The implied volatility (IV) of an asset expresses how much the asset is expected to move until expiration as a percentage. The higher the IV of an asset, the more it is expected to move, and the more expensive options are. Similarly, if IV is low, options will be cheaper. Since the price of an asset and the time to expiry are publicly available inputs, the IV of the asset is the biggest driver of pricing differences between options traders. Volatility is described in more detail in the next section.