Understanding Perpetual Swap Funding Fees: A Comprehensive Guide

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The funding fee mechanism is a core component of perpetual swap contracts, designed to ensure their trading price closely tracks the underlying spot market index. This system facilitates regular cash flow exchanges between long and short position holders, effectively tethering the contract's price to its index price.

When the funding rate is positive, traders holding long positions pay funding fees to those holding short positions. Conversely, a negative funding rate means short position holders pay funding fees to long position holders. It is important to note that the platform merely facilitates this transfer between users and does not collect any service fee from these payments.

How Funding Fee Timings Work

Typically, funding fees are exchanged every eight hours at 00:00, 08:00, and 16:00 (UTC+8). However, some specific contracts may settle fees at different intervals, such as every 1, 2, or 4 hours. The process is executed at a millisecond level, ensuring no interruption to ongoing trading activities.

Only traders who hold open positions at the exact moment of the funding fee calculation are obligated to pay or receive the fee. If you close your position before the snapshot is taken, you will neither pay nor receive a funding fee. Furthermore, if a perpetual contract is delisted before a scheduled funding interval, that period's fee is canceled and will not be collected or distributed. The actual calculation window can last up to one minute. For instance, if a trader opens a position at 00:00:20 (UTC+8) and the funding calculation is still ongoing, they may still be liable for that period's funding fee.

Please be aware that these timing schedules are subject to change based on real-time market conditions.

Calculating the Funding Rate

Original Funding Rate Calculation Logic

The original formula was:
Funding Rate = Clamp [MA (Premium Index – Interest Rate), Funding Rate Cap, Funding Rate Floor]

New Funding Rate Calculation Logic

To provide a more professional trading experience, the platform has rolled out an updated calculation formula. The new logic is implemented in batches across different perpetual contracts.

The new formula is:
Funding Rate = clamp [Average Premium Index + clamp (Interest Rate – Average Premium Index, 0.05%, -0.05%), Funding Rate Cap, Funding Rate Floor]

Understanding Depth-Weighted Price

The depth-weighted bid/ask price is the average execution price to fill an order of a specific "Depth Weighted Amount."

Example: Calculating BTCUSDT Depth-Weighted Bid Price
Assume the Depth Weighted Amount is 20,000 USDT.

Order Book LevelPrice (USDT)Quantity (BTC)Cumulative Value (USDT)Cumulative Quantity (BTC)
1 (Best Bid)90,0000.021,8000.02
289,9000.061,800 + (89,900 * 0.06) = 7,1940.08
389,7000.167,194 + (89,700 * 0.16) = 21,5460.24

The required amount (20,000 USDT) is not fully filled by Level 2 (7,194 USDT). We need 12,806 USDT more from Level 3.
The quantity needed from Level 3 is 12,806 / 89,700 ≈ 0.14276 BTC.
Depth Weighted Bid Price = Total Amount / Total Quantity = 20,000 / (0.02 + 0.06 + 0.14276) ≈ 89,780.8 USDT

Calculating Your Funding Fee Cost

The actual funding fee for your position is calculated as:
Funding Fee = Position Value × Funding Rate

The method for calculating position value differs between contract types.

For USDT-Margined Contracts

Position Value = Number of Contracts × Contract Face Value × Mark Price

Example:
You hold 10 long contracts of BTCUSDT.

Position Value = 10 × 0.01 × 60,000 = 6,000 USDT
Funding Fee (to pay) = 6,000 × 0.1% = 6 USDT

For Coin-Margined (Inverse) Contracts

Position Value = (Number of Contracts × Contract Face Value) / Mark Price

Example:
You hold 100 short contracts of ETHUSD.

Position Value = (100 × 10) / 4,000 = 0.25 ETH
Funding Fee (to receive) = 0.25 × 0.1% = 0.00025 ETH

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How Funding Fees Are Collected and Distributed

The platform's method for handling the transfer of fees depends on your margin mode.

ScenarioProcess
Paying a Funding FeeThe full fee is collected. This deduction can potentially trigger liquidation if it reduces your margin balance critically.
Isolated Margin: Fee is deducted directly from the isolated position's margin. No open orders are canceled.
Cross Margin: Fee is deducted from the available equity in your cross margin account. No open orders are canceled.
Receiving a Funding FeeThe full fee is distributed to you.
Isolated Margin: Fee is credited directly to the isolated position's margin.
Cross Margin: Fee is credited to the available equity in your cross margin account.

Frequently Asked Questions

What is the purpose of a funding fee?
The funding fee mechanism ensures the price of a perpetual swap contract remains anchored to its underlying spot index. It incentivizes traders to push the market price toward the fair value when it deviates, creating a balanced market.

If I close my position right before funding time, do I still pay?
No. Funding fees are only charged to traders who hold an open position at the precise moment the funding snapshot is taken. If you close your position before this event, you will avoid the fee for that period.

Can I earn money from funding fees?
Yes. If you hold a position in the direction that the funding rate favors, you will receive fees from the opposing side. For example, if the rate is negative and you are long, you will receive payments from short position holders.

How does leverage affect the funding fee I pay?
Leverage itself does not directly multiply the funding rate. However, it dramatically increases your position value. Since the funding fee is a percentage of your position value, a highly leveraged position will incur a much larger absolute fee amount compared to an unleveraged position of the same nominal size.

Why did the funding rate calculation change?
The updated formula, which incorporates a dynamic interest rate and a depth-weighted premium index, provides a more robust and market-reflective calculation. It aims to improve fairness and enhance the overall trading experience for all users.