There is the marketplace that looks like stock market and trust me you can make a lot of money from that. But in case we could add alternative credits in the same marketplace, that their value will change independently to the original credits,  effected -if possible- by other server controlled variables,   perhaps that could be interesting...

I think the only feasible way a 'stock market' could work, cheaply, is to have a fake exchange with made up crew 'legit' fronts, and perhaps base their stock price on that entire crew's activity level.

Crew A's conglomerate starts at 100 a share. This would fluctuate hourly based upon all member activity in Crew A. Super active that hour? Price goes up X percent. Super slack that hour? Price goes down X percent.

This gives another way to 'gamble' so to speak, while also perhaps encouraging more activity? Maybe add in business district posts to the share price as well? Although, the downfall I see there is just more spam.

Any other format, in my opinion, would cost you, as the owner, too much.. as I don't really see how you would get a return on your investment, unless currency for said market is in credits.

Could you base stocks off businesses owned by each crew in the business districts, Squishy. Give each Business a starting value, $1,000 a share for example, and then have that value go up and down based on the quality of the posts there in, using the existing exp boost metics? Sure the value of the shares could be rigged by players putting in a lot of work and posting really well, but then is that not a bonus?