BTC: Fitted 30-Day Implied Volatility minus DVOL
Shown as its 3 Oct – 1 Nov 2026 sample; the latest readings and full history are included with Plus.
Our fitted 30-day at-the-money implied volatility for BTC options minus Deribit's published DVOL index, daily.
Why use it. Two ways of reading the same market: our at-the-money fit and the venue's whole-smile volatility index. The gap grows when the smile's wings are expensive, which DVOL counts and an at-the-money reading does not. How to read it. Usually below zero, because DVOL includes the richly priced wings. A shrinking gap means the wings have cheapened.
Calculation. The day's average of our fitted 30-day at-the-money implied volatility (the fitted surface) minus the day's average of Deribit's DVOL index, in volatility points. From 14 October 2026 13:00 UTC, when our surface starts.