This is an idea coming from a discussion a while back in XM chat, I couldn't find a board on stock exchange, so this is my take on turning it into mechanic.
The Stock Exchange could be used as a leaderboard for the different Withmore Corporations. Whenever in game events occur surrounding a corporate entity it will effect their standing positively or negatively depending on the outcome. Players can buy into the market, gambling on what they think the outcome will be, or to manipulate it in their favor. This could open up a whole new level of corporate espionage. Including things like risking corporate status by trading secrets for a large personal monetary gain.