Imo I see the whole in-game stock-market idea as a huge trainwreck in the long run.
What could go in place of that is a currency-exchange. You invest in some Gold/Silver/Bitcoins/Coal, and when the price of what you invested in goes up, you sell in exchange for Dollars. Then you buy when the price of that investment goes down. I think this would be a simpler and easier form of an in-game 'stock market'.
The prices of these currencies would be primarily controlled by supply and demand. If theres more Gold in the market, then the price goes down. Less Gold, and the price goes up. Gold could be conjured into existence by mining ofc. I'm no expert in this stuff, so tell me what you guys think.
(Maybe even add support for buying food/guns/services with gold and other alternate currencies, lol)