Basis
The gap between the spot price of an asset and the price of its futures contract; the sign convention varies by market.
Basis is the gap between the spot price and a futures or perpetual price for the same asset. Commodity markets, including the CFTC, usually compute it as spot minus futures; crypto traders usually quote futures minus spot, as we do here. On that convention, a positive basis, where the future trades above spot, is a premium (contango). A negative basis is called a discount or backwardation. For a dated future, the basis narrows toward zero as the contract approaches expiry.
On our site, basis is shown in dollars and as a percentage of spot. Use the percentage to compare markets with different price levels.
Traders care because basis reflects financing costs, demand for leverage and sentiment. A wide basis on a dated contract can be captured by buying spot and selling the future, after the costs of doing so.
Worked example (illustrative numbers, not real data): spot is 2,000 and the three-month future is 2,030. The basis is 30 points, or 1.5 percent. If the future converges to spot at expiry, the 30-point gap closes.