Hi guys!
I’m currently working on something similar to a real stock market, where the market is controlled by supply and demand. Thus, stock prices will depend based on players’ number of purchases and popularity. There will be some random events (for example, heavy rainstorm cause fishing industry to dip slightly).
My question is, does this count as gambling in TOS? Also if players were able to buy in game currency to purchase stocks, will this not be allowed?
Don’t think that it would count as gambling. I’d say that it’s more like those trading sim games without the trading sims without the trading option.
I wouldn’t think so, to be totally honest. I think what Roblox meant by that was far more direct.
This wouldn’t count as gambling. If it was then limiteds would be gambling.
There was a game in the past that had utilized stocks as an extra way for the player to earn in-game cash, other then working the job they had within the place. The stocks functioned the way you’d expect them to, they changed once per game day, and either soared, fluctuated or crashed. However even if a specific stock had crashed. The player still had the amount of invested shares within that stock, and could still earn back the amount they had originally invested, once the price of the stock recovered. Therefore there was generally no risk of the player losing their money, unless they sold the invested shares when the prices were low.
So, since the question was would the stocks count as gambling. If the player had to spend Robux on the currency in order to participate in the game’s stock market. Then it highly likely count as gambling per defined in the Roblox Community Rules. If that is not at all the case, then you should very well be fine in implementing the stock market to your game without much scrutiny.
The game idea sounds really good, And no this should be allowed. Limiteds Are exactly like it.
Hopping in here 
So if I was to have a stock market, and to buy stocks it cost R$, that would constitute as gambling?
Stocks fluctuate, and you aren’t required to sell, so I struggle to see how that constitutes as gambling
This works exactly like a limited. For some examples, you stated above reply to Wingz_P, Stocks fluctuate, so do limiteds. They go up in price, down in price. Also, If you have Builders Club, you can sell limited’s you have purchased. You aren’t required to sell them, but you still have the feature. Therefore, I think you should be allowed to create a stock game. Good luck! 
EDIT 06/20/2023
As of the same date of this edit, Roblox has officially moved to ban simulated gambling by September 18th, 2023 (in 3 months), which means that all forms of gambling are no longer allowed on the platform. This contrasts the prior stance to which, as long as there was no Robux involved, it could be passable.
The advice in this post is no longer accurate. Please avoid sharing this as an answer. For more information, please see Updating our policy on simulated gambling in the thread Create Experiences for People 17 and Older on Roblox.
Stock markets are a game of chance the same way gambling is. You can lose the currency that you invested into a stock rather than getting the full value of whatever amount of Robux you put in. The currency that you use to invest into stocks can’t be purchasable with Robux either.
Moderation has offered a very specific response to gambling and this may have changed since, considering it was last posted in 2016. I can’t post the exact response as it’s in a private category but my post essentially summed it up.
Feel free to let me know if you find updated information or official responses in accordance to current policies regarding gambling.
If you make a stock market game, there must be no cash-based purchases.
Cash based, are we referring to USD purchases? If we are talking about R$, I struggle to see how this is against TOS.
ROBLOX has their own limited system, so I struggle to see how this is any different.
I addressed this in my post. In-game currency related to games of chance cannot be purchasable with real currency. Robux is purchasable with real currency, thus it cannot be used either. Roblox’s limiteds are different in the sense that all forms of trading are done on-site and regulated by Roblox’s systems.
Limiteds are not gambling.
What if there is an alternative way to earn cash in game?
The plaza did this, they allowed a way to earn cash rather than having it solely be purchaseable.
And the definition of gambling is: take risky action in the hope of a desired result.
Hence, limiteds can = gambling
This was also addressed in my post. The response offered by moderation says that in-game currency that can’t be purchased with actual currency (Robux or otherwise) is permitted. The recommendation around this is to allow players to complete tasks or earn that currency free by playing the game. That’s why The Plaza’s system was given a pass, although under somewhat heavy scrutiny.
True true, but in the plaza it can also be purchasable w/ R$… so?
I haven’t played The Plaza in some time, so I wouldn’t know. Details I know can be inaccurate.
The last I played it, I recall that it had a token system of sorts. Tokens can be earned through non-purchasable methods which you can use at the casino. Winnings add to your in-game currency. You don’t lose anything except earnable currency if you lose a machine, which is why it’s permitted in that circumstance. There’s also a warning about machines when you enter the casino.
The developer and moderation had a very specific response about The Plaza’s system, though I can’t remember specifically what was said. There was a very clear outline regarding the casino system in The Plaza and why it was permitted. The game has been taken down because of its system but it’s operable due to the applied fixes.
That being said; if you find a game that isn’t abiding by the rules, the obvious answer is to report it rather than to follow in its footsteps and take chancing moderation as a good answer.
True, but I believe I read somewhere that you can allow the user to gamble in-game or currency, as long as it IS obtainable in game for free?
Gambling itself comes off as fairly gray and requires some adherence to policies but yes, I did say that in part as well with my original response.
Any in-game currency that is earnable for free can also be put towards these kinds of activities. The only conflict of interest becomes the gambling itself in which it needs to be fair for users and not skewed in favour of any party; beyond that, users aren’t spending Robux or real cash on your currency, thus losing nothing of potential value. Purely in-game currency with no Robux involvement is fair play.[1]
[1] This is only in regards to actually purchasing currency. If you have a Cash Boost game pass (x2 Cash per activity, for example), this does not count towards the Robux-Game Currency restriction.