Overview
A Perpetual Swap is an innovative product invented by BitMEX. The Perpetual Contract is similar to a traditional Futures Contract, but has a few differences:
- There is no expiry or settlement (subject to the Early Settlement).
- Perpetual Contracts mimic a margin-based spot market and hence trade close to the underlying reference Index Price.
- The Funding mechanism is used to tether contracts to their underlying spot price.
- This is in contrast to a Futures Contract which may trade at significantly different prices due to basis.
- Each perpetual contract has its own details which can be found in its Contract Specifications. These details include:
- Reference Index
- Funding Rate
- Maximum Leverage
Leverage
Perpetual contracts do not require traders to post 100% of collateral as margin, because of this you can trade with leverage of up to 100x on some of BitMEX’s contracts. Margin on BitMEX is denominated in Bitcoin and other cryptocurrencies, allowing traders to speculate on the future value of its products using only Bitcoin or other cryptocurrencies.
Payout
BitMEX offers perpetual contracts that have inverse, linear and quanto payouts. This document explains the key differences between these payouts, and some implications for traders.
The product suits traders who prefer to hold positions for a long time and do not want their positions to fluctuate in value due to large swings in basis.
List Of Contracts
Inverse Contracts
| Contract | Contract Specs | Listed | Index | Payout Type | Max Leverage | Multiplier |
|---|---|---|---|---|---|---|
| XBTETH | XBTETH details | 7/31/2023 | .BXBTETH | Inverse Perpetual | 100x | 0.01 ETH |
| XBTEUR | XBTEUR details | 6/4/2021 | .BXBTEUR | Inverse Perpetual | 50x | 1 EUR |
| XBTUSD | XBTUSD details | 5/4/2016 | .BXBT | Inverse Perpetual | 100x | 1 USD |
Linear Contracts
| Contract | Contract Specs | Listed | Index | Payout Type | Max Leverage | Multiplier |
|---|---|---|---|---|---|---|
| 1000000MOGUSDT | 1000000MOGUSDT details | 12/4/2024 | .B1000000MOGT | Linear Perpetual | 50x | 1 USDT |
| 100BONKUSDT | 100BONKUSDT details | 11/20/2023 | .B100BONKT | Linear Perpetual | 25x | 1 USDT |
| AAVEUSDT | AAVEUSDT details | 9/3/2024 | .BAAVET | Linear Perpetual | 20x | 0.0001 USDT |
| ACTUSDT | ACTUSDT details | 11/11/2024 | .BACTT | Linear Perpetual | 50x | 1 USDT |
| ADAUSDT | ADAUSDT details | 10/22/2021 | .BADAT | Linear Perpetual | 33.33x | 0.01 USDT |
| AEVOUSDT | AEVOUSDT details | 3/13/2024 | .BAEVOT | Linear Perpetual | 25x | 1 USDT |
| AI16ZUSDT | AI16ZUSDT details | 1/14/2025 | .BAI16ZT | Linear Perpetual | 50x | 0.01 USDT |
| AIXBTUSDT | AIXBTUSDT details | 1/14/2025 | .BAIXBTT | Linear Perpetual | 50x | 1 USDT |
| APEUSDT | APEUSDT details | 3/18/2022 | .BAPET | Linear Perpetual | 33.33x | 0.001 USDT |
| APTUSDT | APTUSDT details | 10/19/2022 | .BAPTT30M | Linear Perpetual | 33.33x | 0.001 USDT |
| APUUSDT | APUUSDT details | 11/8/2024 | .BAPUT | Linear Perpetual | 50x | 1 USDT |
| AVAXUSDT | AVAXUSDT details | 2/18/2022 | .BAVAXT | Linear Perpetual | 20x | 0.0001 USDT |
| BANANAUSDT | BANANAUSDT details | 8/15/2024 | .BBANANAT | Linear Perpetual | 25x | 0.0001 USDT |
| BCHUSDT | BCHUSDT details | 10/4/2021 | .BBCHT | Linear Perpetual | 50x | 0.00001 USDT |
| BERAUSDT | BERAUSDT details | 2/7/2025 | .BBERAT | Linear Perpetual | 50x | 0.01 USDT |
| BIGTIMEUSDT | BIGTIMEUSDT details | 10/12/2023 | .BBIGTIMET | Linear Perpetual | 25x | 1 USDT |
| BIOUSDT | BIOUSDT details | 1/5/2025 | .BBIOT | Linear Perpetual | 50x | 1 USDT |
| BLURUSDT | BLURUSDT details | 2/15/2023 | .BBLURT | Linear Perpetual | 33.33x | 0.001 USDT |
| BMEXUSDT | BMEXUSDT details | 11/8/2022 | .BBMEXT | Linear Perpetual | 20x | 0.001 USDT |
| BNBUSDT | BNBUSDT details | 10/22/2021 | .BBNBT | Linear Perpetual | 50x | 0.0001 USDT |
| BOMEUSDT | BOMEUSDT details | 3/17/2024 | .BBOMET | Linear Perpetual | 25x | 1 USDT |
| BRETTUSDT | BRETTUSDT details | 12/4/2024 | .BBRETTT | Linear Perpetual | 50x | 1 USDT |
| BROCCOLIUSDT | BROCCOLIUSDT details | 2/14/2025 | .BBROCCOLIT | Linear Perpetual | 50x | 1 USDT |
| CATUSDT | CATUSDT details | 9/12/2024 | .BCATT | Linear Perpetual | 50x | 1 USDT |
| CHILLGUYUSDT | CHILLGUYUSDT details | 11/22/2024 | .BCHILLGUYT | Linear Perpetual | 50x | 1 USDT |
| CYBERUSDT | CYBERUSDT details | 8/15/2023 | .BCYBERT | Linear Perpetual | 4x | 1 USDT |
| DOGEUSDT | DOGEUSDT details | 10/22/2021 | .BDOGET | Linear Perpetual | 100x | 0.01 USDT |
| DOGSUSDT | DOGSUSDT details | 8/26/2024 | .BDOGST | Linear Perpetual | 50x | 1 USDT |
| DOTUSDT | DOTUSDT details | 10/22/2021 | .BDOTT | Linear Perpetual | 33.33x | 0.001 USDT |
| DUCKUSDT | DUCKUSDT details | 1/22/2025 | .BDUCKT | Linear Perpetual | 50x | 1 USDT |
| DYMUSDT | DYMUSDT details | 2/6/2024 | .BDYMT | Linear Perpetual | 25x | 1 USDT |
| ENAUSDT | ENAUSDT details | 4/2/2024 | .BENAT | Linear Perpetual | 25x | 1 USDT |
| ETHUSDT | ETHUSDT details | 10/4/2021 | .BETHT | Linear Perpetual | 100x | 0.00001 USDT |
| ETHXBT | ETHXBT details | 7/24/2017 | .BETHXBT | Linear Perpetual | 50x | 1 XBT |
| FARTCOINUSDT | FARTCOINUSDT details | 12/23/2024 | .BFARTCOINT | Linear Perpetual | 50x | 1 USDT |
| FILUSDT | FILUSDT details | 9/14/2023 | .BFILT | Linear Perpetual | 10x | 1 USDT |
| FLOKIUSDT | FLOKIUSDT details | 9/12/2024 | .BFLOKIT | Linear Perpetual | 50x | 0.1 USDT |
| GMEUSDT | GMEUSDT details | 6/3/2024 | .BGMET | Linear Perpetual | 10x | 1 USDT |
| GOATUSDT | GOATUSDT details | 10/18/2024 | .BGOATT | Linear Perpetual | 50x | 1 USDT |
| GPSUSDT | GPSUSDT details | 3/4/2025 | .BGPST | Linear Perpetual | 50x | 1 USDT |
| HIVEUSDT | HIVEUSDT details | 12/23/2024 | .BHIVET | Linear Perpetual | 50x | 1 USDT |
| HYPEUSDT | HYPEUSDT details | 12/23/2024 | .BHYPET | Linear Perpetual | 50x | 0.01 USDT |
| INJUSDT | INJUSDT details | 10/31/2023 | .BINJT | Linear Perpetual | 25x | 1 USDT |
| IPUSDT | IPUSDT details | 2/12/2025 | .BIPT | Linear Perpetual | 50x | 0.01 USDT |
| JAILSTOOLUSDT | JAILSTOOLUSDT details | 2/10/2025 | .BJAILSTOOLT | Linear Perpetual | 50x | 1 USDT |
| JELLYJELLYUSDT | JELLYJELLYUSDT details | 3/26/2025 | .BJELLYJELLYT | Linear Perpetual | 25x | 1 USDT |
| JUPUSDT | JUPUSDT details | 1/31/2024 | .BJUPT | Linear Perpetual | 25x | 1 USDT |
| JUSDT | JUSDT details | 1/22/2025 | .BJT | Linear Perpetual | 50x | 0.01 USDT |
| KAITOUSDT | KAITOUSDT details | 2/20/2025 | .BKAITOT | Linear Perpetual | 50x | 0.01 USDT |
| KLAYUSDT | KLAYUSDT details | 9/6/2022 | .BKLAYT30M | Linear Perpetual | 100x | 0.01 USDT |
| LDOUSDT | LDOUSDT details | 1/10/2024 | .BLDOT | Linear Perpetual | 20x | 1 USDT |
| LINKUSDT | LINKUSDT details | 9/29/2023 | .BLINKT | Linear Perpetual | 50x | 0.001 USDT |
| LTCUSDT | LTCUSDT details | 10/4/2021 | .BLTCT | Linear Perpetual | 50x | 0.0001 USDT |
| LUNAUSDT | LUNAUSDT details | 5/31/2022 | .BLUNAT | Linear Perpetual | 20x | 0.001 USDT |
| MANTAUSDT | MANTAUSDT details | 1/17/2024 | .BMANTAT | Linear Perpetual | 10x | 1 USDT |
| MELANIAUSDT | MELANIAUSDT details | 1/20/2025 | .BMELANIAT | Linear Perpetual | 25x | 0.01 USDT |
| MEMEMEXTUSDT | MEMEMEXTUSDT details | 6/27/2024 | .BMEMEMEXT | Linear Perpetual | 25x | 0.0001 USDT |
| MEMEUSDT | MEMEUSDT details | 11/3/2023 | .BMEMET | Linear Perpetual | 25x | 1 USDT |
| MEUSDT | MEUSDT details | 12/9/2024 | .BMET | Linear Perpetual | 50x | 1 USDT |
| MEWUSDT | MEWUSDT details | 4/3/2024 | .BMEWT | Linear Perpetual | 25x | 1 USDT |
| MOVEUSDT | MOVEUSDT details | 12/9/2024 | .BMOVET | Linear Perpetual | 50x | 1 USDT |
| MUBARAKUSDT | MUBARAKUSDT details | 3/17/2025 | .BMUBARAKT | Linear Perpetual | 50x | 1 USDT |
| MYROUSDT | MYROUSDT details | 1/22/2024 | .BMYROT | Linear Perpetual | 25x | 1 USDT |
| NEARUSDT | NEARUSDT details | 11/6/2023 | .BNEART | Linear Perpetual | 33.33x | 0.001 USDT |
| NILUSDT | NILUSDT details | 3/24/2025 | .BNILT | Linear Perpetual | 50x | 0.01 USDT |
| NOTUSDT | NOTUSDT details | 5/16/2024 | .BNOTT | Linear Perpetual | 25x | 1 USDT |
| ONDOUSDT | ONDOUSDT details | 1/18/2024 | .BONDOT | Linear Perpetual | 25x | 1 USDT |
| OPUSDT | OPUSDT details | 1/15/2024 | .BOPT | Linear Perpetual | 20x | 1 USDT |
| PENGUUSDT | PENGUUSDT details | 12/17/2024 | .BPENGUT | Linear Perpetual | 50x | 1 USDT |
| PEPEUSDT | PEPEUSDT details | 5/2/2023 | .BPEPET | Linear Perpetual | 50x | 1 USDT |
| PIUSDT | PIUSDT details | 2/20/2025 | .BPIT | Linear Perpetual | 50x | 0.01 USDT |
| PIXELUSDT | PIXELUSDT details | 2/19/2024 | .BPIXELT | Linear Perpetual | 25x | 1 USDT |
| PNUTUSDT | PNUTUSDT details | 11/11/2024 | .BPNUTT | Linear Perpetual | 50x | 1 USDT |
| POLUSDT | POLUSDT details | 9/4/2024 | .BPOLT | Linear Perpetual | 33.33x | 0.01 USDT |
| POPCATUSDT | POPCATUSDT details | 7/23/2024 | .BPOPCATT | Linear Perpetual | 10x | 1 USDT |
| PYTHUSDT | PYTHUSDT details | 11/20/2023 | .BPYTHT | Linear Perpetual | 25x | 1 USDT |
| RAYUSDT | RAYUSDT details | 1/14/2025 | .BRAYT | Linear Perpetual | 50x | 0.01 USDT |
| REDUSDT | REDUSDT details | 3/6/2025 | .BREDT | Linear Perpetual | 50x | 1 USDT |
| SAGAUSDT | SAGAUSDT details | 4/10/2024 | .BSAGAT | Linear Perpetual | 25x | 1 USDT |
| SEIUSDT | SEIUSDT details | 8/15/2023 | .BSEIT | Linear Perpetual | 20x | 1 USDT |
| SHELLUSDT | SHELLUSDT details | 2/27/2025 | .BSHELLT | Linear Perpetual | 50x | 0.1 USDT |
| SHIBUSDT | SHIBUSDT details | 8/29/2023 | .BSHIBT | Linear Perpetual | 33.33x | 1 USDT |
| SOLUSDT | SOLUSDT details | 11/3/2021 | .BSOLT | Linear Perpetual | 100x | 0.0001 USDT |
| SOLVUSDT | SOLVUSDT details | 1/22/2025 | .BSOLVT | Linear Perpetual | 50x | 1 USDT |
| STRKUSDT | STRKUSDT details | 2/20/2024 | .BSTRKT | Linear Perpetual | 25x | 1 USDT |
| SUIUSDT | SUIUSDT details | 5/3/2023 | .BSUIT | Linear Perpetual | 33.33x | 0.001 USDT |
| SUSDT | SUSDT details | 1/17/2025 | .BST | Linear Perpetual | 20x | 0.01 USDT |
| TIAUSDT | TIAUSDT details | 10/31/2023 | .BTIAT | Linear Perpetual | 33.33x | 1 USDT |
| TNSRUSDT | TNSRUSDT details | 4/9/2024 | .BTNSRT | Linear Perpetual | 25x | 1 USDT |
| TONUSDT | TONUSDT details | 8/18/2024 | .BTONT | Linear Perpetual | 20x | 1 USDT |
| TRUMPOFFICIALUSDT | TRUMPOFFICIALUSDT details | 1/18/2025 | .BTRUMPOFFICIALT | Linear Perpetual | 25x | 0.01 USDT |
| TRXUSDT | TRXUSDT details | 11/6/2023 | .BTRXT | Linear Perpetual | 33.33x | 0.1 USDT |
| TSTUSDT | TSTUSDT details | 2/10/2025 | .BTSTT | Linear Perpetual | 50x | 1 USDT |
| TUTUSDT | TUTUSDT details | 3/18/2025 | .BTUTT | Linear Perpetual | 25x | 1 USDT |
| USUALUSDT | USUALUSDT details | 12/18/2024 | .BUSUALT | Linear Perpetual | 50x | 1 USDT |
| VELOUSDT | VELOUSDT details | 12/14/2024 | .BVELOT | Linear Perpetual | 50x | 1 USDT |
| VINEUSDT | VINEUSDT details | 1/24/2025 | .BVINET | Linear Perpetual | 50x | 1 USDT |
| VVVUSDT | VVVUSDT details | 1/28/2025 | .BVVVT | Linear Perpetual | 50x | 0.01 USDT |
| WIFUSDT | WIFUSDT details | 1/16/2024 | .BWIFT | Linear Perpetual | 25x | 1 USDT |
| WLDUSDT | WLDUSDT details | 2/21/2024 | .BWLDT | Linear Perpetual | 25x | 1 USDT |
| WOOUSDT | WOOUSDT details | 12/13/2023 | .BWOOT | Linear Perpetual | 25x | 1 USDT |
| WUSDT | WUSDT details | 4/3/2024 | .BWT | Linear Perpetual | 25x | 1 USDT |
| XAIUSDT | XAIUSDT details | 1/9/2024 | .BXAIT | Linear Perpetual | 25x | 1 USDT |
| XBTUSDT | XBTUSDT details | 10/4/2021 | .BXBTT | Linear Perpetual | 100x | 0.000001 USDT |
| XRDUSDT | XRDUSDT details | 1/16/2024 | .BXRDT | Linear Perpetual | 25x | 1 USDT |
| XRPUSDT | XRPUSDT details | 10/4/2021 | .BXRPT | Linear Perpetual | 100x | 0.01 USDT |
| ZKUSDT | ZKUSDT details | 6/17/2024 | .BZKT | Linear Perpetual | 25x | 1 USDT |
| ZROUSDT | ZROUSDT details | 6/20/2024 | .BZROT | Linear Perpetual | 25x | 1 USDT |
Quanto Contracts
| Contract | Contract Specs | Listed | Index | Payout Type | Max Leverage | Multiplier |
|---|---|---|---|---|---|---|
| AAVEUSD | AAVEUSD details | 9/3/2024 | .BAAVE | Quanto Perpetual | 20x | 0.000001 XBT |
| ADAUSD | ADAUSD details | 9/24/2021 | .BADA | Quanto Perpetual | 33.33x | 0.0001 XBT |
| APTUSD | APTUSD details | 10/19/2022 | .BAPT | Quanto Perpetual | 50x | 0.00001 XBT |
| AVAXUSD | AVAXUSD details | 9/24/2021 | .BAVAX | Quanto Perpetual | 20x | 0.00001 XBT |
| AXSUSD | AXSUSD details | 10/15/2021 | .BAXS | Quanto Perpetual | 20x | 0.000001 XBT |
| BCHUSD | BCHUSD details | 6/1/2020 | .BBCH | Quanto Perpetual | 50x | 0.000001 XBT |
| BLURUSD | BLURUSD details | 2/15/2023 | .BBLUR | Quanto Perpetual | 33.33x | 0.0001 XBT |
| BNBUSD | BNBUSD details | 9/24/2021 | .BBNB | Quanto Perpetual | 50x | 0.000001 XBT |
| DOGEUSD | DOGEUSD details | 9/24/2021 | .BDOGE | Quanto Perpetual | 100x | 0.001 XBT |
| DOTUSD | DOTUSD details | 9/24/2021 | .BDOT | Quanto Perpetual | 33.33x | 0.00001 XBT |
| DYDXUSD | DYDXUSD details | 12/1/2023 | .BDYDX | Quanto Perpetual | 10x | 0.0001 XBT |
| EOSUSD | EOSUSD details | 10/15/2021 | .BEOS | Quanto Perpetual | 33.33x | 0.0001 XBT |
| ETHUSD | ETHUSD details | 7/18/2018 | .BETH | Quanto Perpetual | 100x | 0.000001 XBT |
| FILUSD | FILUSD details | 9/13/2023 | .BFIL | Quanto Perpetual | 10x | 0.0001 XBT |
| GMTUSD | GMTUSD details | 4/8/2022 | .BGMT | Quanto Perpetual | 33.33x | 0.0001 XBT |
| LDOUSD | LDOUSD details | 1/10/2024 | .BLDO | Quanto Perpetual | 20x | 0.0001 XBT |
| LINKUSD | LINKUSD details | 10/15/2021 | .BLINK | Quanto Perpetual | 50x | 0.00001 XBT |
| LTCUSD | LTCUSD details | 7/21/2020 | .BLTC | Quanto Perpetual | 50x | 0.000002 XBT |
| MERLUSD | MERLUSD details | 4/18/2024 | .BMERL | Quanto Perpetual | 10x | 0.0001 XBT |
| NEARUSD | NEARUSD details | 4/29/2022 | .BNEAR | Quanto Perpetual | 33.33x | 0.0001 XBT |
| OPUSD | OPUSD details | 1/15/2024 | .BOP | Quanto Perpetual | 20x | 0.0001 XBT |
| ORDIUSD | ORDIUSD details | 11/10/2023 | .BORDI | Quanto Perpetual | 10x | 0.00001 XBT |
| PEPEUSD | PEPEUSD details | 5/2/2023 | .BPEPE | Quanto Perpetual | 50x | 10 XBT |
| SHIBUSD | SHIBUSD details | 8/29/2023 | .BSHIB | Quanto Perpetual | 33.33x | 10 XBT |
| SOLUSD | SOLUSD details | 10/15/2021 | .BSOL | Quanto Perpetual | 100x | 0.000001 XBT |
| SUIUSD | SUIUSD details | 5/3/2023 | .BSUI | Quanto Perpetual | 33.33x | 0.00001 XBT |
| TONUSD | TONUSD details | 4/22/2024 | .BTON | Quanto Perpetual | 20x | 0.0001 XBT |
| TRXUSD | TRXUSD details | 11/6/2023 | .BTRX | Quanto Perpetual | 33.33x | 0.001 XBT |
| USDTUSDC | USDTUSDC details | 3/11/2023 | .BUSDTUSDC | Quanto Perpetual | 10x | 0.0001 XBT |
| WLDUSD | WLDUSD details | 7/25/2023 | .BWLD | Quanto Perpetual | 50x | 0.0001 XBT |
| XAUTUSD | XAUTUSD details | 4/9/2024 | .BXAUT | Quanto Perpetual | 25x | 0.000001 XBT |
| XBTUSD_BBX | XBTUSD_BBX details | 8/26/2024 | .BXBT | Quanto Perpetual | 250x | NaN XBT |
| XRPUSD | XRPUSD details | 1/23/2020 | .BXRP | Quanto Perpetual | 100x | 0.0002 XBT |
You can view the full list of perpetual contracts currently available for trading on BitMEX Contract List.
Contract Summary
| Payout Type | Inverse | Linear | Quanto |
|---|---|---|---|
| Example Symbol | XBTUSD | XBTUSDT | ETHUSD |
| Underlying | 1/XBTUSD or USDXBT | XBTUSDT | ETHUSD |
| Multiplier | $1 | 0.000001 USDT | 0.000001 XBT |
| Quote Currency | USD | USDT | USD |
| Margin & PNL Currency | XBT | USDT | XBT |
| XBT Value of 1 Contract | 1/Price * $1 | Multiplier * Price | - |
| USDT Value of 1 Contract | - | Multiplier * Price | - |
| USD Value of 1 Contract | $1 | .BUSDT * USDT Value | .BXBT * XBT Value |
| XBT PNL of 1 Contract | (1/EntryPrice - 1/ExitPrice) * $1 | - | (ExitPrice - EntryPrice) * Multiplier |
| USDT PNL of 1 Contract | - | (ExitPrice - EntryPrice) * Multiplier | - |
What is a Quanto Contract?
A quanto is a type of derivative in which the underlying is denominated in one currency, but the instrument itself is settled in another currency at some fixed rate. Our Quanto Perpetuals operate this way.
These contracts are designed to be easy to trade and understand, but keep in mind as you trade them that your underlying margin and PNL are in Bitcoin. You are still exposed to Bitcoin/USD price risk when trading Quanto Perpetuals, even though the underlying and quote currencies are not Bitcoin.
What is an Inverse Contract?
An inverse contract is worth a fixed amount of the quote currency. In the case of the XBTUSD perpetual, each contract is worth $1 of Bitcoin at any price. XBTUSD is an inverse contract because it is quoted as XBT/USD but the underlying is USD/XBT or 1 / (XBT/USD). It is quoted as an inverse to facilitate hedging US Dollar amounts while the spot market convention is to quote the number of US Dollars per Bitcoin.
This product is suitable for traders who want to go long or short US Dollars against Bitcoin.
What is a Linear Contract?
A linear payout is the simplest to describe, and is used for many swaps. The price of a linear contract is expressed as the price of the underlying against the base currency.
Mechanics of Perpetual Markets
When trading perpetual contracts, a trader needs to be aware of several mechanics of the futures market. The key components a trader needs to be aware of are:
- Multiplier: How much is one contract worth? You can see this information under the Contract Specifications for each instrument.
- Position Marking: Perpetual contracts are marked according to the Fair Price Marking method. The mark price determines Unrealised PNL and liquidations.
- Initial and Maintenance Margin: These key margin levels determine how much leverage one can trade with and at what point liquidation occurs.
- Funding: Any position in a perpetual swap that is open when Funding occurs (every 8 hours) will pay or receive funding.
Traders can observe the current funding rate for a contract on the bottom left hand side of the Trade tab under “Contract Details”. Similarly one can view this rate in the individual “Contract Specifications”. Historical rates are in the Funding History.
Funding
Funding occurs every 8 hours at 04:00 UTC, 12:00 UTC and 20:00 UTC. You will only pay or receive funding if you hold a position at one of these times. If you close your position prior to the funding exchange then you will not pay or receive funding.
The funding you pay or receive is calculated as:
Funding = Mark Value * Funding Rate
Your Mark Value is irrespective of leverage. For example, if you hold 100 XBTUSD contracts, funding is charged/received on the notional value of those contracts, and is not based on how much margin you have assigned to the position.
When the Funding Rate is positive, longs pay shorts. When it is negative, shorts pay longs. See examples.
Funding Rate Calculations
The Funding Rate is comprised of two main parts: the Interest Rate and the Premium / Discount. This rate aims to keep the traded price of the perpetual contract in line with the underlying reference price. In this way, the contract mimics how margin-trading markets work as buyers and sellers of the contract exchange interest payments periodically.
Interest Rate Component
Every contract traded on BitMEX consists of two instruments: a Base currency and a Quote currency. For example, on XBTUSD, the Base currency is XBT while the quote currency is USD. The Interest Rate is a function of interest rates between these two currencies:
Interest Rate (I) = (Funding Quote Rate - Funding Base Rate) / Funding Interval
where
Funding Quote Rate = The Interest Rate for borrowing the Quote currency
Funding Base Rate = The Interest Rate for borrowing the Base currency
Funding Interval = 3 (Since funding occurs every 8 hours)
Note: Under each Contract Specification page, the source borrow market is stated for each Interest Index.
Premium / Discount Component
The perpetual contract may trade at a significant premium or discount to the Mark Price. In those situations, a Premium Index will be used to raise or lower the next Funding Rate to levels consistent with where the contract is trading. Each contract’s Premium Index is available on the specific instrument’s Contract Specifications page and is calculated as follows:
Premium Index (P) = (Max(0, Impact Bid Price - Mark Price) - Max(0, Mark Price - Impact Ask Price)) / Spot Price + Fair Basis used in Mark Price
To learn more about the Impact Bid Price and Impact Ask Price, please read Fair Price Marking.
Final Funding Rate Calculation
BitMEX calculates the Premium Index (P) and Interest Rate (I) every minute and then performs a 8-Hour Time-Weighted-Average-Price (TWAP) over the series of minute rates.
The Funding Rate is next calculated with the 8-Hour Interest Rate Component and the 8-Hour Premium / Discount Component. A +/-0.05% dampener is added.
Funding Rate (F) = Premium Index (P) + clamp(Interest Rate (I) - Premium Index (P), 0.05%, -0.05%)
Hence, if (I - P) is within +/-0.05% then F = P + (I - P) = I. In other words, the Funding Rate will equal the Interest Rate.
This calculated Funding Rate is then applied to a trader’s XBT Position Value to determine the Funding Amount to be paid or received at the Funding Timestamp.
Funding Rate Caps
BitMEX imposes caps on the Funding Rate to ensure the maximum leverage can still be utilized. To do this, two caps are imposed:
- The absolute Funding Rate is capped at 75% of the Initial Margin - Maintenance Margin. If the Initial Margin is 1% and the Maintenance Margin is 0.5%, the maximum Funding Rate will be 75% * (1% - 0.5%)= 0.375%.
- The Funding Rate may not change by more than 75% of the Maintenance Margin between Funding Intervals.
Funding Fees
BitMEX does not charge any fees on funding; it is exchanged directly peer-to-peer.
More Information
Further information and examples of trading the Perpetual Swap is available.
Further information and examples of funding calculations are available.