Definition. Options ATM Implied Volatility (1 Month) is the at-the-money implied volatility for options contracts expiring 1 month from today. Implied volatility is the market's expectation of volatility, formally the one-standard-deviation range of expected movement of an asset's price over the course of a year, recovered from option prices given the underlying.

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