How to calculate Bitfinex's contract funding rate?

To calculate Bitfinex's funding rate, use the formula F = p clamp(r - p, -1 * clampCap, clampCap), where p is the Premium Index, r is the Interest Rate, and clampCap limits extreme values.

Apr 16, 2025 at 12:49 am

Understanding how to calculate Bitfinex's contract funding rate is crucial for traders engaging in perpetual futures contracts on this platform. The funding rate is a mechanism designed to keep the price of perpetual futures in line with the spot price of the underlying asset. This article will guide you through the process of calculating the funding rate on Bitfinex, explaining each component involved and providing a practical example.

What is the Funding Rate?

The funding rate is a periodic payment made between traders holding long and short positions in perpetual futures contracts. It helps to ensure that the futures price does not deviate significantly from the spot price. If the funding rate is positive, long position holders pay short position holders, and if it's negative, short position holders pay long position holders.

Components of the Funding Rate

To calculate the funding rate on Bitfinex, you need to understand its three main components:

• Interest Rate (r): This is the average of the borrowing rates for the base and quote currencies. Bitfinex uses a proprietary formula to determine this rate.
• Premium Index (p): This is calculated as the difference between the perpetual futures contract price and the spot price, averaged over a specific time period.
• Clamp Function: This function limits the funding rate to prevent extreme values. The clamp function ensures that the funding rate does not exceed a certain range.

Formula for the Funding Rate

The funding rate (F) on Bitfinex is calculated using the following formula:

[ F = p + clamp(r - p, -1 * clampCap, clampCap) ]

Where:

• p is the Premium Index.
• r is the Interest Rate.
• clampCap is the maximum value that the clamp function can return, which is set by Bitfinex.

Calculating the Premium Index

The Premium Index (p) is calculated as the time-weighted average difference between the perpetual futures contract price and the spot price over a specific period. Bitfinex typically uses a 1-hour interval to calculate this average. The formula for the Premium Index is:

[ p = \frac{1}{n} \sum_{i=1}^{n} (IndexPrice_i - MarkPrice_i) ]

Where:

• n is the number of data points in the time interval.
• IndexPrice_i is the spot price at time i.
• MarkPrice_i is the perpetual futures contract price at time i.

Calculating the Interest Rate

The Interest Rate (r) is calculated as the average of the borrowing rates for the base and quote currencies. Bitfinex uses a proprietary formula to determine these rates, which are influenced by market conditions and liquidity. For example, if the base currency is Bitcoin (BTC) and the quote currency is US Dollar (USD), the interest rate would be:

[ r = \frac{BorrowRate{BTC} + BorrowRate{USD}}{2} ]

Applying the Clamp Function

The clamp function is used to limit the funding rate to prevent extreme values. The clamp function is defined as:

[ clamp(x, min, max) = \begin{cases}
min & \text{if } x < min \
x & \text{if } min \leq x \leq max \
max & \text{if } x > max
\end{cases} ]

On Bitfinex, the clampCap is typically set to 0.05%, meaning the funding rate can range from -0.05% to 0.05%.

Practical Example of Calculating the Funding Rate

Let's walk through a practical example to understand how to calculate the funding rate on Bitfinex.

• Premium Index (p): Suppose over the last hour, the average difference between the perpetual futures contract price and the spot price is 0.02%.
• Interest Rate (r): Assume the average borrowing rate for BTC and USD is 0.03%.
• ClampCap: The clampCap is set to 0.05%.

Using the funding rate formula:

[ F = p + clamp(r - p, -1 * clampCap, clampCap) ]
[ F = 0.02\% + clamp(0.03\% - 0.02\%, -0.05\%, 0.05\%) ]
[ F = 0.02\% + clamp(0.01\%, -0.05\%, 0.05\%) ]
[ F = 0.02\% + 0.01\% ]
[ F = 0.03\% ]

In this example, the funding rate is 0.03%, meaning long position holders will pay short position holders 0.03% of their position value.

Steps to Calculate the Funding Rate on Bitfinex

To calculate the funding rate on Bitfinex, follow these steps:

• Determine the Premium Index:

  • Collect the spot price and perpetual futures contract price data for the last hour.
  • Calculate the time-weighted average difference between these prices.

• Determine the Interest Rate:

  • Obtain the borrowing rates for the base and quote currencies.
  • Calculate the average of these rates.

• Apply the Clamp Function:

  • Calculate the difference between the interest rate and the premium index.
  • Use the clamp function to limit this difference within the clampCap range.

• Calculate the Funding Rate:

  • Add the premium index to the result of the clamp function.

Frequently Asked Questions

Q1: How often is the funding rate calculated on Bitfinex?

The funding rate on Bitfinex is calculated and applied every 8 hours. This ensures that the perpetual futures contract price remains closely aligned with the spot price.

Q2: Can the funding rate on Bitfinex be negative?

Yes, the funding rate can be negative. If the premium index is negative and the clamp function results in a negative value, the funding rate will be negative, meaning short position holders will pay long position holders.

Q3: What happens if the funding rate exceeds the clampCap?

The clamp function ensures that the funding rate does not exceed the clampCap. If the calculated funding rate would be outside this range, it is adjusted to the maximum or minimum value allowed by the clampCap.

Q4: How does the funding rate affect my trading on Bitfinex?

The funding rate directly impacts the profitability of your trades. If you hold a long position and the funding rate is positive, you will pay the funding rate to short position holders, which can reduce your profits or increase your losses. Conversely, if you hold a short position and the funding rate is positive, you will receive payments from long position holders, potentially increasing your profits or reducing your losses.