I've been playing for a while and just had a thought...
When a stock IPOs it releases a certain number of shares, like 100 million. If those are all held long short, that would mean there is no supply except for any shares that people sell/cover post IPO.
When I go to buy or sell shares - where would they come from if demand exceeds supply of shares? Does HSX automatically issue additional stock or do I long/short from that supply or sold/covered shares that would be sitting outside of anyone's portfolio?