vibgg
Guides · 3 min read
Funding-rate arbitrage: how it works and what can go wrong
How the spot-perpetual funding trade works, how to calculate its return, and the execution, basis, margin and exchange risks hidden behind a market-neutral position.
·
Funding-rate arbitrage tries to collect funding while reducing exposure to the asset's direction. A common version buys spot and shorts the same dollar amount of the perpetual when funding is positive. Price gains on one leg should then be offset by losses on the other, while the short receives funding. “Market neutral” does not mean risk free.
How far apart are funding rates between exchanges?
The gap between exchanges is real and changes all the time. Among the 245 contracts listed on all 5 exchanges on vibgg, the widest gap right now is on MEW-USDT: 0.21 percentage points of annualised funding between the cheapest and the most expensive exchange. That is the gross opportunity, before margin on both legs, trading costs and the risk that the gap closes while you hold the position.
How a funding rate arbitrage position works
Suppose a trader buys $20,000 of BTC spot and shorts $20,000 of a BTC perpetual. If BTC rises 5%, the spot leg gains roughly what the short leg loses; if BTC falls, the reverse occurs. At a +0.0100% funding settlement, the short's gross funding receipt is $2.
gross funding income = hedged position value × funding rate net result = funding income − fees − spread − slippage − financing costs
The hedge ratio changes as prices and contract specifications move, and the quoted funding rate normally applies to only the next settlement. Multiplying it across a month gives a what-if figure, not a promised yield.
Execution and basis risk
The two legs do not fill at exactly the same instant or price. During that gap the trader has directional exposure. Even after both legs fill, the perpetual and spot prices can diverge. Closing when the basis is wider than at entry can create a loss that offsets many funding payments.
Fees are paid on both legs at entry and again at exit. A strategy targeting a small rate may need many settlements merely to recover four executions, spreads and slippage. Rebalancing the hedge creates more trades.
Funding can reverse
Positive funding is not fixed income. The next rate can shrink or turn negative, at which point the short may pay rather than receive. Some exchanges shorten settlement intervals in volatile markets. Test the expected holding period against several possible rates instead of annualising one reading and treating it as a forecast.
Margin, liquidation and exchange risk
The perpetual short still needs margin. A sharp rally can liquidate it before spot gains are transferred or recognized as collateral, particularly when the two legs sit on different exchanges. Cross-exchange versions also bring withdrawal delays, network congestion, custody exposure and the possibility that one exchange restricts trading or transfers.
Borrowed spot or a short-spot variation adds borrow interest, availability and recall risk. Stablecoin collateral can deviate from its assumed value. Tax treatment can differ across the spot trade, derivative P&L and funding receipts.
A practical pre-trade checklist
- Calculate all four expected entry and exit fees plus realistic slippage.
- Check the next funding time, interval and which side pays.
- Stress-test a funding reversal and a wider basis at exit.
- Keep enough independent margin for a sharp move before rebalancing.
- Plan how both legs will be closed if one exchange or transfer route is unavailable.
Start with the funding rate table across exchanges, then use the futures trading cost calculator to test whether the expected funding survives the trading costs. The calculator does not model liquidation, borrowing interest, taxes or an exchange failing.