I may have a route out.
Arbitrage isn’t really possibly without differentiation between the stock market value and par (or some equivalent). As I’ve no equivalent to par value (or companies in general), this doesn’t look to be possible unless I can do something which will cause a controlled market price rise sometime during a given stock round. With that players would be able to increase a price and then exploit it for arbitrage mid-SR. (More on that score later) Leverage is possible but harder. it really requires a debt structure, or at least a lien structure within the game. That’s not actually that difficult to add though it will be interesting trying to keep it from being an actually interesting decision versus and automatic decision that should be optimised out.
None of which really has to do with the route out. The route out is simpler.
In the conversation and design process to date I’ve been concerned with creating and then manipulating a relatively mature market. Perhaps that’s the wrong goal. Mature markets don’t spring out of the ether whole cloth, they have to be grown. They rely on investment patterns and intentional structures that while they don’t explicitly require history (the ripe situations could be manufactured and simply handed to the players), only really work well after the players have internalised the relationships through the process of experiencing and intentionally growing the history. Which when I thought about it seemed like a deistic clue: Markets are the grown products of history. Well, why not make the game about the growth and formation of the market, not the manipulation of the mature market? As such the game would focus on the creation of the mature market and would effectively end as soon as a viable market was in fact created.
I’m not sure what the measure of a mature market is. I’m sure the economists have some that I should look at. In the meantime perhaps I’ll steal another page from the 18XX and simply time the game via the bank. When the bank breaks the game is over. Figuring out how big the bank should be will be interesting (and will likely have to vary based on player count), but that is a smaller and simpler problem.