# Basis

Price gap between a futures contract and its underlying spot index.

Source: https://bykaranteli.com/glossary/basis · attribute to ByKaranteli and quote the timestamp.

## Definition

Basis = perp_price - index_price, usually expressed as a percentage. Positive basis (contango) means perp trades above spot; this is the default state in a bullish market. Negative basis (backwardation) means perp trades below spot, often during panic selling or forced liquidations. Sustained basis feeds into the funding rate: high positive basis forces longs to pay funding until the gap closes. Use basis alongside OI and funding to spot structural positioning.

## Related

- https://bykaranteli.com/symbols/BTCUSDT
- https://bykaranteli.com/heatmap
- https://bykaranteli.com/glossary

Everything in one fetch: https://bykaranteli.com/llms-full.txt