I suspect the answer may relate to why "Flam Hill" is being so purposefully vague about how he acquired the shares. But you're right, the story doesn't really make a lot of sense.
I suspect someone paypal'd the original Flam Hill to buy his character when Flam Hill wanted to quit, extracted his skill points (the character went AFK in 2017 right? 2016-2017 was the time when skill extractors were new and it was profitable to buy character and skill extract them for a profit) then a few years later he discovered the char owns shares in a big corp.
If it was real money trading in exchange for the character then they wouldn't want to say it outloud.