Has anyone ever noticed this? several monday back the markets opened higher and the Vix gapped open over 5%, why is this? why does it always open higher?
The VIX is calculated off calendar days but the market trades on business days... There is a lower VIX on Friday as there is no trading on the weekend, so lower average vol.
VIX = index option decay, which is based on calendar days. That's why short option positions love three-day weekends and holidays... free money! :>)