You don’t have to own the stock to sell it. You can go short, that is, sell it at a high price and buy it at a low price. Moreover, the stock may not be delivered on the same day, but may be delivered the next day. In fact, you do not own the stock when you sell it at a high price. , just buy at a low position and deliver that number of stocks for delivery the next day. This is how you make money shorting stocks. It's okay if you ask for 100 million, as long as you can get it the next day. In the movie, Liu was short-selling. In fact, he was not, but he was short-selling 5 million shares. Then buy it back. What you sell is short stock, and what you buy is actual stock.

But using the same account counts as self-buying and selling, so it is illegal!