Why Basis Exists
For dated futures, basis is explained by the cost-of-carry model: interest + storage - convenience yield. Crypto has no dividends or convenience yield, so basis is primarily a 'leverage demand premium.' Bullish periods with concentrated leveraged longs push futures to a premium (contango); bearish periods with short concentration create a discount (backwardation). For perpetuals, the funding rate adjusts this premium every 8 hours.
Measuring and Annualizing Basis
Basis is computed as '(futures price - spot price) / spot price × 100' in percentage terms. For dated futures, annualization uses 'basis% × (365 / days to expiry).' For perpetuals, the annualized funding rate approximates the basis. An annualized basis exceeding 20% is watched as a signal that the market is overheated with leveraged long exposure.
Basis Trade (Cash-and-Carry)
When positive basis exists, buying spot and shorting futures neutralizes price exposure, capturing the basis convergence as profit. For dated futures, basis converges to zero at expiry, yielding a deterministic return. For perpetuals, the return accrues as cumulative funding payments. The structure mirrors fixed-income basis trades in traditional finance, but in crypto the annualized yield is higher, offset by exchange counterparty risk.
Basis Risk
Although theoretically risk-neutral, basis trades face the practical risk of temporary basis widening. If the short side's margin is squeezed by expanding basis, liquidation can unwind the position at a loss. In April 2021, basis briefly exceeded 50% annualized, triggering margin calls on short positions. Designing a basis trade requires reserving additional margin for basis expansion and maintaining ample buffer to the liquidation price.