Predict Fees and Limits

Fees

In the interest of fairness, Predict fees are symmetric.

This means that, in a given market, parties trading the same volume of complementary shares should expect to pay the same fee.

Consider the following two transactions:

• Alice sells 100 YES shares at a per-share price of $0.70

• Bob buys 100 NO shares at a per-share price of $0.30

Here, it stands that Alice and Bob should be charged the same for their activities — but Alice will receive USDB, while Bob will receive NO shares. To standardize the fee, we apply the following calculations:

For selling

$$fee = 0.005*min(price,1-price)*\frac{size}{price}$$

For buying

$$fee = 0.005*min(price,1-price)*size$$

In practice

Alice sells 100 YES shares at $0.70:

$$fee = 0.005*min(0.70,0.30)*\frac{100}{0.7} = 0.005*0.3*\frac{100}{0.7} = 0.214$$

The result provided above references the number of shares extracted as a fee, which is equivalent to 15¢.

Bob buys 100 NO shares at $0.30:

$$fee = 0.005 * min(0.30,0.70) * 100 = 0.005*0.3*100 = 0.15$$

Here, our result is the dollar value extract as a fee — in other words, 15¢.

Limits

For any given market, a maximum of 10 limit orders can be placed concurrently by a single user/address.

In addition, there is a minimum order amount of 1 USDB.