stock B in the pre-IPO market. The frozen amount at this time = 1000HKD

4. Following the example above, if you sell 5000HKD stock B in the pre-IPO market. The frozen amount at this time = 2000HKD

That is, the final frozen amount = the net selling amount of pre-IPO stock A + the net selling amount of pre-IPO stock B.