What Is the “Basis” in Futures Trading, and How Does Arbitrage Affect It?

The basis is the difference between the price of the futures contract and the price of the underlying asset (the spot price or index). Arbitrage activity, specifically index arbitrage, drives the futures price toward the spot price, narrowing the basis.

This action ensures that the futures contract price accurately reflects the underlying asset's value.

How Does the Choice of the Settlement Index Affect Basis Risk?
Does the Basis Typically Narrow or Widen as the Futures Contract Approaches Expiration?
How Does Market Liquidity Affect the Size of the Arbitrage Band?
How Does a Special Dividend Announcement Affect the Basis?
How Does the Convergence Process Differ between Physically-Delivered and Cash-Settled Futures?
How Does the Action of Arbitrageurs Correct an Excessive Contango?
What Happens to the Funding Rate as the Basis Narrows?
How Is the ‘Premium Index’ Calculated for Funding Rate Determination?

Glossar