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Market Making Dice Game iconETF Arbitrage Game

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6
20s
On easy difficulty, prices are rounded to tenths and weights to whole numbers for easier mental math.
How to play
Objective

Spot mispricings between an ETF and its underlying stock basket. Buy underpriced ETFs, sell overpriced ones, and compete against 3 AI traders to maximize your P&L.

What is NAV?

The Net Asset Value (NAV) is the fair value of the ETF, calculated as the weighted sum of the underlying stock prices. Each round you see a table like this:

TickerWeightPriceW × P
AAPL0.25$200.00$50.00
MSFT0.25$400.00$100.00
GOOGL0.25$150.00$37.50
AMZN0.25$200.00$50.00
$237.50

NAV = sum of W × P = $237.50

Now compare the NAV to the ETF prices shown below the table:

ETF bid$233.20
ETF ask$233.40

In this example the NAV ($237.50) is higher than the ask ($233.40), so the ETF is underpriced - you should Buy. If the NAV were lower than the bid, the ETF would be overpriced and you'd Sell.

Each round
  • A random stock basket is chosen at the start and stays the same for the whole game
  • Each round the stock prices shift slightly — the Change and % columns show which moved
  • Calculate the NAV mentally by summing all weight × price values
  • Compare your NAV to the ETF bid and ask prices
  • Decide: Buy (NAV > ask), Sell (NAV < bid), or Skip if the difference is too small
  • Choose how many units (1-20) to trade - more units means more risk and reward
  • Race against 3 AI traders who are also calculating and trading
Scoring example

Continuing the example above - you buy 10 units at the ask price of $233.40:

Gross P&L
($237.50 - $233.40) × 10 = +$41.00
Transaction cost
-$10.00
First trader bonus
+$6.20 (20%)
Net P&L
+$37.20

If you had traded in the wrong direction (sold instead of bought), the gross P&L would be -$41.00, plus you'd still pay the $10 transaction cost.

Tips
  • Sum the W × P column to quickly find the NAV - the table does the multiplication for you
  • Speed matters - be the first to trade to earn a 20% bonus on your profit
  • Skip small opportunities - if the difference between NAV and ETF price is small, the $10 transaction cost may eat your profit
  • Size wisely - more units amplifies both gains and losses