You won’t find that out of the box.
You need some form of membership/user profiles, which in itself is fairly easy, BUT to then have a reactive feed that determines what stocks they own, and their existing value is complicated.
That’s all before you look at the the ability to actually trade/buy/sell/checkout within the site.
There are some plugins like https://codecanyon.net/item/stock-portfolio-tracker-wordpress-plugin/23877899/ but these are a long way from being ready to go as they are.
Also due to the financial element, there are numerous other hosting, security and compliance considerations to address which could add huge cost.