Definition. The at-the-money (ATM) implied volatility for options contracts expiring 1 week, 1 month, 3 months, and 6 months from today. Implied volatility is the market's expectation of future volatility, derived by solving the option-pricing equation given the observed option price. Formally, it is the one-standard-deviation range of expected movement in the underlying asset's price over the course of a year.

Interpretation. Tracking ATM IV over time gives a normalized view of volatility expectations, which often rise and fall with realized volatility and market sentiment.