CardVault
MARKET OPEN · Set Spreads · Manage Risk

Card Market Maker

You are the dealer. Set bid/ask prices on 5 cards, manage your inventory as AI traders buy and sell, and profit from the spread.

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SETUP
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Set your bid (buy) and ask (sell) prices for each card. The fair market value is shown for reference. You start with 0 inventory.

Cards from 10,119 sports cards in the CardVault database. AI trader behavior is simulated.

How Market Making Works

1. Set Your Spreads

For each of 5 cards, set a bid price (what you will buy at) and an ask price (what you will sell at). The gap is your profit margin.

2. Attract Traders

AI traders arrive every few seconds with buy or sell orders. Competitive prices attract more volume. Wide spreads scare traders away.

3. Manage Inventory

You need cards in inventory to sell. But holding too much is risky — if fair value drops, your inventory loses value. Balance is key.

4. Lock In Profits

After 20 trades (or 2 minutes), the market closes. Your score = realized profits + unrealized inventory value. S through F grading.

Real-World Market Making

Market makers exist in every financial market — stocks, bonds, and yes, cards. Card dealers at shows are essentially market makers: they set buy prices (what they will pay you) and sell prices (what they charge), profiting from the spread.

A typical card dealer spread is 30-50% (buy at $50, sell at $75-100). Online platforms have compressed this with transparency. Understanding market making helps you negotiate better at card shows and recognize fair dealer pricing.

Frequently Asked Questions

What is the Card Market Maker?
The Card Market Maker is a trading simulator where you act as a dealer making markets in sports cards. You set bid prices (what you will buy for) and ask prices (what you will sell for) on 5 cards. AI traders arrive with buy and sell orders. You profit from the bid-ask spread, but must manage inventory risk — if you buy too many cards, you are exposed to price changes.
How do bid and ask prices work?
The bid price is what you offer to buy a card for. The ask price is what you will sell it for. The difference (the spread) is your potential profit per trade. Wider spreads mean more profit per trade but fewer trades. Narrow spreads attract more traders but with thinner margins. Finding the right balance is the core challenge.
What happens if I run out of inventory?
If a buyer wants a card you don't have in inventory, you cannot fill the order and lose the sale. This is why managing your bid prices to attract sellers is important — you need inventory to sell. But holding too much inventory is risky if market prices shift.
How is the final score calculated?
Your score is based on total profit from completed trades, minus inventory risk (unrealized gains or losses on cards you still hold). Grades range from S (exceptional market making) down to F. The most profitable market makers balance tight spreads with active inventory management.
Are the card prices real?
All cards come from our database of 9,600+ real sports cards with estimated market values. Fair market value is used as the reference price. AI trader behavior and price movements are simulated to create realistic market dynamics.
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