Game rules

The foundation is geometric Brownian motion — the same model that serves as the starting point in financial mathematics. Prices fluctuate proportionally rather than absolutely, which is why they can never go negative, and why an instrument at 500 moves more in absolute terms than one at 5.

On top of that come three things that make a market feel alive:

• A shared market factor. Every price step rolls a shock that hits all instruments — how hard is determined by beta. That is why stocks move in waves rather than independently.
• Mean reversion to fair value. A gentle pull keeps an instrument from drifting off into nowhere after a lucky streak.
• Your own trading. Every execution shifts the price — roughly with the square root of your size divided by the instrument's liquidity. Part of that sticks, the larger part fades away again.

One real hour equals one trading day. Only then do annual figures such as "30 % volatility" produce visible movement within a single session.

Your order looks for the other side in this order:

1. Limit orders from other players, by price-time priority. The better price goes first; at equal prices the older order wins. Execution happens at the resting order's price — so the impatient side pays the premium.
2. The market maker, who continuously quotes bid and ask around the model price. That way someone is always trading — at the spread, and with a premium for large sizes.

Whatever a market order cannot get immediately is cancelled. A limit order rests in the book until it is filled, expires, or you cancel it.

Announced: new listings and positive special effects. The message reaches you on every device you are signed in on, at the same moment.

Not announced: price crashes. Those simply happen. If you want to notice them, you have to look at the quotes yourself — just as in real life nobody sends you a heads-up before things go down.

Only play money is traded here. There are no deposits or withdrawals, no payment details and no connection to real markets. All companies are fictional. This is a learning game and expressly not investment advice.