Player wants to play a Stock broker / Trader. How do I Implement a lightweight trading system?

Question

Prelude:

Starting an Eberron campaign. I've got a player who is new to D&D. He has asked me if he could play a Broker/Trader in my campaign.

I've outlined to him that while D&D focuses on both combat and social, my game most likely won't accommodate nitty gritty stock trading. However, I really like the idea. It gives another resource I can hand out as a reward while also being something I can use to engage my new player.

Stock markets are hardly a new concept either. If they existed in 12th century France then I'd argue they'd be prevalent in the world of Eberron. He's asked if some of his starting gold to be converted to shares in the current dragon marked house he's apart of also.

Question:

How do I implement a system that is engaging for my new player and not too confusing my more established ones?

A basic system I've thought up is where the price is static and only changes to a pre determined event, Say a railway heist causing a dip in stock price. However I'm concerned at how this would effect my players decisions if I hand out too many shares. It also doesn't reflect the randomness that comes with trading either.

All other ideas involve too much rolling or an understanding of the markets that I don't have. I also don't want to implement a "Free money" System either (Fixed interest rate), because I can see that getting out of hand quite easily.

Any suggestions on price of stocks and how much they should change also would be appreciated.

Answer 1

I would not attempt to design a stock market trading system unless you and a majority of the players are personally interested in historical trading enough to put a lot of work in.

It's a complex topic that people have different ideas about how it works, on top of people having wildly different levels of knowledge about both modern financial instruments and trading them, and historical financial systems.

However you don't have to.

You can simply narrativize it. 'The markets are crashing due to rumours of war in XYZ - everything is down, and you're worried about your investments'. That's not a financial system, that's just setting information and a roleplaying cue. 'One of your fellows at <club/cafe/other informal setting> has come to you with a plan to ship brass instruments to [name of city] to oversaturate the market and ruin a competitor of his' - this isn't a financial market spreadsheet, it's an adventure hook. Fighting mercenaries, dealing with attempts to block things with legal red tape, dealing with unrelated problems like the instruments being bad quality and breaking in some manner that needs repair, dealing with unrelated events like a gold rush on a distant isle leading to the market suddenly wanting the brass instruments at any price and do you stick with the original plan or try to make a killing etc.

This can be a way for you to dump money on the party, take money from the trader character, drop setting information (that he can potentially try to take financial advantage of, harnessing greed in your goal of getting people to care about the setting and what is happening in it), give the players hooks, and give the players tools to deal with other situations (social, political connections, and financial clout). It can also throw complications at the players in a number of ways, from jealous rivals to plots to frame this guy to plots to steal his money to situations where he could make a killing.. if he threw the party under the bus to do so, such as by revealing information (to change the prices of things) that the party needs kept secret for some reason, like that a certain noble is a vampire or that there's a locust plague in a distant province and wheat is going to shoot up in price.

So, focus on the narrative side of it. Have some terms on hand - Grain into Gold is a great sourcebook to have terms for the kind of things commonly traded on hand, and Ars Magica has a few sourcebooks with great information on historical trading and financial systems - but don't try to design a numerical game that the person can play in addition to the numerical game of D&D 5e, unless you and the person both enjoy that sort of thing (and the rest of the party is at least willing to let it affect the game if he breaks the system and ends up inhumanly wealthy).

Answer 2

If you just want a ready-made system, the DMG's downtime activity guidelines for Running a Business should be able to approximate this reasonably well. Those rules reference maintenance costs that are mostly associated with actual physical businesses like a guildhall or an inn, but these could be easily reflavored to represent the risk of losing money on the market instead.

If your goal is to give the player a quick and easy way to face a chance of profit and a risk of loss between adventure, these rules are probably sufficient. However, it's worth noting that a lot of people find them kind of lackluster. They don't allow much room for player choice, and the math is a little wonky and greatly disfavors larger businesses. This Q&A goes into more detail on that and recommends some homebrew tweaks the the system.

Finally, I agree with user2745's answer that you should try to tie fluctuations in the market into the narrative and worldbuilding of your campaign. However, doing that doesn't rule out using a simple random system for profits and losses. Before having the player roll, you can ask them what investments and trades they plan to make, and give a bonus or penalty to the roll if you believe in-game events would move the price one way or another. Perhaps the players have recently disrupted an operation smuggling magical weapons, and so have reason to believe that the Mage's Guild's enchantment services are about to experience a jump in demand. Conversely, you might use the result of the roll to guide your decisions of how events in the world unfolding. If they player rolls poorly on their Mage's Guild investment, perhaps you decide that it didn't pay off because another criminal enterprise has rushed in to fill the gap in the black market for magical weapons, leading to another adventure hook for the party.

Answer 3

Use the one we've got

You can agree on which aspects to implement, such as shorting, using options, etc., but the least breakable system is probably the one people have been trying to break for years. Figure out a conversion of Au<->$, and let him transact by informing you of which real, actual stocks he's trading in game. Nobody can be accused of gaming the system either way, and the real world performance of the stocks drives his results. Easily verifiable, and gives some free semi-real world practice to the player(s).

More realistic than fantasy football.

Answer 4

Why don't you just use the Downtime Activity: Gambling presented in Xanathar's Guide to Everything page 130?

You can take the gamble mechanic, who use Insight, Deception, and Intimidation checks to determine if you win or lose money, even contemplating the possibility of complications.

You can even reskining it if you think it's necessary, which is just rewrite gabling for invest/trade. BTW: I think this Extra History series on the Tulip Mania could be inspirational.

Answer 5

If they existed in 12th century France then I'd argue they'd be prevalent in the world of Eberron

Your link does not say that stock markets existed in 12th Century France, though. It says that financial (debt) brokers existed in C12th France, that open commodity markets developed in C13th Bruges, and that joint-stock companies (the ones issuing shares that could be traded by a stock trader) came into existence in the C16th.

The economic benefit of joint-stock companies is specifically that profits can be retained and reinvested (and losses written off), while accruing capital investment. The investors are insulated from (some) volatility and from management involvement. This insulation has the effect of removing almost all story-telling potential from a joint-stock company (which is obviously desirable in real life but potentially boring in a game).

Similarly, I don't see the roleplaying appeal of pretending to be a broker in agricultural debt tied to one place.

So what kinds of trading activity could be interesting, apart from simply buying (or otherwise acquiring) stuff in one place and selling it in another?

Before joint-stock companies, there were various forms of funding for individual merchant expeditions, such as the commenda. These are sometimes described as joint-stock companies (because they have multiple investors, some silent), but this is inaccurate: they lacked a standardized "share" and secondary market, and were dissolved & returned any profits at the conclusion of a single trip.

If a limited number of expeditions are setting out, and a substantial contribution is required to buy in to one, then you can't spread your risk or build a portfolio, but you can choose one expedition to fund. If it fails, your investment is wiped out completely. Perhaps you can accompany it to improve the chance of success, but either way you have a small number of expeditions to specific places that you can tie into story beats, and there's no need to run an economic simulation that's completely detached from playable events.

Answer 6

Have a look for GAZ11: Republic of Darokin.

It's an old D&D source book for the World of Mystara - a forerunner of Eberron. It has a merchant class with specialized skills/spells and progression which you may be able to retrofit to 5th Ed.

Just to expand on this a little - I dug out my copy of this sourcebook, and I think a lot of the rules regarding trading - putting together caravans and such like can probably be lifted straight out as they aren't really tied in to any specific rules systems - indeed they could probably be adapted to any fantasy game.

The merchant class itself is kind interesting as it was written as an additional class that any character could have alongside their main character class and it would only gain experience from gold obtained from trading (Merchant Experience Points - MXP).

Rising in Merchant level grants access to spells which are related to trading. Some are quite specifically for trading - such as Count Coins and Evaluate - but others could certainly be useful in a more adventurous context. Hold Animal, Charm Person, Resist Magic etc.