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Guides · 3 min
Funding-rate arbitrage: how it works and what can go wrong
Understand the spot-perpetual funding trade, its return calculation, and the execution, basis, margin and venue risks hidden behind a neutral position.
Funding-rate arbitrage tries to collect funding while reducing exposure to the asset's direction. A common version buys spot and shorts an equal notional 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 wide the gap actually gets
The disagreement between venues is measurable, not theoretical. Among the 241 contracts listed on all 5 exchanges we track, the widest spread at the time this page was served is RVN-USDT, at 0.09 percentage points between the cheapest and the dearest venue. That is the raw opportunity — before margin on both legs, execution cost, and the risk that the gap closes while you are in it.
The basic position
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 notional × 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 is a scenario, 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 venues adjust settlement intervals during volatile conditions. Compare the expected holding period with several rate scenarios instead of annualising one snapshot and treating it as a forecast.
Margin, liquidation and venue 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 legs sit on different venues. Cross-exchange versions also introduce withdrawal delays, network congestion, custody exposure and the possibility that one venue 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 venue or transfer route is unavailable.
Start with the cross-venue funding table, then use the cost calculator to test whether the projected funding survives the transaction costs. The calculator does not model liquidation, borrow interest, taxes or venue failure.