# Fees

# Fee Reservation in Margin

The margin system reserves sufficient funds to cover fees for both entering and exiting a position, assuming that position exit will occur with a visible taker order, as in the case of liquidation.

# Fee Reservation Scenarios

# Standard Resting Orders

For orders expected to rest in the order book outside the BBO:

Total Margin = Order Margin + (Order Cost × Maker Fee) + (Order Cost × Taker Fee)

# Example

Given:

Order: Sell 1 BTC at $50,000
Initial Margin Rate: 1%
Maker Fee: 0.02%
Taker Fee: 0.05%
Order price above current best ask

Order Margin = 1 × $50,000 × 0.01 = $500
Maker Fee Reserve = 1 × $50,000 × 0.0002 = $10
Taker Fee Reserve = 1 × $50,000 × 0.0005 = $25

Total Margin Required = $500 + $10 + $25 = $535

# Orders Inside the BBO

Orders placed inside the best bid and offer require two taker fees, even if they would rest, to prevent information leakage about hidden orders.

Total Margin = Position Margin + (Order Size × Mark Price × Taker Fee × 2)

# Example

Given:

Order: Buy 1 BTC at $49,950
Current best bid: $49,900
Current best ask: $50,000
Initial Margin Rate: 1%
Taker Fee: 0.05%

Position Margin = 1 × $49,950 × 0.01 = $499.50
Fee Reserve = 1 × $49,950 × 0.0005 × 2 = $49.95

Total Margin Required = $499.50 + $49.95 = $549.45

# Partial Fill with Rest

Orders that partially execute and then rest still require complete fee coverage for the entire original order amount.

# Example

Given:

Order: Buy 2 BTC at $50,000
1 BTC executes immediately
1 BTC rests in the book
Initial Margin Rate: 1%
Maker Fee: 0.02%
Taker Fee: 0.05%

Position Margin for Resting = 1 × $50,000 × 0.01 = $500
Maker Fee Reserve = 1 × $50,000 × 0.0002 = $10
Taker Fee Reserve = 1 × $50,000 × 0.0005 = $25

Total Remaining Margin Required = $500 + $10 + $25 = $535

# Hidden Orders

Hidden orders and variants require margin for their specific maker fee type plus a visible taker fee.

Total Margin = Position Margin + (Order Size × Mark Price × Hidden Maker Fee) + (Order Size × Mark Price × Taker Fee)

# Example

Given:

Hidden Order: Sell 1 BTC at $50,000
Initial Margin Rate: 1%
Hidden Maker Fee: 0.04%
Taker Fee: 0.05%

Position Margin = 1 × $50,000 × 0.01 = $500
Hidden Maker Fee Reserve = 1 × $50,000 × 0.0004 = $20
Taker Fee Reserve = 1 × $50,000 × 0.0005 = $25

Total Margin Required = $500 + $20 + $25 = $545